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RE: Rear Shock Woes
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"Excessive" play on the top or bottom shock bearings is an MOT failure and certainly won't help the handling wink

We have found MyHermes to be the cheapest courier for shipping shocks.

Brian



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TTRfan wrote:

"Excessive" play on the top or bottom shock bearings is an MOT failure and certainly won't help the handling wink

We have found MyHermes to be the cheapest courier for shipping shocks.

Brian


 

Cheers Brian. I just found royal Mail the dearest! £26!!!

i could of taken it to a local place near me but from what I have read on here Gibbs is the best place. Plus Justin is going to sort me a top bush

 

 

 



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We like MyHermes because we can drop off the parcel at a pick up point rather than having to hang around for a collection from home. Plus the drop off shop is near the Post Office so we try and do the two jobs together. 

Justin should certainly know his way around TTR shocks by now wink

Brian



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Does anyone know what make the rear shock is?



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No make names anywhere on them. Can only think they are made by or for Yamaha Japan specifically for the TTR250. I think that we are all agreed that no other shock will fit.

Brian



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RE: Rear Shock Spring Wt.
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i think you mean SPRING RATE vancor88 don't you?. actually i was wondering who makes TTR250 rear springs. we have a spring manufacturer here in Australia called KINGS SPRINGS and all their springs are exactly the same colour powdercoat as the TTR uses. might give them a ring and find out.

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RE: Rear Shock Oil
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Viene algun kit de reparacion para el monoshock?

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RE: Rear Shock Absorber - Q&A megathread
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Whilst looking at some photos of shock absorbers I came across this photo showing the infamous "clicker" mechanism in its constituent parts. There have been a couple of questions about it recently so hope the photo helps explain how it works wink

Shock lower adjuster showing clicker mechanism.jpg



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evileyeWe want Justin Gibbs to give forum members/totally ttr's buyers, a discount! I think you could earn a finders fee out of it Brian!....wink



-- Edited by peteBLUEttr on Thursday 30th of April 2015 11:50:55 PM

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I got a duff shock so that phone call might be sooner rather than later Pete!

My bro's TTR rear shock didn't so much start pogoing as went lifeless! There was only 3 clicks on the rebound adjuster which was also suspicious.

He was lucky enough to blag a good working shock on eBay so we did the swap and his old shock has been kicking about in my store waiting for attention. Today was that day!

I started off power washing it and it didn't look too bad underneath the crud.

I have a simple test for a shock which is to remove the spring and checking the damping action.

Dismantle shock1.JPG 

 

Compress the spring until there is enough room to pull out the slotted spring retainer:

Dismantle shock2.JPG 

This is what it all looks like dismantled:

 Dismantle shock3.JPG

At this point I pushed the shock together and there it stayed so no pressure in the system.

Dismantle shock4.JPG

This one will be soon on its way to Justin Gibbs for a rebuild.

Brian

 



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I have nearly finished stripping my Raid for spares and just got the shock out. A good time to compare it with an OE shock which I just happened to have been working on today biggrin

Raid v OE shock.JPG

 

The main differences are that there is no compression damping adjuster on the Raid reservoir and the bottom Raid yoke is steel rather than aluminium. 

The Raid's top shock bearing is a bonded rubber affair compared to the rose joint on the OE shock. That might be no bad thing as I haven't come across a Raid one with any play in yet.

The Raid spring is shorter but the yoke is longer such that, overall, the shocks are pretty much the same length.

Having tried them in different frames the two are interchangeable as far as I can make out.

Brian



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I am still struggling to find a sensibly priced bump stop for the 14mm diameter rod of the TTR's rear shock.

The other Yamaha offroad bikes (YZs and WRFs) use 16mm and 18mm rods so their bump stops won't fit snugly cry

Can anyone advise of a source please?

Brian



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I popped into Bike Worx (now just The Worx as Jamie is doing cars as well) this morning to ask about getting some TTR bump stops and the guy I spoke to asked me to hang on whilst he priced them up. I spied that he was looking at the ORO catalogue so said not to worry as I have an account with them. I said I thought they might have a specialist supplier of shock parts but he said no. ORO's smallest bump stop ID is 16mm so I am baffled confuse

I will be interested to see how you get on!

Brian



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TTRfan wrote:

I popped into Bike Worx (now just The Worx as Jamie is doing cars as well) this morning to ask about getting some TTR bump stops and the guy I spoke to asked me to hang on whilst he priced them up. I spied that he was looking at the ORO catalogue so said not to worry as I have an account with them. I said I thought they might have a specialist supplier of shock parts but he said no. ORO's smallest bump stop ID is 16mm so I am baffled confuse

I will be interested to see how you get on!

Brian


 Oh...confuse



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Managed to source a supply of sensibly-priced bump stops - see here biggrinbiggrin

Have you taken yours in to Jamie yet Jason?

Brian

PS Really nice shock also now available - see here



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Rear shock
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Our rear shock on the raid has died, my brother has been trying to contact gibbs with no success so looking at other options as the mot is out and it's all it needs.

are all ttr shocks the same? There is one on eBay 

also has anyone had trouble sending or receiving shocks as I beleibe royal Mail won't touch them now as a mate lost a bicycle shock as they refused to send it 

 

 



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Hi there

Justin isn't brilliant on emails - best to phone - 01752 846888

The Raid and OE shocks are interchangeable and, because of the additional compression damping adjustment available, the OE shock is considered an upgrade. 

The shock on eBay appears to be missing its bump stop which isn't a good sign. The expensive bit is repairing the damper rod if it is worn or damaged.

We send rear shocks by MyHermes without any problems. Because they are pressurised with nitrogen they don't seem to be able to be sent by air freight.

There is a totally rebuilt one here that you can be sure is 100%

Brian



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How do I no if it needs regassing?

Its not lost all its bounce if that makes sense but I did notice that when turning the damping adjuster just under the seat it doesnt seem to make a real difference, The bottom clicker just under the spring also seems to just go stiff after one click from the end.....

 

The bike has done some 29k miles and the shock looks original to me...

 

Anyone know someone decent to sort it for me if it needs doing?

 



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Hi Martin

The only way I know how to check a shock is explained on my 5th May 2015 post on this thread.

However, do a visual check first. Are there any signs of pitting, wear or rust on the rod? 

Brian



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No pitting or rust on the rod. The spring has some paint missing but I think they all do that...I was going to get it powder coated but not sure if they are easy to take off?

I can take the shock out in seconds lol..Master at doing that now like you brian...The bike has damping I mean when you push the back end down its not like a pogo stick. But saying that I adjusted the front forks to fully hard and they are not hard as it solid/stiff. But I guess thats just how they are?

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Got my shock servided and revalved today by Ian at pro moto suspension in the hunter valley NSW 

as the shock is the same internaly as the wr250r he has shimmed it to suit my weight and riding style based on the WR set up ,new fliud, bumpstop, new seal head and gassed it to 175lbs 

i wil let you all know how it works after a ride i have planned on satrday 

The spring was tested and deemed ok for what i need so saved me some cash there 

all up cost $175.00 bargain (places in sydney quoted $480 just for the revalve ) 

a bit closer than sydney managed to fit it in with work so the 600 plus ks trip was part of the normal day which saved taking a day off 

Now the post mortom the old shock wasnt leaking. Gas pressure was 20lbs and shimmed for comfort.  i was told that in a perfect world it should be serviced every six months max every 12 so mine at six years was kinda due 

he gave me a tip on the forks to reduce dive try setting the oil height to 100mm which has the effect of increasing the internal pressure in the second half of the stroke which i hope to try as well on saturday 

ps a leaking seal is usualy a sign of no gas presur, the seals are shaped with thier lip inwards with the pressure forcing the seal onto the shaft 

overal hes a genuine guy has a love of bikes and hapy to give advice 



-- Edited by ttboof on Monday 5th of September 2016 10:58:40 AM

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Cool, good info there. Shock Treatment in NSW did mine about 18 months ago. Think it cost me $230 or something like that. Re-shimmed for my weight and so on. Posting from Tas to them and back in the bike about a week later. mine had been seeping oil for a while and was so much better once done. $175 for all that is a bargain for sure.

I need to re-do the oil in my front forks, its about 3 years old now. I've never touched the forks myself so I keep putting it off.

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don't put the front forks off , its real easy about a 45 min job once you have done it the first time



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yeah I need to sort it. They feel fine but I know they feel better when the oil is replaced from past experience.

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Get the rear shock serviced, valved for your riding style and the proper spring for your weight. It's like getting a new bike! And yes, front fork service and springs go hand in hand with proper handling.


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ttboof wrote:

Got my shock servided and revalved today by Ian at pro moto suspension in the hunter valley NSW 

as the shock is the same internaly as the wr250r he has shimmed it to suit my weight and riding style based on the WR set up ,new fliud, bumpstop, new seal head and gassed it to 175lbs 

i wil let you all know how it works after a ride i have planned on satrday 

The spring was tested and deemed ok for what i need so saved me some cash there 

all up cost $175.00 bargain (places in sydney quoted $480 just for the revalve ) 

a bit closer than sydney managed to fit it in with work so the 600 plus ks trip was part of the normal day which saved taking a day off 

Now the post mortom the old shock wasnt leaking. Gas pressure was 20lbs and shimmed for comfort.  i was told that in a perfect world it should be serviced every six months max every 12 so mine at six years was kinda due 

he gave me a tip on the forks to reduce dive try setting the oil height to 100mm which has the effect of increasing the internal pressure in the second half of the stroke which i hope to try as well on saturday 

ps a leaking seal is usualy a sign of no gas presur, the seals are shaped with thier lip inwards with the pressure forcing the seal onto the shaft 

overal hes a genuine guy has a love of bikes and hapy to give advice 

 



-- Edited by ttboof on Monday 5th of September 2016 10:58:40 AM


 i have put 1000ks on the bike since servicing the suspension. It was well worth the time and money

raising the oil height in the forks is one of the best mods ive done on the ttr. I was supprised that the standard rear spring was ok for my 98 kgs once the shock was set up to suit me ( i have limited use of my left leg since an accident years ago so ride seated 99% of the time )

The bike is not only comfortable and tracks straight at speed in the rough stuff with out the front diving under brakes 

im one very happy ttr rider



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RE: Rear Shock Absorber - which grade of oil?
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I have seen two different oils recommended for the rear shock, 2.5W and 10W.

Is there anyone on here good with suspension can say what should be used please? Also quantity needed assuming some spillage?

Brian



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RE: Rear Shock Absorber - Q&A megathread
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TTRfan wrote:

I have seen two different oils recommended for the rear shock, 2.5W and 10W.

Is there anyone on here good with suspension can say what should be used please? Also quantity needed assuming some spillage?

Brian


Bump - any info please guys?

I think that, given the choice, I would go for the thinnest oil I could get.



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I am about to rebuild the shock on my 2005 TTR 250 so I read through this thread  for ideas.  I have rebuilt many YZ shocks, WP KTM shocks, and hundreds of FOX snowmobile shocks. 
To encourage home mechanics I can say for sure,  fix your shock and service it yourself before you spend money with suspension experts.

1. the big GORILLA  here is nitrogen pressure in the shock,  its absolutely unnecessary for riding a TTR 250.  Same as nitrogen vs air in your tires, every run straight air in your tires ?

2.  anything over 140 psi air or nitrogen in the shock after servicing  works great.  more pressure is a tuning variable,   220psi makes a stiffer acting shock, not good for most trail and road riders. In the TTR 250 shock the nitrogen or air is separated from the oil, so unlike old wives tales about  " YOU MUST USE NITROGEN "     back in the day when  nitrogen was  directly injected  into the oil like many of the  early gas shocks BILSTIEN shocks,  the theory was air would degrade the oil over time.  No so with the TTR 250 bladder/floating piston shocks.  Nitrogen's only advantage is, slightly more inert so heat swings affect pressure less and its cheap in a compressed bottle for MFG. to build shocks.

3.  most shocks have cheap oil stock and 5 years of use its for sure junk now, so service your shocks with new better sythetic shock oil.

4.  take care releasing any old gas pressure, then disassembly is simple and its disheartening to see how little is inside the shock, not much there and not much has changed in 30 years.

5. while servicing, might as well replace the seal.  The only seal replacement listed that I can find is  RACE TECH, about  $55 US.  While I have mine apart I will measure up the seal head to see if other cheaper seal heads from  ALL BALLS  will fit,  I don't think  ID x OD dimensions are that different, but overall seal len ght may differ and a spacer may me necessary if you used a different seal head.

6.  maybe hundreds of video's on U tube about shock rebuilding.  All apply to this simple old fashioned shock. So watch a video and redo your shock,  you really can't hurt it, on a 10 year old bike it really needs new oil. 

7.  FOR SURE        RACE TECH   GOLD VALVES  would make a big difference in how this shock works.  I just redid the valving on 2 KTM 200's and a 2004 KDX 200    with RACE TECH GOLD VALVES.    With in my trail riding group it prompted two KTM riders with 2016 machines to stepup and Gold Valve their suspensions as it was obvious that in one case a 16 years old bike now had way better suspension than their almost new $8k bikesl.





U

 



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I do the all ball ones here https://totallyttrs.com/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectID=2229803

Nice information Michael, very informative.

Steve



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Looking at the pictures of the Raid and OE / Bluey rear shock, if you run the Raid shock with the later bottom aluminium yoke, it would lower the bike some more??



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Hi Mike and many thanks for your helpful post. I am sure it will encourage owners to have a go themselves if they don’t have to find someone to pressurise their rebuilt shock with nitrogen.

I have a Fox bicycle shock pump which I think will provide sufficient pressure.

If not too late, any chance that you might take some photos of your TTR shock rebuild for us please?

 Steve and I intend to rebuild an OE shock using the seal head that he stocks. 

 What grade oil will you use please? Once you have done the deed, an idea as to the quantity would also be good to know.

 Brian



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I finally finished the rebuilt on my forks and shock on my ttr 250.  After reading many rave review on going 3" down on KTM enduro bikes,   I decided my 2" lowering for the TTr was out, might as well go 3", in my part of the world the saying is "    if your going to New York, no use getting off in Chicago "

 

SOME NUMBERS:  14 mm shock shaft diameter

                            46 mm shocky body id  so seal head is about  45.8 mm in diameter with an oil ring to seal it to the body

                            seal head is 21 mm thick.............somewhere out there are other seal head that could fit this,  thinner or thicker seal head would not be a problem

shock spring is   62 mm  ID

spring is  247 mm long

wire diameter and is straight wound  11.7 mm       so lots of other spring could work on this shock,  inside diameter is only thing critical, cut or make spacers for other spring lengths.

I will post putting it together 

                     

 

 

1. Removed the shock and cleaned it up with hot soapy water.  I found my shock to be in as new condition, confirming my suspisions that the TTR I bought has had mostly street use in a clean dry enviorment.

turned the spring adjuster nuts all the way down and that allows room to remove the spring keeper plate, and off comes the spring.

take out the screw in the end of the reservoir , grease up a hypodermic needle and insert through the rubber pellet at the bottom of the hole where the 4 mm screw was just removed. gas should come out, gas as in air/nitorgen

pull out your oild drain pan and over it take out the banjo bolt that holds the reservoir to the body and let oil drain out of the shock and reservoir.

put shock in vise with shaft up,  take a thin chisel and pry up the aluminum crud cap that fits in the shock above the seal, its just pressed in, doesn't unscrew, if you ruin it, throw it away, serves no purpose on an upside down shock.

take a punch and tap the seal head down, won't take much, down just far enough to allow you to take two small screw drivers and remove the wire snap ring that keep the seal from blowing out of the shock body.

clean this cavity with solvent, blow dry, and lube with grease or oil so the seal with come out easier,....... over your drain pan yank on the shock shaft and pull out the seal and rod.

clean every thing up spic and span,

shaft in vise end nut up, unscrew nut and set the parts out in order on a nice paper towel.                    If you drop all the parts, no panic, you need to know that;

 

To get the reservoir apart requires some care.  I use air pressure.   Shove down the aluminum end cap in the reservoir end, pull out the wire snap ring, clean the area and lube with oil or great,    take a great big towel and wrap this up and face a couple of inches from the back of your work bench, now shoot some air into the reservoir hose............i usually put the banjo fitting down on a piece of soft wood and blow air in the exposed side, careful you will be creating and explosion, some pop out...........uneventful, most come out with a lot of force and watch out  ITS CAN BE DANGEROUS.

the valve goes on one way,  close inspection you will see the valve holes different sizes,  when the shock rod goes down ( compression stroke) oil in a nano second has to flow through ALWAYS THE BIGGEST SET OF HOLES, in this case    FLOWING INTO THE OVAL HOLES,   so the opening for oil going into the oval holes is always towards the nut/bottom of the shock/bottom of shock hole.  THE BIGGEST SET OF VALVES always covers this biggest set of holes where the oil comes out, you will see that the valves seal against a flat surface around the oval holes,  SO OIL IN ONE SIDE/ SHIMS RESTRICT OIL COMING OUT THE BACK SIDE,    the valves are always a pyramid/ big valves (  all those thin flat washers ) biggest next to valve in descending order.   Valves/SHIMS can be identified by thickness .005-.015 inch and about 1.50 inch diameter down to barely bigger than the shaft they go over.

when you take apart  good motocross shocks some   SUSPENSION TUNERS HAS WORKED OVER,  you will find that the piston with the holes all over has had all the sharp edges smoothed where oil flows in,  in the case of      RACE TECH GOLD VALVING  you will get in the kit a new valve with radically smooth and improved oil flow bigger ports in the piston and options  and directions on how to build a shim stack out of the 100 or so new thinner shims that come in the kit, all to match your riding preferences.     SO while I was in here, I took a small rotary grinder  dremel tool in my shop with an 1/8  carbide pit and ported my shock piston like the big boys.  Picture that shows some of it,      oil flowing in   S M O O  T  H  the sharp corners, oil flowing out  DON'T TOUCH.

 



-- Edited by sledman 1 on Sunday 19th of November 2017 02:05:50 AM

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PUTTING THE SHOCK TOGETHER

1.   first  when I reassembled the shock shaft,  I pulled out two of the large diameter shims/washers on the compressions stack next to the valve.  My thinking was simply that as a compromise when Yamaha put these bikes together to cover all areas, when in doubt fudge on the side of stiff.  From my experience  too many washer and toooo stiff compression dampening in the stock setup, so I pulled a couple of compression washers.  On the rebound side,   my though is down the road, due to my being old and fat and excessive gear on my soon to build rack I may have to round up a stiffer shock spring, so I left the rebound stack alone because stiffer spring require more stiffer rebound dampening.

2. I put my new seal head on the shock shaft,  to make sure you don't damage the seal head o ring on reassembly, I put plastic sandwich bag over the threaded shaft end, greased it and the ID of the seal, and slid the seal head on with out any problems.   To figure how long a spacer I needed to lower my ride height 3", I had  used a  ratchet strap from frame to swing arm to suck my frame towards the ground until I had a 3" lower ride height,  my shock was  down .780 of an inch, so I had machined out a   .780  x  1.200  x  14mm id aluminum bushing to go on the shock shaft.  As my picture will show I also checked by odd washer bin and metal tube rack and found material that would also make a simple hacksaw only spacer, so I like lathe projects, but unnecessary, most of the suspension companies will send a nylon or plastic bushing when they send out their $75 shock shortening kits.  Pipe and washer will do fine, washer against the back side of the seal head.  So the spacer goes between the seal head and the big thick washer that is the start of the dampening stack.

3.  assemble the shock shaft,   make sure the foam bumper and crud seal are on the shaft, then the seal head, then the spacer you have built, then big thick washer and your valve stacks and piston,    thick washer/compression valve stack big washer towards rod end/piston with oval opening towards shaft end/rebound stack, tighten lock nut.

Put the shock body in vise open end up with the reservoir attached and zip tied to the shock body open end up,   fill 2/3  of shock body and reservoir with your favorite shock oil, add a little more oil,  then work your piston down into the oil and stroke it up and down  gently slowly watching bubbles escape, fill oil to with in 1" or so of top of shock and press the shock seal down past the ring groove...........oil should be coming out the top of the shock around the seal head making a complete mess, all good,  put in wire snap ring, pull up on shock shaft to seat at snap ring.

4.  Reassemble the reservoir.  The reservoir cap has the screw hole where we let out the gas.  In a home work shop the best setup is to drill out this screw hole and fit a schrader valve in the hole so you can air up your shock with a simple bicycle pumps or what ever.  I regularly inject nitrogen with a needle in these type of rebuilds. But here,  I drilled out the cap and installed a short shank schrader valve and will fill with good old mother earth air to  140 lbs.    So the pressure in the bladder from 120-250 psi lbs is just another  shock tuning variable.  Anything over 130 psi will allow the shock to function as designed. Many gas shocks use upwards of 300 psi.  The more pressure, stiffer the ride.  Play with it.  To drill and tap the cap,  note that the bladder slips right of this cap, making drilling and tapping easy.  So again, you want a mess , oil over the top as you install the bladder, go past the snap ring groove and put in the snap ring.

5.  To bleed out any of the remaining air, shock in vise with the bleed screw that is opposite the banjo fitting port for the reservoir, this screw out and highest point for shock, pump the shaft a couple of  mm  slowly working out bubbles, replace screw and move the shock around visualizing air bubbles rising towards this port,   remove screw and let out air if any , repeat until you have nothing but oil topping the screw hole, then screw it down.   Pump air into bladder as per your preference,  120-130 minimum.

 

If your have shortened  your shock in this process, now your spring may be toooo  long.   So its has to be cut down.  I will post a  a note on this.

 



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RE: Rear Shock Absorber - Q&A megathread FORKS ALSO
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I also rebuilt my forks with the intent to lower the front 3" as I have with the back of the bike.   I will post the fork set up where I saw a note about how far can you lower your bike.



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RE: Rear Shock Absorber - Q&A megathread
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That is a superb guide Michael - thank you very much for taking time out to share it with us - most appreciated biggrinbiggrinbiggrin

I think Steve and I are going to have to man up and set about replacing the seal head on his spare shock wink

Brian

PS Are you a professional motorcycle engineer Michael? You are very knowledgeable!!!!



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I am referring here to my two post about rebuilding my rear shock rebuild project    and   adding a spacer to reduce my ride height by  3".

 

the last issue to deal with is the standard spring is toooo   long to fit back on the shock with out using some kind of compression tool to install it.  A pain the the hindend.  

What I do is reduce the spring length by heating it while being compressed to the new spring length that I need to go back on the shock body, when enough heat is applied the spring softens and relaxes and you end up with  shorter spring.  I have also had success with using an abrasive cut off saw and in this case taking   3/4" of an inch out of the spring.  When you cut only ,you really don't have a nice spring end to seat back to the shock washers.  So, my preference is to squat the springs with heat. The goal is to heat the spring coil just above the finished end of the spring, heating until the coil simply relaxes down onto the adjacent coil.   I posted in the " MODIFICATIONS  HEADING "   of the forum my  fork rebuild for this same project and the process whereby I shortened my forK  springs.   In the case of the fork springs I heated the fork spring with a small propane torch and there was sufficient heat to soften and collapse the spring.   I tried the propane torch on the shock spring,    just not enough heat to get the job done, so I had to resort to using my  acetylene torch, just before you can see a little  red in the spring they quickly relax down onto the next coil.  Check out my pictures.  A blast of not that close yellow paint and job done.

 

So   with no special tools its possible to rebuild your shock,   remodel and improve your shock,  modify your shock for a more pleasant ride.   

 

Another issue that comes up is shock oil.  You have a beat up old bike and you're on a budget and you need a working shock.

1. you don't  need nitrogen,  air will work fine,   no air at all will just produce a softer ride.

2.  transmission fluid or  power steering fluid will work fine in shocks or forks.  Low budget, seal friendly, won't foam and a couple of dollars a bottle as opposed to bike shop quarts of synthetic shock oil for $30. I have regassed and changed fluids in probably hundreds of  FOX SNOWMOBILE SHOCKS  with  air and transmission fluid and fixed the seal head with a  .05 cent oil ring...........doing a set of 4 right now.  when you give  people the option of a fresh shock for $24 a piece with transmission fluid/power steering fluid or the deluxe version for $40 with shock oil and the same guarantee to work, most go with the low budget as good as fix for less money.

3.  I will dissect  a seal head when I have time from a TTR 250,  we might be able to cure a leaking seal head with just a good  VITRON  o  ring

 

the sequence of spring pictures is hopefully showing what  happens when I heated the rear spring and collapsed it down by  3/4" to go with my shorter shock in my bike lowering project.



-- Edited by sledman 1 on Monday 20th of November 2017 05:43:39 PM

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when I lowered the TTR 250 3"........kickstand blowout ?
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After completing my 3" front drop and rear shock 3" drop I was anticipating having to redo / shorten my kick stand.  What  a suprise when I took the bike down off its work table and back onto the garage floor and found out what had been a  sort of short kickstand and annoying  lean angle,   the new short 3" down bike gave me what I consider the ideal kickstand length and lean angle...........something had to be simple in this process.   On most of bikes I have modified with lower suspension, that last detail it the kickstand modification which was unnecessary in the TTr 250's situation.



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Any shock experts watching  please?

I am trying to understand how the rebound damping works on the TTR250 shock.

The adjuster/clicker is at the bottom of the shock and works against an aluminium rod that goes up through the hollow centre of the shock shaft. The rod gets pushed up to increase the damping force and down to decrease it.

I found a diagram of what's inside the top of the shock shaft but has anyone actually seen the valve or whatever it is? Is it removable to be checked or serviced?

Shock shaft.jpg

Valve in rod 1.jpg

Any help or advice from a knowledgeable owner would be appreciated biggrin

Brian



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I got some help from a friend on Facebook. Apparently the "damping restrictor needle" (as the hidden and mysterious valve is apparently called) is going to look something like this one which is fitted to a Yamaha IT175E and made of hardened alloy. Sadly, this guys needle had cracked and a replacement is unobtainable so he is turning a new one up on his lathe.

Damping_restrictor_needle_IT175E.jpg

However, I still couldn't see how the needle's seat fitted. Is it screwed in or pressed in? It also begs the question as to what the re-chromers do when they get TTR250 shafts in for re-chroming. I have had one done myself and know of several others that have had to have that done as part of their professional shock rebuild. Maybe they just mask the holes to stop the chemicals getting in?

Well, curiosity got the better of me so I decided to chop up my spare shock shaft to see what was inside!

This is the result compared to a drawing by an unknown artist I found somewhere on the interweb many moons ago - the artist pretty much got it dead on!

The TTR's needle is solid steel as is the needle seat which is a press fit in from the top of the shaft. I think it would be possible to drift out the needle and seat together through the top (threaded section) of the shaft.

2019-02-16_164225.jpg

I now understand that when a TTR250 shock locks up, assuming nothing inside has broken, the usual cause is due to the damping adjuster being wound in too much, pushing and jamming the damping restrictor needle in the shock shaft against its seating thus causing a hydraulic lock. Apparently, it is usually possible to get around the problem by winding off the damping completely and compressing the shock rapidly with a hide hammer. If the shock still does not return to normal operation then you probably need to take the shock apart and take the shock shaft to a specialist for First Aid cry unless of course you are brave enough to try drifting the seat and needle out yourself  biggrin

20190216_155239.jpg 



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TTR Steve and I are rebuilding a shock and intend to use air and ATF oil as suggested by Sledman.

I looked at the specification of the Granville ATF Dexron we intended to use and it has an cSt of 7.48. This converts to just over 25W and I recall the recommended weight for the shock oil being in the range 2.4W to 10W.

Should we be looking for an alternative ATF or stump up for fork oil?

Brian

 ATF weight.jpg

 



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been thinking about this , suspension oil is not my thing , how about synthetic fork oil  you may be able to find the weight you want or blend a couple .

i googled blending viscosity when setting my front forks to Balards specs , i used two  different viscosity and blended to get the right mix .only to find a couple of weeks later that Yamaha had the right oil ready to go .  it worked out much cheaper and fully synthetic .

 

just a thought 



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Having sacrificed my spare shock shaft (see earlier updated post of mine) to see how the damping restrictor needle works, does anyone have a damaged shaft that they are willing to let me have to test my theory that the needle and its seat can be drifted out? All for The TTR Cause winkbiggrinwink

Brian



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As the shock that Steve and I are rebuilding is nearly finished but without its spring, I thought now would be a good time to demonstrate how the rebound clicker works so here is a short video showing it in action!

I should have looked at the owners manual before I took the video as the standard setting is 9 clicks out and I used 8 clicks but I doubt there would be a huge difference.

I hope the video will help owners understand just one more thing about their lovely TTRs biggrin and what else could I be doing on such a horrible wet and windy morning!

Brian



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Great work Bri and nice for owners to see what actually happens with adjustments.



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