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Fork seals - removing and replacing fork seals on a Yamaha TTR250
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See http://www.ttr250.com/TTR_renew_fork_seals.htm

 



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RE: Removing and replacing fork seals on a Yamaha TTR250
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Hi,

Yesterday I followed this excellent guide and I was able to change the fork seals. One thing I don't understand is why one has to loosen the 14mm hex nut on the base valve (6). Please help me understand.

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Doesn't the 14mm hex nut screw into the damber tube base and hold it to the alloy fork bottom so that it slides with the fork bottom up and down the stanchion, thereby forcing the oil through the valve and damping the action? confuse

I've not had any cause or reason to do anything to the forks on my TTR - YET! disbelief

Martyn



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Budleigh Salterton. Devon



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Cubber I'm not sure because all I had to do was loosen it not remove it completely.



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Huh? surely you only need to loosen that nut as a precaution IN CASE you subsequently need to remove the inner tube, and you do it first because it is much, much easier when installed and with weight on the springs.

If, by some miracle, you managed to remove and replace the oil seal without removing the inner tube or scratching it, then this precaution would (in retrospect) have been a waste of time. But as far as I know, most people DO need to remove the inner tube for this job. And the inner tube can't be removed without undoing that nut. Besides, removing it lets you see the condition of your fork internals.

KNjonjo, how did you manage to remove and replace the dust seals and oil seals without taking out the fork tubes? Did you have some sort of special tool, or were you skillful and lucky, and somehow managed to lever out the seal with small screwdrivers or spikes?

And on a slightly related note (but very appropriate for this thread) - has anyone had any experience with installing something like a Race Tech "gold valve" kit on the TTR250, and if so, was there any noticeable improvement in fork action?

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anybody got the torque figures for this including the fork pinch bolts, top cap nut and hex nut at bottom and any others am missing.

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sammyttr wrote:

anybody got the torque figures for this including the fork pinch bolts, top cap nut and hex nut at bottom and any others am missing.


 I suggest that you download the manual HERE and look it up.

Jarrah



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I am going to undertake this job for the first time in my life. Having had over 20 bikes I must be just lucky. Anyway thanks to this thread I am not as terrified now.no

I do however need some help. 

My downloaded manual states to use (suspension oil "01" or equivalent). My local auto shop sells castrol motorcycle fork oil in SAE5, SAE10 and SAE15 in 1litre containers for $20.50. Could someone tell me what the "01" is equal to???. The standard fork oil is fine for me. Also I read that each fork has 555ml oil which means 2 bottles ( why don't they make a 1.110 litre bottle.confuse)



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Aussie Paul wrote:

I am going to undertake this job for the first time in my life. Having had over 20 bikes I must be just lucky. Anyway thanks to this thread I am not as terrified now.no

I do however need some help. 

My downloaded manual states to use (suspension oil "01" or equivalent). My local auto shop sells castrol motorcycle fork oil in SAE5, SAE10 and SAE15 in 1litre containers for $20.50. Could someone tell me what the "01" is equal to???. The standard fork oil is fine for me. Also I read that each fork has 555ml oil which means 2 bottles ( why don't they make a 1.110 litre bottle.confuse)


 Standard oil weight is 5W, you will only need 5W which should be the equivalent of SAE5. I used SAE10 which gives a stiffer fork action for jumps etc..

Enjoy!

Jarrah 



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RE: Fork seals - removing and replacing fork seals on a Yamaha TTR250
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It's 18 months ago that I did my fork rebuild so need a memory jog from someone please.

When rebuilding the fork leg, at what stage do you tighten up the base valve (6)?

I can't see it in the instructions.

Any advice on how to make the instructions clearer will be appreciated.

It all seemed OK at the time but reading it again, it could do with a few points of clarification methinks.

Brian 



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Brian, page 6-40 of the service manual advises the stages of assembly as:-

Fork assembly.jpg

I've never done it to my TTR (yet) but there's always the chance. biggrin

Martyn



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Thanks Martyn - I keep forgetting how good the TTR's workshop manual is no



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I have a few forks to rebuild so decided to invest in a Motion Pro seal driver. I have used one of these before on some WR250R forks and it worked a treat. Will let you know how it performs on TTR forks. Saves messing around with lengths of water pipe wink

Motion Pro fork seal driver 1.jpg

Motion Pro fork seal driver 2.jpg



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How much play is too much on the forks? I have a *tiny* little bit that I can just feel when the wheel is out, but when it's in you can't feel anything (maybe the axle bolt helps hold things more stiffly?

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Its so simple to remove the seal with out pulling to forks apart....
drain the oil... remove any circlip that holds the seal in...
get a compresser... pump the fork up with a 100psi...
whatch that seal pop right out...

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Padowan wrote:

How much play is too much on the forks? I have a *tiny* little bit that I can just feel when the wheel is out, but when it's in you can't feel anything (maybe the axle bolt helps hold things more stiffly?


I think its a bit subjective Simon.

Unless you want to replace the seals and/or change the oil now, I would wait until the forks need a rebuild and replace the bushings then.

I assume it will MOT OK meanwhile.

Brian 



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I cant seem to be able to take off the Base Valve, 6. Am I doing something wrong, it just keeps spinning, both ways after initially loosing it up.
now i can seem to set it nor remove it completely.

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Is there an easy way to replace TTR250 fork seals?
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After an email exchange with the intrepid TTR250 explorer, Ed Gold, I have just done a bit of Googling and found this:

"The only other way to remove the seal without banging it out is to fill the fork assembly full of oil and pressurize it so that the oil actually drives out the seal. " 

Anyone tried that?

Another possibility that Ed has used is to pressurise the fork using a compressor on the Schrader valve at the top of the leg. Not quite so messy as the first method. Again, has anyone ever tried that?

Brian



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peteBLUEttr wrote:

I haven't tried it no but I have heard it can take anywhere up to 180psi to drive them out...


 Maybe he should try removing the retaining clip first...

do the numbers... seal area in sq/inchs X 180psi...

If the seal had 2 sq/inchs of surface area.. then there would be 360 pounds of force on it... 

 

 I have posted about useing air a couple times..

been doing it for years... My compressor maxs out at 120psi...



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I have just received more detail on the two short-cut methods from my informant (Ed Gold - see https://www.facebook.com/EdGold.co.uk ) but all of this comes with a serious warning as it could result in injury, especially the air compressor method!

 

METHOD 1 for TTR250s with air valves on top of fork legs 

1) Make sure your motorcycle front forks have air valves on the tops of them!

2) The forks can either be left on the bike to ‘move’ the fork seals or removed from the bike and operated on ‘loose’. If you work on the fork legs loose make sure you either have a vice OR loosen the fork leg tops (bolts) whilst still clamped by the top and bottom yokes (you’ll need to remove the handlebars to loosen the fork leg caps with a 30mm socket and also to fit the air compressor to each valve if you work on the on the bike. You don’t have to completely remove the handlebars - just undo their two clamps and rest the bars away from the fork tops (still with wires/cables attached obviously)

3) Loosen fork gaiter at top and bottom. Slide bottom of gaiter up fork leg to expose fork dust seal. Push dust seal up fork leg

4) Remove circlip which holds fork seal down. The circlip might be rusty and brittle. Use a flat bladed screw driver carefully to push it inwards and out of its ‘groove’ and then lift up the fork leg

5) Remove black plastic cap on top of air valve. Connect an electronic air compressor. 12 volt ’Mini’ (small) compressors work well. I wouldn't want to risk using an industrial compressor on the fork.

6) Turn the air compressor on and stand well back. Run the compressor up to its maximum psi. This is about 230psi. Don’t switch the compressor off because you are worried it’s pumping too much air in. Watch and wait

7) Wait until you see the fork seal start to move. I can’t over emphasise enough the importance of safety. Wear overalls and eye protection. Fork oil can squirt out under high pressure and make a mess so don’t do this in your home or around animals/children. Apply a rag around the fork if you don’t want to make a mess. You will hear/see oil escape from the fork seal 

8) As soon as you see the fork seal move upwards turn the compressor off. The fork seal might not pop out completely but the main idea is to get it to move upwards enough so that part of the sidewall of the seal is exposed so you can push it with a flat bladed screwdriver. (There is no reason to leave the compressor on for longer)

9) Carefully lift the fork seal upwards and away from where it was seated. There will be high pressure in the fork until the air has escaped. This can take a few seconds or longer so wait until all pressure has dispersed

10) Remove the air compressor from the air valve on top of the fork leg and put the black plastic cap back on (to protect the valve)

11) Now remove handlebars and using a 30mm socket carefully loosen and remove the fork leg cap

12) Now you can remove the front wheel and each fork

13) When the forks are loose slide the dust seals and old fork seals over the end of the fork and off

14) Invert each fork leg and drain out the old fork oil

15) Apply clean oil lightly to inside of new fork seal and slide down fork to where it sits slowly and carefully. In my humble experience ONLY USE GENUINE fork seals. Aftermarket ones only last about 5000 miles tops

16) Attach circlip (either the old ones if still in good condition or new ones). Attach dust seals - replace with new dust seals if necessary

17) Measure out new fork oil and pour into fork leg. Re-attach fork leg cap and tighten as much as you can whilst loose

18) Re-fit gaiters, forks and front wheel etc

19) When forks are clamped by yokes tighten fork leg caps. Re-fit handlebars

20) Check and double check all bolts are tight

 

METHOD 2 for any other motorcycle fork without air valves

1) Start to undo fork end cap whilst fork is still clamped in top and bottom yokes

2) Carefully take the cap off making sure spring doesn't spring out and hurt you. It's best to take weight off the forks so get the front wheel in the air by using a stand or any other idea to keep the weight off it. That way the fork is as decompressed as you can get it and less likely to ping the fork cap into your face

3) Pour new cheap engine oil up to the very top of the fork in each leg allowing room to screw the cap back on to the fork. Don't do the fork top cap up too tight but enough so that it is oil tight. 

4) Remove both forks so they are loose. 

5) Remove dust seals and circlips

6) One at a time, remembering which fork is which side for easy re-installation, lie the fork on the ground on its side. It's a good idea to lay it on a large sheet of cardboard so you don't make a mess of the ground/floor and so you don't scratch your fork leg

7) Put a block of wood between a solid brick/concrete wall at ground level (solid, immovable object) and the fork leg bottom end to protect the fork metal from being damaged. 

8) At the top end of the fork you will also need an immovable object. It is doubtful that anything will be nearby (like another wall unless you are in an alleyway) so use a car as your ‘movable/immovable’ object 

9) Manoeuvre the car with the front wheel about a foot away directly inline from the top end of the fork. 

10) Place a block of wood against the car wheel and a scissor jack or bottle jack on its side against the wooden block. Then place the other end of the jack against the fork. Again - use a wooden block between the jack and fork cap to protect the fork. [Make sure before you do this that you have removed the fork dust seals and fork oil seal circlips]

Failure to add more oil to each fork leg (as a cheat because you don't want to buy oil) will mean that the fork will compress completely but there won't be enough 'hydraulic fork action pressure' to push the seal out with.

All you'll have is a very compressed fork and nothing will happen! Make sure the fork is FULL of oil. Even cooking oil or used engine oil will do if you aren't bothered about dirtiness

11) Start to wind or pump open the jack. The fork will compress and because it is full of oil it will push out the fork seal as the oil will push and move the weakest place (which is now the unsecured fork seal). 

[A word of caution - wind/pump the jack SLOWLY because when the fork seal starts to move you need to stop as the seal should continue to ease itself out on its own. If you wind/pump too fast the seal will shoot out and so will all that engine oil - all over your garage floor and it'll be hassle to clean]

12) Quickly unwind/release the jack, decompress the fork carefully and lift it up, slide the old fork seal off. 

13) Take off the fork end cap (which is not tight and won't need to be clamped to remove) and empty all the cheap engine oil and dirty old fork oil. Leave the fork to drain as long as you like then turn the right way up

14) Measure out new fork oil and pour into fork

15) Slide new seal down over fork tube using a little new oil on the inside of the new seal to help ease the fitting. In my humble experience ONLY USE GENUINE fork seals. Aftermarket ones only last about 5000 miles tops

16) When fitting the new seal lightly tap around the edge of it until it 'seats' where it should. DO NOT use a flat bladed screw driver to push the seal down with as you can damage the seal. If the seal really won't go down then slide a larger diameter pipe over the fork tube to push 'it home' but you shouldn't need to do this. 

17) Put the circlip back into its ‘groove’ to secure the new fork seal in place

18) Re-fit the dust seal using the old ones or new ones

19) Re-fit the forks 

20) Tell everyone else as these two methods save a lot of hassle and…enjoy

 

 

DON'T FORGET THE HEALTH WARNING! IF YOU DECIDE TO TRY THE SHORTCUT METHODS YOU DO SO ENTIRELY AT YOUR OWN RISK!



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Feedback from another owner who has used the air compressor method:

"I used the compressor method to remove my fork seals. I heated the lower stanchion with a hairdryer after removing the clip and dust seal. I then used my small tyre pump to slowly build up pressure in the tube. I used the fork gaiter to act as a shield to protect me and stop the spread of oil (I had emptied the fork first). At 140 psi it went pop and the seal was free. "



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RE: Fork seals - removing and replacing fork seals on a Yamaha TTR250
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Sorry that I missed that question from 2014 but, in case anyone reads this thread, I thought I had better answer it -better late than never!

Answer:

I am lucky to have the use of a rattle/windy gun and that works great on the base valve.

The workshop manual shows a "damper rod holder" which I guess fits into the hex head of the top of the damper rod to hold it whilst loosening or tightening the base valve.

Fork base valve.jpg

Brian

 



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I have a Sealey 24v Impact wrench. Excellent kit. 400ft lb torque. £110.

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RE: Is there an easy way to replace TTR250 fork seals?
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I tried the compressor method this morning and can confirm it works brilliantly!

My mate Bob, over 70 years old and just recovering from a major operation, is still riding his TTR. One of his fork seals started to leak badly contaminating the brake pads and generally making a mess.

I got a new set of fork and dust seals from Totally TTRs and the whole job took less than an hour.

The procedure was as described earlier in the thread. Loosen top cap, remove front wheel, caliper and cable clamp, and then the whole fork leg. 

Took off the gaiter and cleaned up the mess. 

Removed the snap ring and held a cloth around the seals.

Put the airline on and pumped up the fork leg and the dust and oil seals gently lifted out with hardly any mess at all.

We unscrewed the top cap leaving everything in place and pushed down the stanchion to give a gap through which to drain the oil.

Left the fork draining and went for a cup of tea.

Replaced the oil and dust seal with new ones, re-fitted the snap ring and re-filled the fork leg with new oil.

Re-fitted the fork and Bob's your uncle - or your mate!

The longest part was the draining....

One happy Bob!!!

20160621_115459.jpg

 

 

 

 

 



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Another great thread here, just a couple of questions to help clarify things for me.

When you say this Brian "We unscrewed the top cap leaving everything in place and pushed down the stanchion to give a gap through which to drain the oil"

Would you or someone else mind expanding on this? Pretty please ta. 

To just drain the oil, just remove the forks, then caps and let it drain out? Do you need to pump the fork a bit as well? Do I need to do anything special to get it to drain out? Same on adding oil, I am clear on what point to fill it to, but do you need to pump them a few times to ensure you end up with the correct oil height? (I guess adding the same amount in that came out is a start)

When driving the seals in what diameter pipe are people using? (save me measuring and I can continue being lazy!)

Thanks in advance.



-- Edited by leigh on Tuesday 13th of September 2016 01:02:22 AM

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leigh wrote:

Another great thread here, just a couple of questions to help clarify things for me.

When you say this Brian "We unscrewed the top cap leaving everything in place and pushed down the stanchion to give a gap through which to drain the oil"

Would you or someone else mind expanding on this? Pretty please ta. 

To just drain the oil, just remove the forks, then caps and let it drain out? Do you need to pump the fork a bit as well? Do I need to do anything special to get it to drain out? Same on adding oil, I am clear on what point to fill it to, but do you need to pump them a few times to ensure you end up with the correct oil height? (I guess adding the same amount in that came out is a start)

When driving the seals in what diameter pipe are people using? (save me measuring and I can continue being lazy!)

Thanks in advance.


 A picture is probably the best way to show the method of draining wink

Fork and bush seals 006.jpg

 

Bob had only replaced the oil so we weren't too concerned about leaving some in there but my guess is that we got most if not all the old oil out without pumping etc. If you are worried maybe measure what comes out?

Our prime objective was to replace the leaking seal.

I don't pretend this is a precise way of doing things as measuring oil height and matching fork legs would be tricky. We just refilled with the recommended amount - 550cc

Use 50mm diameter pipe - see here 

If you want to a thorough job you need to follow the instructions here biggrin

Good luck!

Brian



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Thank you Brian, you are a legend in your own lifetime! The photo shows it perfectly.

I think I'll just change the oil for starters and then do the seals at another point. They are not leaking but they are probably the originals so must be on borrowed time surely. Thanks for your help, you have saved me so much money and time and it has given me a lot of satisfaction working on my own bike, doing things I probably wouldn't have had the confidence to do.

I thought that might be the case doing the oil this way, you probably get 80-90% of it out or more, I'll measure what comes out and put the same back and check the oil height, and make a judgement call if I am to add more or not.  

When you say measuring oil height would be tricky, is that because you would normally be doing that with some parts removed to get access/correct readings?

Thanks again.



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leigh wrote:

Thank you Brian, you are a legend in your own lifetime! The photo shows it perfectly.

I think I'll just change the oil for starters and then do the seals at another point. They are not leaking but they are probably the originals so must be on borrowed time surely. Thanks for your help, you have saved me so much money and time and it has given me a lot of satisfaction working on my own bike, doing things I probably wouldn't have had the confidence to do.

I thought that might be the case doing the oil this way, you probably get 80-90% of it out or more, I'll measure what comes out and put the same back and check the oil height, and make a judgement call if I am to add more or not.  

When you say measuring oil height would be tricky, is that because you would normally be doing that with some parts removed to get access/correct readings?

Thanks again.


Thank you for the kind comments - nice to get such feedback biggrin

The oil height would normally be measured without the spring - see photo below:

afork rebuild 019.jpg



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I also used this method for removing fork seals in 2 ttr's on the same night. In my case the workshop compressor would not cut it at 130 psi of pressure. I had to use my battery powered portable unit that runs a little higher psi
the seals poped at around 170-210 psi I was worried that they would go off like a gun and cover the workshop in oil but its not the case i had a rag tied around the seal and when they went they just lifted with no mess at all.
Was a very easy way of doing them as Brian says the slowest part is having a beer while the oil drains.


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RE: Fork seals - removing and replacing fork seals on a Yamaha TTR250
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My garage compressor only goes up to 110psi and wouldn't budge the seals so I thought I would warm up the fork legs to soften the seals enough to get them moving cry

I think you may have guessed where I am going with this. I had one hand holding the fork leg, one hand waving the blow torch around and not a hand spare to hold a big rag around the seal area and, yes the seals did soften and move, very suddenly, and I got totally covered in a spray of smelly old fork oil along with a liberal coating on everything else in the vicinity inc my old BSA A10, bench, floor etc etc disbelief

I am sure no one else would be so stupid hmmcryno

Brian



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I am rebuilding some OE forks and one of the legs had some damage so I stripped out a spare fork to get a replacement but soon discovered that, although the fork leg looked the same, the OE internals wouldn't fit it.

Raid fork comparison 1.JPG

The springs are the same length but every part is different in some way.

Even though the springs are the same length they are built slightly differently. 

Raid fork comparison 2.JPG

Raid fork comparison 3.JPG

Raid fork comparison 5.JPG

 

However, the overall height, diameter of the stanchion and the way the fork legs hold the caliper and axle are the same as the OE so they appear to be interchangeable.

I couldn't find a workshop manual that covered the Raid forks so rang the ever-helpful guys at Yamaha UK technical department and the oil capacity is different to the OEs. They take 617cc of oil and, after working the air out by pumping the stanchion, the oil level should be 120mm with the stanchion at the bottom of its travel and without the spring fitted.

Brian



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Sorry to put up another post about forks but you can guess I have been busy rebuilding some recently smile

I had a couple of pairs of forks with the Schrader valves in their top caps so, without thinking, I rebuilt them before realising that the RH lower fork legs are missing the lugs that locate the speedo drive gear and the speedo cable clamp.

I wondered if that would be a problem if the RH fork leg was fitted to a blue TTR with an analogue speedo driven by cable from the front wheel.

The only sensible way to find out was to fit one to my blue TTR. What else would I want to be doing on a Sunday afternoon disbelief

First off I took a photo of the original fork leg so that I had a reference point showing the position of the speedo gear by where the cable joins it.

Fitting OE forks to blue TTR 1.jpg

 

The photo below shows the lugs that are missing from the fork legs off the metal tanked TTRs.

Fitting OE forks to blue TTR 5.jpg

 

The answer to my question is yes, the earlier fork leg fits fine. The gear is held in the right place when the axle is tightened up and the speedo cable clamp holds the cable firmly in the correct position.

So, if you are looking to buy replacement forks or fork legs for your blue TTR then this widens the range of suitable ones biggrin

As a post script I noticed that the axle on my TTR seemed a tad short and wasn't showing enough of its hexagon head.

The reason was that I had inadvertently fitted an axle with the shorter end from a digital speedo model. One of the drawbacks of having too many spare parts lying around disbelief

See the difference in the photo below:

Fitting OE forks to blue TTR 2.jpg

 

With the correct axle fitted, all is now well!

Fitting OE forks to blue TTR 3.jpg

 

Every day is a school day for me biggrinbiggrinbiggrin

Brian



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Exeter, Devon, UK

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