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Decompressor blanking plug and removing decompressor arm
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Hi all have just got off phone to fowlers of bristol and the sharks are saying I need to buy the complete head as you can't buy the plug any more . As this is a 2 minute repair does any body know where I can get one .thanks Keith



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Here's a link that explains it all and includes a pictorial guide to replacing the standard oil plug:-

CLICKY THING

Have a look and see, you may need it some day because they're not immune to weeping rather a lot.  disbeliefblehno

Martyn



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RE: decompressor blanking plug
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Mine was leaking when I bought the bike, I took it to my local bike shop and they said they couldn't get one and fabricated a plug out of black nylon plastic. It lasted for about 4 months, but now leaks again, so I'm after getting the proper plug and fitting it myself this time. If you want a job doing right, do it yourself...

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Am I correct in saying that a blanking plug does away with the decompression lever cable etc.

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Yes - it does, because it blocks the hole where the decompressor shaft fitted.

However, if there is a decompressor fitted and the oil doesn't leak then leave it - even if you don't use it - it's blocking a possible oil leak.

Martyn



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Decompressor blanking plug and removing decompressor arm
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I was surprised that my TTR250 is so much harder than my WR250F to kick start.
So I learned the kick starting drill for the TTR250 (my 2011 model does NOT have a decompression device).

Having recently helped to push a DRZ400 (which has no kickstarter) up out of a steep gully and then bump start because of a blown fuse, I thought I didn't want to be dependent on the TTR250 electric starter (and who knows, maybe a bit of kick starting will prolong the life of that sprag clutch thingo)...

kick starting drill:
(warm engine, tiny hint of throttle)
find presumed TDC (hardest point)
slowly kick thru PAST hardest to next not-so-hard.point and return lever
firm full kick (quickly open throttle a little bit).

BTW, I dont think you would be losing compression just from a leak from the cam box - the internal decompressing device is a little lever which stops the exhaust valve closing filly (I think), but of course it is not there anyway, so it cant be stuck open by default.

It would be nice if there was a sure fire way to blank off that hole forever - I wonder if preemptively covering a not-yet-leaking plug with an extra layer of liquid metal would stop it happening?



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RE: decompressor blanking plug
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I'm with Matt's suggestion.

Since it is a redundant hole and unused for its intended purpose in those not fitted with the decompressopr, I was contemplating running a tap up it next time it leaked and screwing a suitably sized bolt with annealed copper washer to seal for good. blankstare

The cam boxes run with plenty of oil in there and it's only a matter of time before the rubber plug weakens, leaks and looks neglected. disbelief

Martyn



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Budleigh Salterton. Devon



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Removing decompresstion lever??
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what happens when your decompresstion lever is leaking?
Is it easy to remove and plug up?
The lever is not connected to anything and not used
Thanks Don



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Mine never had such a lever but I think all you have to do is loosen the bolt to withdraw the shaft. Perhaps the other end is attached to workings within the rocker box so the cover may have to be removed also.

Beware - there is a copious supply of oil to the cams and the valve recesses in the head swim with it, hence the seepage. hmm

Yamaha supply a circular bung that fits in the hole to block it up - it's a press fit. aww

Martyn



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Budleigh Salterton. Devon



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Hopefully the pic below will explain what is going on with the decomp lever, its retaining screw and seal.

As Martyn says, the whole lot can be replaced by the blanking plug but maybe, just maybe, leaving it in and fitting a new seal might be a longer lasting repair?

Brian

Decomp and seal 002.jpg



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RE: decompressor blanking plug
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hy i was just wondering i read here that the decompression head was not change for newer models there for the plug for the new model should be fixable for old models too right?
i understand that it will be expensive compaired to the stock plug but it seems like a solid fix.
http://www.ebay.com/itm/Yamaha-Head-Decompression-Plug-BLUE-Billet-YFZ-YZ450F-250-YZ-/230689363351?pt=Motorcycles_Parts_Accessories&hash=item35b6285597&vxp=mtr#ht_1091wt_1270


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Decompressor blanking plug and removing decompressor arm
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Hy brian i think its cheap for me to lathe the whole thing because the shipping costs me more than the item it self since i live in sri lanka. so do you mind sending me the exact mesuments for the points iv marked in the image. B is the depth of the grove

Drawing1.jpg



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A = 18.5mm

B = 4.4mm

C = 1.75mm

Diameter of main rod is 8.0mm and of the recessed section 4.5mm

Slightly difficult measuring A and B as there is a bit of a chamfer on the corners.

Brian



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I am looking not to blank out the decompressor hole, but to repair it's weep with a new seal that allows the decompressor still to be used. Can I get one anywhere and what part would I ask for?

A damsel in distress! 

 

SALLY 



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Sallyb wrote:

I am looking not to blank out the decompressor hole, but to repair it's weep with a new seal that allows the decompressor still to be used. Can I get one anywhere and what part would I ask for?

A damsel in distress! 

 

SALLY 


 Hi Sally and welcome to the forum!

Not sure I totally understand the question. Have you got a decompressor fitted at the moment? If so, then you need to get a new seal for the decompressor shaft from your local Yamaha dealer or by post from MotoWard or Fowlers. I haven't seen a fiche with a decompressor on so can't give you a part number - sorry!

If you are looking to fit a new blanking plus then all the info is here http://www.ttr250.com/Replacing_cylinder_head_oil_plug/TTR_oil_plug.htm

Let us know if you need further advice wink

Brian



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The plug on my project TTR started to leak so I chased up my mate with the lathe who was working on a long-term solution for me.

He came around yesterday with a part that he has lathed in aluminium on which he has cut a groove for an O ring.

Alloy oil plug 004.jpg

I had lent my mate a spare cylinder head so there was a guaranteed fit. I therefore whipped my old plug out and fitted the new part today. This was a very easy operation and easier than trying to bang in the standard plug as its in a bit of an awkward spot to get at . 

I used a bit of gasket goo as belt and braces but that was probably unnecessary.

Alloy oil plug 006.jpg

Ideally the original retaining bolt with its copper washer will retain the Mk2 version of the plug but I had to use another bolt for this one as the groove wasn't lathed deep enough. My fault for not specifying it no

Alloy oil plug 008.jpg

The pic above highlights the main problem I have had with the engine I had sprayed with two-pack paint. It is fairly thick and can flake off.

It would seem unlikely that an owner would need to remove the plug but, just in case, the Mk2 version may have a threaded hole that would allow a bolt to be inserted to pull it out. Otherwise it is a relatively simple operation to push it out from inside once the cam cover is off. See below:

Alloy oil plug 005.jpg

Brian



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pedrosan wrote:

Brian, any price on the mark 2 plug?


Now fully tested on my own TTRs and available here wink  



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mud


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Decompressor plug help
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Hi Everyone, I have bought a new metal decompressor plug from Brian but I can't seem to get the old one out? I've tried prising it out, but just the rubber face came off and I'm left with what appears to be a recessed metal face? Does anyone have any ideas how to remove it, or is it going to be a tank/valve vover off job? Any help / pointers would be gratefully received!!

 

Cheers  Mud



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As the old plug is scrap there is no need to be gentle with it if it's stuck in. If it was on my bike I would drive an old screwdriver through the metal plug and lever it out. 

Be very careful not to damage the housing on the cylinder head and make sure the orifice is clean and free from any sharp edges that might damage the O ring on the new plug. Oil or grease the new plug and it should go in relatively easily.

Brian

 



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mud


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Sound advice Brian, plug out after pushing a screwdriver through. Was in very tight, makes you wonder why it leaked? Anyway, it's just drying off after cleaning before I put the metal one in. I will be using some instant gasket for a belt & braces approach. Thanks very much for the prompt reply, I was beginning to lose my sense of humour!

Cheers Mud

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decompressor plug
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right fitted one of the decompressor plugs but while pulling the bolt out it took the treads with it, put bigger tread in and a bolt in with silicone and lock tight it and started leaking recently would chemicame metal but alright to plug the hole and lose the bolt and just fill it in



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Hi Sammy

Did you fit the standard black Yamaha plug?

Brian



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no I fitted the after market off of here, just going to chemically metal the hole up and sand down see how that goes

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JB Weld

Jarrah  wink

 



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so use JB weld where can I buy that halfords ?

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I'm not sure what ''Halfords'' is but you can buy it on eBay if you have trouble. I found THIS with a quick search on eBay.com.uk

Jarrah



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See here



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JB Weld is great stuff, I keep it around and use it for lots of my booboo's. Even works good as a body filler in the right spot.

One little trick I like to do is to put it in freezer for a bit until it is almost, but not quite frozen. It allows you to use it on stuff that is upside down without dripping as quick.

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Thanks for all the replys guys, one thing of my mind now appreciate quick response

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would this stuff work or shall I get JB weld instead

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_223979_langId_-1_categoryId_255230#tab3

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One of the comments on the Halfords stuff says, "Product did not do what I wanted, ie stem a small leak in a water pipe, the water just kept finding a way through even when used with fibre glass gauze in between. I am sure it works for some people but not for me, eventually used the whole tube for a pin hole. Then called a plumber."

Beware of inferior stuff. hmm

I have used JB Weld (bought off eBay supplier £4 + £1.15 p&p) and I can confirm that it is VERY GOOD and does what it says on the packet.

Martyn



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Chemical Metal also very good and a tad easier to come by wink



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got Jb weld off amazon for a fiver delivered not bad,

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RE: Decompressor blanking plug and removing decompressor arm
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Hi all i have also machine one of these plugs up and will be makng more and i work for a hydraulic firm so if someone sends me their decompressor plug seal i am sure id be able to get them a new seal

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ttr250slw wrote:

Hi all i have also machine one of these plugs up and will be makng more and i work for a hydraulic firm so if someone sends me their decompressor plug seal i am sure id be able to get them a new seal


 I have already fitted one of ttr250slw's machined decompression plugs with the Viton 0-ring. I must say I was impressed with his work and it sealed the hole up nicely.

Once again, thanks HEAPS!

Jarrah



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Decompressor blanking plug to loose?
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Hi all,

 

I have just replaced the decompressor blanking plug on my TTR and was surprised how easily the old one came out and that I could push the replacement in with my thumb. I am now wondering if it is too loose and might fall out when the engine is hot (aluminium expanding more than steel with heat).

I used a hand drill with a 3mm bit to drill a pilot hole in the blanking plug for a self tapping screw which I thought I would need to screw in and grip with pliers to pull the blanking plug out, but it just came out with the drill bit! It had a smear of silicon sealant on it so I'm guessing it wasn't the original one. To fit the replacement plug I degreased the hole and put a very fine coating of Wellseal (Used to join crankcase halves) on both the hole and the edge of the replacement plug and just pressed it in with my thumb. I guess the sealant may have acted as a lubricant, but it is very tacky.

Can anyone else that has changed one tell me whether they had a similar experience?

Thanks

Lama

 



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"Fitting is simple. Remove the old rubber plug and clean up the socket. Unscrew the retaining bolt. Grease the new plug and just push it fully into the socket by hand - no force needed. Screw the retaining bolt back in (don't forget its copper sealing washer!) and job done."
taken from here

http://www.ttr250.com/TTR_extras/#decompressor_plugs



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 First of all, are you talking about the standard blanking plugs or the aluminium type that Brian sells.

If you are talking about the standard plug- To remove it I used a blunt screwdriver and hammer and hit one side of the blanking plug. It ended up making a hole in the blanking plug by the time I got it out but it came out a treat none the less. Can't verify the fitting of the standard plug though as I fitted an aftermarket type and my old TTR had the decompression lever fitted. I have fitted them on other bikes easily enough with the use of a little aviation non-hardening sealant, a hammer and socket the correct size for the plug ( like a welch plug).  Not much force in needed!

Fitting the aftermarket type was simple (as Brian mentioned)- Remove the old rubber plug (mentioned above) and clean up the socket. Unscrew the retaining bolt. Grease the new plug and just push it fully into the socket by hand - no force needed. Screw the retaining bolt back in (don't forget its copper sealing washer!) and job done. HIGHLY RECOMMENDED!

If you somehow fitted the aftermarket type without removing the retaining bolt first, I'd say the blanking plug is not made right!

If you pushed a standard plug in by hand, you are either stronger than me or a hell of a lot more lucky lol :)

It seems Brian uses a '' large pair of pliers with an old cloth over the jaw to protect the plug''. See here- http://www.ttr250.com/Replacing_cylinder_head_oil_plug/TTR_oil_plug.htm

Jarrah



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Thanks for your replies.

It is the standard Yamaha part that I fitted (wish I had bought Brian's alternative now!)
Not sure that I am lucky it pushed in quite easily by thumb, I would have prefered it to have been a bit tighter.
Anyone else found that theirs went in this easily and not had any problems with it afterwards?

Lama

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yamalama wrote:

Thanks for your replies.

It is the standard Yamaha part that I fitted (wish I had bought Brian's alternative now!)
Not sure that I am lucky it pushed in quite easily by thumb, I would have prefered it to have been a bit tighter.
Anyone else found that theirs went in this easily and not had any problems with it afterwards?

Lama


I have fitted a few of the Yamaha plugs over the years and they have always been a tight fit and required careful knocking in with a hammer and piece of round dowel. 

I am not sure why yours is loose. I can't think that a previous owner would have opened out the decompressor hole for any reason. Could you have a defective new part? Otherwise I am confused confuse

Brian



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Decompressor blanking plug and removing decompressor arm
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Scott's most excellent plugs are available to purchase here.



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I bought one of these plugs off Bri n Trish about a year ago and its never weeped oil since!

Cheers guys

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gaz googe wrote:

I bought one of these plugs off Bri n Trish about a year ago and its never weeped oil since!

Cheers guys


Good to hear Gaz!

New fitting instructions for the ali plug here - http://www.ttr250.com/Replacing_cylinder_head_oil_plug/TTR_oil_ali_plug.htm 



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TT-R250M wrote:
ttr250slw wrote:

Hi all i have also machine one of these plugs up and will be makng more and i work for a hydraulic firm so if someone sends me their decompressor plug seal i am sure id be able to get them a new seal


 I have already fitted one of ttr250slw's machined decompression plugs with the Viton 0-ring. I must say I was impressed with his work and it sealed the hole up nicely.

Once again, thanks HEAPS!

Jarrah


 1500klms since fitted and still sealing strong.

Highly recommended!

Jarrah



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Top left next to the decompressor oil plug
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So on the top left of the head there is a bolt next to the oil plug. I just purchased the bike and noticed when I got home it's stripped out.. I can not find any info on what it's there for. Does anybody know what it does?

2015-03-31 19.21.13.png



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RE: Top left next to oil plu
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Hello, Brandon, and welcome to the TTR forum.

The object pointed to in your photo is the decompressor plug.

Oil_seal%20007.jpg

This CLICKY LINKY will give you more information.

It is not a problem for all but stumps quite a few when it happens. wink

Martyn



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Top left next to the decompressor oil plug
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Welcome to the forum Brandon!

These bolts, which would hold in the decompressor if one was fitted, can be troublesome. New bolts and washers available here.

The threads easily strip in the head - see here

Brian



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Thank you guys very much. This is my first dirt bike and got it for a steal. Once I rode it I loved it.

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I had a problem recently with this, on some ttr's it holds the alloy blanking plug for the decompressor in (it did on mine) on other ttr's the blanking plug is a rubber thingie so this bolt just plugs the hole, (thats the larger round bit to the left of the bolt you mean on cubbers photo). I was able to fix mine, because the thread inside the cylinder head actually goes in further than the thread on the bolt, so i got a longer bolt which reached the female thread and it tightened, it literally only needed a few millimetres more.  Because mine held the blanking plug in i then had to machine the end (With a file) to fit i the groove on the blanking plug.. But I guess that if you have the rubber blank you may not need to do this..



-- Edited by Baggers on Thursday 2nd of April 2015 02:13:27 AM



-- Edited by Baggers on Thursday 2nd of April 2015 02:14:19 AM

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Mine is the rubber one. I just sealed the hole off.

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