A forum for owners of Yamaha TTR250 trail and enduro bikes!

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. 

Martyn

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?

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

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

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

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

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 

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.

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.

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 

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:

Brian

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

Hi Sammy

Did you fit the standard black Yamaha plug?

Brian

See here

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.

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

ttr250slw wrote:

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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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 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

"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

Scott's most excellent plugs are available to purchase here.

gaz googe wrote:

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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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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 

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?

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

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