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

hertsrider · Senior Member

Base Gasket issues

Cubber · Super Guru

RE: Base Gasket replacement

hertsrider · Senior Member

Martyn...the oil leak wasnt part of the MOT..i just asked them to look at it while it was in there...
There are no pipes leaking and you can see the oil seeping from the area....i've cleaned it..run the engine and sadly watched the oil seep out again...
I'm going to have the piston rings replaced and all of the other gaskets at the same time...I may have the cam chain done but to be honest, the bikes not rattley so i may not bother...
I've had a definative back on cost...£350 all in inc labour...ouch...

Cubber · Super Guru

Ah - clarity - I read your post and presumed the MoT was refused because of an oil leak. Has the bike passed the MoT then? confuse

Have you considered a DIY approach to cure the leak? It's not that difficult for an owner to do and would be cheaper than the quoted £350. aww

HERE is a link to cylinder head removal/replacement advice and there's only the cylinder to remove after that.

Full gasket sets for the job are available for £23 + p&p HERE

I'm sure you will find lots of support for any procedures you may find difficult. wink

Martyn

TTRfan · Super Guru

Hi Neil

Bad luck on the leak although I have to say that it is rare for the base gasket to leak. Maybe a build up of pressure in the sump for some reason - maybe the breather is blocked? If there is a blockage and you free it then maybe the leaking will stop.

If you do have to replace the base gasket then, if you are methodical, it is a job within the scope of the average owner. The Yamaha manual is superb and supported by a number of "show and tell" threads linked on here.

You will need a head & base gasket set at the very least but it would make sense, as Martyn says, to replace the rings if the bore looks OK plus to decoke the head, clean up the valves and replace the valve stem oil seals at the same time. All of these parts would cost about £60.

None of this is madly difficult although, if you haven't tinkered before, it might be worth asking a mechanically competent mate to give a hand.

Brian

hertsrider · Senior Member

Martyn/Brian, thanks both for taking the time to reply and to give thought to my problems! The biggest problem i Have is that I'm "time poor" at the moment, I'd love to attempt the repair myself but with a hectic job and young family my spare time is desperately short....it would take me 4 months not 4 hours!!!!!
Brian , ill send you a pm regarding some parts.
Thanks again.

rattlyolddt · Senior Member

Neil, Martin at Torque Racing in Stotfold will do it far cheaper than that. The man knows his onions. (Paris Dakar mechanic) also a whizz on setting suspension up. Charges are vert very reasonable.

I'll text you his number if you like. Say Ed the TV man sent you.

burton500 · Veteran Member

My base gasket has been leaking for quite a while now so I've finally got round to ordering the gaskets. It's been losing only about a capfull of oil per ride, and since I pressure wash the bike after each ride I've never really worried too much about it.

Are there any other detrimental effects on a four stroke with a blowing gasket? Eg performance?

Lee

TTRfan · Super Guru

It must take quite a bit of pessure to blow the base gasket. Gotta be a blocked breather or worn rings allowing a lot of "blow by".

Brian

burton500 · Veteran Member

Thanks - if it is the rings, that will be apparent when I lift the cylinder. Where is the breather located?

Cubber · Super Guru

The breather pipe comes off the rocker cover on top of the head.

It's item 17 in the image

Martyn

TTRfan · Super Guru

On some of the older TTR engines the breather pipe attached to an outlet on the RH crankcase as shown in pic below. This outlet is blanked off on later models and the breather outlet is in the cam cover.

Was your outlet just open to the elements or had it been plugged?

burton500 · Veteran Member

Thanks for the diagram. It turns out my bike has no breather pipe fitted hence I couldn't find it!

burton500 · Veteran Member

Bingo, found it! Yes this is the earlier model with it on the crankcase.

Cheers

Lee

TTRfan · Super Guru

Excellent news! Was it clear?

burton500 · Veteran Member

Yes, breather is clear. I'll do a compression test which ought to give an idea as to the condition of the rings, and then strip it down to change the gaskets.

burton500 · Veteran Member

Right then, my base gasket has been leaking oil for a few months - not much, but enough to be a pain. I've had the bike for a year and knew nothing about it's history as I bought it from a dealer who had taken it in PX. The breather was clear, so I expected rings to be the problem.

So today I set about taking the cylinder off. Luckily none of the bolts had been mullered by any of the previous 8 owners which was encouraging. The hardest bit was getting the exhaust header pipe off the bike - must be a knack to it to get it to clear the frame, but it came off in the end just before the angle grinder came out.

The two interior bolts that hold the cylinder on were not done up - not even finger tight, which I am guessing is the cause of the base gasket blowing. Everything else came off easy, and the top end was in as new condition. The camshafts were as new. What was a surprise though was that the piston and rings actually were brand new. No wear at all - still a shiny polished finish. The cylinder was showing fresh hone marks as well. So I am guessing the previous owner had all this work done just prior to selling it, but whoever did it forgot to tighten all the bolts. The piston was marked up "XC" - is that an aftermarket piston? More good news was that all valve clearances were spot on.

Bunged it all back together with new gaskets, and just taken it for a spin - good as new!

All in all, the job was just over 4 hours in total, and went better than expected!

Cubber · Super Guru

Welll done. Well sorted.

If you put your address up I'll bring my TTR (and a few more) for you to do. biggrin

It's nice to have a success. smile

I presume you made a saving on the original £350 quote.

Martyn

TTRfan · Super Guru

burton500 wrote:
Bunged it all back together with new gaskets, and just taken it for a spin - good as new!
All in all, the job was just over 4 hours in total, and went better than expected!

Result wink - and well done for giving it a go!

Brian

burton500 · Veteran Member

Cubber wrote:
Welll done. Well sorted.
If you put your address up I'll bring my TTR (and a few more) for you to do.
It's nice to have a success.
I presume you made a saving on the original £350 quote.
Martyn

Cost was about £30 for the gaskets. It was "hertsrider" who got the £350 quote. I guess I must be in the next county (essex)?

Perhaps bring it over on a trailer? Otherwise have a go yourself as no special tools needed.

Lee

-- Edited by burton500 on Sunday 10th of March 2013 12:00:56 PM

Cubber · Super Guru

You are right, Lee. Sorry for my presumption that you had the quotation. confuse

At least it should illustrate the saving that Neil will be able to make if he decides to explore DIY. wink

I think I've decided to fettle my TTR myself and save trailer time/cost. Thanks for the offer. aww (I was joking!) wink smile biggrin

Martyn

hertsrider · Senior Member

burton500 wrote:
Cubber wrote:
Welll done. Well sorted.
If you put your address up I'll bring my TTR (and a few more) for you to do.
It's nice to have a success.
I presume you made a saving on the original £350 quote.
Martyn
Cost was about £30 for the gaskets. It was "hertsrider" who got the £350 quote. I guess I must be in the next county (essex)?
Perhaps bring it over on a trailer? Otherwise have a go yourself as no special tools needed.
Lee

-- Edited by burton500 on Sunday 10th of March 2013 12:00:56 PM

Fair play Lee...i'm pretty 'time poor' so impossible to find 4hrs flat to do the job myself....young family and demanding job don't let me have 4 mins to myself...let alone 4 hours!!! I'd love to have saved the £300 odd though it has to be said!!!

Should get mine back tomorrow, the valve clearences were checked and they're within tollerence, the piston and bore were in great shape so i'm hoping she'll run like a dream when i collect her!!!

hertsrider · Senior Member

Delighted to say the bike is back and is running very sweetly indeed...the mechanic who worked on it said he was fearing the worst when opening up the engine as its a 19yr old bike....he was really shocked to see what great condition the engine was inside!!! He's only seen 2 TTR's in the last few years and really enjoyed working on the bike.
All the work was done and i must say, the engine sounds a lot smoother and quieter, on tickover and on the revs....it feels great knowing that all the internals are in good order and i've breathed new life into the old motor!! Many more years happy trail riding to be had out of this old TTR Raid!!!
Thanks to all of you for your comments/advice/help etc...a great forum with great members.

Cubber · Super Guru

Good result, Neil.

I'm pleased your TTR's mended and running sweetly. Long may it continue so. wink

Was your given estimate of price reached? confuse

Never mind - enjoy the bike and even more so now that Spring and Summer are on the way (Supposedly) smile

Martyn

hertsrider · Senior Member

Cubber wrote:
Good result, Neil.
I'm pleased your TTR's mended and running sweetly. Long may it continue so.
Was your given estimate of price reached?
Never mind - enjoy the bike and even more so now that Spring and Summer are on the way (Supposedly)
Martyn

Thanks Martyn...actually came in cheaper than the estimate, i bought all the bits and pieces from Brian and the labour bill was less than they thought! Result all round really...it's running so well right now...just need some warmth and sunshine!!

TTRfan · Super Guru

Yep - good result Neil!

Rings, head & base gasket set and valve stem oil seals are usually all that's needed for an engine "refresh" - just a tad over £70 if you do it yourself - and not a great deal more if you take it to a bike shop by the sounds of it smile

I agree we need some better weather - 5C outside but it feels like below zero. It wasn't nice yesterday laying on the drive fixing an exhaust mounting on the car for MOT

But I got my MOT this morning so it was worth it biggrin

Brian

burton500 · Veteran Member

Neil
Glad you are sorted now. You can't be based too far away from me. If you want to do some lanes midway sometime, give me a shout.
Lee

sammyttr · Senior Member

Base gasket gasket

sammyttr · Senior Member

Hi I am replacing the base gasket on my TTR I need to know all the tightening torques for head bolts, camshaft caps and tightening sequence, also replacing sprag clutch need to know fly wheel tightening torque and any other major bolts and also tightening torques forrebuilding front forks and which fork oil is best to use and quantity

thanks Sam

Cubber · Super Guru

CLICKY THINGY to a previous request for torque settings and the replies.

Martyn

sammyttr · Senior Member

Mint thank you just need tightening sequence if there is one

Cubber · Super Guru

A little at a time and diagonally - there's not that many holding the top to the bottom, so it's unlikely to warp as much as a straight eight would. biggrin

Martyn

WillsTTR · Veteran Member

BASE GASKET OIL LEAK?

ttboof · Super Guru

id go the wisco 2mm oversize it would give a bit of a tourque with out splitting the cases .

ive done big bore kits on other bikes in the past and find they tend to get a bit hotter in the hard going on 30deg plus days .

tge bottom gasket leaking isnt a common problem just an opertunity to freshen things up a bit

TTRfan · Super Guru

I agree with Les in that the bottom gasket leak is unusual. It can happen where an engine has taken in water and "hydraulicked" as this can stretch the head bolts enough to allow the base gasket to crack and leak. But this won't be your situation.

It can be very difficult to identify the source of a leak as leaking oil gets blown or creeps around the engine and can drip far away from the source of the leak. You may have seen my efforts with talcum powder to identify (successfully!) the source of a leak on my own TTR

The most common source of a leak is the decompressor plug. Are you sure that one is oil tight?

The "280" piston kit is the quick and easy way to go.

It is also worth replacing the valve stem oil seals whilst the head is off if they are still the originals.

Good to hear the Venhill brake hoses worked out well biggrin

Brian

WillsTTR · Veteran Member

G'day Guys,

When I first bought the TTR it had a badly leaking decompressor plug, and the engine was covered in oil. I wrongly assumed that the oil was from the leaking plug, and an easy cheap fix. Turns out I was wrong........I think the seller knew a little more than he said he did!

When the RH crankcase gasket was replaced the mechanic said the internals were very clean, so it appears to have been maintained. The K&N filter fitted was also clean and freshly oiled so that was a good sign too. It was the sellers only transport for years, and his brothers' before that who bought it as a Japan market import in 2000.

I'll ask my mechanic to strip the top end down, and if it is all stock and in good shape I may just have the cylinder honed an a set of new rings fitted. If there is a rebore required I'll go the +2mm piston kit from Brian[is that the '280' kit mentioned above?]and just ride the wheels off it.

I've just spent AUD$600 on a fork service, two new dual sport tyres, valve clearance check and service, plus the AUD$220 on the front and rear Venhill brake line kit.

I'm quoted about AUD$400 in labour to tear down and rebuild the top end plus parts. At the current exchange rate it'll cost me AUD$335 for the 263cc Wossner kit plus head and base gaskets, and a set of new valve stem oil seals. That's plus whatever a local rebore for the bigger piston kit will cost.

I'm still undecided about which way to go....the TTR owes me about $2,000 already. What if the bottom end carks it? :-/

ttboof · Super Guru

If you can find a mate with a few tools the top end rebuild is pretty easy .labour is the biggest cost fortunately something I've never paid for

If the bikes been looked after the bottom end should be ok for at least 70k kms

Pendo · Veteran Member

Lower Head Gasket Leak

Cubber · Super Guru

I would advise that it's NOT YET time to replace it, especially if the engine is otherwise running well. smile

If, on the other hand, the engine is knocking, rattling or not performing well then it would be soon time to dismantle, check it all out and overhaul.

The amount of oil seepage through the "cylinder base gasket" that you show is not half as bad as mine was leaking from the decompression plug before I renewed it!

I take it that the "cylinder head gasket" you replaced is still OK. confuse

No - I'd leave it alone - but keep your eye on it in the mean time. wink

Martyn

WillsTTR · Veteran Member

RE: BASE GASKET OIL LEAK?

WillsTTR · Veteran Member

RE: Lower Head Gasket Leak

TTRfan · Super Guru

Make sure that your oil breather pipe from the cam cover (blue TTRs) or crankcase (white TTRs) is not blocked and that you have been emptying the emulsifier pot between carb and airbox regularly.

This will help keep the crankcase pressure down but, ultimately, if the piston/rings are worn the pressure in the crankcase will be much higher from the "blowby".

Brian

Pendo · Veteran Member

Thanks for the replies, I'll keep an eye on it.
What you said Brian makes sense, I'll check the pipe and pot. I really appreciate the advice of all on this forum

WillsTTR · Veteran Member

RE: BASE GASKET OIL LEAK?

ttboof · Super Guru

Good to hear your back on the road . Best part is you know that she's all good inside with many miles ahead biggrin

WillsTTR · Veteran Member

ttboof wrote:
Good to hear your back on the road . Best part is you know that she's all good inside with many miles ahead

Absolutely. Buying a twenty year old trail bike is always a bit of a gamble!! biggrin biggrin

Pendo · Veteran Member

RE: Lower Head Gasket Leak

TTRfan · Super Guru

Good to hear the leak has reduced.

The two "outside" head bolts can be very tight in the casing threads and give false torque readings. I have had this before and blew two head gaskets before I realised what was happening. The bolts seem to thread in OK before the build but seem to seize a bit when under pressure.

It is really important to check the two outside head bolts run easily in the threads and if not run thread cleaners over the bolts and in the casing threads.

Brian

Moo · Senior Member

I just cleaned out my emulsifier pot and crankcase breather... Glad I did!! It was brimmed with the stuff!!

Was suffering a tiny weep at the front base gasket area, just looked like a damp area when dirty.. Hoping this will solve the issue... If not it'll be head off and replace it. Luckily I got two genuine gaskets with the bike when I bought it. Is it worth changing the rings and cam chain while I've got it apart? This girls got a bit of mileage on her (40k)

heffh084 · Veteran Member

RE: Base gasket fitting, wet or dry?