hi all,

somewhere between mendoza and santiago my TTR started developing a new issue: it spills a lot of oil from the airbox.

from the searchengine on HU i read there's two basic causes for this: warped valvestemseals and/or pistonring leakage. am i right?

i recently checked the compression and it showed 9.0-ish (engine ambient temp). also, i don't seam to have lost a lot of power. so thats a good sign right??

any other stuff i can check before opening up the top-end?


thanks for any suggestions.
sanderd.

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First check the engine crankcase breather return pipes and any other engine breathers, to make sure they aren't blocked. If you've been doing some shorter runs in cold/damp weather, condensation can emulsify the oil & make it sticky & can block pipes, etc.

If you've topped the oil up recently, re-check the level, coz too much can cause this problem.

Its more likely to be ring bypass, which pressurizes the crankcases, and a compression check is only valid on a HOT engine:


Minimum 900 kPa (9 kg/cm2, 128 psi)

hi Pigford,

thank you for your reply. the oillevel is not the problem, it's at the bottom of of the glass in the oiltank. i normally top it up till the top of the glass, doing this for a long time without problems.

The manual doesn't state if the compression should be checked with hot or cold engine. Can i assume that if i have a 9.0 compression with a cold engine, it will be higher when hot?

I'll check the breathers. There's two, one from the cranckase leading back to the oiltank and one from the geabox (i think) leading to the airbox.

I'm in Pucon right now, and there's nothing here, so i'm contemplating to get to Osorno, i know there's a workshop there. I was thinking: To prevent any oilspill, is it a good idea to seal off the breather hose to the airbox thus force the oil to go through the crankcase vent back into the oiltank? Or is this a bad idea?

Thanks,
Sander

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Compression test when HOT - as stated in my last post (lol).

If you start blocking vents, it may compound any problems, coz if it is pressurizing, the build up will have to vent somewhere, and could blow a gasket or seal ?

yeah, i realize that. just thinking about a way to cover about 250kms, preferable without leaving an oiltrail ;-)

otherwise i just have to tap the oil every 100kms from the draintube at the bottom of the airbox.

i just stopped raining, good moment to check the venthoses....

2bc-ed..

cheers,
sander

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Sanderd,
Just a thought.If you're worried about to much oil venting into the airbox, why don't you route the breathers into a temporary catch tank?
Mark

I'd say this is the way to go - I've done it on old Brit bikes. It can give you a good indication of how much oil is being blown out, and how much is left in the sump! - also keeps it off the back tyre/out of the air box. Use a narrow neck coke bottle and cable tie it where you can easily see it. Obvious, but don't be tempted to put the oil back in...it probably looks like mayo anyway.

Another idea - a blocked breather valve: is there a breather valve in the system - a plastic box on a largish bore pipe emerging from the crank cases? They sometimes stick or clog thus causing overpressure, so the oil travels the wrong way - have had this on Guzzis in the past.

thanks for the input guys.

adding a bottle or such is a good idea. the vent hoses are just hoses, no additional stuff there.

its funny, bike doesn't seem to burn oil, or at least not more than is used too: the exhaust tip is the same color as it is since i replaced my piston/-rings/valveseals 20kkm back in Colombia.

(if that's an indication, its dark grey, where i suspect it to be black when there's too much oil being burnt. is this assumption correct?)

so my primary suspect is still a warped valvestemseal although this should cause smoke from the exhaust, right? i have to check that, but currently i don't think there's excessive smoke from the exhaust. i did notice that the intake channel of the secundary carb was pretty black/oily when i took off the carb a while ago. bad news?

will see tomorrow. its still pretty cold down here. i liked the tropics more!!

lucily i'm not at a timeschedule, i can linger around till it gets summer in Patagonia!

saludos,
sanderd

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hi had the same thing happen to me coming back thought france in august .I believed i was checking and filling the oil ok , any way took right hand side clutch cover off just to have a look and also helicoil the two top oil filter bolt holes found the oil seal that the crank goes into slightly disloged and the metal plate on it marked by the nut on the end of the crank so replaced with new seems better but im not sure its fixed it 100% yet .had a leak down test done by a mechanic when i had my mot he said it was good no leaks from the valves or airbox As you said seems to go as well as she ever did still a little oil in air box its a puzzle? steve

i connected a tube and bottle to the draintube of the airbox which saves quite a bit, but oil is leaking out the airbox, oiling my exhaust and rearbrakedisc... apparantly airbox is air, but not oiltight.. (?).

managed to find 3 new valvestemseals and i'm inclinged to take off the cilinderhead to see what's going on. a while ago i took the carbs off to solve overflowing of floaterbowl and i saw the intake of the 2nd stage carb all black, which makes me believe that the problem is the valvestemseals.
but i replaced them about 22kkm ago, after 60kkm. which is weird, valvestemseals shouldn't wear out that quick. Is there an underlying problem?

am in Bariloche, seems ok to hang out here for a few days. and there's at east three workshops in town.

cheers,
sander

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hi all,

well, i replaced piston rings and valvestemseals in Bariloche and thought that was it. NOT!! Ushuaia the problem returned. Oil from airbox and compression loss.. The cilinder looked very smooth, piston also, so i suspect the aftermarked rings (couldn't get original parts in short notice) are made from crap material.

...i really shouldn't have have choosen for a oversize piston in Medellin ;-(


So, as Mark suggested, i'm riding around with a sodabottle and tube from my airbox. Works, sort of, still have oil leaking from the airbox on my exhaust, on my rear brake etc. which is a bit messy.

Need to repair it again. Am in Bahia Blanca at the moment anyone can recommend a workshop?

Thanks,
sanderd

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Hi Sandred
My TTR also had an oily inlet on one carb. I was told this is normal.
Might be worth checking with Dave Lambeth before any further work.
good luck

hi any up date on your oil in air box problem did you fix it if so please tell as im still puzzled as what to do next.As i said ive had a leak down test done 100 psi at tdc losing about 10 psi which i was told is normal for a good engine and she seems to go as good as ever. I only fill up to top of glass sight in oil tank when shes hot after a run so thats only about half way up on the dip stick so it is not over filled but still leaks mind you it oils the chain nice but i want her back as she was as this problem would hamper me doing big miles thanks steve

hi,

i'm back in Holland, with my TTR. Did a lot of maintenance on it in the past weeks. As for the oil spill through the breather hose:

removed the topend and the piston had a lot of blowby marks. Also LOTS of carbon/ burnt oil inside the cilinder head and on the piston, probably the reason why i ran like crap. Definetly one or two valvestemseals were gone.

took cilinder and piston to a motorcycle shop and they measured the play between cilinder and piston. i was almost at wear-out spec. The piston didn't had significant wear marks. The cilinder was oval instead of round and way to smooth. accoording to the mechanics. (i always thought the smoother the better, but apparantly not...)

So i let them bore and hone it to the 2nd oversize (already was at the first), cleaned out the carbon in the head, polished the valveseats, put new valvestemseals on and put the whole thing back together.. Didn't do a proper testdrive yet, because my rear shock decided to start leaking oil after i cleaned it, but the engine runs very smooth.

I used compressed air to dry and clean the shock and probably ruined the piston seal Be careful with compressed air guys!

So, in short, as of yet i don't know it the problem is fixed, but i'll let you know. Will do a 500+ km ride this weekend.

cheers,
sander

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hi is your bike sorted now hope so enjoy lots of fun miles im trying to work out the differences between my bike and your bikes symptons mine seems to run as good as ever, starts 2nd to 3rd kick neally every time, ticks over nice ,leak down test when hot 100 psi only losing 10 psi which ive been told is normal for a good engine which should indicate rings are good ,no leak sounds from air box or exhaust which would indicate valves are sealing good ? reading taken at tdc maybe wear further down the bore ? have taken the 2 engine breathers off no obstructions could there be a obstruction in one of the external oil lines? or oil tank? as i said before i took the clutch casing off to helicoil the top 2 oil filter housing screw holes and noticed the oil seal that the crank shaft goes into was dislodged so replaced with a new one i dont know no what to try as ive said apart from the oil in air box issues im happy if i can just find out what it is and put it right thanks steve