BLOWN OIL SEALS....AGAIN

[lammy mark]

Need some help here... I have, with the help of a great mate, rebuilt the engine for the second time...replacing the oil seals, bearings & gaskets...after about 15 minutes, the oil seals have blown again .... grey smoke from the exhaust, black oil in the end can of the exhaust, bike not interested in ticking over, very hard to start again.

The first time it happened, we replaced the crank to a G.P. 200 one, replaced the flywheel, stator, mag flange as I have an L.I. engine with a Stage 4 175 kit....this time we are stumped.


Thinking it could be a hairline crack in the casing after the accident ???



Any ideas would be appreciated.

[monkey boy]

Hi Mark
I take it your chaincase Breather plug is clear and not clogged up,try blowing through it and clear any blockages.

[RBG]

Is your chaincase breather blocked?
If so as the temperature increases so does the pressure, if the chaincase breather is blocked
the pressure only has one way to go through the seal.

[lammy mark]

The breather plug is clear.... I made sure of that before the first re-build.

[Rude De]

Some of the mishaps Ive encountered are
seal in backwards
the retaining screws too long "everything looks right but the fiber/Halite washer/gasket not crushed" Difference between 12mm verses 15mm long screws
and omitting the washer/gasket entirely also attempted to use sealant instead of
spring on the seal was popped off when inserting the crank
some one managed to find a seal that wouldn't seal on the crank to large of ID
and a crank with a gouged sealing surface that acted like a file reaming the rubber til it leaked
sealing plate warped/gouged/cracked " it was a alloy gp one
bearing not seated and engine warmed up it shifted and started to leak
dust seals without springs at all
shorter "s1?" spring that allowed the crank to float from side to side
Who says all the bodges are in Asia some are done in your own garage

[byron]

...
sealing plate warped/gouged/cracked " it was an alloy one

yeah, these should be avoided.
a mate had his engine built by a very well known dealer who'd fitted one of these.
of course it warped and he had all sorts of running problems til the engine was stripped down and he rebuilt it himself, with a steel plate.

[lammy mark]

...
sealing plate warped/gouged/cracked " it was an alloy one

yeah, these should be avoided.
a mate had his engine built by a very well known dealer who'd fitted one of these.
of course it warped and he had all sorts of running problems til the engine was stripped down and he rebuilt it himself, with a steel plate.

Cheers guys... the plate looks to have been replaced with an alloy one at some stage... it seems to have caused all the problems !!