What shoud these be replaced with?

Ive heard varying reports of new replacement ones failing, or of people fitting 2 single ones each side.

Whats everyone using?

Thanks

I have always fitted stock Dowty type lip seals, and never had any problems.

Wayne...

I think you will find you have an early motor here - and certainly the club foot rear silencor will not belong etc ( may hit shock when you try to fit)

As far as seals are concerned. When you strip - if early motor it will only have 1 single type oil seal in each seal carrier - so just replace with a new one each side.

If it was a more modern motor the Bultaco original is a double lip affair on both sides and two single seasls - back to back are your best option.

Sorry for confusing things, wrong bike was in the pic, it is the later type 199, that blue one has been put on the long finger for the moment,

one money pit at a time

1977 model 199 Sherpa there for sure, (missing a few items like airbox and front mudguard fitments I see) they had twin lipped oils seal carriers fitted, as John Collins says, fit two seals each side and back to back will suffice. Bultaco supplied a wide twin-lipped type seal, but I'm not sure how these are sourced nowadays. Try Bultaco UK.

I have found that crankcase seals are a very important nay critical component on a two-stroke motor, any leakage and the bike runs like a dog.

My model 80 (not the twin-lipped seal fitment) used to smoke like crazy, misfire, do all sorts of things when the clutch seals were needing replaced. Everyone used to say, "no it'll be the timing side seal going as they don't run in oil", it always turned out to be the clutch side seal that had given up. However I used to replace both sides just to keep her running sweet!

Big John

Edited February 2, 200917 yr by Big John

I don't know what other bikes are like but I found the Butlaco seals to be relatively easy to replace. Sure you have to pull a few things off but once you get to the seals it's straight forward.

Thanks for the replies, what size seals shoud be used?

I don't know what other bikes are like but I found the Butlaco seals to be relatively easy to replace. Sure you have to pull a few things off but once you get to the seals it's straight forward.

Got to agree there Dave.Pretty easy job,only hassle is having to take the clutch and primary chain off with the flywheel.

On my Husky scrambler the right hand seal is inboard so if it goes the cases have to be split to change it.Needless to say the last time I had to split the cases for gearbox work,I changed the seal anyway.

Thanks for the replies, what size seals shoud be used?

You mean if you want to buy them from somewhere other than the Bultaco dealer?

Dunno. You can always take out the old ones and measure them.

Use a non-detergent oil and the seal will last much longer.