crankshaft seals on 1985 fourtrax

[paulpic]

Hi all.
Here in Australia i have a 1985 model honda 250cc quad bike 4 wheel ( i think they are called fourtrax in the USA).Anyway when i remove the gearcase filler plug i get lots of blowby coming from crankcase so i suspect the crankshaft seals are worn .Can these seals be replaced by just removing the side covers on the engine in the bike or does the whole engine need removing,stripping and seperating.

 

[roscoFJ73]

Hi all.
Here in Australia i have a 1985 model honda 250cc quad bike 4 wheel ( i think they are called fourtrax in the USA).Anyway when i remove the gearcase filler plug i get lots of blowby coming from crankcase so i suspect the crankshaft seals are worn .Can these seals be replaced by just removing the side covers on the engine in the bike or does the whole engine need removing,stripping and seperating.

I would have thought it more likely to be compression leaking past the rings. I would compression it test before going any further.