See full version: Symptoms of bad crank seals
In my experience a left side (ignition side) leak will cause your bike to run lean. If its bad it can run very lean and potentially seize. If you take the flywheel and ignition off you can sometimes see it leaking oil. Some bikes you can replace it from the outside, some you have to replace from the inside which sucks cause you have to split the cases to do it.
A right seal leak I've never had, but I understand that this is a wet seal between the crankacase and the gearbox. So when it leaks the bike sucks in oil which causes the bike to run rich - I think. more
There's a good thread or article on eric gorr's site about this. I was just reading it, but don't remember exactly where. [links]
A couple of plates and a $3 pressure gauge is too much money?
actually, its not my bike. its a bike i may consider for purchase. older 125cc dirt bike, 70's, rare, honda, and i just wanted to inform myself before going to check it out.here
TRY THIS TEST AT YOUR OWN RISK, I HAVE NEVER TRIED IT ONLY READ ABOUT IT ON THE NET-
when idling, use an unlit propane torch, and try sending some unlit propane behind the flywheel, if the idle goes up, you're sucking in air. more
actually, its not my bike. its a bike i may consider for purchase. older 125cc dirt bike, 70's, rare, honda, and i just wanted to inform myself before going to check it out. [links]
High output engines that have significant air leaks will usually run fine so long as the rpms are kept low. This accounts for why many freshly assembled engines operate well during the break in period, but seize the first time the throttle is hung wide open. Piston seizures related to air leaks are not just a result of an engine being run with an air-leak, but rather a result of the engine being run at close to maximum output with an air- leak. here
B) Seal off the exhaust port with an automotive expanding rubber �freeze plug�.
Where to Look for an Airleak here
A) Seal off the intake manifold with a plug or rubber gasket
F) If your gauge shows a leak, spray the gasket seams and seals on the pressurized motor with WD-40. The WD40 will make visible bubbles, and a leaking sound, when you spray the leak point. more
Not sure what is going on. I guess I will tear it down and check evrything out. I have never done anything this big to a boat motor. I do have 2 shop manuals so that should help. Question is is it as bad as it sounds to tear everything down?? Estimated time on how long this might take?<br />I know I will have to get a gasket for the tear down. Anything else? I might need? Should I replace the reeds while I am at it?<br />Have hdd motor for 2 years only but I imagine everything on this unit is original equip.<br /><br />Thanks for any advice. more
Wkoch<br /><br />If lower seal IS your problem, its replaceable without disassembling a lot. Pull powerhead. A couple of bolts underneath ( 6 I think ), and two nuts above, at sides of powerhead, a bit tricky to get at.<br /><br />You dont need to strip powerhead. Lower seal carrier is held by three small bolts. Seal ( $ 20 ) is easy to change, remember to clean everything and check oring around carrier. Clean up end of cranckshaft if needed. Then back on.<br />No big deal if you have a manual and go step by step. UU I tried to mail you a photo, but got mail back - new adress ? [links]
On a 2-stroke the crancase is a part of the air/fuel mix flow's way to the combustion chamber. If not tight the cylinder will not fill/exhaust properly which will lead to reduced perfomance and other running related issues.<br /><br />Strange, however, that no oil or fuel is visible as the crancase pressure would force a little amount out if the seal is not tight? Could it be that it comes out in a way or place that you cannot see?
Re: Lower Crankshaft seal bad?? more