Posts
36
Joined
10/16/2016
Location
AU
Hello, I need some help with my 1992 PW50 that hasn't been used in around 8 years.
I think before I stopped using it I had topped up (probably over filled too) the transmission oil with normal 2stroke oil, which I found out later was obviously wrong. It was dripping a bit of oil for a while but I think it still ran fine at first. After a few rides it started to blow way too much smoke and that's when I let it sit for years.
Now I have got it out again to get it running if possible or just get rid of it.
I checked the fuel tank and lines which are fine. I cleaned out the little petcock filter which was full of rubbish. Cleaned out the carb and put it all back together. The oil pump is still there but not used, the bottle is gone and need to premix fuel. Put some mower fuel I had leftover in there today just to try it and it started after about 10 attempts.
First problem is the excessive smoke. Thick, white smoke. While it idles it blows about as much smoke as you should see but it gets crazy when you rev it and clouds up. There is also a small amount of oil leaking from the plastic cover (with Yamaha on it) on the left hand side, where there should be no oil. From what I have read a blown right side oil seal could cause excessive smoke. Is it possible both the seals are gone in mine? Possibly burning some oil causing smoke and also letting some get over to the left side?
Second problem, also used to happen but might not have been as bad, is that at times the bike would start to rev by itself. Could that possibly be caused by the above problem or something else?
It died on me a couple times too while idle. Had to put the choke back on at times to keep it running.
There is also a little ringing/rattle sort of noise that sounds like it's coming from something in the top end, that was there when I bought it. I think the previous owner told me he had just had new rings put in, or possibly it needed new ones... can't remember. Seems common on the pw50s with some people saying it caused no problems and others saying that a new top end stopped the noise. Similar to this noise:
I'm a complete beginner so any help would be greatly appreciated.
Thanks
I think before I stopped using it I had topped up (probably over filled too) the transmission oil with normal 2stroke oil, which I found out later was obviously wrong. It was dripping a bit of oil for a while but I think it still ran fine at first. After a few rides it started to blow way too much smoke and that's when I let it sit for years.
Now I have got it out again to get it running if possible or just get rid of it.
I checked the fuel tank and lines which are fine. I cleaned out the little petcock filter which was full of rubbish. Cleaned out the carb and put it all back together. The oil pump is still there but not used, the bottle is gone and need to premix fuel. Put some mower fuel I had leftover in there today just to try it and it started after about 10 attempts.
First problem is the excessive smoke. Thick, white smoke. While it idles it blows about as much smoke as you should see but it gets crazy when you rev it and clouds up. There is also a small amount of oil leaking from the plastic cover (with Yamaha on it) on the left hand side, where there should be no oil. From what I have read a blown right side oil seal could cause excessive smoke. Is it possible both the seals are gone in mine? Possibly burning some oil causing smoke and also letting some get over to the left side?
Second problem, also used to happen but might not have been as bad, is that at times the bike would start to rev by itself. Could that possibly be caused by the above problem or something else?
It died on me a couple times too while idle. Had to put the choke back on at times to keep it running.
There is also a little ringing/rattle sort of noise that sounds like it's coming from something in the top end, that was there when I bought it. I think the previous owner told me he had just had new rings put in, or possibly it needed new ones... can't remember. Seems common on the pw50s with some people saying it caused no problems and others saying that a new top end stopped the noise. Similar to this noise:
I'm a complete beginner so any help would be greatly appreciated.
Thanks
Have used the kits on many PW's ,as well as the knock off carbs. They work fine.
If you have a flywheel puller, about 2-3 hours, for less than $100 in parts, it should run. There is not much else to them. Provided it is not just in terrible overall condition.
I have heard new top ends on these little bikes give a little rattle within minutes of replacement. If compression is really low, they won't start, or if they do, will run real weak. This one had a little tingle, but still ran well.
The Shop
Should I replace the transmission oil with the correct amount/type and see if it makes any difference? As long as the transmission oil isn't completely drained, is there any risk of further damage by running it for a couple minutes?
Is there anything else I can check or a way to be sure it's the crank seals without having to remove the engine?
Project Racer, do you think the clutch cover gasket needs to be replaced or do you just recommend doing it while the engine is already out, even if the current one appears to be fine? There is no oil leaking on that side. I can get an engine gasket set (7 pieces) for $10 so the cost isn't an issue.
I haven't replaced the old air filter or spark plug yet, was going to do that if/when the other stuff gets sorted out.
If I don't replace the top end just yet, will it just eventually stop working or could it cause more damage if I let it go?
Do you think the wrong transmission oil damaged the seals (or anything else) or have they just gone with age?
I don't know if the previous owner tightened everything up way too much or if it's just with age but I think just removing everything on this bike is going to be a major hassle.
Cheers
This bike has had the spark arrestor removed. I had a look in the end of the exhaust and it's wet with a small (oil?) puddle. Tried to get a photo but it wouldn't show up.
"Exhaust pipes, mufflers and ports on two-stroke engines should be cleaned according to manufacturers specifications. Excessive build-up of carbon causes loss of power and excessive smoke emissions."
Any chance a badly clogged up exhaust could be the cause or is that wishful thinking? If I remove the exhaust should the bike still be able to start/idle to eliminate that being a problem? I know it won't run properly, just to see if the smoke changes.
I'm going to need a steering bearing kit (hopefully that is all it needs) too as there is movement when I hold the bottom of the front forks. Can see the crack in this photo:
Project racer, do you remove the oil pump setup on any of your ones?
Sorry for all the questions, I'm in over my head!
Post a reply to: PW50 help