Help Santa get the PW-50 started in time.

[CR REV]

OK, I need help!!! The 94 PW50 that used to run doesn't. It has 80lbs compression, good blue spark on the start mode and no spark on the run mode. The choke is not functional (tried manual choke) but I have gone through the carb and I don't think its a fuel problem. Won't even cough even with starting fluid. New plug and tried a different cap. Air filter is off.

How much compression should a PW 50 have?

I am getting my hands on an organ donar PW tonight and will swap the coil. Any other ideas?

Thanks

 

[bluerider125]

nope. sounds like an ignition problem to me, and GOOD LUCK, SANTA :p

 

[CR REV]

It's not the coil, and the running bike has the same spark pattern. good spark on start and mild on run. Back to compression.

 

[rickyd]

Have you looked into the switch itself?? Maybe try and bypass the switch and see what happens, good luck Santa :thumb:

 

[bluerider125]

i must have read it wrong, i thought you said "no spark" on run. oh- it does(in your original post) i thought maybe the ignition "map" was gunked up or something, but it doesn't even cough when you have spark. this is a weird problem. :think:

i don't have any experience, but 80psi sounds good to me. so that leaves only fuel, but you said you thought it was OK. hmmmmmm...:think:

 

[CR REV]

Well, my son was thrilled with his really clean, non-running, Pw 50 this morning. It took him a while to figure out why I gave him a liter of yamalube for Christmas. We took the cylinder off today and looks like its compression. The rings are worn. I don't have a manual but I'm sure they are past service limits. I just hope I can find a topend kit and gaskets at a local shop tommorow. 80 lbs sounded good until a tested the old yellow bike and it had about 40lbs more. I will know for sure after I install the the new topend. I sure wish topends were that simple on the big bikes 3 bolts exhaust, 4 bolts head and cylinder, remove parts.

Thanks for the ideas.

Merry Christmas and God Bless

 

[Jasle]

sorry too late to help but I'd agree that 80 was too low for a pw. probably more like 150 or so. Another common problem is the exhaust port clogging up. Use motol 600. About the only one I have not had carbonize in the exhaust port. Even yamalube carboned up the port. Especially when the exhaust restrictor was installed.
Also with out the air filter even with a choke the bike was extremely hard to start. I had to use carb cleaner ever time to start it when cold. Once I added a filter it started fine on its own. While your at it swap out the 70 main jet for a 65 main jet.
Also check out this link http://www.mxeast.com/motoprof archive/pw50.htm some good info on pw's