engine failure today..

[jak stoll]

I had the pin that holds the top ring from rotating come loose & wreck the piston & cylinder :-(

the engine had maybe 1000-1500 miles on it & when I took it apart I noticed a little play in the lower rod bearing so I split the case.... when I did I noticed that the main bearings were generic & in pretty bad shape
Im going to take the crank to my machinist & see if he can do the bearing & machine off some material from the pin side to help ballance it
Ill use all japanese bearings & I was even thinking of using an iron sleeve in the cylinder
I can see the # on the mains I think they are 3202 (common bearing) the lower rod though may be harder
thanks for reading
take care
JAK

[Dave31]

Sorry to hear about your motor Jak

[deacon]

I'm also sorry to hear you had problems. It's a shame to have that kind of thing happen so soon. I think all these engines are a crap shoot. Like a game of chance at the country fair, you pays your buck and you takes your chances. I think I have just been lucky with mine. It could have gone your way just as well.

good luck with your repairs. If will probably cost you as much as the kit.

[jasonh]

Sorry to hear about your motor. Good luck getting it all buttoned up.

Definitely keep track of part #'s and costs and whatnot. Some of the info (especially about the bearings) might be of interest to a lot of people.

I for one would definitely like to see how balancing and better bearings would help out.

[jak stoll]

the countershaft? bearings are 6202FS which just means they have seals on both sides
the main bearings I believe had single shields & that they were put toward the inside which starved them for oil, one of them was really dry there was shields between the main bearings & the flywheels on both sides some of which escaped & got dragged around the inside of the case a bit by the flywheels on both sides :-)
I took pics of the inside of the case & the bearings
there is no de burring at all with the castings so there is allot of potential for case material sluffing off & getting cought up in the piston .....

on the rod Im not sure I think the rollers may need to be measured
I looked very carefully at the lower rod bearings through the slot in the bottom of the rod & they look Ok as well the play in the rod is mostly vertical & not lateral so IM thinking the rod is stretched & that the bearing is Ok
Ill edit & ad pics later
take care
JAK
PS I did get in touch with the supplier & maybe hopefully he can be of h elp somehow
thanks for the condolences :-)

[jak stoll]

I have it all back together & running accept one of the jam nuts (the one that holds on the sprocket lost tis threads as I tightened it
the shaft appears to be fine
I did porting work on the cylinder & de burred everything
just a few odds & ends & it will be better then new
take care
JAK

[paul]

now thats good news

[ran49]

Hey jak: Where did you find the lower rod bearing?I have my flywheel split and no luck finding the lower roller bearing.Also was it any problem pressing the flywheel back together and indexing the shafts? Ron

[General Disarray]

Jak,Also sorry to hear you had that problem. I had the same problem with my 50 cc about a year ago, rebuilt it and it seized up again. My 70 cc and my Titan both run flawlessly. I never could find a cause for the seizure and the consensus was bad porting since the damage was only on the port sides of the piston.
Good job for sticking with it and finding the solution.

[velardejose]

Hi
General Disarray and jak stoll
What fuel/oil ratio are/were you using?
Thanks in advance