So this is odd.

[Jpeezie]

Pulled the engine out of my blaster today and took the jug off. Didn't see any major issues, but had some questions while I figured out my issue.

Should a piston be scratched up like this after a few runs?

This looks like it's missing a bolt... Am I wrong??? And the culprit.

Looks like my stator dynomited in my flywheel... Time for a complete unit from Ricky Stator as well as reed upgrade for now.

 

[Awk08]

no, a piston should not look like that, my guess is your piston to cylinder clearence is out of spec, and that skirt was badly slapping the bottom of the cylinder on the way up

look at the parts diagrams on bikebandit.com to see if anything is missing on that shift shaft
go to oem parts for your bike/year and find the clutch side diagram

and you may need a new flywheel too, do i see some magnet damage too ???

 

[blasterdemon7]

Wow! Did you do a leak down test and a plug chop on the motor? That piston looks screwed.

 

[blasterdemon7]

 

[Jpeezie]

So looks like a top end rebuild then. yeah the flywheel is all beat up. The screws on the lighting coil backed out from what I can tell. I'm going to take the cyl to my work to see what size it's honed to. The company I work for hones and sells tubing so we got all sorts of I.D. Gauge calipers (got a few Starrett calipers myself). Hopefully it's something I can work with.

 

[Jpeezie]

Are parts 7, 2, and 6 inside the case or outside???

 

[mud runner]

Wow! Did you do a leak down test and a plug chop on the motor? That piston looks screwed.

are you sure i think he might be able to re use the piston

 

[blasterdemon7]

You will need to redo the top end. Just be glad you didn't break a skirt off.

 

[blasterdemon7]

are you sure i think he might be able to re use the piston

Just wrap it with duct tape and use it on the next bore.lol.

 

[yamaha28]

are you sure i think he might be able to re use the piston

Nope, that piston is shot

 

[Jpeezie]

Lol the guy that rebuilt it sure as hell didn't know what he was doing. It kinda pisses me off. Oh well it will be built right this time.

 

[mjgnslngr]

those shift shaft parts are internal.

 

[Jpeezie]

Ok, should the shift shaft have play in it???

 

[mjgnslngr]

Ok, should the shift shaft have play in it???

back and fourth or side to side? very minimal play in and out, and no side to side. theres something up with the shaft, i just cant put my finger on it. ill see if i can did up some real time photos for ya.

 

[mjgnslngr]

 

[mjgnslngr]

 

[mjgnslngr]

looks normal enough, just check for excessive play.

 

[Budget_Blaster]

are you sure i think he might be able to re use the piston

SERIOUSLY??????????????????????????????????????????????

 

[Jpeezie]

SERIOUSLY??????????????????????????????????????????????

Hahaha as a paperweight maybe

 

[sicivicdude]

Are parts 7, 2, and 6 inside the case or outside???

All of the parts shown in that diagram are external to the case halves. The Spring washer and spacer sit "under" that plate what's welded on (in your picture) but that's perfectly normal.

Ok, should the shift shaft have play in it???

back and fourth or side to side? very minimal play in and out, and no side to side. theres something up with the shaft, i just cant put my finger on it. ill see if i can did up some real time photos for ya.

The shift shaft is held "side to side" by the washer and spacer (#2 and #6) and the clutch cover. Without the clutch cover on to keep the shift shaft from "shooting out" of the case, it'll come on out until it hits the back of the clutch basket. What you really want to check for is any "up and down" movement. The shift shaft is put through a series of bored holes in the case that are only cut out of aluminum. As it doesn't actually spin, just sort of "rocks", it doesn't need to have bearings but I have seen cases where the shift shaft actually broke out the bored hole and could wallow all over everywhere!

OBVIOUSLY, you need a stator and I would buy a new flywheel just to be safe. A massive failure like that more than likely weakened the flywheel magnetism even if it did no physical harm to the magnet....

You probably need to take that cylinder to a machine shop and have it measured (and probably bored!).