Did i ruin my engine?

Kreidler MP-9; General Knowledge Question

Recently, my first gear clutch pads fell off, probably due to heat. While waiting for borrowed clutch tools to come in the mail, I swapped out my bottom end with one I had laying around. However, this alternate bottom end was previously seized up; I got the crank to move by soaking it in PB Blaster as advised. I figured 'eh, let's give it a go and see what happens'. I made new gaskets and put my top end on it. I remounted the alternate MP-19 engine..... and, it was loud as hell. (I also swapped out the magneto because the old one was removed and sold).

As it turned out, the crankshaft bearings were bad; there was some play in the shaft of the crank, which I know is bad. It was also timed incorrectly-- but, no matter where I had the stator plate, it made no difference in performance.

I rode the bike a little here and there, and some this morning to go get a bite to eat (Chicago downtown). It ran very poorly, and stopped running about a mile away from where I live-- just walked it back since the pedal chain is not hooked up.

I took off the top end, and looked at the internals-- not good. Some of the chrome on the inside of the cylinder is gone (worse than before) and the piston is scored pretty bad-- to the point of making the rings stuck so I can't rotate them. Is it salvageable?

Also-- should I look into another, different-branded engine maybe? This shit breaks all the time, or has weird problems... I've spent sooo much money on this thing, some of it due to learning / stupidity, but I'm stuck. Again.

For further thoughts-- I have a kitted Hobbit which doesn't run (needs tires, tubes, points, condenser, H/T coil, lights. Has a plate / sticker) as well as some spare Kreidler stuff. Very little spending $. Any thoughts?

Additionally, I have a spare Kreidler piston-- but it's the wrong size, and the rings are stuck / broken.


Thanks. (edited)

Re: Did i ruin my engine?

Looks like the wrist pin clips let go more then anything. Deffinitly not worth messing with that piston.

Re: Did i ruin my engine?

yea that's pretty done for. the condition of the cylinder's gonna be more important in terms of running it again, if the cylinder's scored that bad it's a lost cause. if not, you can try gotting the rings off and smoothing out the piston and the ring slots. take the ring off and pu it into the slot on the piston and roll it around it to make sure it doesnt catch anywhere. also swap the top/bottom rings so the scored gauges don't line up. might work again.

As far as the hobbit, make that work! brand new ignition's 90 bucks. you could score a used point setup for probably under 50 on buy/sell.

for the rest you could if you're feelin crazy cheap, swap on the kriedler's tubes & tires or i'm SURE someone around Chicago has some trash spares laying around. same goes for lights.

Re: Did i ruin my engine?

Doug Wilhelm /

Thanks for the advice!

I've got a hook-up on some Kreidler parts, so I'll have to wait and see how that works out.

I am thinking of buying the ignition parts I need for the Hobbit and trying that out-- I will probably swap tires out if I do that, or use a buddy's set from his non-running Hobbit.

I also have a few spare pistons, but they're both shot / rings are stuck. Are stuck rings (not broken, just gooped up) usable? I have a cylinder + good piston, but it has one broken ring and one stuck ring.


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