Scooterotica

I'm rebuilding my lower end (not the tranny) & top end on Jet/SX cases with new everything. New bearings, seals, MEC black crank, etc. All quality bits.
I've run into something that concerns me and I'm wonder if I'm being paranoid. It's been over a decade since I mucked around this deep in a Lambretta.

After I put the mag side back on (stator not in yet) the crank was a bit hard to turn. I was able to push it (by the con rod) a bit and it could be turned with a little effort. Not too concerned, but not real loose ether. "Just new bearings" I thought. "They need to settle in a bit and loosen up". However, I did have a hell of a time getting the drive side bearing in. The "freeze the bearing & heat the case" thing didn't work out too well and the bearing kept getting stuck in at an angle. I'd bang it out with a hammer and a piece of wood. I was finally able to get it in by using a rented drift. That worked perfect and quickly.

I got all the bits / chain / sprocket back in the chain case side and torqued everything correctly. Crank still turns with a little effort.

I buttoned up the chain case and now the crank is REALLY hard to turn. I don't hear any scraping inside the chain case, but again, I cant' turn the crank fast enough to really get it going. I don't' hear any grinding or scraping at all actually.

Any ideas / suggestions before I take the chain case cover back off? Will it loosen up on it's own with a little use? Is it possible I fooked up the drive side bearing banging on it? I was very careful not to hit it on the inner ring.

I'd hate to get the whole rebuild done and have the engine come to a screeching halt 3 seconds in.

Thanks in advance for any suggestions / tips or ideas.

could be just the newness of the set up- or you may have damaged the main bearing with the "angled" insertion.

You could run it and see, but that thought will always be at the back of your mind.

I'd be inclined to strip down and replace the main bearing just in case

Chris

strip again bet your oil seal has turned the spring out, it needs to be reasonably free to turn with just a little resistance from the oil seal,check this before fitting sprocket and chain also dont hit the crank in use a tube that fits over outer bearing cage and weld a large washer over other end and use a bolt to pull crank thru bearing while turning it repeatedly. make sure you lube crank and oilseal b4 fitting as well.

Is the spring and retainer on your front sprocket seated correctly, there's not a lot of clearance from the chain case to the bolt, it could be fouling there.

Sounds like a pinched oil seal.
use the shaft that the front sprocket goes on,and the bolt to pull the crank in!And turn the crank a few time as i do it! (not the correct tool but it works)

Just thinking . . . you haven't fitted a 60mm MEC EUR crank have you?

The crankcase needs relieving or the big end boss rubs if you have.

Thanks everyone for your replies. Nope, I have the 58 Mec crank, not the 60, but that was a good point to make. I'll check all the things suggested by y'all. I've got a spare seal and I'm ordering a new bearing now. Then it's off to the garage with high hopes.

Chris, I know the gentleman who built up that motor. He lives in Bakersfield, California here in the States. I can put you in touch with him if you like. He told me there are a couple of unconventional "tricks" about the motor that most would not think about or recognize.