Installing Bearings

[SuperRat01]

Hey guys, I am going to install new bearings in my Super Rat bottom end. I have access to liquid nitrogen, I was wondering if this would be a good alternative to freeze the bearings for easier installation? (I would submerge the bearings in the LN2) Thanks, Linc

[thrownchain]

Doesn't freezing them in Nitrogen make them brittle? Freezer would be fine.

[tvrc18]

Heat the cases and throw the bearings in the freezer over night and they usually just drop right in. I use my gas grill to heat the cases or you can use a torch.
Terry

[Bullfrog]

You'd be breaking new ground in the history of Hodaka maintenance. Since standard freezer temps are adequate for this particular situation, I'd lean toward saving the liquid nitrogen for some other fun thing.

Don't forget to put a back up block directly under the bearing boss when pressing/driving the bearings "home".

Ed

[---]

Liquid nitrogen is used for cryogenic steel treatment, like brake rotors. I would not want to do that to bearings that are, supposedly, already hardened correctly. I would not trust the bearings if subjected to that kind of cold. Not to mention that if you did that and then dropped them into the cases, you would be shock heating the outer race at least.

No, I would not try it.

[socalhodaka]

Like Ed said or this could happen

[socalhodaka]

It can be fixed


Thanks Charlie Robinson

[thrownchain]

But it is an extra cost to fix what you don't need to break.

[---]

Using liquid gas cooling is an interesting notion, but not practical for this purpose. After posting that it would shock the bearing to drop it into even a room temp case, it occurred to me that it might also shock the aluminum case. Photo above is case in point. Oops.

What I would avoid is an extreme in temperature differential. Freezing a bearing to maybe zero, and heating a case to perhaps 200 gives a differential of 200 degrees. That's a lot. Since the bearings can, in fact, be installed without heating and cooling, a more extreme differential is self-defeating, I think.

Thanks for the photo example...

[---]

But it is an extra cost to fix what you don't need to break.

Amen. I once tossed a rod through the engine case of a VW Beetle. Okay, so I was doing in excess of 85mph for more than five minutes. Point is, the cases were successfully repaired by helical-arc. Luckily, I had an expert welder just around the corner, and he fixed the case for ten bucks, but that was in 1972. The fault was mine for installing two pistons backwards. Wrong thrust angle, high rpm, boom. Live and learn. Eventually, the Beetle would do 107 mph. It wouldn't stop at that speed, but what the heck.

[dcooke007]

After wondering if the bearing was seated and giving it one more whack....broke bearing stop also. But just once in my life time so far.

I have a large toaster oven with timer, digital temp control and convection cooking that I use to cure my engine coatings and install bearings. Heat cases to 275 degrees for 15 minutes and bearing will almost fall into place. No real force to install bearings and no more broken bearing stops. Also no need to freeze bearings.

Danny Cooke

[SuperRat01]

Ok....after reading your comments, it sounds like my idea is maybe NOT a good idea. The crane crew here on base will use cryogenics to install bearings so I thought it sounded like something worth trying. However, maybe not for motorcycle bearings. I will stick to the standard practice. But, more importantly, GMc , you actually got 107 out of a Volkswagen Beetle!!! WOW, that's amazing!! I've had Bugs my whole life and when I was in high school I had one that would do 88 mph down one of the local bridges. You just crushed me...I thought I had something. Linc

[---]

The only thing stock in that Beetle engine was the crankshaft, and then, only because at that time I could not afford a stroker or forged crank. 300cfm Holley, high lift cam, valve springs to match, headers, opened the ports a bit, 1,600 cc kit on the original 1,300 engine. Actually could spin the tires in second gear, and once, for some reason I couldn't understand, a guy in a Pontiac sedan with a 400 CDI V8 decided he could outrun me light to light. He couldn't. Maybe it was the racing stripe on the Bug that offended him. Anyway, he got the jump, and that was all he got.

I later put that engine with a shortened chassis into a kit car called the Vokaro. The whole thing was around 700 pounds. I never got to run it full speed because the tires were out of balance and I ran out of spare time to fool with it, but in second gear it fish tailed from line to line down the blacktop. The tire were spinning so freely it didn't even squeal, it just made a whizzing sound. Probably good that I didn't find out how fast it would go.

But as I said, with stock drum brakes the Bug would not stop at high speed. The brakes just fluttered until speed dribbled down to about 60. Fade was instantaneous at over 100, so it wasn't safe by any means, but it was a hoot.