Ace 100 mainshaft

[Jakefoo]

Hi all, working on a 69 Ace 100 basket case. I was wondering if the main shaft gears should drop into the right case bearing or is it a tight fit?
Same question with the countershaft on the left side. Should it drop right into the bearing or be a tight fit?
Thanks

[Dale]

They should slide in easily. Be sure to use either transmission lube or assembly lube.

[Al Harpster]

Absolutely should slide into the bushing.

On one occasion I had to "finesse" the spline end of the main shaft through the inner race of the ball bearing.

I think I pulled it through with the Main Shaft Nut. I may have used a socket as a spacer or collar around the threaded section, put the nut on and gently tightened it.

I had a Very slight interference through the ball bearing. I also put the shaft in the freezer for an hour or so before assembly to shrink it.

[Jakefoo]

Thanks for the reply. When i put bearings into a case half i heat around the outside of the case and put my bearings in dry ice. They drop right in.
When i went to put the mainshaft in it was a tight fit. The shaft would stop on the bearing about half way in. The main shaft looks fine. Splines are straight. No mushroom on the end. So since i had some dry ice in the cooler still from the bearing install i used it on the mainshaft. After about 30 minutes i tried again and it dropped in. I havent tried to pull it back out yet but im guessing its in there for good.
The countershaft drops right in on the other case half no problem.
Bushings arent the problem. Its the inner bearing race for the mainshaft that im wondering about

[Jakefoo]

I just went to see if i could pull the mainshaft out by hand. It aint budgin. Spins fine and clears the case side wall. But it is definitly not a drop in and pull out of the inner bearing race kinda thing.

[dirty_rat]

All of my engines the shafts have been a easy slip in fit. If you are having problems with both bearings, could it be the bearing inside diameters were slightly undersized? Did the shafts come out of the old bearings easily? If so, it sounds like the new bearings, not the shafts.

[viclioce]

I’m with dirty_rat. The ID of the new bearings must be a bit smaller. If you got them from Terry, I’m sure he’d exchange them. If you didn’t, they may be an SAE diameter instead of metric??? Victor.

[Jakefoo]

I got the engine in pieces. The mainshaft was already out of the case. Ive always been partial to NTN bearings which is what i used. 6203 c3 bearing.
Shaft is all the way in, spins fine and clear. Primary gear on the other side goes on smooth and bolts up.
Ive talked to a couple of well known Hodaka engine builders who told me they should just drop into the bearing. But it shouldnt hurt anything if the mainshaft is seated in the bearing. Only problem will be removing it if i ever need to. Which i hope i dont.
However, my obbsesive cumpulsion disorder is making me want to drive out the mainshaft, get a new one from Terry, get a new bearing and try again. If im going to do it now is the time.