Crank bearing question

[trimoto.125]

Is it ok if I put bearings with the side ball bearing covers in my crankcase sides for my crank? I was thinking it could be a problem and just wanted to know :TrikesOwn

[Vealmonkey]

If what you are referring to are sealed ball bearings, that would probably be a problem. The reason why the factory doesn't used sealed bearings is so they can get lubrication. I'm not sure where you would find sealed bearings that would fit your crankshaft, but I guess it wouldn't be that hard.

[trimoto.125]

They have the crank bearings for my trimoto 175 at Princess Auto. I didn't find any other places that had the bearings around my area. I will see if I can pop the side covers off. Would that be better if I did?

[old-yellow]

bikebandit list them for sale, the link is for the year of my trimoto but they all use the same crankshaft bearings, if you want you can look your own trike up.

Here's the link.
http://www.bikebandit.com/houseofmotorcycles/yamaha-atv-yt125j-1982/o/m8780

[Nick_R_23]

They have the crank bearings for my trimoto 175 at Princess Auto. I didn't find any other places that had the bearings around my area. I will see if I can pop the side covers off. Would that be better if I did?

As long as the bearings are the same as the ones originally on the crank, you can use them. Those dust covers will pop right out with a small screwdriver. Just as Vealmonkey said, you dont want bearings with covers on your crank, because the cover prevents them from getting any lubrication.

Also, since they have covers on them, they are most likely packed with grease, which you would need to clean out before you used them in your engine.

-Nick :TrikesOwn

[trimoto.125]

Well I bought the bearings yesterday and didn't try yet to see if I can get the side covers off yet lol. They were pretty cheap so its no big problem if I can get them off. So is it a big problem if you grease the bearings? I saw a guy on youtube who replaced his crank bearings and some others on one of his maico v.m.x dirtbikes and he greases them up after they were put in the case.???

[Dirtcrasher]

Remember that bearings are all made the same size but with DIFFERENT tolerances.

Try to get a name brand bearing such as Nachi, SKF (SFK??), Timken etc etc etc. Avoid the no name bearings.......like "CHINA"

I can buy 8 different brands of a 6202 - all different costs and all different tolerances.

2 stroke bearings are lubed by the premix in your gas and 4 strokes get the splash oil from the lower end. Those rubber seals pop out with a tiny screwdriver. There are also "shielded" with a metal side seal. It's just meant to keep out larger debris but it's in no way a water or oil seal and they pop out just as easy.

[Nick_R_23]

They use a different type of grease, assembly lube is what its usually called. It stays on only for a bit and helps lube the bearings/moving parts on rebuilt motors until oil gets to those parts. The grease thats on the bearings you have is meant to stay in there throughout the life of the bearing, just clean it out before you install the bearing on the crank and pour a little bit of 2 stroke oil in the bearing before assembly.

-Nick :TrikesOwn

[trimoto.125]

I'm plan on putting the bearings in tomorrow. They are in the freezer right now. The brand of the bearings are NBR. Has anyone heard of them and are they good or bad?

[Dirtcrasher]

^ Those will be just fine, it's the no name brands or "CHINA" that need to be avoided.

Lots of time the bearings we buy are the same ones manufacturers actually used in assembley.

[trimoto.125]

Ok cool. I took the dust caps off and I'm not sure what I should do about the grease inside? I might put the bearings in today if not tomorrow.

[Dirtcrasher]

This is a 2 stroke correct??

If so, I'd gas or carb clean wash that grease out of there and just lightly oil them with the same premix your gonna run.

Don't lose any sleep over it, a bearing is a bearing. They have different applications that don't require tight tolerences. And they can be used in ANY application, some want the bearing to be "permanently sealed with grease", some bathed in oil (like a 4 stroke) and others that use the 2 stroke premix as a lubricant.

I will say this: Not only since I was a young dumb kid but till now that I'm an old and dumb adult, I find it AMAZING that the teenie tiny amount of oil in the premix is enough to lube the crank bearings. It never made sense to me and still doesn't but it seems to work!! :D

[trimoto.125]

Yeah the bearings are for my trimoto 175. I guess I will clean the grease off the bearings and put the cases back together, I think I might put like 50ml of some 2 stroke oil in the case before I put the top end on. Is that alright or is 50ml to much?

[Nick_R_23]

Cant really picture how much 50ml is in my head, but before you assemble everything, just pour a thin layer over the crank bearings, rod bearings, etc, and assemble it. That will be enough to lubricate everything.

-Nick :TrikesOwn

[trimoto.125]

Alright. Thanks for all the help and advice from everyone who responded.

[1BFC]

30ml is a tiny bit over 1 oz.

50ml is around 1.7 oz

[trimoto.125]

The crank bearings are in. I plan on putting the cases back together tomorrow.

[Dirtcrasher]

Just a tip:

If that crank shaft doesn't slip in easy, your gonna have to get creative and "pull" the shaft into the bearing on each side or you risk knocking the crank out of true and or damage to the bearing.

On many models, either side of the crank shaft halves are either threaded internally or externally. If you use those threads and cut collars out of pipe, EMT or copper tubing along with the right sizes and washers, you can get it done.

90% of us do not have the right OEM tools, but being creatve is just as well! Just understand that spacer you use to "pull" the crank in has to slip OVER the crank shaft, yet only touch the bearings inner race. That way there are no sideloads on the bearing.

What I'm getting at is the worst thing you can do is just put the crank a bit in each halve and bang them together. I like to "pull" it into the right side dead on and then use a combonation of homemade stuff to "press" the left side over the crank without stressing it or damaging anything!

When in doubt, get some help! or follow the service manual.

There's a reason why these motors lasted 20 yrs and it's not because someone got lucky :D

[trimoto.125]

Ok got the cases put back together.Just need to bring it to the shop tomorrow to get the clutch basket removed to put the gear on that is attached to the crank.

[trimoto.125]

UPDATE. I put it all back together runs like it used to(good) I am having problems with the clutch I think. The clutch has a 16 ball chamber and I put 8 bearings in 1 ball ,space ,1 ball etc.. I can feel the clutch grab slightly when I change gears but it won't move under its own power. I had it in 3rd and I moved for about 4 ft then I shut it off cuz it was barely moving. I have the clutch adjust ment bolt threaded ALL THE WAY TO THE POINT WERE IT GETS TIGHT. I didn't even back it up 1/4 or or anything. Is having only the 8 clutch ball bearings the problem or is it something else. It also grabs in all gears when its not running.

[trimoto.125]

Update: I fixed the problem I put the other 8 ball bearings in for the clutch and realized that one clutch friction plate and one pressure plate were missing lol. Its back together running and driving now. I still might have to do some small clutch adjustments though. I haven't driven a trike for a year now..but that will change soon.