Tight crank after rebuild

[Agro2424]

I just got my cases back together after installing a new Vito's +3 crank. I used Boss Bearings, and they felt great after I got them in place. After I got all the screws tightened down, the crank is pretty hard to turn by hand. This was before the seals were in. As far as I can tell, the crank is centered. Dropped some 2 stroke oil down the holes and on the crank. Seemed to help a little.

Is this something that will have to work itself out, or is something wrong somewhere? I don't feel or hear any grinding. Pretty sure the crank is straight. My only guess is the bearings are wider than OEM, or I didn't get them all the way in. Does anyone have any thoughts?

 

[scotj77]

sounds like the bearings might not have sat properly

 

[Awk08]

did you lube the seals ???
might have to use a soft brass or copper hammer to "set" the crank, by smacking it on both ends and see if that helps
if not, split her back open

 

[Wifesblaster]

I just went through this 2 weeks ago on my buddies bike. We used hot rods bearings. Can you turn it with one hand using the flywheel? I did not like the way ours was fitting so i put it in and out 3 times. I everything. Finally we said F it and put it together. We fired it up and now it feels great. It's not the bearings. You should be able to spin it pretty easy using the flywheel, but ours was nowhere near as loose as the stock one.

 

[Wifesblaster]

I guess it's just the way they fit. I froze the bearings and heated the case. They were seated all the way. Every moving piece got luber in premix.

 

[scotj77]

it should spin extremely freely without the piston and top end bolted on. you should feel no resistance besides the weight of the assembly

 

[Wifesblaster]

Well that's bad news for me too then! I tried everything possible to get it loose. We have two rides on it so far. Can some people chime in on this please. I am curious to see what the fix is.

 

[scotj77]

did you keep pressure on the bearings as they warmed up and set to the cases? they can lift themselves out if not held for the first 30 sec or so

 

[scotj77]

if you have ridden it that means you put the top end on. if the top end is on it will have resistance from the piston.

 

[Agro2424]

did you lube the seals ???
might have to use a soft brass or copper hammer to "set" the crank, by smacking it on both ends and see if that helps
if not, split her back open

I did lube the seals, but it was already tight BEFORE I put the seals in. I smacked it on one side trying to get it as centered as possible. Splitting it back open was what I was hoping to avoid. Doesn't look that is going to happen though. lol

I just went through this 2 weeks ago on my buddies bike. We used hot rods bearings. Can you turn it with one hand using the flywheel? I did not like the way ours was fitting so i put it in and out 3 times. I everything. Finally we said F it and put it together. We fired it up and now it feels great. It's not the bearings. You should be able to spin it pretty easy using the flywheel, but ours was nowhere near as loose as the stock one.

My flywheel is currently in Ken OConnor's possession. I can spin it somewhat easily with the drive gear. Yeah, my stock one was very easy to turn too. This concerns me.

 

[Agro2424]

did you keep pressure on the bearings as they warmed up and set to the cases? they can lift themselves out if not held for the first 30 sec or so

Didn't use heat. Just assembly grease with some careful hammering. Probably not the best idea, but they felt flush with the case and spun very smoothly.

 

[Awk08]

try smacking both sides, use a block of wood to protect the threads if ya don't have a soft hammer

 

[scotj77]

well it sounds like you have pinched something, somewhere I would assume its a seal set too deep or bearings not set all the way. did the cases have the locator pins in?

 

[Agro2424]

Alright thanks guys. I'll try beating both sides in the morning and if that doesn't get anywhere, I guess I'll split it again.
So nobody thinks this is just something that will work itself out after a break in?

 

[scotj77]

that is just a very risky choice to make. no one wants to make that call blind man.

 

[Wifesblaster]

if you have ridden it that means you put the top end on. if the top end is on it will have resistance from the piston.

I did hold pressure on the bearings when they were set. We even had spare cases and compared the bearings to them. I am 110 percent sure they were seated. It was tight without the cylinder on. We took it apart and reinstalled 3 times using the tust puller. Let me clarify what I call tight. I could spin it with one hand on the drive gear. I was just tighter than the stock one. Like I said we have been out on two rides (10 hours) and so far so good. I pressed the crank all the way into the one case, then put the other case on. We used a rubber mallet to join the cases. VERY light tapping. The dowel pins lined up correctly. It only got tighter when we torqued the case screws down. We inspected the crank very carefully and found no signs of rubbing. It was just tighted through the whole stroke. I wasn't like there were tight spots in it. Now I'm a little nervous! I guess only time will tell!!

 

[Agro2424]

if you have ridden it that means you put the top end on. if the top end is on it will have resistance from the piston.

I did hold pressure on the bearings when they were set. We even had spare cases and compared the bearings to them. I am 110 percent sure they were seated. It was tight without the cylinder on. We took it apart and reinstalled 3 times using the tust puller. Let me clarify what I call tight. I could spin it with one hand on the drive gear. I was just tighter than the stock one. Like I said we have been out on two rides (10 hours) and so far so good. I pressed the crank all the way into the one case, then put the other case on. We used a rubber mallet to join the cases. VERY light tapping. The dowel pins lined up correctly. It only got tighter when we torqued the case screws down. We inspected the crank very carefully and found no signs of rubbing. It was just tighted through the whole stroke. I wasn't like there were tight spots in it. Now I'm a little nervous! I guess only time will tell!!

Sounds pretty much identical to what mine is like.

 

[01BLAST3R]

heres a dumb question did you put the crank in the right way i did this once and it was stiff to turn and the caes was hard to put together and then i took it apart and realized i put the crank in backwards..

 

[Wifesblaster]

I am NOT telling you to put it together and hope it loosens up! I may have made a huge mistake and I would love some more input. I just dont see how I could have got it freed up anymore than I did. Maybe we will pop the cylinder off and check it out.

 

[Wifesblaster]

heres a dumb question did you put the crank in the right way i did this once and it was stiff to turn and the caes was hard to put together and then i took it apart and realized i put the crank in backwards..

If it was in backwards we wouldn't be riding it! LOL