Crank Bearing Help

[lambchop]

So I started my build. I had a mild dune port done. Went with the WSM pistons (they look really trick and wanted to try something new). The bore was already at 66, but was done sloppy and the 66 Wisecos that were in it had way to much play. So my machinist recommended boring to 66.25 and do it right this time. I showed up and he had ordered 66.5. Anyway, we split the case to check everything and replace the seals but noticed one main bearing has a little rough part (when you roll the bearing you can feel one area that isn't smooth rolling). It's barely noticable. I really can't afford to have the crank rebuilt right now, but i know now is the time to do it. It is a Hot Rod crank for what it's worth. I run good oil I'm just concerned about the reliability. All the other bearings feel fine and the crank feels tight.

 

Also, Anyone think the stock carbs will be OK. Damn this quad is costing me alot and I havn't even rode it yet!!! Anyone a machinist? The guy who did my porting and bore has the tools, but has never done a head before. I was wondering if anyone had some hands on experience to steer us in the right direction to increase my compression. I don't want to run straight race fuel but don't mind running 50/50 if I need too.

 

Thanks in advance.

 

One more thing. Is the Clutch basket supposed to have any play on that gear it's mounted to? Mine has a little slop in it.

Edited February 14, 2009 by lambchop

[blowit]

So I started my build. I had a mild dune port done. Went with the WSM pistons (they look really trick and wanted to try something new). The bore was already at 66, but was done sloppy and the 66 Wisecos that were in it had way to much play. So my machinist recommended boring to 66.25 and do it right this time. I showed up and he had ordered 66.5. Anyway, we split the case to check everything and replace the seals but noticed one main bearing has a little rough part (when you roll the bearing you can feel one area that isn't smooth rolling). It's barely noticable. I really can't afford to have the crank rebuilt right now, but i know now is the time to do it. It is a Hot Rod crank for what it's worth. I run good oil I'm just concerned about the reliability. All the other bearings feel fine and the crank feels tight.

 

Also, Anyone think the stock carbs will be OK. Damn this quad is costing me alot and I havn't even rode it yet!!! Anyone a machinist? The guy who did my porting and bore has the tools, but has never done a head before. I was wondering if anyone had some hands on experience to steer us in the right direction to increase my compression. I don't want to run straight race fuel but don't mind running 50/50 if I need too.

 

Thanks in advance.

 

One more thing. Is the Clutch basket supposed to have any play on that gear it's mounted to? Mine has a little slop in it.

 

 

Depends on what is causing your rough spot in the crank rotation. I would guess just some funk in it. If that is the case, you better get it out before running it. That is just asking for a failure. You may have got something in there in the tear down. Now if the rough spot is in the bearing itself, your bearing life is likely going to me measured in minutes. No worky very long like that.

 

Are you sure you this is not from the flywheel magnets or damaged PTO gear? Might pay to have an experienced tuner put a hand on it. NOT your machinist since he opted to hose you out of your last bore.

 

Brandon

[AKheathen]

i would try to flush the bearing with gas, or carb cleaner, and see if something comes ou, like dirt, or is it one spot on the bearing? use a paper towel to collect the run off. if the race is flaking, or has play, don't run it. it has to turn smoothly. you may be able to find a used drop in crank for cheaper than rebuilding yours.

the head can be milled, but i wouldn't use a belt planer to do so; they tend to take off material more on one side, than the other, leaving it flat, but uneven. it is possible, with practice, and constant re-orientation over several passes. the stock heads vary in chamber size, so you will have to measure the chabers before, and after, shooting for 21cc, if you are under 1000ft asl. you can do this, by using a piece of plexi, cut a small hole, and fill with water, and empty it with a syringe to measure. start wit a .020 cut to get you close. around 150-160 psi, switch to 50/50. on this, i am assuming you are around sea level, have pipes, stock timing, and not to wild on the porting, or that may change things a little.

as for the clutch gear, it shouldn't have play by hand, but there are bushing kits out there to rebuild them, if the basket's not groved.

 

this is my.02, and would emplore you to take advise from more ppl than me, because there are several on here with way more experience than me, banshee specific :thumbsup:

[twizted269]

just replace the bearing. is it really worth taking a risk in a rebuild and waste that kind of money and time?

[lambchop]

i would try to flush the bearing with gas, or carb cleaner, and see if something comes ou, like dirt, or is it one spot on the bearing? use a paper towel to collect the run off. if the race is flaking, or has play, don't run it. it has to turn smoothly. you may be able to find a used drop in crank for cheaper than rebuilding yours.

the head can be milled, but i wouldn't use a belt planer to do so; they tend to take off material more on one side, than the other, leaving it flat, but uneven. it is possible, with practice, and constant re-orientation over several passes. the stock heads vary in chamber size, so you will have to measure the chabers before, and after, shooting for 21cc, if you are under 1000ft asl. you can do this, by using a piece of plexi, cut a small hole, and fill with water, and empty it with a syringe to measure. start wit a .020 cut to get you close. around 150-160 psi, switch to 50/50. on this, i am assuming you are around sea level, have pipes, stock timing, and not to wild on the porting, or that may change things a little.

as for the clutch gear, it shouldn't have play by hand, but there are bushing kits out there to rebuild them, if the basket's not groved.

 

this is my.02, and would emplore you to take advise from more ppl than me, because there are several on here with way more experience than me, banshee specific :thumbsup:

HE flushed it really good in the wash tank and he had brand new solvent. There was a ton of dirt in the case when we split it. It feels like it may have some flaking or something chipped because when I roll the bearing really slow and find that spot it never moves. It's always the same location. That's a pretty cool trick with the water. Should I be trying to acheive 150-160 PSI or is there an optimum number you try to acheive? I don't think he's using a belt planer. He has all kinds of full-on machinist equipment and is really good

[swrbansheeboy]

which bearing is it thats bad? if it's an outer bearing it should be a no brainer, pull it and install a new one. i dont remember hot rods cranks being welded from factory so if it hasnt been welded then you could swap an inner out also but you need to have someone do it thats knowlegable with banshee crank tolerances.

 

as for milling the head, i've heard people say they have run 19cc domes on pump gas but i still run 50/50. i'd rather drop a few extra bucks on fuel than detonate one of my motors and cost me $300+...

 

you can cc the head with water, just make sure your plugs are in tight... for my money cascade does an exchange, i wanna say $50 and your stock head for whatever spec you want. that way you know it's done right. i'm sure there are several other shops on here that do the same thing. better to leave it to somebody who does it on a regular basis rather than the guy who says he can "get er done" i always say...