Symptoms of unaligned crank

[RickSA]

Has anybody had the issue of a crank out of alignment? If so what were the symptoms?

I have a well running 00' 200 and top end was getting a bit worn so decided to do a rebuild, at the same time I decided to to Ron Black's mods to the head and carb.

Because of the power of the fresh top end I decided to do the big end, conrod, seals and all bearings too, so not to have the bottom blow up. after having my crank split and the new conrod and bearing put on, I pulled the crank back into the case and everything seamed ok. At the first start the bike was running well but I now have a whirr, whirr sound that increases with RPM.
I went for a ride up and down the street and it seems strong with no trouble just the sound.

Oil is above the sight glass and everything is torqued to specs.
I was thinking that it could be the main bearings singing because of the stress on them from the crank being unaligned.

Has anybody seen this before or know what else it could be?

Any help appreciated.

Thanks
Rick

 

[NCFRC]

Talk to the person who pressed your crank back together. Did the cases go back together nice and smooth ? There's always the possibility of a crank bearing being bad when new or being damaged when pressed on to the crank. I'm sure you've thought of this but it should come back apart to find the problem ,, yea , it sucks .

 

[helio lucas]

main symptom of a misaligned crank: vibration...

 

[sr5bidder]

kdxden has same whorrling noise so I doubt it would be the crank..
Idea!! pull the clutch in and does the noise change next put in gear with clutch in change??/ I had a drz400 with bad primary shaft bearings sound funny and it changed sounds when pulling clutch in ...just an idea

 

[whenfoxforks-ruled]

2nd the vibration. Your issue is something else. Is the stator plate installed correctly, look for shavings somewhere. That noise is likely cheap machining as it runs.

 

[IndyMX]

I'm going to throw in another possibility..

Sounds to me like you didn't get one of the seals seated properly.. Since Kawi crank seals go in from the crank case side, you have to make sure they are seated well, and that the bearing isn't rubbing against the lip, or else it will make that noise. Plus it will start to rub metal off of the bearing and seal, wearing out your cylinder.

You should be able to check that the seals are seated from the outside.. as for the bearings, you'll have to split the cases to do a proper inspection.

 

[mudpack]

If the crank halves are misaligned enough to matter, the crankcase halves will not go together.

 

[IndyMX]

If the crank halves are misaligned enough to matter, the crankcase halves will not go together.

Not entirely true, but thanks for playing along.

 

[julien_d]

Right. Tolerance for crank half alignment is something like .001", right? you could be WAY more off than that and still have it fit in the cases.

 

[mudpack]

I can tell that you've not tried to assemble an engine that had a crankshaft out of alignment.
The main bearings are in very precise alignment. A crank that is out by more than the service limit (.0032") will not line up with the main bearings. Oh, you could hammer it all together, but a little birdie would be telling you that something is not right. :nod:

RickSA, your description makes me think that one of the bearings...mains, big end, transmission.... is bad. (even new bearings could have been abused)

 

[whenfoxforks-ruled]

If it was like an 1/8th inch out, it would not clear the cases. Clutch spring bolt loose and hitting the case? Does it have a water pump?

 

[RickSA]

Thanks for all the response, should have been a bit more specific. The sound is there the whole time regardless of load on the motor, what gear, hot or cold or clutch in or out. That is what made me think of something other than the gearbox area. Never thought of the water pump seal or bearing, I'll try that next.
Thanks IndyMX checked the crank seals and they are ok, will split the case again and check the main bearings if the water pump bits don't solve it.

Thanks
Rick