06 Ne5 Engine Sounds Like It Is Falling Apart At Full Rev

[POLQWA]

Update

I took head off and everything looked fine. I then checked everything Quenton said outside of looking at the piston better. I would have to take the jug off to look at the piston real good. The piston looked good on the top side however. The cylinder wall looked as new. I rotated motor while I had off and everything seems to be tight. I put back together and let it idle for a while in the garage because of the downpour outside. I put a big fan in front of the motor so it would not over heat. After a little while I noticed a slight growling noise in the clutch area. Before I tear into it I want to ride this and listen for sounds better. I think it might be the bearings in the clutch because this noise dosen't do it till I ride it a couple miles. Do you think I am on the right track?

 

[RdKryton]

It sounds like your on the right track. These engine are all but bullet proof. I have heard of the clutch bearings going south. Keep us informed please. Good luck

Jim

 

[Quenton Guenther]

Hi Polqwa,
If you have the automatic clutch, most [99%] use a reversed threaded bolt to mount the clutch to the arm. If you have the manual clutch the mounting bolt is standard thread. Be careful when re-assembling the clutch to the arm, because if you over tighten the mounting bolt you will destroy one if not both of the small bearings. Use Loc-tite on bolt.
If the problem isn't in the clutch, you might want to look at the relationship of the camshaft & crankshaft. By removing the side cover [easy to do on the NE & SE motors] you can see if the camshaft gear is rubbing against the crankshaft throws. If it is touching, you will see faint swirl marks on the crankshaft. The only reason I mentioned this is because I once "beat" the camshaft bearing deeper into case [flywheel side] so that I could use a larger base on the lifter, but when I reved the motor it sounded really bad. I removed the camshaft and "smoothed" the inner edges of the gear, re-installed it and has run perfectly for the last 3 years.
Hope some of this information is helpful, let us know what you find.
Have fun,
Quenton

 

[POLQWA]

Update On Noise

I took clutch off today and I believe it is the bearings. They feel rough when I put my finger in the center and spin it. I seen a number on the bearings and it is 6901v. I looked this up at a bearing company and all they have are 6901z. Has anybody used this number of bearing? I also noticed my big washer on the bolt has a big groove in it where it wore a scrape on the mating surface on the clutch. I think that bolt had worked loose on me also. I believe I found the noise!!! thanks for all the help guys...

 

[Quenton Guenther]

6901Z is correct. Be sure to not over tighten when installing clutch to arm. Check the alignment of the clutch and the front flywheel pulley, if the belt isn't running true, then use different washers to space the clutch to the arm.
Have fun,
Quenton