What is full revs?
Which ratio clutch are you using?
What weight oil are you using?
How many miles on bike?
Check the lifter clearance. The factory setting on the NE motor is .009". The factory setting on the WC-1 is .012". When I use mushroom lifters, I set the intake .006", and the exhaust .008".
Hi let me add to quentons list.Have found loose hardware on motor mounts and loose hardware on exaust please check allen set screw at head pipe under cover at head connection, comes loose often. Other than these two things Quenton has it covered.Hope this helps Bill Green
The full rev would be going about 30-35 MPH.
This is all stock on a NE5 motor except you planed the head and ported it Quenton.
I will check the valves again.. I hope it is that simple. I believe it is too noisy for that problem but will check it for sure.
I have 900 miles on this engine.
Thanks for all the input and is there any other ideas?
intro: I am from central Illinios, 51years old
I finally had time to check valve clearance and they both checked right on... I started it up and did some more intense checking. And when I rev this up I here a loud thump noise in the upperend. Could this be a rod bearing!! Am I correct to say you have to replace the crank and piston assembly on this motor as a unit?
Hi POLQWA, You are correct the crankshft & rod is one assembly [piston is separate item]. I have never seen a crankshaft go bad on the new edition Whizzers. I have even rebuilt motors that were run completly out of oil, and the crankshaft was fine. The only issues I have ever run across concerning the crankshaft was one that had "twisted" [do not use a power driven impact wrench when tighteneing the flywheel bolt], and the motors that had run out of oil needed the bushing at the top of the rod re-surfaced [where the wrist pin attaches].
Another area that could be causing the problem could be the sparkplug, and or the valves hitting the inside of the head. I haven't run across the sparkplug problem, but I heard some of the earlier NE heads were made slightly different, but usually hit the sparkplug and closed the gap [wouldn't start].
If you have the copper head gasket [re-usable], I would suggest you remove the head and look at the combustion chamber to make sure nothing is hitting. I once worked on a motor that the wrist pin clips weren't installed on one side, but it didn't make a "thumping sound", just started to smoke [ruined the cylinder wall]. You might also check the piston for possible cracks [never had this happen] and take a good look at the wrist pin for extreme wear. You might also take a look at the alternator coils under the flywheel to make sure the bolts holding it in place haven't loosened and allow the flywheel to contact the coils at higher RPMs. I am sorry I can't be of more help, but just never had any similar problems with the Whizzer motor..............