Assembly defects, with pics & other stuff
This thread is for technical reference only. It is intended to be an aide to the end user as well as the resellers of these kits. It is not for the benefit of pointing fingers and naming the resellers of these particular engines, (so please don't ask). The resellers do not want the factories to ship them scrap engines. They want thier business to prosper, and I want them to prosper as well.
I think we should all, as a group, set a simple precedent:
Take care of an obvious manufaturing defect...whether you offer a warranty or not! You are the one dealing directly with the factory, not us. We buy a product from you fully expecting a limited life span...don't expect us to deal with your manufacturing defects in the first few miles of use...It's not reasonable.
If you cobble-up part of your kit, don't blame the reseller! They aren't Wal-Mart! It is already common knowledge that the fasteners should be replaced. To expect a reseller to replace your engine because you broke off a stud is ridiculous!
Loss of power:
The first 2 pics below show an engine that was disassembled due to a major loss of power. The bearings were installed backwards with the seals facing inward towards the crankshaft. The bearings got so hot due to a lack of lubrication, that the seals melted and clogged the bearings. The bearings were completely seized. The crank was spinning in the inner races of the bearings. The crank journal and the inner races were blue. It just goes to show how a simple error in assembly can cause major problems.
Excessive gear noise:
The next 2 pics show the clutch gear of a bike that was used for 3 hours. I didn't even need the gear puller to remove the hub. It fell off once the nut was removed. The countershaft taper was not correct to the taper of the hub. The same was true for the sprocket on the opposite end. I didn't even need the puller to remove it! It just fell off. The entire countershaft assembly is scrap.
The CAD graphic at the end shows how the gear hub is assembled. It is easy to check this on a new engine. Simply remove the gearset cover and check the gear for any excessive play. I have a new engine on the shelf that was assembled without the 2mm ball bearings shown in the graphic. The gear can be moved up & down, or side-to-side about 1/16".
Last edited by Creative Engineering; 03-18-2009 at 04:25 PM.