JE 290 Quality Control Problem

So I'm installing my JE 290 kit yesterday...

I get everything nice and clean, gasket in place, piston started into the cylinder, cylinder over the dowel pins, and the cylinder won't seat properly. It's hung up on the short coolant pipe that sticks up. I tap lightly with a wood block and hammer and still no go.

So I take it apart again and I can see where it's interfering by the marks left from the pipe hitting the bottom of the cylinder.

On closer inspection, it's obvious that the cylinder wasn't machined properly. You can see by the photo below that the machining doesn't go all the way around the hole. With calipers I determined that the problem isn't that the hole is in the wrong location, it's that the hole is not completely machined (The diameter is smaller in the direction where it's not machined). So either the endmill broke or the cylinder moved in the vice during machining.

I called JE, but of course they aren't open on Saturday and I want to get my bike back together. So I brought it over to my Dad's house and put it on his vertical mill. I plunged with a 11/16" endmill, which is .0055" larger than the original hole, but it's sealed with an "O" ring, so I should be fine. I'm lucky I have the ability to machine it myself. I pity the poor guy who tears his bike apart and has to wait another week for good parts to arrive.

I have to say, the JE Piston looks like a very high quality part, but the cylinder isn't very impressive. I've read that the cylinders are made in China.

This is my first experience with a JE part and right now I'm not very impressed.

Here's the cylinder as I received it:

cylmachining.jpg

Here it is after I fixed it:

cylmachining2.jpg

Good eye and good machining skills!! Lucky you know somebody that has a mill in their shop.

I got a nice call from JE, replying to the voicemail I sent them over the weekend. It turns out that JE doesn't sell kits. Other companies buy their pistons and put kits together.

I've sent a message to atvunlimited on ebay. We'll see what they have to say.

- Brad

next time try Athena

I saw those guys on eBay. I see they are selling Wiesco big bore kits. So they probably get old cylinders, bore them and replate them then put together a kit. Wonder if you just got an unlucky one or are they all like that? If the cylinder you got was an old core then how did it work before like that? Maybe they buy defected cylinders from other companies and then do their work on them then put a kit together

The cylinder is new. The casting quality doesn't look nearly as good as what I took off, though.

ATV Unlimited gave me a whopping $25 refund for my troubles.

- Brad

It's most likely a cylinder made by "Magnum". I bought my last 2 big bore kits from lukesracing.com because he goes over and above and even installs a copper ring on the top of the cylinder for the head gasket to seal better on. He inspects his kits before selling them.

I called them a while back and asked them who was making thier cylinders and they said we are?

I saw those guys on eBay. I see they are selling Wiesco big bore kits. So they probably get old cylinders, bore them and replate them then put together a kit. Wonder if you just got an unlucky one or are they all like that? If the cylinder you got was an old core then how did it work before like that? Maybe they buy defected cylinders from other companies and then do their work on them then put a kit together

i bought an wiesco kit from them and have 70 trouble free hours on it. bolted right on no problem. it came with a magnum cylinder

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