A peek inside my '05 DE250

[blitz11]

Don't forget the piston pin needle bearing. It's a shame to do the top end and not replace that. Those tiny needles are taking the full brunt of each internal explosion. That same load is transferred to the big end, and look at the size of that bearing/those needles.

Don't cheap out here.

In the old days, we'd get a needle bearing with a piston kit. Not so anymore. Make sure you get the needle bearing.

blitz

[AZRickD]

Good thought. I'll look to see if motorhelmet or GoFasters has the needle bearing kit.

[AZRickD]

I ordered the piston kit through motorhelmet.com and the gaskets and wrist pin needle bearings through Gas Gas Southwest.

[widebear]

Just for reference. Here's a pic of what I believe to be, a piston from a properly jetted, my mc 250 engine. amsoil 100-1 @ about 100 hours running time. Notice the less than perfect transfer pattern.

[AZRickD]

What do you make of that transfer pattern? What's the fix?

Nice pic, btw.

[widebear]

You can see the clean spots on the piston where the cooler incoming charge enters the cylinder but one off the transfers seems a little out of balance with the rest, still not to bad though. Alot of attention to detail would help but bear in mind that this is just a snapshot so to speak of the internal goings on. I'll bet that after the most recent work Ive done on the engine the pattern will be more pronounced.

[AZRickD]

Originally Posted by AZRickD

I ordered the piston kit through motorhelmet.com

Crud !!

I got an e-mail from motorhelmet.com that they were "out of or no longer carry the piston.

I went to OEMcycle.com from a member who said he got his Vertex piston kit there (numbered as a TM250) and all they list are kits for Suzuki, Kaw, and KTM.

Poopie.

Advice appreciated.

Edited to Add: Google is a wonderful thing. No matter how poorly a small business's web site is hyperlinked, Google can find it. http://www.oemcycle.com/Item/product/1268

ETA: Oh poo -- "Sorry, this item is not currently available"

ETA: CJ CHROME & CYCLE to the rescue. Southbend, Indiana $111

[widebear]

monkeybuttparts.com. Application 86 to 96 honda cr-250. they sell Wiseco and Athena in stnd and marginal oversizes.

[AZRickD]

I'm trying to find a vendor that sells wrist pin bearings.

Is this a standard bearing that will fit any piston make (Wiseco, Vertex, Pro-X...)?

What should I get for the my 250?

[widebear]

Well yeah, think about it, all those piston choices available all have to work with the factory con rod. So yes one bearing. Wiseco easy'st to get.Once again , monkeybuttparts.