A peek inside my '05 DE250
 

While it was up on the stand (tire changes) I decided to take off the pipe (to straighten it), and take some pics of the piston and stuff in preparation for my June-ish top-end inspection and R & R.

A series of photos starting with the exhaust area.

The photo's aren't showing so just click on the links...

http://i20.photobucket.com/albums/b2...g?t=1241395246

Next is a pic of the side of the piston (no rings showing)...

http://i20.photobucket.com/albums/b2...g?t=1241395904

Next is the top of the piston with a little ring action...

http://i20.photobucket.com/albums/b2...g?t=1241395943

And finally a glance at the back of the cylinder wall. Notice the cross-hatching direct from the Spanish factory...

http://i20.photobucket.com/albums/b2...g?t=1241396016

It looks like you have a lot of carbon in there.

Thats due to come apart. What oil was run in that bike? Very dirty PV, my bikes PV parts and exhaust port have been little more than stained brown running Amsoil.

I run Maxima at 40 to 1.

Usually jetted just a little richer than optimum.

One thing to keep in mind is that digital flash photography (mine was in Macro mode), makes things look pretty nasty. It's like watching your local news on Hi-Def and discovering that your the hot news anchoress has an issue with wrinkles.

Let's revive this ol' thread
 

In two weeks I'm going to do my top end (with the help of a mucho-experienced buddy).

We'll do the squish band measurement for RB-Designs and then commence with the tear-down. We'll give everything a good cleaning and see if my deck height is where it should be.

I'd appreciate some advice on the best vendor and manufacturer for the gasket kit, piston and rings. I've used Wiseco before but I've always been concerned with the forged piston heat cycle thing. I'd be willing to consider others.

Thanks.

The dimension to the top of the piston varies by manufacturer. The top of the replacement Vertex piston was 0.2 mm higher than the original piston as measured by squish. I would measure the squish after installing the new piston.

Okay. I'll do that.

Any advice on a source for piston/rings, gasket kit?

This is the link to the gofasters page http://www.gofasters.com/index.php?m...ort=20a&page=1

The piston is $200 to $300 !!

Going back in time... this from Glenn "GP" over at woodsracer.com from 2005:

This site has GG Vertex pistons ('02-06 models) for $111 (for all four sizes). Is that around the ball park?

This appears to be the price for the kit (including rings, circlips, etc).

http://motorhelmets.com/htm-enginepa...ke-gas-gas.htm

While I'm at it, this site has some pics of a GG top-end teardown http://www.scottysdirtbikespares.com...e-base-ga.html
Thanks.

OEM is now Vertex. Last Vertex kit I bought in winter '07/'08 was around $130. I hope those prices are a mistake, $300 is just stupid expensive for a two stroke piston. :mad: The Vertex piston is and always has been the same for a TM250, and I beleive is listed as a standard Vertex part. Call around, there has to be a dealer with a 250 piston in stock for a reasonable price. Failing that, if that $300 is for real, try getting one direct through a Vertex distributor (Sudco I think).

Now were talkin'

The kit should include rings and pin, ring kit for re-ringing later if desired.

I just got an e-mail from Go-Fasters. That was the "a la carte'" price. The kit price is $182. Another $15 for the gasket kit. I'll ask him what type of piston it is.

Answer: Wiseco.

I think I'll give Vertex a try.