It tear down on the 250x.

Welp after 115 hrs I figured I'd tear down the bike and do the top end.i can't believe the blow by,maybe I should have been a little harder on it during the break in,idk.crown definitely got a little hot, I did get the bike to 250 degrees 1 time per my voyager guage on some super nasty rock up hill.ring gap measures 0.21in.so time to put a new piston in probably gonna go vertex or weisco.also gonna get the squish fixed while the heads off.tried calling Eric gore no luck,should I just send him the solder and head?any recommendations on this,the squish .99.do I need to measure squish with the new piston?will the dome be different from the factory one?definitely don't want race fuel in this bike,I already have a yz like that and never ride it do to the inconvenience.thanks in advance for any input.20171113_160424.jpg20171113_154611.jpg20171113_154516.jpg20171113_154419.jpg20171113_154408.jpg20171113_154350.jpg

did you do a compression test before tear down, just curious? 

115hrs,  seems like a good bit, how was it running towards the end of that?  

I was planning on doing my first rebuilt at 70hrs give or take.  

did you do a compression test before tear down, just curious? 
115hrs,  seems like a good bit, how was it running towards the end of that?  
I was planning on doing my first rebuilt at 70hrs give or take.  

Ya it came out at 175 3 times,honestly it ran good but I'm no rock star,mostly tight single track.lol,I don't think I'll go over the hundred mark again.

New piston "can" change squish, so I would put it in, and measure, then send. This is because you are changing from OEM to other. 

115 hours of Single track is hard, but it looks pretty good for that.

175psi is done for a 250. 

New piston "can" change squish, so I would put it in, and measure, then send. This is because you are changing from OEM to other. 
115 hours of Single track is hard, but it looks pretty good for that.
175psi is done for a 250. 

Agreed on all,I will wait for the piston kit to get here and measure again.cant make up my mind to go with RB or Eric gore.any input?
Just now, mudmixer said:


Agreed on all,I will wait for the piston kit to get here and measure again.cant make up my mind to go with RB or Eric gore.any input?

It seems Eric is overwhelmed and backlogged at times.

RB I hear does great work also.

Either can get it done. 

But just the FYI-I haven't used either, and have two heads cut. 

what is stock fresh top end compression on a 250x?

My 03 yz250 was always right around 215 - 220psi on a fresh build 

what is stock fresh top end compression on a 250x?
My 03 yz250 was always right around 215 - 220psi on a fresh build 

Mine was 205 at 15hrs.

I had Ron do a Kawasaki head for me, was great. I know a machinist that does them locally, so will take the YZ head to him, but if I sent it out, it would definitely be to Ron Black.

It seems Eric is overwhelmed and backlogged at times.
RB I hear does great work also.
Either can get it done. 
But just the FYI-I haven't used either, and have two heads cut. 

If you wouldn't mind giving away who did them for u I'd be pleased to give them some business, if u recommend them still.

Look into the rk Tek head if you got a few extra dollars to spend. It’s worth the money and it does what he says it will.

Just now, mudmixer said:


If you wouldn't mind giving away who did them for u I'd be pleased to give them some business, if u recommend them still.

Sorry bro, can't help yah. They came with bikes I bought over the years. One is cut for race gas, the other is not. 

Welp after 115 hrs I figured I'd tear down the bike and do the top end.i can't believe the blow by,maybe I should have been a little harder on it during the break in,idk.crown definitely got a little hot, I did get the bike to 250 degrees 1 time per my voyager guage on some super nasty rock up hill.ring gap measures 0.21in.so time to put a new piston in probably gonna go vertex or weisco.also gonna get the squish fixed while the heads off.tried calling Eric gore no luck,should I just send him the solder and head?any recommendations on this,the squish .99.do I need to measure squish with the new piston?will the dome be different from the factory one?definitely don't want race fuel in this bike,I already have a yz like that and never ride it do to the inconvenience.thanks in advance for any input.20171113_160424.jpg.fb204de039bbb23a22ffcdc378ea3e4c.jpg20171113_154611.jpg.9159fefea511023c7d98bc9f88e8a933.jpg20171113_154516.jpg.6bbcd822ee2e9d7fcabe9792d0cfde18.jpg20171113_154419.jpg.8002e5244fe7b2a53a8a0ee668ed81f7.jpg20171113_154408.jpg.64c763e46ebdef9e156bee0a2ca705cb.jpg20171113_154350.jpg.3a12df27858239965acdd8c142c953b3.jpg


Why do you choose to aftermarket pistons vs OEM?

Why do you choose to aftermarket pistons vs OEM?

I've always ran weisco in my bikes,last rebuild on my 08 I went vertex,no reason either way but they are a little cheaper than oem.im my opinion all but Namura are worthy.

My 250x came with a complete spare top end. Piston, rings, gaskets. Didn't yours?

Just now, Doc_speeder said:

My 250x came with a complete spare top end. Piston, rings, gaskets. Didn't yours?

That has got to be a northern brother thing. Didn't it come with a 12 month warrenty also? 

My 250x came with a complete spare top end. Piston, rings, gaskets. Didn't yours?

NO,I think the bastards at the yamaha shops keep them and sell em.ive heard of this before but I'm yet to personally know anyone that has received one with a bike.
4 minutes ago, mudmixer said:


Thank u doc,just ordered a weisco kit from rmatv,they always treat me right and my rmatv money is getting to be a good retirement planemoji106.png

I miss the old 10% on your next purchase. Man I got good deals back then as orders are 500-1,000 sometimes.

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