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more out of my 07 cr250

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Hi I need to know how to get more out of my cr 250 it only has a pro circuit muffler (not expansion chamber) and rc Valves. I'm thinking fly wheel and rejetting the carbie.do you think I should do anything else. mainly riding in the bush but sometimes around a track so I still need some snap. Thank you

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depends on how much you want to spend really....

best bang for your buck is lowering the head. send it to RB designs for head mods. lookup shrubitup's posts on fixing the mikuni carb or invest a couple hundred in a PWK swap. get the head fixed and the carb dialed and you will be plenty happy.

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First thing I would do is if your bike still has stock jetting, I would buy a JD jet kit for it, or swap it for a PWK carb. I myself have had very good results with the JD kit. Second would be to get the squish fixed by milling down the base of the cylinder then having the head re-shaped to run pump gas or leave it alone if you want to run race fuel. The cylinder and carb mods alone will make a huge difference on the way the bike runs and responds.

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Macz is giving you excellent advice. Follow it.

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My 07 was stock when I got it, stock pipe, muffler, reeds, carb everything.......and pretty disappointing to ride.

Spent a bit of money on eBay and BTO sports to get some bolt on goodies and WOW! Big improvement!

About $500 got me an FMF fatty pipe, FMF Powercore 2, Vforce 3 reed block and some bling parts too!

But i still knew there was more power hidden in there.

The best thing I did was to hunt around for a blown up KX 250 and raided the Keihin PWK carb from it. The same carb can be found on YZ and RM 250s, just search on here and there's heaps of info on them, plus jetting info that will be 99% right for your bike.

It was an easy fit and definite upgrade to the way the bike ran and made power.......and it only cost me a carton of beer!!

Do these easy bolt on mods and you'll be happy.

My bike is so much better than the stocker I started with, BUT.............there's one last thing to do..........

The 07 CR's have an issue with detonation due to a poor cylinder head squish clearance that needs to be tightened up, also the port timing is slightly wrong resulting in a doughy bottom end.

A lot of members here on TT have machined .030 thou off the bottom of the cylinder which fixes the bottom end and tightens the squish in one job, CamP has a great post on here about his 07 and the .030" mod.

That's next on my list when I freshen up the top end.

Good luck

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My 07 was stock when I got it, stock pipe, muffler, reeds, carb everything.......and pretty disappointing to ride.

Spent a bit of money on eBay and BTO sports to get some bolt on goodies and WOW! Big improvement!

About $500 got me an FMF fatty pipe, FMF Powercore 2, Vforce 3 reed block and some bling parts too!

But i still knew there was more power hidden in there.

The best thing I did was to hunt around for a blown up KX 250 and raided the Keihin PWK carb from it. The same carb can be found on YZ and RM 250s, just search on here and there's heaps of info on them, plus jetting info that will be 99% right for your bike.

It was an easy fit and definite upgrade to the way the bike ran and made power.......and it only cost me a carton of beer!!

Do these easy bolt on mods and you'll be happy.

My bike is so much better than the stocker I started with, BUT.............there's one last thing to do..........

The 07 CR's have an issue with detonation due to a poor cylinder head squish clearance that needs to be tightened up, also the port timing is slightly wrong resulting in a doughy bottom end.

A lot of members here on TT have machined .030 thou off the bottom of the cylinder which fixes the bottom end and tightens the squish in one job, CamP has a great post on here about his 07 and the .030" mod.

That's next on my list when I freshen up the top end.

Good luck

 

Your beginning to scratch the surface of how good the case reed motor can be.   After owning a 93 model I was always trying to mimic that powerband with cr250's owned afterwards.  I tried different bolt on parts like you but it wasn't till I had some port work done that really realized the potential.   I never thought it can get any better than the 92-96 motors but they are with some work.  Good luck on your quest..    

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