CR 250 Tear Down

[luvtolean]

Well, I decided my bike was kinda "ratty feeling" after riding Boomer's new CRF this past weekend. I decided since I'll be traveling the next few weeks it was time to tear it down and do some work. It's never had a new top end, so I started with that. I pulled the jug last night.

I have run race fuel with Mobil MX2T since about the third tank of fuel in this bike. This motor is fairly sensitive to jetting (and can be made to predetonate easily) and I got sick of having to rejet every time I bought fuel out of a different batch of pump premium. With the good fuel it carburetes well, doesn't predetonate (and consequently overheat) and is consistent. Perfect for a lazy bastard like myself. I set it slightly fat to keep it conservative as it's a playbike, and I don't need the last 1Hp.

Well, when I tore it down last night I couldn't believe my eyes. Everything had a very slick feel, but there was practically no carbon build-up on anything. I've never seen the inside of an engine, 4 or 2 stroke, look so clean after more than a year's use, including my 929. (Hell I've seen rebuilt motors that didn't look this nice) The RC valve (power valve) was blackened, but had absolutely no fouling or build-up. All a very pleasant surprise since my plugs usually come out brown to very dark brown on the insulator. The cylinder wall still had the final hone marks from honda, and a very light mark from the center of the rear skirt as the only indicator it had been used. It was visible with a maglight, but I couldn't feel it with my fingernail.

Honda's new bikes are famous for leaking dirt around the boot to airbox seal. People sell all kinds of kits to fix it. I pulled mine apart when new and applied some tacky gasket maker to the stock foam gasket. It certainly worked good enough. People also say the stock air filter is bad. I used it with No-Toil the whole time. It worked good too. And it's plenty dusty out here in Kali to test it....

Anyways, big fan of Mobil MX2T, No Toil, and race fuel! YMMV

Dump it---Buy a CRF450---you know you want one--hehehehehe

[luvtolean]

Nope, promised myself I wouldn't do that. But it won't be a CR250 when I'm done. Compromise you see...

[ConqSoft]

Bah. Get a 4 stroke. So much less work.

[luvtolean]

Not when you gotta start it (a CR450)...especially when it's hot and you fall off.

Originally Posted by luvtolean

Not when you gotta start it (a CR450)...especially when it's hot and you fall off.

Started first or second kick----try again---the blue light is ON!!!!!!

[luvtolean]

Yeah yeah,

Originally Posted by luvtolean

Nope, promised myself I wouldn't do that. But it won't be a CR250 when I'm done. Compromise you see...

You could buy my CR500 and blow right by boomers 4stoker.

[luvtolean]

We'll see, my "little CR250" might do it...

A dude up there had a Service Honda Cr500 AF with an Ohlins shock, that sure was a nice looking machine.

Originally Posted by luvtolean

We'll see, my "little CR250" might do it...

A dude up there had a Service Honda Cr500 AF with an Ohlins shock, that sure was a nice looking machine.

OH MAN!...Talk about a wet dream.

Originally Posted by nedro

OH MAN!...Talk about a wet dream.

CR500AF: I race a guy on one of those vibrating monsters regularly in the vet class. He occasionally beats me to the first corner - after that I leave him like his chain came off.

The only thing an open class two stroke is good for is blasting across the dessert or an open cornfield.

Originally Posted by luvtolean

Well, I decided my bike was kinda "ratty feeling" after riding Boomer's new CRF this past weekend. I decided since I'll be traveling the next few weeks it was time to tear it down and do some work. It's never had a new top end, so I started with that. I pulled the jug last night.

I have run race fuel with Mobil MX2T since about the third tank of fuel in this bike. This motor is fairly sensitive to jetting (and can be made to predetonate easily) and I got sick of having to rejet every time I bought fuel out of a different batch of pump premium. With the good fuel it carburetes well, doesn't predetonate (and consequently overheat) and is consistent. Perfect for a lazy bastard like myself. I set it slightly fat to keep it conservative as it's a playbike, and I don't need the last 1Hp.

Well, when I tore it down last night I couldn't believe my eyes. Everything had a very slick feel, but there was practically no carbon build-up on anything. I've never seen the inside of an engine, 4 or 2 stroke, look so clean after more than a year's use, including my 929. (Hell I've seen rebuilt motors that didn't look this nice) The RC valve (power valve) was blackened, but had absolutely no fouling or build-up. All a very pleasant surprise since my plugs usually come out brown to very dark brown on the insulator. The cylinder wall still had the final hone marks from honda, and a very light mark from the center of the rear skirt as the only indicator it had been used. It was visible with a maglight, but I couldn't feel it with my fingernail.

Honda's new bikes are famous for leaking dirt around the boot to airbox seal. People sell all kinds of kits to fix it. I pulled mine apart when new and applied some tacky gasket maker to the stock foam gasket. It certainly worked good enough. People also say the stock air filter is bad. I used it with No-Toil the whole time. It worked good too. And it's plenty dusty out here in Kali to test it....

Anyways, big fan of Mobil MX2T, No Toil, and race fuel! YMMV

Good Oil, Proabably your maintenances helped a lot. IMO nothing is more important than air filter maintenance.