Hot cams ?

[GWsXR250R]

Fellas

Im running a 2001 Xr250r. My buddy and I re did the top end last season and contemplated putting in a hot
cam but didn't. Bike starts great from cold, but once shes hot im kicking it a lot.

There's an auto decompression system in this bike, super complicated a ton of research and time went into figuring it out. Ive found ways to delete that system from the bike but it will be a lot of work and time, but a hot cam might take care of it.

Is there anyone out there that has dealt with a similar issue? and does the hot cam make a difference?

Opinions?

Thanks

GW

[giantjoe]

Sounds like the valves need to be shimmed. I think poor hot starts is a symptom.

[cerealkiller]

Jetting issues can cause this too. I had the same symptom on my yz450 before going down a size on the pilot jet.

[axel99]

Check your tappets with the engine warm, I thought the XRs had a cable actuated decomp...just use the cable adjustment to put enough slack in the cable so it doesn't engage. I don't have any experience with a hot cam, if there is no wear in the top end don't waste your cash, bike may start harder, depending on the specs of the cam.

[GWsXR250R]

Thanks for the input guys,

I thought valves initially as well, luckily they are the screw adjustment style and i have that down to a science. It definitely makes a big difference when the adjustment is slightly off but i strongly believe its not the issue. Ive tried multiple configurations with no luck, it clacks like a train or don't even run.

Ive tried adjusting them while the bike was warm as well, all was good until the next time i tried to start it from cold. Tappets were so tight couldnt even get the feeler gauge in. Found it best to adjust at room temp. This bike has both the auto and cable decomp. Ive slacked that cable right off made no difference. When we pulled the head off last April the little plunger that controls the out decomp was sticky, cleaned it up was working nice thought my problem was solved, no luck.

Jetting, i haven't looked into. How does that help the hot start? Too much fuel? Is it a simple thing to change? how do i determine the right adjustment?

Appreciate the help

[cerealkiller]

I'm not much of a jetting expert. I changed my pilot jet based on a recommendation on the thumpertalk forum... and it worked for me. Incidentally, my gas mileage improved quite a bit too.

It's usually easy to do, but I don't know how the carb is positioned on your bike. You might be able to loosen the rubber boots on either side and rotate it 90 degrees, or you may have to take the carb off the bike. Then you just remove the screws holding the float bowl on and you can get at the jets.

[GWsXR250R]

Thanks Jared

Im gonna do some digging around on that. Ill let you know what I find out.

GW