Hobbit 70cc DR - running hot?

Barry (Bob) Brown /

How hot should a kitted engine run? Mine is running about 360 degrees, it's got a DR kit and head, a jammy pipe and new crank/seals and bearings. It runs great just seems a bit warm.

Re: Hobbit 70cc DR - running hot?

start to worry when u creep past 400. og head? if so, get a bigger one

Re: Hobbit 70cc DR - running hot?

hobbits are notorious for getting hot. I've seen people hit 500 and be OK, and other's who treat 450 as their upper limit. I try to keep it average under 400 and pull over if it gets to 420, which I've had DR's thatd do that on big climbs or whatever, but full speed there was enough air to cool down. Bigger head helps shed heat. Retarding timing pushes more of the heat out the pipe, bigger jetting is not a good solution bu very important to be sure you're not too lean and especially not airleaking. A bigger pipe helps dump heat out too, they're extra prone to overheat with the littler pipes like the jammy or worst if you tried to use a kit with stock exhaust.

Re: Hobbit 70cc DR - running hot?

If you aren't breaking 360 your bike is not making the right power. Seeing your other posts, something is not right in that build.

Re: Hobbit 70cc DR - running hot?

Beach Club Nick /

Personally I don't think it's anything to worry about. You have the 46mm puchonda head off treats with no decomp on it, right? I don't personally know what kind of temps to expect with that head but I max out at like 430 with my stock head w/sealed decomp. The highest I've hit was 500 before I sealed my decomp though.

Speaking to DPC's point, what's the top speed you've hit? And are you getting better variation now?

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