Had this 2002 CR85 for a while and been trying to get it going properly for my son.
It starts in the first 3-5 kicks and once it's warm, its slow in the low-end lags in the mid and finally starts to rev properly in the top-end.
It gets harder to start when hot, like it can't be started by kick start and takes 5-10 hard tries to get it to bump start. Kinda backfires sometimes before it wants to go. Spooges quite a lot.
Started by replacing the plug, right side crank seal, piston and rings, top-end gaskets, inspected the reeds. Cleaned the carb and noted 120m, 48pj, clip on the top slot, AS 2 turns out.
I'm thinking of giving it a run without the silencer to see if a repack is all that's holding it back.
After that, possibly starting with trouble-shooting the main electrical components like the stator and coil?
Does anyone else have any suggestions? Would love to breath some life back into this old bike as my 13yo has almost outgrown it while I've been figuring it out and will eventually need to sell it (ideally in good running condition).
It may be a leak between the crankcases, sucking oil and air from the gearbox.
That jetting looks lean.Backfire can be lean or coil.
I would try a coil. If it's misfiring that can make it rich when the jetting is not.
What's the compression at?
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I don't have a good gauge at the moment but I've been kicking bikes for 40 years and this thing feels great after I repaced the piston and rings in the last 2hrs of run time. thx.
I’m no expert but I think your pilot is way too rich, try a 42. I had hard starting, spooge etc with my sons 50 and leaning the pilot fixed it. Airscrew should be close to 1.5 and put the needle back to middle clip. I think the main is probably too lean as well but start at the pilot and work from there
STD and Pro Circuit Jetting:
Here is what Pro Circuit says about their jetting specifications:
Obviously, what is interesting is the use of C12 with the STD jetting but a clip move to the 2nd position. It might be good to start with Standard jetting and work from there. The assumption here that this would be the stock round slide carburetor.
In my experience C12 is a couple jets leaner than pump gas.across the board. I can't see him being rich on the jetting. If your pilot is lean it won't start for shit.
Addic, Don't disagree on C12 and the pilot being too lean. My point is to put it back to stock and baseline. I'm troubled by the clip position at the top.
The Pro Circuit chart was posted for reference both STD and their settings with C12, Altitude, Temp, and oil/ratio.
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