[Tinman]

Hey guys, first post here. I just bought my first "real" dirt bike. I've been riding a chinese 250 honda knockoff and just purchased a 2002 crf450r. When I got it he said the jets were on order because it was running lean. The silencer had blown apart and he had it rebuilt by a welder that apparently didn't repack it correctly. It is very loud and pops on decel. The header is turning red (only visible at dark) and it ran hot while trail riding.
My question is, should I put the jets in that the honda dealer recommended to fix it (should be here tomorrow), or replace the silencer with a Jardine RT-Four that I have sitting around. If I do use the Jardine, do I still need to install different jets or will the jets that are in it work. I just got the bike yesterday and haven't pulled the jets to see what is in there. The previous owner did race the bike and has many upgrades on it.

[crfsonly]

welcome to CRF's Only! congrats on the new ride. you will need to get the jetting correct. the best jetting is provided by the JD Jetting kit we offer. you will also need to make sure the header gasket is there and in good condition. any air leak at the header to the head will increase decel popping. i am not familiar with the Jardine. if you'll be using it off-road (not at a closed course track) then you'll need a spark arrestor and quiet muffler like the FMF Q4 we offer. if the Jardine does offer these you'll need to verify if the places you ride allow you to ride without a spark arrestor or being over USFS sound limits.

as for it running hot, if you have not already done so, replace the engine and trans oil. use a new engine oil filter. replace the coolant so you know it's good. these motors are designed to run at speed to get air through the radiators for cooling. don't let it idle long. if you stop for a break turn it off.

again, congrats!

ken