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i just bought a blown up 2006 crf 250 r i put a hot rod stroker crank in it and a weisco racers choice piston. i cant seem to find the problem i have been thorugh the carb a few times now
tried all jetting from a
40 pilot 170 main
to a 60 pilot 180 main the bike just is idling really choppy and when i get on the gas it does not go away it almost sounds like a hot rod when running and i cant seem to find the right jetting i thought it was running lean but the jetting is very rich compared to my other 2 bikes that are identicle one with a high comp weisco and hot cam1 gs one with a hot cam 2gs

any suggestions what could be wrong and what to do?

there are so many things that "could" be wrong. but lets start with the most common things.

1. check your timing and verify it's spot on
2. if you've removed your carb's slide verify the floating valve cover is on correctly. it's very easy to get it upside down and this will cause some of these same symptoms you describe.
3. replace your pilot jet with a new one. better to make sure it's clear then hope it's clear after cleaning. even the smallest debris in the jets will make a big difference
4. fuel screw 2 turns out to start. remove the fuel screw and inspect the o-ring to make sure it hasn't been damaged or a piece of it missing. if it's damaged/piece of it missing your pilot circuit could be clogged. when reinstalling the fuel screw make sure you have the spring, washer and o-ring installed correctly.
5. Air boots on correctly and completely.

ken

timing is spot on i have checked it multiple times.
the slide is in correctly
boots are all on good, no vaccume leaks
pilot jets i have been playing with and put all new ones in
i will check the pilot screw tomorrow right now i have a 180 main jet and a 58 pilot with the srew set at 1 1/4 turns out.
the plug appears to be a light brown on and around the tip which if i am not mistaken should be about right. but the outide ring of the plug is very black. any suggestions on the jetting.
the bike runs pretty good on top end but on the low-end and idle it is very choppy

when you installed the slide did you remove the floating valve plate? if so, was this installed in the correct orientation?

58 pilot is too rich. most are running 42-45 successfully. what needle is installed and what clip position?

stock needle with the 3rd clip down.. right now i have a 175 main
45 pilot in it and nothing i do with jetting i have tried every combination from a 168-18 main and a 38- 58 pilot and nothing makes it better or worse...the floating valve plate isinstalled correctly

if this is carb related then something isn't right with your pilot circuit or the slide. the slides, floating valve seal, can wear and cause rough/inconsistent idle. it could also be that your pilot circuit is partially clogged. here's a link to a great carb servicing how-to:

http://www.dirtrider.com/tech/141_0707_ ... index.html

it's worth a read to review what work you've done and what is still possible.

ken

i found the problem with the bike after searching for the problem nearly 70 hours i decided to change the plug even though it looked to have good spark and sure enough the new plug fixed the problem right away. i guess if nothing else this was a learning experience haha

thank you so much for your help ken. you guys are awesome. btw anyone looking for a great mod that stroker crank is awesome. i have three bikes now all with different mods i will list them in order as to which has the most power they are all 2006 crf250r
1) has a hot rod stroker crank weisco racers choice
12.8:1 piston ported and polished head with stainless
faction valves with 5 way valve seats
2) has wiseco 13.5:1 high comp. piston with a st.1 gold
series hot cam ported and polished head stainless
valves (This is
currently my race bike and has a tbt suspension
which i love but i think the motor off #1 is going on
here soon)
3) Ported and polished head wiseco 12.9:1 piston st.2
gold series hot cam and stainless valves