Posts
37
Joined
6/20/2017
Location
Seaford, DE
US
Hey all, been working on my project RMX 250 for a while and I'm finally getting somewhere. Its a 92 RM250 bottom with the rmx250 top end, Pro circuit platinum head pipe, pro circuit 304 silencer, Vforce3 Reed valve, UNI air filter with the air box lid removed. Using an Iridium Denso IW24 spark plug.
I had an issue with the bike after rebuild bogging when getting into the main jet area of the throttle. (bought it as a basket case essentially). Its got the factory Mikuni TM carb. I took it apart the other day fully and found a few things, its got a 290 main jet, and the metering needle clip was at the bottom position (i dont know if thats considered 1st or 5th) but I do know that position was letting as much fuel in as possible. With research from FMF's website (bare with me while I get to my point), Its recommended setting would be a 260 main jet with the clip in the 3rd position. So I moved the clip up to the 3rd position and its remarkably better. I can get into the power band finally and see all my hard work coming together. BUT, its still not 100%!
It bogs and starts smoking more up top, just like it did before the needle position change. I think Im on the right track, seeming like its getting TOO much fuel IMO if the only change I did was technically make the needle go further down into the main jet. Pro circuits website though, recommends a 360 main jet!!!! Umm, that seems like wwaayyyy too much fuel as I have a 290 now with issues as it is..
So in quick terms with this info, my questions are...
From top to bottom of the needle, which would be considered position 1 to 5?
Does this sound like too much fuel being a problem and Im on the right track?
Should I try a 260 main jet over the 290 thats currently in it?
Is there a better spark plug of choice?
Should I ditch the TM and install the PWK38 Air striker I have on order and try to tune it instead?
I had an issue with the bike after rebuild bogging when getting into the main jet area of the throttle. (bought it as a basket case essentially). Its got the factory Mikuni TM carb. I took it apart the other day fully and found a few things, its got a 290 main jet, and the metering needle clip was at the bottom position (i dont know if thats considered 1st or 5th) but I do know that position was letting as much fuel in as possible. With research from FMF's website (bare with me while I get to my point), Its recommended setting would be a 260 main jet with the clip in the 3rd position. So I moved the clip up to the 3rd position and its remarkably better. I can get into the power band finally and see all my hard work coming together. BUT, its still not 100%!
It bogs and starts smoking more up top, just like it did before the needle position change. I think Im on the right track, seeming like its getting TOO much fuel IMO if the only change I did was technically make the needle go further down into the main jet. Pro circuits website though, recommends a 360 main jet!!!! Umm, that seems like wwaayyyy too much fuel as I have a 290 now with issues as it is..
So in quick terms with this info, my questions are...
From top to bottom of the needle, which would be considered position 1 to 5?
Does this sound like too much fuel being a problem and Im on the right track?
Should I try a 260 main jet over the 290 thats currently in it?
Is there a better spark plug of choice?
Should I ditch the TM and install the PWK38 Air striker I have on order and try to tune it instead?
ps- The top of the needle is 1st clip (leanest) and richest is the bottom (usually 5th clip)
I have some experience with your project trying to mix and match RMX and RM.
At the point you are now, with the info you gave I might follow these steps?
Two people makes this test easier.
1. start cycle. if it bogs and you think it's fuel starvation apply the choke and see if the bog disappears with the huge fuel hole the choke allows for massive amount of extra fuel, is your bog gone with the choke or way worse?
2. remove airbox, see if bog is better, rev cycle and apply air hose pressure of about 5 psi at carb intake and see if the extra turbo air supply makes the bog go bye bye.
After determining if you are rich or lean you can adjust the carb.
If the extra fuel, or the extra air does nothing the bog is something else...
The Shop
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