| Author | Message | ||
     Beltfedman |
Well, havent had this problem yet. I have thunderstorm heads, pistons, cylinders, 6800 RPM ECM. etc. i am getting a bogg at higher RPM's and some backfire i assume its running Rich yes? Do i adjust this on the back bottom of the carb where there seems to be a a nice shiny brass flathead screw to lean it out. or do i have to do the adjustment a different way? | ||
| Ratbuell |
What jets are you running? Exhaust? Where's your base timing set? | ||
| Cyclonecharlie |
Did the bike come from a much lower elevation? Your Bio says Denver, could be your problem. | ||
| Littlebuggles |
Standard starting place for your air fuel mix is 2.5 turns out. Screw you've located should be the one. I've not fiddled with mine once since setting it there, though it may need fine tuning up here in the mountains. I think mine could benefit a little from it and plan to do that this winter. But it runs pretty well otherwise. Your cams are different but besides that we have the same motor. Check my profile for jetting at 4500 feet. | ||
| Pash |
Assuming you have the throttle wide open, tis the main jet that controls the fueling. The little screw will have an effect up to 1/4 throttle... Take the bottom of your carb off and see if the main jet is clogged (or has fallen out). If you are running the standard carb, you should have a mainjet of around 200 (at sea level), if a Mikuni you should be running a mainjet of around 155 (at sea level)... These are ball park figures, I am sure everyone has a favourite mainjet size... As you go up in altitude, you need to reduce the mainjet size to compensate for the lower air density... | ||
| F_skinner |
I cannot tell for sure from your profile picture but if you are using a Mukuni 42 and live at 6K feet then a 157.5 main and a 27.5 pilot should work well as a baseline. | ||
| Guell |
Stock I think is a 195 main, which should be fine, I would try a 45 and 2.5 screws out and go from there. | ||
| Ratbuell |
Hm. Granted, I'm only a couple hundred feet above sea level...but with my thunderstorm motors and race exhausts, I run 45/190 and 2.5 turns out on the stock carbs.... | ||
| Beltfedman |
hey guys, i have a standard carb i think, I got this bike off a trade and i did not build it. it wasn't bogging originally i had it sitting for about a month and a half with the tank off and redid some wiring. all seems great except that. oh yea i did replace my PUSH cable ad have adjusted it properly i think. Exhaust is straight pipe, the guy i got it from most likely put different jets in it wont know unless i tear it down right? it was at a higher elevation prior. | ||
| F_skinner |
You might as well rebuild the carb to get the gunk out and check, replace the jets while in there. It is easy to do. I am down the road from you so if you need help let me know. Frank | ||
| Littlebuggles |
Then replace those straight pipes with something that will give some back pressure, or at least add a baffle if they aren't baffled. Straight pipes do not improve the performance on these bikes at all. | ||
| Beltfedman |
yea i probably should rebuild the carb..... checked out you page Frank, is that you in the video? i always wish i would be a comedian.... anyways. | ||
| Firemanjim |
Pash is correct---if it is bogging at higher rpm/throttle opening it has to be main jet as the slow jet works til 1/4 throttle,needle works in mid throttle but is completely out of main after 3/4.What do the plugs look like? | ||
| Beltfedman |
plugs are a little on the bad side. maybe thats it. ill go get new plugs.....  | ||
| Beltfedman |
ok UPDATE. Got new plugs in it 10r12a's gapped at .040 and it made no difference. Heres an odd find. the brass screw mentioned above is screwed all the way in and runs fine at idle. i thought this was impossible. i think i should just rebuild the carb and check everything out..... any other thoughts before i rebuild the carb any good links to a great kit? | ||
| Beltfedman |
ok finally got the carb off and open.. i have a 195 main and a 45.... neddles not bent and says N650 on it there was no gunk or anything in the carb... any thing else i should check before spraying the carb down and re assembling it? oh yea my manifold rubber on the carb had a few splits in it. im going to put new ones on it. already got those. (Message edited by beltfedman on March 10, 2011) | ||
| Littlebuggles |
I'm running a 200 here at Salt Lake City altitude, 5,000 feet above or so. Maybe you can try a larger main jet if you still get that cough after putting it all together. You've got new intake seals for it? | ||
| Beltfedman |
yes new seals......... ok if i switch the main i dont need a different neddle? | ||
| Littlebuggles |
Don't know on the needle, let's see how the committee weighs in.... | ||
| Beltfedman |
it could read N65C hard to tell..... oh yea i seem to have had a small washer on the needle between it and the carb also whats the deal? doesn't show this in the carb breakdown manual.......... | ||
| Beltfedman |
ok little research did good. i have the 1/8" hole on my slide also. my washer measures .040 and im running a velocity stack. humm my idle adjustment screw was only turned out 1 rotation. everything says 2.5 or so.... (Message edited by beltfedman on March 10, 2011) | ||
| Littlebuggles |
The washer was a shim, used to raise the needle and eliminate a cough or surge at part throttle and/or when you roll on the throttle. | ||
| Skntpig |
Explain the bogging better (if you could) and what RPM-Throttle position it starts at. |
