hi guys, i need a little help. for quit some time now i have this massive bog in low to mid range, around 1/4-1/2 throttle, it feels kinda like the boging you get when you run out of fuel.... but if i continue on the gas for a few more second's it pull's over it and runs stong all the way to the rev limit. it also does the same thing when i wheelie, even in a bit higher rpms. anything? could it be the flote sticking? i have no idea...... it hapen's on hard acceleration and when i drive slowly, even when i work the cluch.
i've try'd messing with the needle position and main jet, dosnt help much..... i'm running a 185dj main (a bit under 175 mikuni) and stock needle on 4th, so i dont think its the jetting. also cut 4 coil's from the slide spring. any idea's? i'm lost here.
thanks

 

i'd clean the carb first, while doing that check the diaphram on top. have you ever adjusted your valves?

 

yes i did about 6 months ago. i have a very small hole in the diaphram, which i had before, so i replaced it and it didnt help anything, now i have the same little tare. i sandpaper'd the problem area in the carb so i hope it wont get bigger..... can this be it? thanks

 

do you have water if your gas...i had water in mine and it did what yours is doing...it would be fine until about 1/2 throttle..then it would start acting up...sometimes it would rev out but it didnt feel like normal...it felt like it had more almost..

 

When I installed my Mr. HP end cap a few months ago, I experienced similar symptoms (i.e. a bog at low and mid RPMs in second and third gear along with a "pop pop pop" sound coming from the pipe). This was at sea level and I was jetted with a 172.5 Mikuni main jet, needle in the fourth position, three loops cut from the spring, K&N air filter with Outerwears). The spark plug was black and sooty.

I changed to a 170 main jet and the needle to the 5th (richest) position, and the problem seems to be gone. Plug is now the correct tannish/greyish color. I was very suprised to be too rich with the 172.5, but that appears to have been the problem. Perhaps you are in the same boat? What do your spark plugs look like? I also read somewhere that the cut carb spring trick can sometimes cause a rich condition. Don't know if that is true, but I went back to the standard length spring on mine. Hope this helps. Good luck.

 

he said there is a tear in his diaphram.

yes that is a problem, the slightest tear or hole in the diaphram is a problem and must be replaced, you can't repair it either, buy a new one. sounds like you took care of what's tearing them.
the slide opens by vacuum on the diaphram, the slightest tiny tear will enable vacuum leak, and this will prevent slide from opening as far as it should when it should.
the same symptoms can occur if you don't get the diaphram lip in the groove right and pinch the lip with the cap when reinstalling.

 

guys i just took out the plug (kinda brown...), and i saw the breather tube for the cranck, and just behind the pipes where it touche's them, there's a big size hole in it? wtf? thats just about the worst place to route a rubber tube on the bike! could it have coused damage to the cranck?
oh and i orderd a new diaphram, hope it getts here faster then the a-arms......(which are still not here)
thanks

 

if stuff got in there there isn't much you can do now besides change the oil. oh and fix the hole

 

ok thanks i'l do that.
any idea's on what can i do so the pipes wont burn a hole in the new tube?

 

run the breather hose straight out off the hose barb to the frame upright that the fan mounts on - run it up just like the oil return hose is ran up the other side, then bring it over the top of the motor. needless to say, you need a longer hose, but you'll never worry about it again.