Duncan racing 250r eliminated motor bog

[robertmitch85]

Hey guys just trying to figure this out so I don't blow up my top end this weekend. Just bought this trike and it was acting weirs where if I just slammed the throttle from idle the bike would bog, the take off OK first through third, 4th and 5th kinda lagged and never really got completely on the pipe. The jetting in the bike was a 178 main, I tried a 175 170 and a 168 with the 168 the Bike still has a bog but the top is now wild and keeps pulling the front end up. Plugs are still coming out orange ish brown but wet.

The bike has a PJ carb Paul turner pipe high rev port cool head vforce reeds FMF turbine core etc. I really don't wanna fry my top end.
Any help is appreciated.

[robertmitch85]

[yaegerb]

airbox or pod filter, if airbox is the lid off or you running stock setup?
current temp?
fuel/oil ratio?
Pilot?
Needle clip position?
Throttle position you are experiencing the bog in?

[robertmitch85]

I'm not sure i think its a 36-38

[robertmitch85]

Temp 80 degrees f, 32:1 no air box lid, mods listed above, pilot is now a 168, clip on third position, if you easy the throttle past 1/4th it's fine. If you push the throttle fast from idle it'll bog, the bike is fine in top end now.

[JesseA420]

having a topend port and a ptr pipe it is going to pull hard on the top end. the way you stated that is liek you dont want it to.

[yaegerb]

Temp 80 degrees f, 32:1 no air box lid, mods listed above, pilot is now a 168, clip on third position, if you easy the throttle past 1/4th it's fine. If you push the throttle fast from idle it'll bog, the bike is fine in top end now.

168 is your main.
Need to know pilot size and how many turns out your airscrew is.

[robertmitch85]

168 is your main.
Need to know pilot size and how many turns out your airscrew is.

Airscrew is 1.5 turns and sorry the pilot is a 55

[robertmitch85]

I did notice that if I put the lid back on it seems worse.

[yaegerb]

Airscrew is 1.5 turns and sorry the pilot is a 55

Put in a 50 pilot and move needle clip 4th from top clip position. Leave airscrew at 1.5 turns.

Try that and report back.

[robertmitch85]

Alright thanks a lot man! So I take it you think it was rich? Sorry but I'm a total newb with carbs.

[yaegerb]

yes, with what you are doing 55 is way too much. Do post back with your results if you don't mind.

[robertmitch85]

I will it won't be till tonight though do to work.

[robertmitch85]

yes, with what you are doing 55 is way too much. Do post back with your results if you don't mind.

Makes sense sometimes when it had the 178 it would do a quite back fire or whistle out the pipe, like burning fuel in the expansion chamber. But usually still started within 3 kicks

[yaegerb]

Makes sense sometimes when it had the 178 it would do a quite back fire or whistle out the pipe, like burning fuel in the expansion chamber. But usually still started within 3 kicks

I have actually set you up a little fatter than I would run because we need to try this before we go leaner. IMO, you should be able to get away with a 48 pilot, middle clip and 162 main. But for now, leave it as 50 pilot, 168 main and 4th clip from top.