cutting out at 8 grand

I was riding my xj750 seca today, took it down the street and it was a little choppy at around 8,000 rpm`s almost cutting out, and when warming up the carbs cough almost like a misfire sometimes until warm, could this be a sing of needing to both bench synch and vacum synch the carbs? :roll:

 

Sounds like it could be float levels. I'd check those first.

You only need to bench sync if you have been tearing the carbs apart - or have really screwed up the sync. Otherwise you can just sync on the bike.

 

ok i think i chased it and it could be my attempt to make my own intake manifold gaskets, i have a vacum leak going to take them off again and retorque the bolt i think i may have overtourqed and caused a leak. i`ll post if it corrects or not....Thanks

 

I tested with carb cleaner today and no vacum leaks actually ran nice they only change i made was turned down the idle screw and it comes down off the revs much better but the idle sucks, more like camed harley at a stop light so i think my carbs maybe out of synch because they idle screw only works on one carb in theory and the rest follow Right i have a nice right up on here saved i think its rick on bench synching so i will give a try tomorrow and also give the pilot`s another cleaning while i check the float levels.

 

Could be your sync. While you have them off to check you pilots do a bench sync.

Bench sync
http://www.xjbikes.com/Forums/viewtopic/t=6366.html

 

Will do thanks 8)

 

Getting my hands dirty tomorrow with the carbs tomorrow been real busy chasing a stupid headlight relay problem(4 days) but i pulled the plugs out tonight just to check and #1 looked great nice tan color,pulled # 2 and it was half whit and half black???,pulled #3 was greyish (lean) and finally #4 whick was completly white. Seems strange to me but i thought i would post the info and see if anyone can pick up on that. 8)

 

you need to reset your idle screws to 2.5 turns base
hook up a vacuum gauge and set the idle screws to that.

ride it for a bit and check them again. you may want to invest in a colortune plug.

 

I`m going to be out of town for a few weeks but i think i`m definetly going to invest in a colortune and also a new carb tuner handy to have. Will give update when i make progress.