Rough idle, possible vacuum leak? Hawk 250

Desuboi941 · 05-15-2023, 01:02 PM

So I installed my nibbi or 28fl and the bike idles really rough. It’s as it the bangs of the engine are inconsistent as if one stroke it wants to die, other stroke too much power. I just went from a 40 pilot down to the 35 and the 112 main to a 115. Pilot jet is on the way. I accidentally bought mikuni jets and had to reorder. I’ll have to upload a video so you can hear it run, revs don’t hand and it doesn’t bog anywhere in the throttle. There is some popping though. All of this was happening before I changed the jets btw. Anyways, I was wondering if any of you had a paper gasket and a black thermal spacer between the intake and the head. On min it seemed like they were glued. I ended up taking them off due to my air box not lining up with my new carb. I ended up switching to a pod filter and I left the paper gasket in there but left the black spacer out because my dog ended up chewing it up… some of you have said I don’t need the spacer between my intake and carb, but I couldn’t get the carb to fit on all the way without it. Also ended up getting a quick turn throttle and my cable is too short. New cable is on the way but for now it’s not too bad. I’ll be doing the valve adjustment either today or tomorrow because I feel like that could be causing the rough idle as well. Basically I’m asking for a direction to look in. Does this sound like jetting, vacuum leak, valves or all of the above? Sorry for being such a nuisance, I’m learning as much as I can on my own, but I also don’t want to damage my baby. I absolutely love this bike…. I just wish I could get her running smooth.

05-15-2023, 01:02 PM	#1
Desuboi941 Join Date: Apr 2023 Posts: 33	Rough idle, possible vacuum leak? Hawk 250 So I installed my nibbi or 28fl and the bike idles really rough. It’s as it the bangs of the engine are inconsistent as if one stroke it wants to die, other stroke too much power. I just went from a 40 pilot down to the 35 and the 112 main to a 115. Pilot jet is on the way. I accidentally bought mikuni jets and had to reorder. I’ll have to upload a video so you can hear it run, revs don’t hand and it doesn’t bog anywhere in the throttle. There is some popping though. All of this was happening before I changed the jets btw. Anyways, I was wondering if any of you had a paper gasket and a black thermal spacer between the intake and the head. On min it seemed like they were glued. I ended up taking them off due to my air box not lining up with my new carb. I ended up switching to a pod filter and I left the paper gasket in there but left the black spacer out because my dog ended up chewing it up… some of you have said I don’t need the spacer between my intake and carb, but I couldn’t get the carb to fit on all the way without it. Also ended up getting a quick turn throttle and my cable is too short. New cable is on the way but for now it’s not too bad. I’ll be doing the valve adjustment either today or tomorrow because I feel like that could be causing the rough idle as well. Basically I’m asking for a direction to look in. Does this sound like jetting, vacuum leak, valves or all of the above? Sorry for being such a nuisance, I’m learning as much as I can on my own, but I also don’t want to damage my baby. I absolutely love this bike…. I just wish I could get her running smooth.
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