nikki shutter valve/carb very hot exhaust
 

So I haven't delt with a lot of these carbs usually if I deal with a 12a they have dell's or webers easy clean setups but I picked up this bone stock GS that had a bad clutch for 300 bones it has 265,xxxmiles i did the normal first start procedures if i know a rotary hasn't been started for a long time fuel filter,oil change,oil the housings,drain the fuel tank,plugs & wires the normal stuff well got it started first try no problem ran fine till warm and had a slight hick up at idle every so often wasn't to bugged about it drove it around and notice on deceleration at give or take 2k sputtering and a slight jerk sounded like it was on one rotor from 1500 to 1000 rpm if i let the throttle drop well first thing i came across on the forum after checking all vac lines many times over just to be sure is the shutter valve simple test just block it see if it runs better right?? well it in fact ran better didn't take the blip at idle out but i didn't feel like the power came on in waves at like 2k and 4k it was nice solid feeling power and pulled much harder and no lurching at 2k i drove maybe 3/4 of a mile round trip and when i pulled in the driveway the rmps stuck at 1500rpm i shut it down and the obviously aftermarket cat was really smoking so much so that i pulled out a hose incase i seen fire! the exhaust is stock aside from the 3 cats being replaced with the after market one that doesn't look all that old...any input would be appreciated.

Sounds like you have a good start on getting it on the road. Did you run and SeaForm through it yet?

If you could use some punctuation it would make it easier for us to read and understand a little better.

Sorry for the long paragraph like sentence I was on my way out the door when I wrote it..i did pickup a can the other day but haven't ran it through cuz the exhaust gets so dang hot started it this morning it ran okay with the shutter port open and even better with a small chunk of duct tape over the port. I shut it down when I seen the exhaust getting hot im assuming its running lean to get so hot?? I really hope my experiment didn't just F*** up my carb it was running pretty good drove it almost 2 weeks straight no problems beside the little jerk from 2k down

You might have a clogged cat.

I guess ill have to throw a straight pipe section on that I have laying around tonight or tomorrow. I hope its not though I like the sound of this exhaust as it sits the only tire churp iv done was described as the tires being louder than the engine and I kinda like that

yeah sounds like a clogged cat...that hiccupp at 2k might be excess fuel introduced throught the secondaries on deceleration...I had this happed and a glowing red cat set my carpets on fire. Run a straight pipe till you have it sorted for sure.

Wow!!! Please use periods! It's hard to understand. Sorry, but it does sound like either a clogged cat or an ignition problem.

Check your leading ignition to make sure you've got spark. If you only have spark on the trailing ignition, then it will heat up the entire exhaust system very quickly... Timing that is extremely out of whack can also cause this (if extremely retarded). ;)



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