Revs won't come down - KZ750 E2 1982 + Keihins

nuwonder wrote: I've tried to check those boots with brake cleaner repeatedly 'cos they seem to be usually the first place to look for super lean symptoms but no matter how much i spray them, it doesn't affect the idle. It's really weird. Is brake cleaner bad stuff for that, should i go for carb cleaner instead?

I don't know if brake cleaner would work well or not. I used carb cleaner and with the idle set very low it immediately changed the idle speed. In fact, it momentarily stopped the engine from running. Ed

When I had K&N pods on my 1980 750 E1 with 4 into 1 exhaust I had the same jetting 140/70/35 with pilot screws 2 turns out and no problems. I would not drill those pilots any further. It's something you cant undo.

Like others suggested I would be looking at carb holders or throttle cable or linkage or a Dynojet kit..

The last set of carb holders I bought only lasted about 5 years and had to be changed last year. Cracks can be hard to see unless you look closely

A short video will help to analyzed your running condition.
A good mechanic will here and see what a bike need to get the proper "medicine"

Ordered new boots and gonna pick them up tomorrow and hopefully get to test them right away. Fingers crossed!

I'll try to include a little video later if needed

Do you have the stock airbox? If so, did the bike run fine with it?

Nope don't have the airbox. Bike was bought with some cheap pods on and carbs were on stock jetting. Now K&N pods and rejetted.

Got my new intake boots today, gonna post later did they do the job

Okay the new boots helped a lot but it's not perfect still. I got it to idle nicely and revs come down in few seconds but they still don't come down as fast as I would like. I think I might settle for this so can do a bit of riding before weather gets cold. Can't belive it's autumn already!

Now you must adjuist idle mixture screw for highest idle on 4 carbs and the adjust idle at 1100 RPM.
Carbs are synch?

I'd adjust the pilot screws for highest idle and error on the side of more open (rich). After about 3.5 turns open you are maxed out though.

Vacuum sync is critical to a smooth idle.