Forum

[Girish]

I recently bought 2001 500cc bullet from PA,USA. It ran really well. I then replaced the exhaust with Goldstar and Mikuni TM 32-1 Carb.
Since then I really am having issues with idling. I tuned it well but after riding for minutes (when engine is warmed up), I get this idling issue. Every time I put the motorcycle in neutral gear, rpm rises sharply. I have tried tuning Pilot Air Screw when engine is warmed up but with no luck at all. I have put the proper jitting (P6 Needle jet 190 main and P30 Pilot jet).
It runs well at all throttle positions. I ony have problem with high idling issue when I put the bike in neutral gear.
Anyone has any idea why this would happen?

[Frank]

An air leak somewhere?

[papasmurf]

If it ran well put it back to the way it was. (If it ain't broke don't fix it.)

[Girish]

What could be the sources of air leak? I check air filter and manifold. don't feel any leaks. exhaust pipe has some air leaks where connects with header pipe but that shouldn't effect right?

[Gwilly]

Just my opinion that your always going to have some problem dialling in a non standard carb, and if other variables are not spot on than you will chase your tail for longer than necessary.

So yes get that exhaust sealed up and secure, Your ignition timing spot on and advance/ retard working smoothly. (assuming points, not electronic)

Plug chops are the only way to go, so you want to be looking at idle to 1/4 throttle range.

Type of air filter if any, can affect greatly.. You could try a 35 pilot to richen idle, Too weak can make the motor race like it does when you turn the petrol tap off and let it run the float chamber dry..
How many turns out is the air screw?.

[Girish]

Thanks Gwilly! I'm using KN Air filter with this.
Air screw is only 1/4th out. trying to open it more that 3/4 turn drops the rpm. So I assume highest rpm is between 1/2 to 1/4 turn out.

[Thack]

Girish, could you outline how the idle speed is set on the TM32-1?



Forgive me for being stupid, but my first thought is "Why not just turn down the idle speed screw?". I realise you must have done this, but I just wanted to get my head around how the TM32-1 is put together.

[Girish]

I tried it the normal way. First i use the idle screw to raise idle speed little bit then turned air screw out and in to find the highest rpm. The moment highest rpm is found i used the idle screw to low the rpm to optimum level. It works good but after few minutes of riding (means when engine is hot), I see this problem. Everytime I stop at traffic signal and put the bike in neutral gear, rpm rises sharply!

[Thack]

Oh, I see. I've downloaded the catalogue and can see that it has a knurled screw for the idle speed (slide stop, I assume) and a brass mixture screw.



So, I repeat: what happens when you unscrew the idle speed screw?

[Thack]

Sorry, Girish, our posts crossed! I understand now how you did it.