Mikunis won't idle down

these are RS34 flat slide carbs. the mixture screws are only good for 1/8th to 1/12 turn out.
it seems that part of the problem with tunning these is that they diont seem to make an autable dif when u adjust them.

I mentioned last night that I was considering replacing the mixture screws and o rings cause they seemed nonreactive, well this morning I could tell I was adjusting them, so I'm gettin closer. Again maybe that Old Kaw man knows somethin when he says to buy 115s and put them in before you even mount the carbs. I kinda did the same thing puttin bigger idle air jets in. At least it feels like it.

mark1122 wrote: these are RS34 flat slide carbs. the mixture screws are only good for 1/8th to 1/12 turn out.
it seems that part of the problem with tunning these is that they diont seem to make an autable dif when u adjust them.

:laugh: Pardon my ignorance, I memory lapsed that out of the equation.

A month to tune carbs. Lol

Godfrey wrote: I mentioned last night that I was considering replacing the mixture screws and o rings cause they seemed nonreactive, well this morning I could tell I was adjusting them, so I'm gettin closer. Again maybe that Old Kaw man knows somethin when he says to buy 115s and put them in before you even mount the carbs. I kinda did the same thing puttin bigger idle air jets in. At least it feels like it.

On these carbs, the pilot screw is a "mixture" screw, and therefore enrichens the mixture at idle when turn out (counter-clockwise), and thus leans it when turned in (clock-wise).

Incase you didnt already know :blush:

If the rpm continues to increase right to the max, or min (around 1/4 turn open), then that tells you what step to change the pilot. All the way out higher rpm - larger pilot, all the way in - smaller pilot.

PS. THIS:


Would solve all your problems in a jiffy - trust me!

Kidkawie wrote: A month to tune carbs. Lol

Quiet your blabber hole boy. A good tuner gets them done in a weekend. A great tuner gets them perfect in a season.

TeK9iNe wrote:

Kidkawie wrote: A month to tune carbs. Lol

Quiet your blabber hole boy. A good tuner gets them done in a weekend. A great tuner gets them perfect in a season.

Very true.

A month to tune carbs. Lol


Walk a mile in my shoes;) , yeah I know you would rather ride:)

Sigh, I'm beginning to wonder if I even have a carb problem, if its cam timeing or degreeing, that is out of my league at present.Last night I installed the manifolds for the stock 26's from my 650, and this morning installed the carbs, once again when the engine gets heat in it it hangs up around 3000-3500. Its entirely possible I suppose I was sold a completely unworkable( for street) combination. All I know is on the stock 650 engine these carbs worked perfectly.

but your stock 650 carbs are not jetted properly for a 750 hi performance motor either.
this also tells u that the lower vacuum signal provided by the larger carbs is not the problem, since the problem still exists with smaller high vac carbs.

.

I saw where you posted what you thought was the camshaft lift. If it is .380, that should be fine for a street motor. But are they? If you get back inside the valve cover there should be Marking on the cams. If no one here knows them, Web is still a large supplier and should have the info, including where the suggested install degreeing should be. Also what really effects signal is the duration and how they are timed. A late closing of the IN valve will cause Reversion in the intake track at low RPM. This is a drop in signal, measurable with a vacuum gauge. On a bike you need restrictor in the line to a vacuum gauge to steady it. You won't see the reversion, just a drop in vacuum.
Nothing wrong with an Idle speed of 1300, its the fact that once warm you can't get it to return. I'm sure you've eliminated the cable, and other mechanical. All slides set at the same height, etc. The fact that is seems the same with a second set of carbs, and manifolds, that suggests either a ignition or valve train issue.
I never saw anything posted about the ignition timing? Have you a good quality light that has a degree function, so you can track the advance through the RPM range?

The cam lift is .380 I checked it with calipers, I had the timing light on it yesterday and this morning dead on the f mark at 1000 rpm and between the 2 marks for advanced timing reved. Yeah I expect I'll have to call web in the morning, I know these cams are no longer in production; 10-15 yrs ago when ground. Yes I've gone all thru that , all thats left is cam timing.