Power down since fixing air leak.

Coyote · Post by **Coyote** » Fri Jul 10, 2009 6:11 pm

I rode the bike today for the first time since fixing the air leak. It starts instantly and idles great. However it is definitely down on power and acceleration is only about 2/3 what it was. I am unsure of what way to go but I can't help but believe that it is too rich now.
On page 113 of the Clymer manual. there is mixture trouble shooting. It is confusing at best. I will try to answer all the best I can and see what you guys think.
Condition :rich mixture:

Rough idle --- no
Black exhaust smoke -- no
Hard starting when hot -- no
Blubbering under acceleration -- some
Black deposits in exhaust pipes -- Yes. Oily black deposits
Gas fouled spark plugs -- Say WHAT?
Poor gas mileage -- unknown
Engine performs worse as it warms up -- no

Condition: Lean mixture:

Backfiring -- no
Rough idle -- no
Overheating -- doesn't seem to be
Hesitation on acceleration -- barely discernible
Engine speed varies at fixed throttle -- no
White color on spark plug insulator -- no
Poor acceleration -- yes

So poor acceleration does not fall under the rich condition, but blubbering does. Seeing as how I just richened everything up by curing the air leak, I think I need to go to leaner pilots. I am at 2 over now. Maybe back to one over or all the way back to stock.
The engine is not modified in any way. No shaved head or other trickery. It's bone stock with the exception of pods and chambers.
So what do you aficionados think? Which way is up?

Wayne Meuir · Post by **Wayne Meuir** » Fri Jul 10, 2009 9:46 pm

There is a REALLY good procedure for tuning carbs on the Kawasaki Triples Resource Pages that apply to tuning all 2-stroke carbs. It tells you the exact step by step procedure. You might want to look it up and make a copy to keep for reference.
Basically, what it says you have to do is first, sync the carbs. Then adjust the air scews to obtain fastest idle on each individual cylinder and that will tell you if the pilot is the correct size. After that is done, reset the idle speed. That fixes the idle to 1/4 throttle settings. After that is tuned to spec, then move on to the needle to tune out any stumble/blubbering from 1/4 throttle to 3/4 throttle. Once that is done, then tune the main by doing plug chops and that will tune the 3/4 to WOT.
I would think that the pilot needs to be at least one size larger with pods and chambers, maybe two, basically, if you have to open the air screw more than about 1/2 turn from the factory spec, then a smaller pilot should be fitted, conversley, if the air screw needs to be screwed in more than about 1/2 trun from factory spec, a larger pilot should be fitted.

The article above has some detailed instructions as to how to trouble shoot carb jetting.

Wayne

rngdng · Post by **rngdng** » Sun Jul 12, 2009 11:19 pm

On Blueboy and the TS400, with chambers and pods, I only increased the mains two sizes. Pilots stayed the same.

Lane

tz375 · Post by **tz375** » Mon Jul 13, 2009 8:37 am

Chris,

The trick is to determine at what throttle openings it is good or bad.

When you start to accelerate does it blubber at small throttle openings or does it do it all the way to wide open throttle? Does it clear up when you open it all the way up, or is the blubber all the way through the range?

At steady revs at say 1/4 throttle, 1/2 and 3/4 is it the same? In other words does it run bad at say 1/4 but is fine at 1/2 or is it flat and blubbery all the way through?

One possibility is that it always leaked some air and that you jetted around the problem, so going back to the original jetting might fix it. If you are on teh same mains etc as before and it's worse at mid to full throttle, something is wrong.

Are all 3 pots as hot as each other (as best you can tell)? Are the pipes all a similar heat?

Did you check teh oil supply to that right pot, just to be sure?