Low RPM bogging, Curvy.

hello fellow riders,
02 650s 30,000 miles
stock air filter, stock muffler (DE-Baffled), New NGK Plugs, New full synthetic oil.
Current Carb setup:
Main Jets 137.5
Pilot Jets 17.5
A/F mixture 3,3 out
1 0.030 shim on needle
So i am running 147.5MJ and 17.5 PJ I cleaned the carburetor completely 3 times, 1 shim on needle, and the bike is still bogging on low RPM? I am on 3.5 turns out on Rear carb and 3.75 on front. what else can I do to fix it?
the bike is jerking/bogging/hesitating under 3,000 RPM on 3rd gear 3th,5th... it never did this until I de-baffled the stock muffler. if anyone can help me please let me know
thank you
also here is a link to my thread on svrider.com
http://www.svrider.com/forum/showthread.php?t=207129

Have you looked at the spark plugs after the bike has been run at idle?
This will tell you what's actually happening as far as fuel/air mixture, and whether you actually have the idle mixture set correctly for each cylinder.

Probably not related, but could be- are your carbs synched?

[yorkie_chris]

Is this bogging when you give it a gert handful of throttle at low revs?

[johnnyrod]

If I remember rightly the stock pilot screw isn't set nearly that far out, so do you really need to adjust it at all?

PS link doens't work

For just knocking the baffles out of the stock muffler, you probably don't have to change anything. Likely this bike is hugely rich everywhere and fouling up the plugs.
Does it smoke like an old diesel?

Originally Posted by svrdr0213

A/F mixture 3,3 out
1 0.030 shim on needle
So i am running 147.5MJ and 17.5 PJ I cleaned the carburetor completely 3 times, 1 shim on needle, and the bike is still bogging on low RPM? I am on 3.5 turns out on Rear carb and 3.75 on front. what else can I do to fix it?

You are waaayyy rich!!!
For 17.5 pilot jets(your case)A/f mixture should be 2.5 turns for stock filter,who told you to go 3.5 and 3.75?

Apart from being too rich you risk the screws loosening and dropping because you have them too far out!

Put a/f screw at 2.5 turns for both front and rear carb.

PS:when we say 2.5 turns out we mean from fully closed.
Turn them clockwise until they GENTLY(I repeat GENTLY) bottom out.Then turn them 2.5 turns counterclockwise.


PS2:for stock muffler ( even if it's de baffled) use stock main jets(137.5)

[yorkie_chris]

Whoa yeah didn't see that. The air filter makes a massive difference, the can not so much. You can even get away with the stock mains with an aftermarket system let alone a mullered stock can!

I'm not sure how you go about de-baffliing a stock muffler, and I don't know what the internals of one look like, before or after, but there's a good chance you've created a higher-than-stock pressure in the muffler. This would decrease airflow a bit through the engine, which means you'd need less fuel everywhere, not more.
When you want to know if your mixture is good, pull the plugs and look at them!
Start at idle, get it right, then do a half throttle chop and check/adjust the needles. When that's right, do a full throttle chop and adjust main jets if needed.
Modern engines are very well made. Tolerances are held close to design spec, but, no two engines will flow exactly the same amount of air, so no two engines will need exactly the same amount of fuel. Idle mixture screws can only be set properly by checking the plugs, or using sophisticated gas analyzers on the exhaust.
Throwing more fuel into an engine that isn't flowing more air will simply make it run worse.