You could try raising the needle one notch and see if it helps. This will allow more fuel into the motor at a lower throttle setting than before.

 

First of all you need to figure out what is causing the bog, clutch problems, too much fuel, too little fuel ect. Mine was doing the same thing and it turned out to be pluged idle air jets casing a rich mixture at idle. If its a carb problem you can determine if its rich or lean by putting on the choke for a second when its bogging, if the bogging stops, the mixture is too lean if it get worse the mixture is too rich. Many things can cause a bog, try one thing at a time.

 

thanks, I will try that.

 

The 94 580 zr with 40mm had 3.5 slides and they changed to 3.0 slides on the 95 models along with 370 main jets. the use the same jet needles and needle jets. I switched my 94 slides to the 3.0's and it helped with mine. also make sure the pilot air ports are clear and set them 1 turn out to start.

hope this helps.

 

right on tskin these motors were very rich from factory, I run mine with the 370s too and stock pilots. just right for 1100ft.
i also ran my needle in the #2 position (2nd from top)

 

I will check my carbs first, it seems to be alittle rich right know, thanks guys!

 

I fail to see how playing with his main jet is going to help his problem. Correct me if I am wrong, but according to his post he is bogging just of idle and it clears itself after the throttle is opened and the engine is at higher RPMs. The main jet only cuts in at 3/4 to WOT and thats where the sled is running its best. His problem (if its even a carb problem and not a clutch issue) will most likely be in the idol or pilot jet circuts.

 

it sounds like its not getting the gas it needs if you choke it and it takes off. check your filters and pump and every hole in them some jets.If everything was good at first it must be something simple....i would say nothing wrong with twin pipes! good luck!!

 

Was this supposed to be in my thread? (The one about the twin pipes?). Thanks! I am going to go through the filter and carbs again.

Thanks again

 

I nede to get home to work on the sled thank you for the advice.

 

be sure you check the function of the needle/seat too, take a tube and blow through the tube as you tip the carb you should not be able to blow through with the carb upside down, it should release itself so you can blow through with the carb upright. And cover all the bases with the carbs, including boots, sync etc.

then

check jetting. I had to grit my teeth to go down 50 sizes (420 to 370) from factory. but then it ran great, not too lean, nice cardboard color, etc.

yes, by the book the main affects mostly higher throttle positions, however, in reality main and needle together affect anything off idle.

i've built and tuned a lot of reality, with good results.:sledder:

 

I had the exact same problem with the exact same machine and I too thought the same thing, it must be my main jets, everyone talks about them and how they effect bogging. Changed them 6 times and never fixed the bogging off idle, it was in my idle circut all along. Follow this KISS rule and you can never go wrong.

 

A pipe is not what you need. You need to learn to read the spark plugs and piston wash and do a proper baseline jetting set up.

Does the bogging get better as the temperatures get colder? If it works better in colder conditions then that would lead me to suspect overly rich jetting. I found the factory jetting chart to be about 4 - 5 sizes too rich, and the big 40mm carbs make it more sensitive to changing conditions.

What RPM's does the clutch engage at? The ideal is close to 5000 RPM. If engagement happens below 4500 you can expect boggy low end operation.

 

Clutch is engaging about 5500, but is been fairly warm lately, 25 degrees. my gaps have been good, I am planning on adjusting the jets this week end when I have time to mess with it.