Kawasaki VN750 Forum banner

1 - 8 of 8 Posts

·
What a new jack!!
Joined
·
2 Posts
Discussion Starter · #1 ·
I just got done throwing on my Vance and hines Cruzers duals. The problem is now as i accelerate, it sounds great until i pull in the cluch to shift it backfires real bad and loud!!! Also when i engine brake. I'm assuming that means i need to adjust the carbs or something but i'm not sure what to adjust. Maybe the jets? I'm on the Kentucky/tennessee border if that helps, i heard it has to do with the climate. I'm not sure, but i know i need help, cause it's not pretty anymore!!!! I'm in the military so i don't have time to search google for answers, that's why i came to the owners/pros! Thanks guys.
 

·
The Professor
Joined
·
3,147 Posts
Did you use new exhaust gaskets and do you still have reed valves or did you coaster?

Did you remove the baffles?

An exhaust leak will cause popping on decell and the fresh air let in by the reed valves escilates the problem.

If you bike accelerates and runs fine at higher rpm's then a re-jet is not needed, you may need to adjust air/idle screws.
 

·
What a new jack!!
Joined
·
2 Posts
Discussion Starter · #3 ·
I used brand new gaskets. I'm not sure what a coaster is. As far as the baffles, i just installed them. The baffles that i'm running are the ones that came in them.
 

·
The Professor
Joined
·
3,147 Posts

·
The Professor
Joined
·
3,147 Posts

·
Premium Member
Joined
·
1,126 Posts
Can I put some tips on the V and H cruzers without jacking up the backpressure?
 

·
Premium Member
Joined
·
3,027 Posts
I just got done throwing on my Vance and hines Cruzers duals. The problem is now as i accelerate, it sounds great until i pull in the cluch to shift it backfires real bad and loud!!! Also when i engine brake. I'm assuming that means i need to adjust the carbs or something but i'm not sure what to adjust. Maybe the jets? I'm on the Kentucky/tennessee border if that helps, i heard it has to do with the climate. I'm not sure, but i know i need help, cause it's not pretty anymore!!!! I'm in the military so i don't have time to search google for answers, that's why i came to the owners/pros! Thanks guys.
If you still have the air injection, you need to get rid of it pronto. It even causes problems with the stock exhaust. Make sure there are no air leaks, and turn the idle A/F screws out 2 1/2 to 3 full turns from seated. I had mine 3 turns out ever since I got the bike new. A lean idle A/F mixture will definitely cause backfiring. As for whether you need to rejet or not depends on the altitude where you live, and whether you have stock or aftermarket air filters. I live at a very low altitude, and intend to rejet, even though I'm keeping the stock filters. My bike seems a little lean even with the stock pipes, the V&H pipes will make it worse. Put in 2 new plugs, one front, one rear, go out and ride 100 miles, then pull the plugs. The insulators should be a nice tan color. If they are still white, like they were new, you are running to lean. If they are black and oily, you are running too rich. Jerry.
 

·
Premium Member
Joined
·
3,027 Posts
Can I put some tips on the V and H cruzers without jacking up the backpressure?
I actually wish it were possible to increase the back pressure back to stock, without changing the sound. Then I wouldn't have to rejet. If it is possible to build a nice sounding exhaust system with stock backpressure, I would think the manufacturers would do it, especially for cruisers, where a .5% increase in power at redline is not important anyway. Jerry.
 
1 - 8 of 8 Posts
Top