Well, I am still pretty much stock. The dealer here put in 138/142 jets for my elevation. (4500ft)
It starts rough, and runs rough untill it's warmed up. I checked the plugs and they were dark so I thought that I should lean it out. I bought "low boy" vents for my air filter box that can be opened or closed and thought that would help a little to lean it out. It runs worse with them open so I have kept them closed. Today, it backfire out the exhaust when I was in revurse.

Am I lean or rich?

If I am rich, Why did the extra air in the box hurt rather than help?

I am doing Nyroc's exaust mod within the week, and according to the vents, this added air may worsen things even more.

What do think is wrong?

 

Check your pm that should help ya out.

 

I am going by hearsay rather then experience as i have not put any holes in my P650 airbox lid, so so take it for what its worth.

From what i have picked up the V-Twin does not do well like other powerplants with the air box lid off or greatly modified (Big or several holes). Something to do with turbulant air caused by design or something. Is it an all or nothing open...if not, I would try to open it a tad bit at a time until you found your sweet spot...have you put put a bigger snorkel on to replace the restricted stock one...that will help lean it out as well. If you are backfiring badly and its a little difficult to start then you are running to lean...that is how i was when i did the muffler mod and aftermarket snorkel. It would be difficult to start and backfire.

You can go to home depot or lowe's and get a piece of pipe to replace the stock...do a search and you can probably find the stock number...this does alot for improving air flow...this remedy will cost you about $14...or for a garaunteed fit you can pay diamond g racing 65 bucks and have them ship you one of theirs. Then jet up...

Can anyone with experience mod'n their Airbox help him out????

 

138/142 jets are the Kawi stock size for sea level to 1600 feet. That is what the dealer should have taken out, not put in. The reverse rev limiter is causing the backfiring in reverse. Push the over-ride button to eliminate the backfiring.

 

See i told ya LOL ha ha ha[img]i/expressions/face-icon-small-shocked.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-smile.gif[/img]

 

Heh, I think 2003650 was trying to save him a little embarrasment. As for the airbox lid, it's the same with any other engine. It doesn't care if it's getting air through the snokle, or the vents, it only cares about the air. But placement of the vents IS important as Bosox said. Turbulent airflow is bad, smooth airflow is good. Generally you can run without the lid as long as the cover plastic is in place. I've run without lid/cover/and filter and lost about 2mph on the top end. Looking into the carbs you could see the turbulence. Just blocking the airflow with my hand smoothed the airflow and I picked the speed back up. Running with the filter only no lid/cover kept the airflow smooth enough that I didn't see any loss, and my midrange improvement was incredible.

 

Ya think?

I know about the overide and use it quite often. This was deffinately different. My bike shows all the signs of being rich but when I added more air to lean her out , she ran worse. What gives

 

If it backfires out the exhaust only in reverse, there's something wrong with the over-ride system. These "low boy" vents - how big are they and can you open them partially rather than just wide open? Have you had this problem since new?

 

It has run rough since new. I realize that it needs to be re jetted but the symptoms have me confused as to if it truly is rich as the plugs indicate. The low boys are about 2 inches square in the opening and I have two of them. I thought that would give me the added benefits of the snorkle with out the cost.

 

Trust in the almighty spark plugs.[img]i/expressions/face-icon-small-wink.gif[/img] If they are dark black you are rich..... if they are white or real light tan you are lean.

I told you newgate didn't have there head screwed on straight.[img]i/expressions/face-icon-small-mad.gif[/img][img]i/expressions/face-icon-small-disgusted.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img]