Hello,
I installed a K&N Filter on my Roadstar and while test driving it, it seemed to accelerate fine and then suddenly bog down like it wanted to cut off. When I rolled back on the throttle a bit, it would run correctly. Before installing the air kit, I had no problems. Well one, terrible gas milage. (about 140 miles per tank) So, I am planning on rejetting.

Anyone know what settings I should follow???
I have a 2000 Silverado with a K&N Air kit and Boomcan exhaust.
The exhaust is made by BUB for Drag Specialties and is very similar to the BUB 2-1.

Thanks!

Jes<br><br>Post edited by: Wirkinman, at: 2007/04/09 03:33

Sounds like you may be too rich but it's difficult to comment unless we know your current settings.

Before you go tearing in there, try the WOT test outlined in the Tech Tips section.

Doc

Doc's right. However, it may be that you are also bumping up against your rev limiter. My bike was doing the same thing, so I installed a tach a few days ago to see where it was cutting out at and put it on a dyno...runs great, but cuts out at 4500 rpm. The solution is a aftermarket ignition module with a higher rpm setting if the factory setting is too low. Good luck! - Rod.

Good point Rod!

We sometimes forget the obvious.

Doc

Well, I went and did it.
I tried rejetting my carb.

I have a 2000 Roadstar Silverado with Bub Boomcan exhaust and a K&amp;N Filer kit.+

My stock carb had 165 main and the needle was set up as washer-spacer-clip-washer.

It ran decent (IMO) with the Bub Exhaust and Stock filter.
When i added the K&amp;N Air Kit, acceleration was good and then it would hesitate. If I slightly rolled back on the throttle, it would respond.

I was told the Main Jet was lean. So, using a Barons kit, I installed a 170 main. The Barons kit called for a the needle to have a clip on the 4 slot from the top and the washer placed back as stock. When I stared my bike, It stumbled on quick acceleration. And would sometimes backfire (intake and exhaust) too. I tried all different combo's with the needle. I tried all sorts of combinations using the Barons needle. It got late and I had tothrow in the towel until tomorrow.

One thing I didn't do was try to adjust the PMS Screw. The Barons kit said the set it 3.5 turns out from a light seat. I left it at it;s stock adjustment of 2.25 out from light seat.

Could the PMS set too lean cause a backfire during hard acceleration? Do you think my main jet (170) is too rich or lean?

Anyone have a recommendation on where I should go from here?

Thanks!

jes

I do (Sorta). I found with my personal experience that these bikes are kind of an all or nothing machine. I changed the pipes after I first bought it and nothing else. Ran great. Then I wanted more, so I started fiddling with jetting,drilled box, k&amp;n filter,etc.... Bike responded poorly to a jet kit minus a better airbox(figures). Now , I've just installed a BAK (last week, sick weather since) rode about 50 miles, seems to like this combo (only problem is this combo cost 300.00). Also, my gas mileage suffered when I rejetted on the stock airbox.

Truthfully, you might try turning the pms out some to richen the idle circuit, but it really only helps popping on decel not acceleration from my experience.

The 170 main is probably very close to what you need. Try the WOT to verify.

You need to adjust the PMS. Warm the bike up first. Turn the PMS in slowly until the bike begins to stumble the counting the number turns, turn the PMS out until it stumbles. Halfway between these two points is where you want to set the PMS.

If you still get a bit of popping, turn the PMS out 1/4 turn at a time.

Doc

Big Bear and DOC,
Thank you for the info.

I have another question...

After I added the K&amp;N air kit, the bike accelerated fine. After it picked up speed, it would hesitate unless I rolled back on the throttle.

Now, If I accelerate hard, it hesitated and backfires immediately.

What would cause the latter???<br><br>Post edited by: Wirkinman, at: 2007/04/15 22:31

I have a question for you. When you say K&amp;N kit, do you mean a replacement filter in the stock box or a whole new airbox? Couldn't tell by the pic. Where do you have the needle now? PMS definitly has to be tweeked.

Wirkinman wrote:
Now, If I accelerate hard, it hesitated and backfires immediately.

What would cause the latter???

Usually 'cause you're lean somewhere.

Reset the PMS as I outlined, do the WOT and then get back to me.

Doc