I am roughly at 950ft. elevation. I wouldn't really want to go to 135/138, when my rear was 140 stock, would I? I checked for choke problems, seemed o.k. So isn't that a little far apart, back to 135 on front, and leaving the 142 in the rear? That would be two sizes right? it seems that if I am going to go up one size it has to be 142 in the rear, I will ckeck rear plug tommorow. Can you get to that without pulling battery? So, so far my best options are to go back to stock 135 on front, rear seems to be o.k, unless plug is loaded up, or add some air? If I lean my front down, does that automatically richen the rear? Thanks again....

 

The battery just lifts out after you take out the two bolts. I have a flex spark plug socket that fit quite nicely, took only a few minutes to check both plugs.

 

Are you sure the dealer ship put the right jets in the right carbs? I have seen that before. Are you sure they didnt put the 142 in the front and the 138 in the rear? You may want to check that. Sounds a bit fishy.

 

I put the jets in myself, I am sure I put them in right. But I will double check if my only option is to get back into the carbs, without doing something to the airbox.

 

O.K., I won't get to work on my quad until Saturday because of my work load this week. I got thinking about putting the 135 back in my front carb. That puts me at 135 in front, and 142 in the rear. mtecate4g said I need to be one size apart, that wouldn't be one size apart anymore. And if I let some air into the airbox, won't I make the rear carb run lean, if it is running right now? Like I said at the dealer, I thought the front plug, which was the only one taken out, looked black. He said there was no carbon build up. 2lman says his exact set up is running great at only 300 ft. difference in elevation with stock jetting. The only reason I changed mine was because of the white smoke at startup after the install. I probably only rode the quad actually a mile or so, then I changed the jets because I thought I had to. I was afraid of running too lean, and damaging my motor. So let me ask you guys if this is the right action to take this weekend, so I don't waste my riding day away. Pull both plugs, check for color. If back is also black, go back to stock jetting, but what if smoking persists? If back plug is brown, change front jet back to a 135, more than a one size difference makes me wonder why I should have changed the rear jet, if the front was o.k. stock? Or undo the the two clips on the airbox, allowing more air, leaning out both carbs a little? Thanks for your time guys, I just want to be able to wrap it up as sonn as I can, that why I want to be informed.

 

Heres what you have to do.

1st Check the plugs. Do a wide open run for 4 seconds after your topped out. Shut the bike off and check the plug color.

2nd adjust your jetting to get the proper jetting. You are right now 2 sizes apart. 138-140-142.

Also the black smoke may be coming from the air scew being out of adjustment. Check the choke cables. You may also want to call MBRP and see what they have to say. They may have some ideas for you since they designed the exhaust.

 

O.K., I think I'm good to go. I pulled both plugs, and the back one was black also, they were close to the point of fouling. Had a noticeable sputter in the midrange too. So I took out the new jets, and reinstalled the stock jets and two new spark plugs. I then took it up and down a dirt road and around the field a couple of times, on and off the throttle pretty hard. The best part of this story is it RIPS now!! I mean standing up front end, stone throwing rips. I was blown away by the difference that this made in performance, very nice. I had a friend who also drove it both with and without the pipes and other jets in, test drive it agian, before we check the plugs. He said the same, night and day difference. Top end has substatial difference in power, honestly. We then pulled both plugs, front was slightly brown, back was like a chocolate tan, a little darker than the front. I think my problem is solved, I know I am happy with the power. I can't wait to race my buddy's Raptor again. How can this be, running so good with no jetting change?

 

The reaon is that if your V was like mine it ran slightly rich stock. meaning no jet changes needed for the pipes.

 

I just ordered a set of MBRP duals for my V-Force. They tell me that rejetting is NOT necessary unless I want more performance. VFORCEONE says his runs best with stock jets. Sounds like we have some conflicting information here. I guess I will install the exhaust system and go from there.

Has anyone found a K&N filter for the V yet?

 

Check in the MBRP forum, I just got my reply back form the factory. Yes it is true that some engines were rich stock, I am running way better than before. I can really tell a difference throughout the power band. The plugs look good with stock jetting, the rear is a little darker. I will keep an eye on them. But I think I'm good where I'm at. Thanks for all your help.....