Crossover Jetting

KFXHELLRAISER · 08-31-2009, 09:05 AM

Ok how much does the jetting change with the crossover intakes on a closed air box?

05-BF-750 · 08-31-2009, 09:55 AM

To my understanding your going to be wasting your time if you are not going to open up the lid.

2007 650 SRA UPP intake, closed lid, DG snorkel, and Muzzy 155f 155r

2005 V 700 UPP intake, 12 hole lid, Muzzy pro 5/64 (or 3/32 cant remember) drilled mains front and rear.

Whit a closed lid I guess you be around 150 to 160. That's where I'd start anyway

KFXHELLRAISER · 08-31-2009, 10:22 AM

Im staying with the air box unmodded. I tried the 12hole and got better performace with it closed. I mean I have a unmodded air box and have had no problems with a race yet no matter what it was. I have been beat once and that person knows who they are.

Anyhow I found this interesting with that you said!

Quote: Originally Posted by VFORCEJOHN

I have got better results with closed airbox and Napa hose mod. both Dyno and track.

12 hole mod has decent power on top, but low end power "wheelie power" is less.

closed airbox is just a hair faster

150-155 range stock intakes

145-150 crossover intakes with these and closed box. you have to jet down

John

flipper · 08-31-2009, 11:39 AM

Open the box!

I got a thread in here somewhere titled "return of snap". It does act more responsive and feel like the closed box is better but it is a short lived feel.

The V has no problem impressing with it's low end even stock. It's where you don't feel it that it really comes into play but will notice it instead.

I have to say though that I have not tested this against the napa hose mod but if that were true wouldn't just fewer holes and only up front get a similar result?

Whats the gaff now man?

**VFORCEJOHN** · 08-31-2009, 02:58 PM

The closed box...That's on a prairie. the 12 hole mod isn't that great as the plastics hug the airbox cover on a stock prairie. Not true for a vforce

do the 12 hole mod and jet with #43 drilled jet and a 42 series 74C pilot

easy...

John

**twyztid** · 08-31-2009, 05:23 PM

That's what John suggested for mine (with the 12-hole mod) when I installed the cross-over intakes and it runs AWESOME! He really took all the guesswork out of getting them jetted. I would have never thought I would have needed jets that large but it runs great.

Mine seems to be just a little less cold-blooded and has even snappier throttle response now that I put in a 6-degree key but I haven't had a chance to do a test ride yet.

2qk4u · 08-31-2009, 06:06 PM

Yeppers, i ddi the UPP mod myself and jetted 3/32 and 42 pilot and 12 hole mod and a 730 kit and all i can say is WOW. My buddy has a stock V and he did the UPP intake mod him self, exact same as mine and it made a huge difference on his bike also. like john did one time on a stock motor and got an impressive 4-6 HP increase. i rode it also and it felt real good. you really need to open the lid up to get all the potential out of your machine.

**twyztid** · 08-31-2009, 06:17 PM

Yeah, I think that now that I have installed the 6-degree key on my green V I am about to the end of the mods that can be done to a stock bore.

KFXHELLRAISER · 08-31-2009, 06:31 PM

Once I make these crossovers I will just check the A/F and rejet if I need to and see what it does. I guess I waited too long on doing this since its going BBK this winter

**twyztid** · 08-31-2009, 06:32 PM

So you're doing the MS Mod or buying the UPP X-over intakes?