Stage 7 with OEM Exhaust - Runs a Bit Off...

[pipelinepete]

I finally got Mr Max for the very first time since getting him 4 months ago. The bike came with a Stage 7 kit installed and full UFO exhaust. I sold the UFO exhaust because we have strict noise laws here. So the current setup is Stage 7 and OEM exhaust. The bike starts and idles fine, but there's little power at low RPM, so I've really got to rev it up, to around 3-4K, just to get going. Once past 4K the engine sings and I've really gotta watch the tach (might need a shift light on this thing!). Anyway, I have no idea what jetting or carb changes have been done to the bike, other than the S7 kit. The AF screws are accessible so they've probably been messed with too. I have all the original intake equipment so theoretically I could return it to stock. But if I want to keep it like this (S7 + OEM exhaust), is there something I could do to beef up the low rpm throttle response? Or is it even possible with this setup? It's probably running too lean, no (?). I checked previous posts but didn't find an answer.

Would installing a slipon exhaust help? I have an opportunity to buy a Two Bros system.

Pic of my kid on the Max:

 

[CaptainKyle]

The best thing to do would be get rid if the stage 7. Slip on pipes will not help.

 

[VMax-Mike]

U should have changed the mufflers.

 

[Traumahawk]

Or go with Marks Performance exhaust.....Good sounding without being obnoxious to neighbors.

 

[Rollie]

Buy back the UFO ......... and move. :rofl_200:

 

[Itgoes]

Yes....what everyone else says. Stage 7 with stock exhaust is a bad combination. You are down on power for sure.

Either install a full pipe, or return the intake to stock including the V-Boost function if it's removed.

That's your best bet.

 

[VMax-Mike]

You could try the delvac slip ons but you might need to jet.

 

[dannymax]

The OEM headers are the limiting factor, anything you do downstream from them will make little to no difference. Either go to a full system exhaust or return the carbs to stock config.

 

[pipelinepete]

Yes....what everyone else says. Stage 7 with stock exhaust is a bad combination. You are down on power for sure.

Either install a full pipe, or return the intake to stock including the V-Boost function if it's removed.

That's your best bet.

So is it best if I just find the S7 installation instructions and reverse them?
Peter

 

[CaptainKyle]

So is it best if I just find the S7 installation instructions and reverse them?
Peter

Yep if your gonna keep stock exaust. You will need a stock airbox & stock needles & jets & remove the air correctors. I probably have everything you need here.

 

[ninjaneer]

don't forget stock springs. fyi. air correctors are usually superglue'd in, so taking them out's prolly gonna be the biggest hassle. also, there's a good chance the carb diaphragm slides were drilled, so returning fully back to stock is unlikely. i don't know what to expect with stock parts playing with a quicker slide. prolly not much to loose sleep over.

 

[dannymax]

So is it best if I just find the S7 installation instructions and reverse them?
Peter

You may be better off to trade the complete stg 7 rack for an OEM rack, as mentioned there are a couple steps in building stg 7 carbs that are difficult to reverse.

Money wise it would probly be a wash.

 

[pipelinepete]

Yep if your gonna keep stock exaust. You will need a stock airbox & stock needles & jets & remove the air correctors. I probably have everything you need here.

Kyle,
OK thanks that's good to know. The PO gave me a box full of OEM parts (airbox, vboost, jets, etc).....of course I don't know if it's all there but it's a good starting point. It'll give me something to do waiting for all this damn snow to melt!! Peter.

 

[Fire-medic]

Man, did I have just the thing for you! Too-bad you already sold your UFO 4/1!
check out my #19 on this thread: http://www.vmaxforum.net/showthread.php?t=28588&page=2

I just modded my UFO 4/1 w/a sportbike exhaust canister, I have a DJ Stage 7, and still use VBoost, it runs fine and sounds like a stock Jap sportbike, which is not unusual, given the canister, right? The UFO was just too-loud, I had both the "balogna-cut" "muffler" and the megaphone w/both rear tips (different sized openings); I liked the sound, but decided to see what could be done to easily modify the system to be quieter.

As you can hear from the videos, there is a considerable difference. The sportbike canister is still a work-in-progress, as I have details to finish, but I had no drivability issues after installing it & going for a spirited ride yesterday. Much-cheaper than a replacement rack of carbs and I have a couple of those in both stock & DJ Stage 7.