Stage 7 loses power at 7000 rpm

[Swoosebag]

I recently bought an 88 with a stage 7 jet kit and 4 into 1 kerker. It sounds good, but I think it is lacking power, especially at 7,000 rpm. It accelerates smoothly until 6,500 then it will hesitate for half a second, pull to 7,000 and then it is like it hits a rev limiter--no more power. I can't get the rpms any higher. My mostly stock 93 knocks the socks off this which leads me to believe something is wrong.

Is this a carb/tuning issue or something more extreme?

Full disclosure, the bike tipped over in the trailer when I was bringing it home. It leaked a little oil onto the trailer floor. Maybe that had something to do with it???

Thanks for any help you have to offer.

I also put new plugs in. The right front cylinder plug was oily, the rest looked okay.

 

[scuff]

air filters clean? i would check all vacum hoses anything could have come loose falling over

 

[Traumahawk]

Did it have this issue when you bought it.....or did it develop after?

 

[Swoosebag]

I bought it and it tipped over on the way home, so it has had the issue as long as I have owned it (about two weeks).

 

[tugla]

got same set up....whats your elevation...and carb set up...jets ..needle position etc

 

[sdt354]

A throttle chop at 7k and plug read should tell a story. Sometimes a big jolt will fk things up carb. wise. I'm not sure if the bike falling has anything to do with your issue though.

 

[tugla]

when mine did that i fixed by going back to clip either two or three....float height was too low and dj 160. ..bike was close to sea level...just couple hundred feet up.

 

[Swoosebag]

I am at 700 feet. I haven't torn into the carbs yet, but I will tomorrow. Thanks for the ideas.

 

[Woody]

This is my go to answer for every bike that sputters at higher rpms.

"DRAIN YOUR FLOAT BOWLS" any water or gunk will collect in the bowls.
high rpm's during acceleration sucks the gunk up through the carb.

5 min. with a screw driver and no money spent. it's worth a shot.

 

[Swoosebag]

Thanks Woody, I'll try that before I rip the sucker apart.

 

[Dragmaxster]

Thanks Woody, I'll try that before I rip the sucker apart.

I put another heatshield on the front to better hold the plugs at that rpm as one was moving on me- just a little cutting and it fits fine.

 

[Woody]

I put another heatshield on the front to better hold the plugs at that rpm as one was moving on me- just a little cutting and it fits fine.

i switched my plug wires to 8mm accell automotive wires. i use the boots that came on the wires. (NO ISSUES at any rpm)
although i do need to run the screw on tips on my plugs.

NO heat shields

 

[Swoosebag]

Just an update. After cleaning the carbs and checking all that I could think of I looked at the needles again. I assumed they were stage 7 needles (p.o. told me it had a stage 7 kit installed). Turns out they are stage 1 needles with stage 7 jets. Needless to say I have been running a little on the rich side...

 

[adambweird]

That will do it!

 

[thor_eyerdhal]

Stage1 needle make mixture leaner than stage7 ones, look at tip diameter, so it could be worse

 

[Traumahawk]

I'm wondering what size your main jets are? If someone followed the directions......you are super rich all the way around.

Sent from my SCH-R890 using Tapatalk

 

[Swoosebag]

I haven't checked them yet. Can you check the size without pulling them out? What size should I run? I'm at 700 feet, the paj 2 (I think) is a dj 190, I haven't checked the paj 1 yet.

 

[Traumahawk]

Ok.....the DJ190 is equal to the mk 177. Stock is the mk 170. The 177 will lean it out thru the ENTIRE RPM range.....and not needed unless your Vboost is open at all RPM.

The only way to see what the main jets are is to pull the carbs.....and its not hard to do.

Most people on this forum run mikuni (mk) jets.....for tun-ability sake, here is a list to cross reference.

Just be forewarned...the Vmax likes to run lean......and dynojet likes their kits pig rich. You will have to make some adjustments.

 

[Swoosebag]

The vboost is removed. Should I go with 150 mains or a bit smaller?

 

[Traumahawk]

PAJ#1 should be a 90....PAJ#2 should be a 170 and the mains should be a 150. The stage 1 needles can be made to work first clip from the blunt end.

EDIT....vboost removed....are there cross over tubes installed?

Sent from my SCH-R890 using Tapatalk