Losing power?

[Kuprebel]

I ran out of gas with my max yesterday (not too uncommon) but after I started it up again it seemed as though I didn't get much power past 5k rpm or half throttle, and when I go over I hear alot of popping but no power. With lower throttle and lower rpm I get the same amount of power and torque I had before. I had adjusted the AF mixture screws beforehand and made them alot more lean, would that make a big difference at 5k+ rpm? I got some particulates out of the fuel filter and drained the carb bowls and the gas was clean. Any suggestions? Would the shotgun or peaahooter make much of a difference here?

 

[Tex85]

I would sync the carbs up first as that is probably the easiest as long as you have the right tool. If ran fine before adjusting I would think it was just out of sync. K.I.S.S theory.

 

[Kuprebel]

I would sync the carbs up first as that is probably the easiest as long as you have the right tool. If ran fine before adjusting I would think it was just out of sync. K.I.S.S theory.

I just had the carbs synced about a week ago, would messing with the AF mixture screws move it out of sync?

 

[Traumahawk]

I just had the carbs synced about a week ago, would messing with the AF mixture screws move it out of sync?

No....moving the A/F screws will not make it go out of sync. Now I'm always a big fan of doing a shotgun because all it takes is just one bit of particulate to clog up a pilot jet and affect everything. Now pilot jets don't really make a difference at higher rpm. ....but they do make a difference.

Sent from my SCH-R890 using Tapatalk

 

[jfeagins]

Pilot jets shouldn't have that much, if any, effect on his upper RPM range.

If it ran well right up until you ran out of gas, then started acting up as soon as you filled it up again, I'd be looking at maybe a fuel pick up problem. Perhaps after introducing air into your pickup line through to the pump, you have dislodged one, or both of the rubber diaphragms inside it? Does your pump pressurize the lines and carbs when you first key on? Or does the pump continue clicking a lot?

Maybe a partially stuck (shut) float in a carb? Because it sounds to me as if you are getting enough gas to run properly up through mid range, but then not enough to accelerate beyond that?????

 

[Kuprebel]

Pilot jets shouldn't have that much, if any, effect on his upper RPM range.

If it ran well right up until you ran out of gas, then started acting up as soon as you filled it up again, I'd be looking at maybe a fuel pick up problem. Perhaps after introducing air into your pickup line through to the pump, you have dislodged one, or both of the rubber diaphragms inside it? Does your pump pressurize the lines and carbs when you first key on? Or does the pump continue clicking a lot?

Maybe a partially stuck (shut) float in a carb? Because it sounds to me as if you are getting enough gas to run properly up through mid range, but then not enough to accelerate beyond that?????

My pump properly pressurizes the lines, because it stops clicking and starts really easy (read; one to three turn overs). My floats getting stuck sounds kind of plausible other than the fact that it gets issues outside of the float tuning range? 5k+ rpm? I'm not entirely sure but I might try the shotgun and run the AF screws a bit richer and see how that helps as I believe my gas tank is not in the cleanest state and something might have clogged my pilot jets. I'm open to suggestions and appreciate any input in the meantime while i figure this out before having to bring it to my mechanic :ummm:

 

[Traumahawk]

My pump properly pressurizes the lines, because it stops clicking and starts really easy (read; one to three turn overs). My floats getting stuck sounds kind of plausible other than the fact that it gets issues outside of the float tuning range? 5k+ rpm? I'm not entirely sure but I might try the shotgun and run the AF screws a bit richer and see how that helps as I believe my gas tank is not in the cleanest state and something might have clogged my pilot jets. I'm open to suggestions and appreciate any input in the meantime while i figure this out before having to bring it to my mechanic :ummm:

There are people on this forum that are WAY better than any mechanic that has never seen a Vmax...much less never touched one.

 

[[email protected]]

Is your tank clean?
Maybe when you ran it empty the carbs siphoned some trash. Empty the float bowls into a clear, glass container and have a look.

 

[Kuprebel]

Is your tank clean?
Maybe when you ran it empty the carbs siphoned some trash. Empty the float bowls into a clear, glass container and have a look.

I emptied them into a steel container because that's all I had but the gas looked pretty clear. I was hoping it was just some **** I could clear out:bang head:

 

[Kuprebel]

There are people on this forum that are WAY better than any mechanic that has never seen a Vmax...much less never touched one.

Very true, but these guys are pretty good it's just the labor costs that kill me. Rather go through you guys, it's way betterunk:

 

[Traumahawk]

Very true, but these guys are pretty good it's just the labor costs that kill me. Rather go through you guys, it's way betterunk:

Ok cool. Just holler and someone on here has the right answer.

 

[Kuprebel]

UPDATE: I rebuilt my carbs and moved back to stock jetting and everything. Got them synced and I'm still getting an odd sound/power return at around 5-7 grand. the bike will lurch a bit and not give me full power. It runs perfectly fine out of that rpm. I tried shimming the needles out a bit to get it richer but it didn't make a discernible difference. Any suggestions?

 

[Traumahawk]

So lets go over what the settings are. What size are jets? Are the needles stock? Stock springs? What are the A/f screws at?

 

[Dragmaxster]

Did you put the hoses on i sent?

 

[Kuprebel]

I got those hoses installed, the mains are 147.5 mikuni. Stock springs, needles, and the A/F screws are at 2.5 turns each.

 

[davesax36]

And what pipe and air box?

 

[Kuprebel]

And what pipe and air box?

Currently using supertrapp black slips with 9 disks in each side. Using stock air box with y removed and k/n air filter

 

[Dragmaxster]

Currently using supertrapp black slips with 9 disks in each side. Using stock air box with y removed and k/n air filter

My 2 cents-Not sure if you have the spark arrestor or open end cap-
I remember Dman999 running his with 8 disks and spark arrestor caps and it running well and then changing to no plates and the open end cap.
http://www.ebay.com/itm/SuperTrapp-...ash=item4d208e4257:g:~GwAAMXQVT9TAllR&vxp=mtr

 

[Traumahawk]

I got those hoses installed, the mains are 147.5 mikuni. Stock springs, needles, and the A/F screws are at 2.5 turns each.

I'm wondering if your just a bit lean. The Vmax really likes 150's for the mains with slips. When I was running a stock airbox, I made the most hp running 150 mains and the Y removed. I would leave everything else the same.....even the A/F screws and swap to 150's.

 

[Dragmaxster]

+1 on the 150 mains-
By adding more discs in the supertrapp on a vmax you are actually making it run richer- most other bike engines that would be opposite.