Backfiring into airbox and high idle.

[Kratos]

That would be great if that is all it is, I'll give some more Seafoam a try.

Thanks for the input!

 

[naughtyG]

Another thing you can try is to shim your stock needles. My bike ('86) had those shims (just small standard washers) on when I got it, and after I took them off I had a similar problem - cruising around 4k rpm it would keep on surging and missing and feeling like it was running out of fuel, which Mark identified as a lean mixture symptom.

However, since I took my carbs off, cleaned them completely and replaced a few o-rings and gaskets, it's been cruising fine without the shims.

I can send those shims to you if you wanna try them, but I think they're a bit of a workaround for dirty carbs..

 

[Kratos]

Thanks naughtyG, but I'll try the Seafoam, and/or going back through the carbs again first. Thanks for the info though.

 

[shawn kloker]

I ran 11 discs with open end caps on each side and stock jetting here at 1200 feet with no issues. How high are you?

 

[Kratos]

I'm in southern Indiana at about 500 feet or so above sea level.

 

[shawn kloker]

If the jetting is still stock,there is no way that you are too lean.Specially at 500 feet.

 

[Kratos]

Yes, jets and needles are still stock.

:worthy: I appreciate everyone's help on pointing me toward the fact that the carbs are probably still dirty rather than being too lean as a result of the slip-on exhaust. I am learning quite a bit about the VMAX carb issues on this forum.

:ummm:
Once I go back through the carbs and the bike is running as it should, would the needles from the Factory Pro jet kit be of any use, or should I stick with the stock needles as well?

:ummm:
Does anyone have the same set up I do that have had their bike tuned on a dyno that can tell me the number of discs that worked best with the K&N filter and the airbox Y removed? I would also like to know the fuel mixture screw settings

:ummm:
Is there a way to go about setting the fuel mixture screws? Or do you just try different settings and ride to see how the bike performs?

 

[shawn kloker]

Yes, jets and needles are still stock.

:worthy: I appreciate everyone's help on pointing me toward the fact that the carbs are probably still dirty rather than being too lean as a result of the slip-on exhaust. I am learning quite a bit about the VMAX carb issues on this forum.

:ummm:
Once I go back through the carbs and the bike is running as it should, would the needles from the Factory Pro jet kit be of any use, or should I stick with the stock needles as well?

:ummm:
Does anyone have the same set up I do that have had their bike tuned on a dyno that can tell me the number of discs that worked best with the K&N filter and the airbox Y removed? I would also like to know the fuel mixture screw settings

:ummm:
Is there a way to go about setting the fuel mixture screws? Or do you just try different settings and ride to see how the bike performs?

I would leave the needles stock and put the Y back on. Till you get after market headers you are better off this way. The stock headers do not flow as good.Put all the discs back in!

 

[Kratos]

Will do Shawn,

Should I only go with the 8 discs, per muffler, that came with the exhaust, or add more discs? I have some more 4" discs laying around that I had used on a buddies bike.

 

[cstove]

Actually a few ounces of Techron Fuel Cleaner will do loads more for effective cleaning over Seafoam. Seafoam gets tons of hype but it really doesn't pack the punch many guys think it does.
Seafoam is only made of isopropyl alcohol and a light sewing machine grade oil. It will burn the fuel easier because the alcohol acts as a combustion enhancer. And the light oil may provide some momentary valve cushion. But as a valid cleaner, it really can't do much for removing fuel gums.
On the other hand Techron contains polyether amine, a strong nitrogen-based fuel detergent. Although it won't give you the "one-tank-wonder" throttle response that Seafoam does due to the alcohol boost, it will actually remove fuel deposits 100% from your fuel system.
This by far is the better way to go...actually remove deposits versus "spiking" your fuel with a faster burning solvent.

 

[shawn kloker]

Yah and acetone mixed 2 ounces per 10 gallons of gaS CLEANS THE SHIT OUT OF EVERYTHING.

 

[shawn kloker]

Will do Shawn,

Should I only go with the 8 discs, per muffler, that came with the exhaust, or add more discs? I have some more 4" discs laying around that I had used on a buddies bike.

It is up to you what sound that you want.

 

[ssnsltd]

Handy thing about SeaFoam is it also acts as a fuel stabilizer. Since I got my family to use it in all the small engine appliances they never have a bad gas issue and all run better-year round.

Yah and acetone mixed 2 ounces per 10 gallons of gaS CLEANS THE SHIT OUT OF EVERYTHING.

yah it does, add a gallon to 5 gallons of gas and it will even clean out a tank from a car sitting in storage for 10 years. . .

 

[Mitchell]

Actually a few ounces of Techron Fuel Cleaner will do loads more for effective cleaning over Seafoam. Seafoam gets tons of hype but it really doesn't pack the punch many guys think it does.
Seafoam is only made of isopropyl alcohol and a light sewing machine grade oil. It will burn the fuel easier because the alcohol acts as a combustion enhancer. And the light oil may provide some momentary valve cushion. But as a valid cleaner, it really can't do much for removing fuel gums.
On the other hand Techron contains polyether amine, a strong nitrogen-based fuel detergent. Although it won't give you the "one-tank-wonder" throttle response that Seafoam does due to the alcohol boost, it will actually remove fuel deposits 100% from your fuel system.
This by far is the better way to go...actually remove deposits versus "spiking" your fuel with a faster burning solvent.

+ 1 and well said!