Losing power?

[DMAN999]

I do run mine with stock airbox, jetting and needles and Supertrapps with 8 discs
and closed caps for longer or group rides and open caps with no discs around town.
Both ways run well without any bogging BUT it does run a tad rich (slight gas smell at idle and the end caps get sooty).
Supertrapp recommends using 6 to 8 discs with closed caps for a Vmax, the open caps are supposed to be equal to 10 discs.
So I plan on installing 150 mains this winter and see how they do.

 

[Traumahawk]

+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.

With CV carbs....if you have a decrease in back pressure, you will have more air flowing out the exhaust. With that.....you will PULL more air into the carb....and with that, pull more full making you richer.

So stock jetting is 152.5's. Slip on flow a bit better than stock....so you drop 1 jet size to 150's. By removing the Y on the airbox, that will lean you out a bit as well. So the 147's.....plus removal of the Y.....is why I think that your just a bit too lean.

If you were having that spot around 4000 rpm....I would say that you were too lean on the needle, BUT your basically running a stock Vmax....so it will probably run better with the needle in the stock spot.

Hopefully that help explains the WHY I think that your too lean.

 

[Dragmaxster]

Stock mains being 152.5 and you lowering 2 increments in mains jets to 147.5 is the reason i believe you are lean. I would try 150 main jets and if it helps you know you are going in the right direction.
Have you done a reading of the sparkplugs?

 

[Kuprebel]

Stock mains being 152.5 and you lowering 2 increments in mains jets to 147.5 is the reason i believe you are lean. I would try 150 main jets and if it helps you know you are going in the right direction.
Have you done a reading of the sparkplugs?

Haven't gotten around to do a reading of the spark plugs yet - I may pull one and see what I get. It seems odd that my mains would mess so much with my 5-7 grand response. Once I move above 7 grand I get full power and no noticeable issue below 5 grand. It just is jumpy and inconsistent between 5 and 7 grand.

 

[Dragmaxster]

Haven't gotten around to do a reading of the spark plugs yet - I may pull one and see what I get. It seems odd that my mains would mess so much with my 5-7 grand response. Once I move above 7 grand I get full power and no noticeable issue below 5 grand. It just is jumpy and inconsistent between 5 and 7 grand.

That would be the needle range.
You and TB99Max are having the same issue. Sounds like.

 

[Kuprebel]

That would be the needle range.
You and TB99Max are having the same issue. Sounds like.

Yea it seems as though, but shimming my needles didn't make a noticable difference. I'll pull the plugs and see what they look like but I'm not entirely sure its my needle that needs adjusting. Anything else that would affect the needle range?

 

[Dragmaxster]

From 1/4 to 3/4 shows the jet needle---also some members here shorten the springs to make the slides lift quicker and that helps eliminate that dead spot.
https://www.google.com/search?q=mik...c5V3LeAAM:&usg=__apf_MBYrDAuWcJyH-Sjub1eFRcM=

 

[Kuprebel]

Alright, while I was inspecting my slides taking the shims off I noticed there were two holes. One where the needle goes through and one where nothing goes through. I assume this means my slides have been drilled? Would this effect my performance on a now stock setup? from what I believe was a stage 1 kit? (stage 1 needles, mains)

 

[Dragmaxster]

Alright, while I was inspecting my slides taking the shims off I noticed there were two holes. One where the needle goes through and one where nothing goes through. I assume this means my slides have been drilled? Would this effect my performance on a now stock setup? from what I believe was a stage 1 kit? (stage 1 needles, mains)

It depends on the size hole? It was already there but would have to have been drilled with a 5/32 bit.

 

[Kuprebel]

Alright, while I was inspecting my slides taking the shims off I noticed there were two holes. One where the needle goes through and one where nothing goes through. I assume this means my slides have been drilled? Would this effect my performance on a now stock setup? from what I believe was a stage 1 kit? (stage 1 needles, mains)

I'm no expert on these kind of things, I have no idea what stock slides look like on the vmax, any help?:hmmm:

 

[Dragmaxster]

Air goes through that second hole and the hole where the needle goes should never be drilled larger.