My Vmax performing like a 500cc

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
anyone purchase a manometer, recommendations?

the plastic cover of the cutoff, well, i inadvertantly switched it with another, so I couldnt figure out where that spring was supposed to be at.... but, it is working properly right now without it, so, I'll keep it around til next time i rebuild or whatever.

it's an amazing feeling to get her running. my manometer is shit so i gotta just buy a real one. cuz she's soooooooooo far off.. my setup is more headache. if it was closer, no problem, but as is, need to sync her up good.

still gotta figure out actual wet float level-i know how, just saying.

still gotta figure out a/f mix screw,,,, do i do this based on what soark plugs look like after warm up?

think that's it,,... before front fork rebuild, fix vboost, ..... maybe mod a bit?.....

First of all set the A/F screws to 2.5 turns out, and just go from there. Take it out and ride, she will let you know what she likes.

Yep, with the carbs being split, you will need to sync. I like the Morgan Carbtune.

https://www.carbtune.com/

Glad that you got it up and running.
 
First of all set the A/F screws to 2.5 turns out, and just go from there. Take it out and ride, she will let you know what she likes.

Yep, with the carbs being split, you will need to sync. I like the Morgan Carbtune.

https://www.carbtune.com/

Glad that you got it up and running.

ye thanks.. she's set at 2.5 turns out right now so we'll see how that goes. Gotta renew the insurance, wasn't sure if i'd be riding her this year or not.
it's amazing what properly rebuilt carbs will do, thanks for all the help everyone. will try to sync it up best i can with what i got. now need to figure out what's doing what with sync screws.... as far as what is happening to the carbs when a guy turns CW or CCW on the sync screw... trial and error was a big headache yesterday, esp when they were so far off after rebuild.
 
ok havn'et gotten 20 miles since carb rebuild.

went to watch a ballgame, was good going there, on way back couple miles in, the power seemed to have dropped suddenly like a third.... accelleration was way sub par, sounded and felt like i was in 5th gear going 25 miles an hour, felt that way with every gear... and not til 4500 rpm would the bike kinda "jump" a little bit. getting home and there was a significant amount of dark smoke exhaust coming out from left side. right side still ok...

not sure if significant, but my Vboost isn't working, certainly dont feel what it's for, but when i would roll past 6K (before recent power loss) it would rev up into 8K then back off automatically, like i'd rev into 6K and try to power thru and feel that rush but the bike would feel like i pulled the clutch in...

wouildnt power thru it, but immediate problem is the loss of power and lots of exhaust coming out of left side...

thoughts?
 
supertrapp slip ons

Ok, so black smoke means that your running rich, on those cylinders. The Vmax pairs the opposite side cylinders together. So I THINK, the cylinders for the left exhaust is the left rear, and right front. So pull the plugs and see if they are rich. Take the airbox cover off (with the bike running......your not gonna try and ride it like this) and see if the slides are moving at idle, or when you slightly goose it.

It could be something small like the plug caps arent on fully....etc, so now is the time to investigate.
 
Ok, so black smoke means that your running rich, on those cylinders. The Vmax pairs the opposite side cylinders together. So I THINK, the cylinders for the left exhaust is the left rear, and right front. So pull the plugs and see if they are rich. Take the airbox cover off (with the bike running......your not gonna try and ride it like this) and see if the slides are moving at idle, or when you slightly goose it.

It could be something small like the plug caps arent on fully....etc, so now is the time to investigate.

And after all that go out into the world and collect all the animals by 2 and put them into the ark.:clapping:
 
Acting like it did before carb rebuild. Crank on throttle and boggs down again... hmm.
took 2 videos, one before taking airbox off, you can see the exhaust pouring out. Good thing is that the bike at least idles and runs but having similar issues as before.

https://youtu.be/9yQIIvCvDRc

next vid , you can see the diaphragms moving... but again when blurp throttle, starving or something... filled up on fuel 12 miles prior.

https://youtu.be/XJFrFHXPHp8
 
Acting like it did before carb rebuild. Crank on throttle and boggs down again... hmm.
took 2 videos, one before taking airbox off, you can see the exhaust pouring out. Good thing is that the bike at least idles and runs but having similar issues as before.

https://youtu.be/9yQIIvCvDRc

next vid , you can see the diaphragms moving... but again when blurp throttle, starving or something... filled up on fuel 12 miles prior.

https://youtu.be/XJFrFHXPHp8

Float levels set?:ummm:
Did you get your slides springs in correctly under the carb caps?:ummm:
 
haven't properly set the float levels. just got my aux tank so I can bench set them.

she ran good for 15 miles... slide springs in for sure, i'll check the diaphragms make sure all set, also i'll pull plugs and see what's going on there... i dry set floats 1.25" for starters but we'll see what i get for wet float test, i'll do all taht tonight..
check fuel level in bowls
pull plugs check out waht they look like
check diaphragms placement and spring..
 
haven't properly set the float levels. just got my aux tank so I can bench set them.

she ran good for 15 miles... slide springs in for sure, i'll check the diaphragms make sure all set, also i'll pull plugs and see what's going on there... i dry set floats 1.25" for starters but we'll see what i get for wet float test, i'll do all taht tonight..
check fuel level in bowls
pull plugs check out waht they look like
check diaphragms placement and spring..
or 1.125 whatever it's supposed to be for dry float level set....
 
pulled the plugs here is what they look like.. in order as pictured, cylinder 3,4,1,2.


look at that first plug, don't look too good as far as all the crud on it... thoughts on that?

anyways been waiting to let ya'll know what these look like before proceeding. I mean the bike runs, but it's running like a 500cc, lol. but at least it's running and idles and stuff... but... don't really wanna take it too far plus without that acceleration, not that great fun factor...
 

Attachments

  • IMG_0455[1].jpg
    IMG_0455[1].jpg
    39.4 KB · Views: 22
  • IMG_0456[1].jpg
    IMG_0456[1].jpg
    38.8 KB · Views: 19
  • IMG_0457[1].jpg
    IMG_0457[1].jpg
    37.6 KB · Views: 19
  • IMG_0458[1].jpg
    IMG_0458[1].jpg
    41.5 KB · Views: 18
pulled the plugs here is what they look like.. in order as pictured, cylinder 3,4,1,2.


look at that first plug, don't look too good as far as all the crud on it... thoughts on that?

anyways been waiting to let ya'll know what these look like before proceeding. I mean the bike runs, but it's running like a 500cc, lol. but at least it's running and idles and stuff... but... don't really wanna take it too far plus without that acceleration, not that great fun factor...

Depends on the mileage on the plug?:confused2:
The last one #2 looks about where you want the other 3 to look like-nice and tan-:clapping:
#3-too rich
#4 too lean-
#1 is ok-
I would try a new set to get a more accurate reading-That first #3 looks to have been in for a while.
 
Depends on the mileage on the plug?:confused2:
The last one #2 looks about where you want the other 3 to look like-nice and tan-:clapping:
#3-too rich
#4 too lean-
#1 is ok-
I would try a new set to get a more accurate reading-That first #3 looks to have been in for a while.

thanks Donny,

I replaced all plugs with new last year, probably 200 miles on them... i'll finely tune 3 and 4 as you recommend and sync and see how it runs. i think there's a bigger problem though cuz i lost power big time the other day.... til 4500rpm, then it's like things clicked in and i'd finally feel some pull..
 
till 4500rpm, then it's like things clicked in and i'd finally feel some pull..
That was the same RPM problem zone I "HAD" before using Seafoam. Even 4 carb breakdown baths with the ultra sonic cleaner could not get me past that stumble at 4500 RPM. I put 1/2 can of Seafoam to 1 full tank. Did this twice. When I was about do do it again for the 3rd tank, out of no where, the bike started pulling smooth and strong across the full RPM range. So far (4 years now), I did not have to re-apply Seafoam.

Just something to think about.
 
That was the same RPM problem zone I "HAD" before using Seafoam. Even 4 carb breakdown baths with the ultra sonic cleaner could not get me past that stumble at 4500 RPM. I put 1/2 can of Seafoam to 1 full tank. Did this twice. When I was about do do it again for the 3rd tank, out of no where, the bike started pulling smooth and strong across the full RPM range. So far (4 years now), I did not have to re-apply Seafoam.

Just something to think about.

That something to think about was probably a jetblock clogged.:confused2:
 
Here is a very good pic, thats been posted here on the forum a couple of times to help diagnose which area of the plug corresponds to which area in the carbs.

Now, to actually "read" plugs, there is a whole procedure, but this pic will get you in the ball park, to allow you to fine tune later.

http://kawtriple.com/mraxl/carb/plugchop.htm
 

Attachments

  • sparkplug.jpg
    sparkplug.jpg
    24.7 KB · Views: 20
Back
Top