Bought a vmax all ive had is trouble help

VMAX  Forum

Help Support VMAX Forum:

julian_39

Member
Joined
Aug 14, 2021
Messages
6
Reaction score
3
Hi all i bought a 1990 vmax and found it not as said fast so put new fuel in and much better but i checked the carb mixture screws and they are all over the place so i set the left side to two n half turns out moves to right side and the screws are rounded so i cant move them
How can i get em out please
The bike runs ok just not what i was expecting in turns of power
v boost does its cycle on start up
 

Parminio

Well-Known Member
Joined
Apr 22, 2016
Messages
1,418
Reaction score
954
Location
Suwanee, Georgia
I wouldn't know where to begin, pal. It sounds like you bought a bike that has been rode hard and put up wet. The rounded off screws are a really bad sign. It tends to make me think somebody has been messing with them a whole lot that had no idea what they were doing.

First thing I would do is hook up some vacuum gauges to sync the carbs and see what's going on. Make sure each carb is at least pulling its own weight. That will tell you a lot about what is going on.

Mixture is one thing. Actual flow is another thing entirely.

I would start there: sync the carbs first and see what's going on.
 

02GF74

Well-Known Member
Joined
Mar 26, 2020
Messages
1,501
Reaction score
706
Location
UK
If you coming from a couple of years old Zx14 or Hayabusa, then I guess a motorcycle that is 35 years (which is when it wad first launched and remained mostly unchanged), then it may indeed feel slow.

Question is is it slow because somethings wrong or perceived to be slow because you are used to riding faster bikes.


OK, so to remove the mixture screws, pretty sure this had been discussed so a search should reveal all. I seem to recall using a dremel type tool to cut a slot but certainly a left hand drill and an eazi out would do it.

Take care and time ad it would be easy to f**k up the carbs.
 

Fire-medic

Well-Known Member
Staff member
Moderator
Joined
Mar 25, 2011
Messages
13,298
Reaction score
2,894
Location
Miami Florida

julian_39

Member
Joined
Aug 14, 2021
Messages
6
Reaction score
3
I wouldn't know where to begin, pal. It sounds like you bought a bike that has been rode hard and put up wet. The rounded off screws are a really bad sign. It tends to make me think somebody has been messing with them a whole lot that had no idea what they were doing.

First thing I would do is hook up some vacuum gauges to sync the carbs and see what's going on. Make sure each carb is at least pulling its own weight. That will tell you a lot about what is going on.

Mixture is one thing. Actual flow is another thing entirely.

I would start there: sync the carbs first and see what's going on.
I bought it from a old man only done 13k it looks almost new but i think he may have been tinkering with it
 

ColoradoPhil

Member
Joined
Jun 8, 2021
Messages
24
Reaction score
6
Hi all i bought a 1990 vmax and found it not as said fast so put new fuel in and much better but i checked the carb mixture screws and they are all over the place so i set the left side to two n half turns out moves to right side and the screws are rounded so i cant move them
How can i get em out please
The bike runs ok just not what i was expecting in turns of power
v boost does its cycle on start up


Was curious .. what were you expecting in terms of power ? By crotch rocket standards a 90 vmax isnt quick at all ... most 600's would beat it in a drag race... I remember when my 85 was stock and i was racing a cbr600 f2 and the guy had his GF on the back and it was all i could do to hang with him .... It will smoke a harley and most cars but its not a fast bike ...i dunno about Gen 2
 

DreamV4

Well-Known Member
Joined
Jun 30, 2021
Messages
1,041
Reaction score
278
I just need power for bragging rights. I am sure 50 HP is enough for me.
 

Screwloose

Well-Known Member
Joined
Aug 17, 2020
Messages
630
Reaction score
433
Location
Glasgow
Looks nearly identical to one of my carbs that I chopped away one of the tubes to get at the A/F screw. Put some heat on it and drew it out. When it's all back together you do not notice it. Although if I were to tackle another I would go for the left handed drill bit method mentioned on here previously.
 

Fire-medic

Well-Known Member
Staff member
Moderator
Joined
Mar 25, 2011
Messages
13,298
Reaction score
2,894
Location
Miami Florida
Looks nearly identical to one of my carbs that I chopped away one of the tubes to get at the A/F screw. Put some heat on it and drew it out. When it's all back together you do not notice it. Although if I were to tackle another I would go for the left handed drill bit method mentioned on here previously.
Yes, no-need for butchery. If you don't think you can do it yourself, take it to a machine shop with a new needle, so they can chase the threads and you have a ready-to-go carburetor, and you avoid the hack-job.
 

Screwloose

Well-Known Member
Joined
Aug 17, 2020
Messages
630
Reaction score
433
Location
Glasgow
Yes, no-need for butchery. If you don't think you can do it yourself, take it to a machine shop with a new needle, so they can chase the threads and you have a ready-to-go carburetor, and you avoid the hack-job.
I can do it myself, I started my career as a turner fitter. The reverse drilling method on this forum superseded my thoughts though. Nobody's perfect 🤪
 

Parminio

Well-Known Member
Joined
Apr 22, 2016
Messages
1,418
Reaction score
954
Location
Suwanee, Georgia
I remember when my 85 was stock and i was racing a cbr600 f2 and the guy had his GF on the back and it was all i could do to hang with him
Then you had a missing cylinder or something bad wrong with your bike.

The Hurricane had a horsepower to weight ratio of 5.05 to 1.

The Vmax has a horsepower to weight ratio of 4.38 to 1.

So unless you weigh about 500 pounds, you should have EASILY left them behind.
 

desert_max

Well-Known Member
Joined
Mar 14, 2010
Messages
1,534
Reaction score
1,246
Location
Chandler, Arizona
Then you had a missing cylinder or something bad wrong with your bike.

The Hurricane had a horsepower to weight ratio of 5.05 to 1.

The Vmax has a horsepower to weight ratio of 4.38 to 1.

So unless you weigh about 500 pounds, you should have EASILY left them behind.

My thoughts exactly.
 

Screwloose

Well-Known Member
Joined
Aug 17, 2020
Messages
630
Reaction score
433
Location
Glasgow
What is it?
Work a turning lathe, milling machine, vertical borer, grinder, etc, they are all called machine tools. CNC and manual are all classed as machine tools also.

But when you do an apprenticeship in the UK it is common to have 'fitter' attached as it allows a person to perform handcraft duties on top of operate all machine tools.

I really enjoyed it at the time, but politicians during the day stripped Scotland of allot of engineering work, so I left it and moved onto something else.
 

Latest posts

Top