v-max dial a jet HELP

D

dlvsdh

New member
hey everyone its been a while.

ive got my 92 v-max 4 750cc bored to 800cc with some mods on top of that. and im having a problem with it. there is a dead spot in the throttle from idle to about 3000 rpm. i dont know everything thats been done to it but what i do know is it is a 750 bored to 800 it has psi pipes the clutch to go with it and dial a jets.
with choke off it has a dead spot with choke half applied it allmost looses the dead spot compleatly so i know that its not getting enugh fuel, corect me if im wrong, and then it just takes off. any help would be greatly apreciated. if there is any more info that you need that would help out let me know. thanks

dyllan,
 

gitterdun1985 said:
sounds to me like to need some clutching
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well i really think it has to do with the carns because i just cleaned them. and lets just say that it was my first time going thorugh these carbs so idk it didnt do it befor i messed with them. i wish now i didnt mess with it.
 
for not knowing much about your sled and u saying it sounds like its starving for fuel on the lo end id look and see what pilot jets u have and make shur your carbs are clean clean clean... these sleds love there fuel. what jets are you running and what dial a jet kit are you running on that 750
 
0 to 3000 rpms doesn't even hit engagement yet so clutching isn't the issue.

Will it idle??? Do you have fresh GOOD!! fuel in it. Old fuel (doesn't have to be very old) burns like schnitt. Can and will cause issues like this.



If so then it sounds like a transition issue between the pilot and main systems.

Make sure the pilot jets and all the air passages the pilot system need to function are clean. Make sure the pilot air screws are set right. The same with the main fuel system. Check the jetting. Pilots may be to small or needle dropped to far on the main and /or main to small.

Clean jets don't make a clean carb. There are air passages for all the systems that function on any carb. If they are plugged or partially plugged you won't get them to work right.

Check it out.

opsled
 
Low speed circuit

More then likely dirty carbs. Make sure you remove pitot jet and fuel screw and soak with carb cleaner and blow out with compressed air. If the low speed circuit is not clogged you will get flow between the pilot jet orfice, the fuel screw orfice and the air jet on the intake horn of the carb.

Check this out for ref. http://www.vmax4.com/vbulletin/show...o-and-what-order&p=23707&highlight=#post23707

I think dial-a-jets are the bomb especially with psi pipes as they like a lean setting down low and the dial a jet fattens up the top end as required.

Also check tors they maybe acting up.

/Good Luck, Dan
 

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Dan, Are you talking "bomb" in a good sense or bad???

Never messed with them but they seem to work similar to a power jet but with easier adjustment and air pressure compensating ability.

Am I on the right track or all effed up? (effed up on this subject I mean)lol

Thanks, opsled
 
Phil, probably a poor choice of word (bomb) lol. I think they are awsome. They are similar to a power jet but won't over fuel. Here is a comment I made back 2006 on this subject.

The following is IMO and my vary with others considering I do not have mountain experience. Remember that my comments are "in a nutshell) terms. I am sure that their are people out there that could a 300 pags thiesis of this topic.

The Holtzman VARI Flow is simply a vaccum sourced control that varies the pressure in the float bowls via the float bowl vent lines. The carbs. need to be jetted for your lowest altitude riding conditions and average temp. As you climb a moutain you can simply adjust the knob to the leaner position. This allows more air flow and leans the mixture base on vaccum demand. I can see how these devices can be attractive to the montain rider as elevation is increased and then decreased or whatever the combination and a pretty good fuel curve to the motor is maintained.

The Dial-a-Jet works on a completely different theory. It is a independant jetting device that extacts fuel from the float bowl, atomizes it and is inducted into the carberator before the carb itself starts to atomizes its own fuel charge to the engine. Since the DaJ's fuel charge is atomized before the carberators own fuel charge, it flows to the path of least resistance filling in any lean area throughout the fuel curve.

Since the DaJ won't flow a fuel charge in a rich or adaquete fuel situation you have to set your MJ, possibley needle and needle jets to get the motor to run in a lean condition. This will excite the DaJ into service. The advantage here is you can run a leaner mixture at bottom end to get that great holeshot for you racers or run along at 10mph for you trail guys and not load up. The DaJ will add fuel as required by the motor to maintain a optimized fuel curve.

The DaJ has 5 positions. The middle or neutral position S/B for your every day riding conditions. Like the Vari-Flow it will have to be adjusted as the temp goes up or down 10-15 F or your altitude changes 1000- 2000'. However you have to open the hood and get a screw driver out. The change will take you only a couple of minutes once you get use to it.

Again just my opinion in a nutshell.

Vmax535:drink1:​
 
Thanks Dan, I thought you meant "bomb" in a good way.

That clarifies it for me.

Thanks again, Phil (opsled)
 
VMAX535 said:
More then likely dirty carbs. Make sure you remove pitot jet and fuel screw and soak with carb cleaner and blow out with compressed air. If the low speed circuit is not clogged you will get flow between the pilot jet orfice, the fuel screw orfice and the air jet on the intake horn of the carb.

Check this out for ref. http://www.vmax4.com/vbulletin/show...o-and-what-order&p=23707&highlight=#post23707

I think dial-a-jets are the bomb especially with psi pipes as they like a lean setting down low and the dial a jet fattens up the top end as required.

Also check tors they maybe acting up.

/Good Luck, Dan
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do you know if the length of the hose going from the bottom of the bowl to the top of the dial a jet matter.
 
fuel octane is 96 plugs dont look to bad altho one cilinders plug is a little dryer then the outher three
 
It sounds like you have had them on and off a few times put them on and fuel them up very carefull pull fuel bowls check to see where your ate make sure fuel pumps are filling the bowel good would also check your needle and seat for the bowls they will hang up sometimes may get fuel but not enough
 
dlvsdh said:
do you know if the length of the hose going from the bottom of the bowl to the top of the dial a jet matter.
Click to expand...

I have no experience with dial-a-jet but I would imagine that hose length/diameter principals would apply in way as they do on a power-jet which I have dealt with.

Here is what I know.

The fuel level in the hose will be even with the fuel level in the bowl.

In either system the fuel being drawn into the carb is done via vacuum.

That vacuum changes with air flow through the carb but has a high end limit to the amount of draw it can achieve.

A longer hose will take more time to transfer fuel than a shorter one. (A hose that is to long can cause a delay in fuel transfer, lean bog)

A hose who's ID is to large can cause the same thing and will decrease the effectiveness of the carb's vacuum to a point of making the system inoperable as the hose ID is increased.

It is easier to suck water out of a bucket through a 3/8" hose than it is to suck water out of a bucket through a garden hose. The same principals apply here and the vacuum available from the carb is limited.

The line for these systems need to be sized (ID) so it can feed the jets in the system without starvation and the length should be as short as possible so transfer response time is minimized.

The line length/ID should also be the same on every carb in the system to insure consistency between the carbs.

I have tested this and seen lean burn down of one cylinder on a muliti cylinder engine because of one PJ line being over sized.

opsled

PS,
You can test to see if your system is working buy holding the carb in your hand, slide all the way up and fuel in the bowl.

With compressed air and a blow gun that has volume blow air through the venturie. If all is right you will see the fuel being drawn up through the hose and delivered to the carb.
 
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After looking at the carbs again i see the problem, its your beer switch from bud light to budweiser this will give you that little extra you need lol so any more testing were are you at, has anything helped.
 
okay everone thanks for the help. i am going to re clean the carbs soon im relly busy right now with outher things. so ill clean them out im going to find out what length my daj hose should be im prety sure there the right length but its best to check. ill update everyone when i get to it.

thanks for all the help everyone

dyllan
 
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