Mixture is wrong

[josephjhaney]

Ok, so my wonderful 1985 vmax that was running ok when the carbs were totally out of sync, now that the carbs are synced is running like crap. When I checked the mixture screws they are all 3 1/2 to 4 1/2 turns out. The bike came with VooDoo 4 into 2's installed, and my guess is they just mucked with the carbs till it ran right, without replacing the jets. I'm strongly considering taking it to someone here in Harrisburg, PA who would know what they are doing to get it running right-

(It dies as soon as you give it throttle, not totally, just the rpm's drop hard, then come back up).

Anyone know of such a place in this area? I plan to take it on the first warm day (it will run, just not well) and then pick her up when she's done.

Thoughts?


Joe

 

[davesax36]

Send them to DannyMax... It won't take long, and they'll come back actually set up right, not just "working".

 

[josephjhaney]

Send them to DannyMax... It won't take long, and they'll come back actually set up right, not just "working".

My problem with that thought process is that I have non stock pipes, so the jetting for my system would still be off, no?

Joe

 

[davesax36]

Make sure he knows what setup you have. Opening up the exhaust requires increasing the air, not the fuel. Add a Morley airbox and jet kit, and you'll really get the benefits.

Danny can get you squared away and Sean can get you jets if Danny doesn't have them on hand.

 

[blaxmax]

Did YOU sync the carbs and if so what device did you use?

 

[Traumahawk]

With non stock pipes you need to run a tad leaner than stock. So instead of the stock 152s. ....you need 150s....or 147s. ...everything else can be stock. This is assuming you still have the stock air box.

 

[jfeagins]

Did YOU sync the carbs and if so what device did you use?

+1

And, if the carbs are synced, are your A/F screws set properly too?

You should be able to set the idle down as low as possible w/o dying, and turn one a/f screw in sloooowly until you hear a slight hesitation, then back it out about 1/2 turn from there. Do the same thing for all four carbs, one at a time. Should have done this procedure at the same time as synching the carbs to ensure they remained close on synch. If that don't help, try adjusting all four out further by 1/4 turn each. If that helps, go again. If that makes it worse, go back the other way and turn them all in tighter. You see how that would work. When done, be sure to reset your idle back up to 1000-1050rpms. If no adjustment helps, THEN maybe your carbs are not already jetted properly to match your pipes. Or you could have some junk in one or more idle circuits.

 

[Traumahawk]

+1

And, if the carbs are synced, are your A/F screws set properly too?

You should be able to set the idle down as low as possible w/o dying, and turn one a/f screw in sloooowly until you hear a slight hesitation, then back it out about 1/2 turn from there. Do the same thing for all four carbs, one at a time. Should have done this procedure at the same time as synching the carbs to ensure they remained close on synch. If that don't help, try adjusting all four out further by 1/4 turn each. If that helps, go again. If that makes it worse, go back the other way and turn them all in tighter. You see how that would work. When done, be sure to reset your idle back up to 1000-1050rpms. If no adjustment helps, THEN maybe your carbs are not already jetted properly to match your pipes. Or you could have some junk in one or more idle circuits.

+1

You can be 2 jet sizes off.....and its not really gonna make a difference, EXCEPT at wide open throttle. Look at the pic.....your not even on the main jet until 1/2 to 3/4 of WO throttle.

The first time that I dyno'd the bike.....I was 2 jets sizes off, and instead of the A/F being 13.0....I was around 12.5.

 

[blaxmax]

Your best results will be to setup the carbtune sync and with the engine at 1200 rpm's
Turn each a/f mixture screw until the rod reaches it's highest point it can on the carbtune.
Then start syncing #1 and #2 carb-Go to the other side and sync #3 and #4.
Then sync #1 & #2 to #3 & #4.Make sure your timing is set first.

 

[josephjhaney]

This is the tool I used.

http://www.amazon.com/gp/product/B003CJGDE8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[davesax36]

This is the tool I used.

http://www.amazon.com/gp/product/B003CJGDE8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I have a carbtune, and I still want one of the gauge setups. Did it come with restrictors that kept the needles from jumping around like crazy?

 

[josephjhaney]

I have a carbtune, and I still want one of the gauge setups. Did it come with restrictors that kept the needles from jumping around like crazy?

Yes, it does have them, and they do stop the needles from jumping all over.

Joe

 

[blaxmax]

This is the tool I used.

http://www.amazon.com/gp/product/B003CJGDE8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

You can still use that tool to set the a/f mixture screws

 

[PATMAX]

If it were my bike I'd turn in those screws one to two turns and see if that changes anything.

 

[josephjhaney]

You guys are great, as soon as it's not "freeze my balls off cold" here in PA I'm going to give this a shot and see how it turns out. I'll update ya with my results!

Joe