First gen is a V-twin!

[hot rod]

Hey all, I've got an issue. My '85 Vmax is only running on the left hand cylinders. In order to alleviate this problem, I have replaced the plugs, and now the coils and wires with a COPs set from Morley's Muscle (Thanks!!), but the problem is still there. any suggestions?:confused2:

Thanks in advance!

 

[Rhoy Carter]

There is a number of things that can cause your problem. One thing you can try is to unplug the sidestand switch and see if that helps. If you are getting a spark look towards the carbs.

 

[hot rod]

The Carbs were just gone through by Dannymax.

Unplugging the right rear coil doesn't cause any noticeable difference. Plugging it back in causes a small surge Unplugging the Left rear coil kills the motor. I'll try the front two after work. I will also check the sidestand switch, but I'm not sure why that'd kill only 2 cyl.

 

[johnpclynch]

#1 do you have spark at all plugs - pull the COPs and check each with one of your old plugs (check connectors & wires between the COPs & CDI for corrosion)

#2 is fuel getting to the right bank - drain the carbs and see if they refill when you turn on the ignition (could be a blocked hose or stuck floats)

 

[06VMAXIMUS]

Start with the basics. Check each cylinders compression with a gauge. Then check that each cylinder is getting good spark, and fuel.

 

[wildweasel_pt]

Maybe ignition unit related or bad coils. change them around and check if the problem persists on the same cylinders.

 

[hot rod]

Well, I have spark on both cylinders, and the fuel drains out and refills fine, so the floats are not stuck. I guess next up is looking into the carbs. I pulled out my Vacuum gauges, and will try to see what I can find there. . .

 

[hot rod]

OK, Well, I found the two offending cylinders to have way more vacuum than the other two, played with the outside screws by the base until all 4 were equal. this seemed to greatly increase my idle, sound, and exhaust temp on those two cyl. Now they all seem equal.

Put it back together, take it for a ride, and she wont go above 4k. She just boggs and warbles.

 

[ninjaneer]

OK, Well, I found the two offending cylinders to have way more vacuum than the other two, played with the outside screws by the base until all 4 were equal. this seemed to greatly increase my idle, sound, and exhaust temp on those two cyl. Now they all seem equal.

Put it back together, take it for a ride, and she wont go above 4k. She just boggs and warbles.

"outside screws"? are you talking about the three synch screws? if so, are you saying that you haven't or hadn't synched the carbs? or are you talking about the 4 A/F mixture screws? bogging sounds like too rich? dunno.

 

[Rhoy Carter]

The air box has to be on with no air leaks for the engine to rev

 

[hot rod]

I replaced the airbox with K&N pods.

There are only 3 of the screws I was fiddlin' with.

 

[Rhoy Carter]

With the pod filters you will need air restricters

 

[ninjaneer]

+1 rhoy. i misread your first post, hot rod, thinking that you had installed a morley air box, which sean would have packaged air restrictors with. i guess this is not the case. running with the indy pods and no air restrictors is exatly why you can't get over 4k (ask me how i can be so sure...been there done that). i'm thinking that you are experiencing more a "rev limiting" sensation as opposed to a "gurgling drowning" sensation, no?

so since you were fiddling with the three synch screws, sounds like you had neglected to synchronize the carbs when you remounted them, which for future reference, you should do any time you dismount the carb rack AND especially if you overhaul them.

 

[hot rod]

I had Danny Max go through the carbs, I heard he is one of the best. He did find a bunch of issues.

Where can I get restrictors? Morley's, I would assume. Grr.... Knew I shouldn't try to do so much at once...

 

[ninjaneer]

I had Danny Max go through the carbs, I heard he is one of the best. He did find a bunch of issues.

yep dan-o has a great reputation for rebuilding carbs, and prolly did a bench-top synch to get it in the ballpark, but you still have to do a post-mount synch.

Where can I get restrictors? Morley's, I would assume. Grr.... Knew I shouldn't try to do so much at once...

woah woah woah. you definitely are getting ahead of yourself. so let's say that you do put in air restrictors and snap on the indy pods--you have just drastically leaned out the intake side. this will most likely require you examine your jets and needles, prolly going with a couple sized bigger jets and shimming the needles, else risking melting a piston or two. who knows maybe you won't have to rejet or reshim, but are you prepared in case you have to?

if you end up having to rejet and reshim and since you already dumped cash into the indy pods, i'm thinking you should consider dynojet's stage 7 kit. either that or accept the loss and invest in a Morley Muscle kit. in either case you get everything you need, from the air restrictors, to some kickass needles, to a selection of jets.

i quite frankly, don't know if you'll even see/feel the benefits of upgrading the intake if you are still on stock exhaust setup. in my honest opinion, if i were you, before running with a modified intake, i would get my hands on either some slipons (not cobras. supertrapps if i were you), or a full-up exhaust system.

good luck.

 

[hot rod]

Bike has Supertraps on it. I don't know if the header is stock or not. If we plan to throw more fuel at it anyway, why restrict the air?

Can the carbs be rejetted without removal?

I don't want to go full on race with it, just performance street machine. Stage 7, with drilling the carbs and all, might be too much.

 

[hot rod]

Also, the stock Airbox might or might not be broken. . . Hence the Pods.

 

[ninjaneer]

header is prolly stock.

rejetting requires carb removal.

nah stage 7 isn't too much.

i suppose theoretically you have a point about the air restrictors. but how much fuel do you want to put into the mixture. i thought you said you didn't want to go full on "race" mode. hahahaha. but practically speaking you are limited by the physics and mechanics.

http://vmaxoutlaw.com/tech/airbox_mods.htm

without the restrictors you are essentially drowning the bike with air. i'm not sure, but i think 190 is the largest main that we can put into the carbs, which assumingly isn't enough to produce the ideal stoichmetric ratio with the unrestricted air.

 

[Rhoy Carter]

The slides will not open with out the restricters with the pod filters. You will be better off putting the stock air box back on running the stock header pipes with slip ons, The stage 7 kit works well with a full header, and you are wasting time and money on the stage 7 kit with out a full header.