Need some ideas

[goatman]

I have ignored my vmax for months because it won't run right and just makes me angry. I gave up on it and bought an 81 goldwing for $1200 and have been riding that to work everyday, no problems. Anyhow, I am looking for ideas as to why it runs crappy because I need to get it back on the road(goldwings are slow). I have Marks exhaust, Morleys muscle kit, dyna ignition box. Plug wires and caps are new NGK's. The bike starts and idle fine, but as the rpms rise, it starts to cut out and run poorly. I had Sean rebuild the carbs last winter with high hopes, but it runs no better. The coils have been replaced. Sean sent me a regulator and a CDI box to swap out for my dyna, but it made no difference. I have installed every jet included in the muscle kit and that did not solve it. I have unplugged and cleaned every electrical plug on the bike. I have replaced the carb boots with new OEM. I have changed plugs twice. Maybe you can see why I gave up and strayed to the goldwing forums.
Looking for help before I part it out on ebay. Thanks.:bang head:

 

[one2dmax]

Maybe we need to try one size larger pilot fuel jets.

 

[twistedmax]

PICK UP? Ive been chasing "issues" for a while :bang head:,I know its not the carbs (I dont have any) so............ this winter Im doin new pick up, cops,R1rr,exactrep stator:clappingalready had it,just not in the bike) and if that doesnt do it :damn angry:.....................................BYE BYE EFI.

but anyway Id maybe think bout the pick up :ummm:

 

[goatman]

I'll have to read up on how to check the pick up coil. Larger pilot jets sounds easier. Thanks for the ideas.

 

[dmax1]

Mentioned everything but the fuel pump and fuel filter. You said idles fine but as you raise the RPM's runs bad. Maybe starving for fuel. :confused2:

 

[mattness]

if the bike isnt getting fuel it wont idle for long...

i bet its electrical. it takes more power to spark than you think

 

[goatman]

The fuel filter is new OEM, and the pump operates correctly. I have not replaced the fuel lines, but I don't think that is it. When you crack the throttle wide open (not in gear), it responds well up to redline and finishes off with a crack and belch of fire out the mufflers. If you slowly throttle it up, when you get around 6k it starts stumbling and won't go much past 8k, even if you then open the throttle all the way. It currently has 160 mains in it.

 

[mattness]

no comment

 

[adamax]

Question: did it start doing that after you changed something ?
I have Mark's exhaust and Morley's kit and I live at sea level and my vmax pulls like a train and I am very satisfied with the performance AFTER I did some changes.
Before those change, if I whack the throttle opened it accelerates until about 5000 rpm where it gargles and runs like crap with absolutely no acceleration.
Need me to elaborate?

 

[VMAX1260]

adamax what changes did you make so you fix this problem on your bike??

 

[Saml01]

Lightly feel the pipes as the bike warms up. If you get uniform heating your pilots are ok, if one is colder to the touch you may have found your problem.

 

[davidon]

I would still borrow a KNOWN good carb set, swap it out and recheck.

 

[goatman]

adamax, what changes did you have to make, please elaborate. I pretty much did everything at once as soon as I got the bike. The exhaust and muscle kit were installed at the same time and I have not gotten the bike to run correctly since. I only put a few miles on the stock bike when I bought it, and it ran OK, not great but I figured the carb work would take care of that. It definitely runs worse now than when stock though. Thanks again for the replies.

 

[ColoNat]

i would also still check/change the fuel lines... had a starving prob on mine as i ran at higher rpm... found a crack in the 180* bend line coming directly off the tank. was sucking just enough air to starve as the bowls got low after going up in rpm.

 

[Kratos]

Maybe I missed it, but I didn't see that you had done any battery tests. If the bike ran poorly when stock, and now runs worse after the exhaust and jet kit, it makes sense to me that possibly the battery could be at fault. Since the stock bike was probably more lean than the setup you have now, it probably took less spark to run half way decent before. Now that there is more fuel being introduced, but the spark isn't any stronger, maybe that's the reason. The battery could seem to be OK while cranking and idling, but will cause the bike to cut out as the rpm get higher. If you haven't replaced the battery, might be worth a try. I know mine cranked and idled ok, but when I tested the battery at idle, the voltage was too low. When I actually took the battery out, I saw that the acid was very low in all of the compartments. Since you say it will respond fine when the bike is not under load, that makes me lean toward the battery/electrical even more. I've had the same thing happen on an older Yamaha FZR 600 and a CBR 900rr, would rev fine when in neutral, but driving down the road was a different story.

 

[goatman]

I measured voltage at the battery, I get about 12.5V at idle and 13.3V at 5k rpms. My haynes manual calls for 14V-15V at 5k. Do my outputs sound too low? Maybe I need a new
r/r? I did swap that out with Seans loaner program, but the loaner was also used, maybe it
wasn't good either? I also noticed my negative battery cable has a small wire that comes off
it and attaches to the frame up near the faux tank. That wire is green with corrosion. The main cable that attaches to the motor looks fine. Could that cause trouble?

 

[adamax]

Goatman: I do not want to mislead you or distract you.
My vmax ran normally like any stock Vmax before the modifications. It was slightly low on power in my opinion but it accelerated smoothly through the rpm range and went like stink when the vboost kicked in - so no complaints.
My case only started just AFTER the mods.
Did your vmax ran normally before the mods?

 

[Kratos]

I measured voltage at the battery, I get about 12.5V at idle and 13.3V at 5k rpms. My haynes manual calls for 14V-15V at 5k. Do my outputs sound too low? Maybe I need a new
r/r? I did swap that out with Seans loaner program, but the loaner was also used, maybe it
wasn't good either? I also noticed my negative battery cable has a small wire that comes off
it and attaches to the frame up near the faux tank. That wire is green with corrosion. The main cable that attaches to the motor looks fine. Could that cause trouble?

Those voltages look low, may be worth taking the battery out and checking the acid levels and having it tested as well as making sure all of the battery electrical connection points are clean.

Probably need to start with the battery, if it is bad, you may not get the correct readings from the other electronics throughout the rest of the system.

Since the problem was there before the mods and only got worse, it seems like the problem is following something on your bike that hasn't changed rather than the mods you have done.

 

[goatman]

adamax, its hard to say if it ran normally before the mods. It had been sitting in a shed getting little to no use, so you would expect it to run poorly from sitting. The problems it is having now, severe cutting out above about 6k and general uneven running are not the same as when it was stock. When I rode it home, it just seemed like a carb cleaning or maybe just some seafoam was in order. But then I started the mods. Kratos, the battery is the same one that was in it when I brought it home, so could definitely be a problem. I keep it on a battery tender.

 

[VMAX1260]

goatman i have this issue all this summer it went away as i installed bigger main jets. 2 days now it appeared again. if you don't open your throttle all the way does your engine rises th rpm or you still have the problem? in my sittuation when i slightly close the throttle it cleans but again when i turn the throttle all the way it appears again. it feels like going from 4 cylinder to 3 or something like that. it comes and goes and it comes again like it trying to work properly but never does. i dont know if it is the weather that got cold and i have to change to even bigger jets.