Need some ideas

[goatman]

VMAX1260, if you crack the throttle wide open from idle, it will go smoothly up to redline. If you rev it slowly, when it hits around 6k it loses power, if you then open the throttle from there, it will not rev any higher. I have to back way off the throttle to get it to clear up. This is all done when in neutral in my shed. Driving it is just worse.

 

[VMAX1260]

wow it is a little bit confusing. how do you feel it ? like the fuel isn't enough. you know when your max lights the fuel light and you dont switch to reserve. you know the sound of switch me to reserve because there is no fuel in me , when it loses power it is the same feeling??

 

[goatman]

It doesn't feel like it is running out of gas, more like it doesn't know what to do with the gas if that makes any sense. It could be a fuel issue for sure, but with the fuel pump pumping fuel and the carbs rebuilt, I am thinking more along the lines of electrical.

 

[Kratos]

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.

Yea, I kept mine on a tender as well, but I never actually took it out of the bike to inspect the acid levels. I may have been able to just fill it back up and charge it, but I just opted for a new battery to eliminate that as a possible issue.

I know all of our bikes are different and like different settings..... I have the exact same setup as you, but I recently did the COP mod. None of my carb settings changed because of the COP mod as far as main jets or needle position. I had to actually go down to 147.5 mains for my bike to hit the correct a/f ratio at full throttle when I was tuning after adding the jet kit and Mark's 4-2 exhaust. I would think yours is probably already a bit on the rich side with the 160's.

 

[goatman]

It will be awhile, but eventuallly I will do the COP mod also. I have a dyna ignition box and from what I have heard, that doesn't work with the COP mod. I will take the battery out of the bike and inspect the acid level since that is free! Thanks.

 

[Thevmaxrider]

Had a guy here in Ontario who's bike was acting that way and we found that one of the vent hoses from the carb bowl vents was kinked off. Just a thought, but you might want to check the hoses to make sure they are not plugged or kinked. You did say that the bike sat for a while and spiders LOVE to nest in nice dark little spaces like vent lines that are open to atmosphere.

 

[Kratos]

It will be awhile, but eventuallly I will do the COP mod also. I have a dyna ignition box and from what I have heard, that doesn't work with the COP mod. I will take the battery out of the bike and inspect the acid level since that is free! Thanks.

Gannon here on the forum makes wiring harnesses with a built-in resistor so you can use the Dyna 3000 with COP's. I purchased them from him when I did the mod, the harnesses are very well made, he does an awesome job.

http://www.vmaxforum.net/showthread.php?p=165096#post165096

 

[mattness]

both you guys need to get new regs just to eliminate it as an option.

 

[goatman]

The bowl vent lines are not kinked, but I have not checked to see if they could be blocked. I will do that, thanks.

 

[rebar]

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.

I had the same problem. But mine kinked.

Does your fuel pump click like crazy when you turn the key on and then again when the engine starts? It could be that pesky diaphragm which likes to fall out which you cant replace.

 

[88vmx12]

I was going to say "pick ups" too. For some reason I am feeling it to be an electrical issue
G

 

[Kratos]

It will be awhile, but eventuallly I will do the COP mod also. I have a dyna ignition box and from what I have heard, that doesn't work with the COP mod. I will take the battery out of the bike and inspect the acid level since that is free! Thanks.

While you have the battery out of the bike, would probably be a good idea to get it tested.

 

[goatman]

rebar, fuel pump clicks to fill bowls, but after that it shuts off. Doesn't click when starting. Thanks for the idea. The battery levels were all at the minimum level, but one cell looks suspect, looking thru the plastic casing the plates in one cell look like they are covered in white. I will get it tested when I get some time. Thanks again for all responses.

 

[adamax]

Surprisingly my vmax was hungry for more fuel. I read your post VMAX1260 and amen to your 170 main jets. I installed 167.50 AND stage 7 needles at Sea level in Alexandria Egypt, then the Tboost seasoned it.

 

[adamax]

Goatman, I feel that it could be what VMAX1260 and myself are suspecting. What mine did when I twist the throttle quickly to wide open: it accelerates quickly and progressively until about 5000 rpm where the acceleration suddenly ceases and the the bike sounds like it is missing 1 or 2 cylinders from the intake ( kinda throaty gargling sound ), I have layed a rag to cover more than 1/2 the air filter surface and the symptom was better, then started increasing the main jet size. Before the kit the bike had the stock untouched carbs so it ran like crap but no such strange behaviour, it was just low on power, that cutoff behaviour only started after I installed the exhaust and the muscle kit. Please let me know if you need more details, I will be more than glad to elaborate.

 

[goatman]

adamax, that's a good idea to partially block the airflow to help determine if it is a lean or rich issue. I did go up to a 170 main and still runs like crap which makes me suspect electrical. Please elaborate how you got your bike to run right since we did the same mods.
Thanks for the help all who have responded.

 

[VMAX1260]

ok i installed my k/n filter and the things got worst. i had 170 main jets with just the filter boc and no filter in it. with the filter in it it is worst.goatman remove your filter and post please the difference

 

[VMAX1260]

did you find any solution in your problem?

 

[goatman]

No, I have not had time to work on it, hopefullly I can get to it later today.

 

[adamax]

Goatman,
first I remind that my poor running/stumbling at about 5000 rpm started after the mods, and before that it was just running smouth but no real power- this is very important if we wnat to isolate the root cause of the problem-. My symptom was that when I twist the throttle, it pulls hard up to about 5000 rpm then the acceleration stops accompanied by a strange gargling sound from the air filter....no acceleration at all and just a throaty ghghghhgghghghhg and you could also hear the exhaust note changing, it was like the engine gasping for air .
I made sure that I followed all the instructions of the Morley's kit and that I installed the air correctors and air jet as instructed. I also installed the softer diaphragm springs. The thing that made the difference in my case was the stage 7 needles from Morley. after that I went all over again changing main jet size until I am happy with the 167.5. Afterwards I changed the diaphragms with others that have the bigger size hole. I also kept the V-boost operational and recently I installed the T-boost kit and happy with the 3000 rpm kick...
I was close to be frustrated at that time butnow I am very happy with the results. Now I cruise at about 60 mph on 5th gear, I twist the throttle and the bike just goes until about 150 mph where I feel I will be thrown off the bike without a minor glitch.
Good luck... and please let me know if you need more details.