Seems to be starving

[jimmytee]

ok, yesterday went for a ride . The day started rough with both of us needing batteries. With the unplanned delay, and coincidental nature of both our battery failures ,I'm giving thanks to God for whatever trouble we might have avoided. I knew my battery was on it's last legs, but his was under warrenty. During our  400 mile trip, I noticed an issue. While running at  , ok 85 mph plus,( my buddy doesn't like this) and giving more throttle or under an increased load ie.. a hill,  my bike would sometimes feel like it was missing or stuttering as if it were running out of gas.

I haven't had time to investigate, but was looking for thoughts and opinions. I think I've felt this before. Could  it be vacuum leaks , the vacuum operated OEM petcock, even ignition issues . I bought this bike in Feb . of this year. It is my second Valkyrie. I bought it with Cobra six into six pipes and the PO had not rejetted the carbs , so the carbs have been rejetted with a new Jet kit from Cobra. My friend didn't say when or where ,but did mention that there were times he smelled what seemed like straight  unburned gas coming from my exhaust. Now this could be another issue or related. Would starving for fuel cause this rich smell he described, doesn't equate in my mind. The bike runs great ,or seems to other than the above.Although I think I did feel this a time or two at 75 mph similar conditons as above.
Thanks
Jim

[Thunderbolt]

my vacuum side of the diaphragm had worn a small hole and had similar symptoms, though mine was at 60 or so.  Either get the petcock repair kit or like a lot have done, get a Pingle replacement.  Cover set part no. is 16953-MBZ-B51.

[Thunderbolt]

either kinked or debris

[Ricky-D]

You ought to give a little thought to the pipes being part of the problem.

The only way to get it right would be on a dyno with a smart tuner mechanic.

There have been past reports regarding performance with those 6 into 6 pipes and generally they have been negative, talking about loss of power.

***

[jimmytee]

Yeah I'm aware that there is generally a small horsepower sacrifice for using these pipes over stock, but I don't have the stock pipes and do like the sound. This is more than a scrub of horsepower, it's just like running out gas before switching to reserve.

[Patrick]

I'm not familiar with Cobra's,, but,, generally the needles are raised or changed and the jets are not touched.. But,, I wouldn't bet on anything..
But, I'd first suggest looking into having a good fuel supply which would mean checking the petcock and vacuum to it if you still have one supplied by Honda.. I can't remember too much about those,, mine went in the trash a dozen or so years ago after I got fed up with it..

[Challenger]

If you haven't had the tank off, I would pull it and check the air filter, if you have had it off, I would double check the vent line, fuel line and vac line to #6 for kinks.

[jimmytee]

No Patrick, the Cobras require rejetting. There are some who have gotten by with shimming the needle valves as the PO owner of my bike had done, but I'll testify to the marked difference that the Jet kit makes. Cobra sells a kit specifically for the 6 into 6 pipes.

I'm betting on  the petcock, fuel or vacuum lines being the source. Just a little thrown by my friend's comment on the gas smell from my exhaust.

[Challenger]

jimmytee: If the vac diaphram in the petcock tears, it can suck raw fuel into the #6 runner and cause a rich mixture in that cylinder, also not pulling the diaphram completeley open will reduce fuel flow to the carbs. easily determined by removing line at carb runner and see if there is fuel in it. Hope you master this quickly.

[jimmytee]

,I'll pull the tank this week. Challenger,I've seen where some have chosen the pingle that is non vacuum operated. Is this because of distrust of the reliability of vacuum operated petcocks or just the pingle? Are there modifications necessary to make the Pingle work. Seems I recall posts about some modifications.
thanks

[donaldcc]

My friend didn't say when or where ,but did mention that there were times he smelled what seemed like straight  unburned gas coming from my exhaust. Now this could be another issue or related. Would starving for fuel cause this rich smell he described, doesn't equate in my mind.

  a few months ago a friend was out riding with me a few days and mentioned the same thing about gas smell when i was accelerating hard. 

    when i fill up with gas, after the auto shutoff with the fuel hose i then straighten the bike off the kickstand as i sit on bike and fill with another .25 - .4 gallons up almost to the vent hole under the cap. i had previously had tank off and petcock and lines were in good shape.  i finally decided that after getting gas i was likely getting a little  gas out the vent line with the extra "fill up".