Hesitation at steady highway speed.

[Chasjen]

Hello Everyone,

My Vmax seems to hesitate while cruising (steady throttle) at highway speeds (75-85) in top gear. If I crack open the throttle at highway speeds it takes off, pulls strong. At lower speeds and on smaller roads it runs fantastic. The jetting and throttle response are spot on.

I shimmed the needles up to try and richen up the mid range. I just replaced the R/R and direct wired it to the battery (thank you Vmax forum). New battery. Carbs rebuilt last year. It runs great everywhere else.

I am stumped. Electrical? Fuel?

Any help would be appreciated. Thanks Charlie

 

[Fire-medic]

That probably has something to do with the needle, as the RPM's are in the middle of the rev band. Maybe remove the washers and see how it runs. The bikes are jetted rich from the factory.

 

[Chasjen]

That probably has something to do with the needle, as the RPM's are in the middle of the rev band. Maybe remove the washers and see how it runs. The bikes are jetted rich from the factory.

I’ll try it. Maybe I’ve been going in the wrong direction! Thanks

 

[marsmax85]

when carbs were rebuilt did you sync them after install your bike ? may not have anything to do with your issue but was wondering because
most don't

 

[Chasjen]

when carbs were rebuilt did you sync them after install your bike ? may not have anything to do with your issue but was wondering because
most don't

Yes they were synch’d. This is a frustrating nagging small problem. Honestly the bike runs great. The easiest solution is not ride on the highway. More fun too.

 

[El Canadiense]

Yes they were synch’d. This is a frustrating nagging small problem. Honestly the bike runs great. The easiest solution is not ride on the highway. More fun too.

While travelling in Mexico with a great bunch of bikers, I learned they have a name for people who never ride in the highway except for short runs to a bar or restaurant. They call them "Banqueteros" because they only dress up to go to banquets.

 

[one2dmax]

Sounds like a slide issue with pin holes or cracks in one or more of them?

 

[Chasjen]

Sounds like a slide issue with pin holes or cracks in one or more of them?

Do you mean the diaphragms? Anyway will scrutinize them. Thanks

 

[Fire-medic]

No the plastic slide, which the diaphragm attaches to.

 

[one2dmax]

The rubbers on the slide is what likely has gone bad.

 

[Fire-medic]

Oh sorry Sean, I thought you were referring to cracked slides, not torn rubber diaphragms!

"Sounds like a slide issue with pin holes or cracks... ."

Yes, deteriorated CV diaphragms are more-common. I recall someone on here said he patched his diaphragms with roofing tar! He claimed success in the long term.