hesitation between 4-5k in 5th gear

[maro]

eevvveerryy once in a while I can feel a slight hestiation of "pull" between 4-5K in 5th gear. What I mean is that is feels like it's not getting gas for certain moments... the pull hesitates. Once I pass about 5k it stops. I've only noticed it about 1/2 dozen times this summer, but it's enough to annoy.

What's the deal with this. I realize it's a carb issue, but what exactly.

Mind you, my bike is running smooth so this is nit-picky. But still...

thanks

 

[Nessism]

Sounds like a lean condition. If the bike is stock try shimming the needles - works wonders.

 

[maro]

thanks ness, I was going to attempt shimming the needles over the winter. Not willing to play the carb game just yet.

what exactly will shimming the needles yield as far as performance?

Is the lean condition (which I'm pretty sure I'm not generally running lean according to plugs and pipe) something that is natural(ly stock) or an issue that has arisen over time?

 

[Nessism]

thanks ness, I was going to attempt shimming the needles over the winter. Not willing to play the carb game just yet.

what exactly will shimming the needles yield as far as performance?

Is the lean condition (which I'm pretty sure I'm not generally running lean according to plugs and pipe) something that is natural(ly stock) or an issue that has arisen over time?

Maro,

I’ve been playing around with needle height on my 850 lately and it takes less than 20 minuets to do the entire job.

Shimming the needles richens the mixture in the midrange. All GS bikes are lean, some worse than others, so shimming the needles really perks up the bikes.


Good luck.

 

[maro]

Maro,

I?ve been playing around with needle height on my 850 lately and it takes less than 20 minuets to do the entire job.

Good luck.

I get get my carbs off quick, but not that quick....or are yo telling me this is possible to do with the carbs on.........???

 

[TheCafeKid]

I get get my carbs off quick, but not that quick....or are yo telling me this is possible to do with the carbs on.........???

He IS telling you that

 

[Nessism]

You have to remove the tank and then the top cap on the carbs so the slides can be removed. To get the needles out, you need some long reach snap ring pliers similar to those used to get a master cylinder apart. To shim the needles some small washers are needed – some people get them from Radio Shack. Lots of good info on this mod in the archives. One of the best bangs for the buck you can make.

 

[maro]

One of the best bangs for the buck you can make.

BINGO! thanks!

 

[tlepac]

Nessism

Is this something you do only with CV carbs or does it relate also to VM Carbs? I am having a hesitation between 4 and 5000 rpm on the bike and am wondering if this may relate to my problem. I am also changing out all of the vacuum tubing with new to see if this makes a difference. (As far as I can tell the vacuum tubing to my petcock and the breather hose is original with the bike so I am changing that out for new just on general principles) My problem does seem to be getting a bit better as I ride it more but the bike is still very cold blooded and I havent been able to get the idle down to 1100 to 1250 yet on my 79 GS 750L in addition to the above problems. It has new O rings, valve shims done and new petcock from Z1---Old one was shot.

I have not done recent plug chops but the plugs when I pull them are tannish to slightly white.

Thanks for any thoughts

 

[tkent02]

The VMs should have several clip positions on the needle to choose from, you can go half steps too with the shims.

 

[TheCafeKid]

The VMs should have several clip positions on the needle to choose from, you can go half steps too with the shims.

Only bitch is that every time you pull the slides to change the needle, you have to resync on the VM carbs.. WHICH is easier than the CVs, but still..

 

[tkent02]

Only bitch is that every time you pull the slides to change the needle, you have to resync on the VM carbs.. WHICH is easier than the CVs, but still..

I don't. I leave the adjusters alone, remove the screws down in the slides. After all the tweaking is done I resynch them. Synching only takes about five minutes anyway.