Needle position effects

[hexec]

After spending a ton of time fiddling with my carbs I fixed a couple stupid mistakes and I'm running fairly good now. Starts easily, no more popping, no mid range crackle. My lat problem is to fix the response after a few minutes of starting. The engine can die if I give it too much throttle. When the engine reaches operating temp it responds good. My bike is a 1985 Canadian version which has the adjustable needle. I suspect that the clip is in the wrong position. Does anyone know the riding effects of the needle being too lean or too rich? I'm trying to figure out which way to move the needle to solve my problem (if infact the needle position is the problem). I feel like I should go leaner to take the cold stumble out. Oh yeah, the pilot screws are set at 3 turns.

 

[alorio1]

Moving the clip towards the blunt end makes it leaner....

 

[alorio1]

This chart may help you in the future........

 

[Rhoy Carter]

level off in 4th gear at 4000 rpm and give it full throttle if it hesitates your too lean on the needle if it boggs a little your to rich if i remember right

 

[hexec]

alorio, thanks for the chart. What is a throttle valve cutaway?

Rhoy, thanks that also makes sense. However, Bike acts great across the entire range when its warm. At least I haven't noticed an issue.

My setup it totally stock.

To reiterate, the problem only present when the engine is below operating temp. I;ve always remembered it to responsive when it reached the first temp notch (slightly above cold). It starts fine, it idles fine, but needs a lot of time to warm up before I can begin riding.

All jets are stock.

Current setup is needles at mid clip (3 of 5) and pilot at 3 turns.

According to the chart the issue is pilot related. I'm going to try setting pilots a bit leaner since Rhoy note indicates bogging in the needle circuit when rich. That's how it seems to act but with a different circuit.

 

[alorio1]

Throttle valve cutaway? I really don't know the answerer to that, but it sounds like a dissected carb drawing with the flow circuits shown.

alorio, thanks for the chart. What is a throttle valve cutaway?

Rhoy, thanks that also makes sense. However, Bike acts great across the entire range when its warm. At least I haven't noticed an issue.

My setup it totally stock.

To reiterate, the problem only present when the engine is below operating temp. I;ve always remembered it to responsive when it reached the first temp notch (slightly above cold). It starts fine, it idles fine, but needs a lot of time to warm up before I can begin riding.

All jets are stock.

Current setup is needles at mid clip (3 of 5) and pilot at 3 turns.

According to the chart the issue is pilot related. I'm going to try setting pilots a bit leaner since Rhoy note indicates bogging in the needle circuit when rich. That's how it seems to act but with a different circuit.

 

[Rhoy Carter]

The V-max take a good 15 minutes to completely warm up, this includes the oil

 

[sdt354]

The V-max take a good 15 minutes to completely warm up, this includes the oil

Plus 1 to that. My bike takes a while to warm up too, and doesn't run well till it does warm up. Even in the summer.
Steve-o

 

[tmosel]

The V-max take a good 15 minutes to completely warm up, this includes the oil

Agreed

 

[alorio1]

I usually allow 5 minute warm up here, but the temp here where I live the temp. is much higher than your local (90 degrees @ 11PM tonight). Most Vmax owners allow their bike to warm up before riding, If not warmed up you can expect a little sputtering . I have read reports that some Vmaxes don't run right unless their Faux cover is not on , which is heat related in my opinion.

 

[hexec]

I just don't ever remember it taking this long. I remember it running ok when the temp needle reached the first notch. Now, if I give her too much gas it will die. I understand guys that it take longer to warm up than most other bikes, but mine is taking too long, in my opinion.

 

[KJShover]

Throttle valve cutaway? I really don't know the answerer to that, but it sounds like a dissected carb drawing with the flow circuits shown.

We don't have one in our carbs.

Throttle Valve Cutaway will influence the performance in the area of 1/8 to 1/4 throttle. It changes the air velocity over the main needle jet which changes when the main system begins delivering fuel. On FCR carbs there is a corner "cut off" of the slide to allow the bike to breathe.

With CV carbs (the stocker Vmax carb) The carb works a little different. The throttle turns a plate (the butterflies) that controls airflow behind the CV slide. The slide or vacuum piston in a CV carb is controlled by engine vacuum.

 

[hexec]

good to know...thanks.