V-Max cams, do I need springs? And carb jets.

[lonestarmedic]

Tearing down the bike to rebuild carburetors and adjusts the valves. I have brand new V-max cams. Seems like a good time to install them. However I do not have the springs. Not intending to rev up over stock Venture redline. So, are the springs needed or just a nice extra?

 

Next thought is carb jets with the cams. Sizes? Should I increase the mains a bit? Bike is stock except for Mac mufflers.

 

J.B.

[jakester]

Hey JB, I have read where Dingy has made many similar mods on his first gen. Might be a good source for knowledge. Lucretia and I had a great time last weekend riding the sisters. Great to see everybody again.

Bill

[GaryZ]

I was told the valve springs allow you to rev to Vmax redline (9000 ?)

Without the springs the valves will likely float above 8000.

 

I found this . . .

 

Pilot circuit (zero to 1/8 throttle)-

The mixture is lean if:

* the bike surges while holding a steady throttle at about 4000 rpm in second gear.

* there is excessive back-firing on closed-throttle overrun.

* the throttle is lightly 'blipped' and the idle speed 'hangs up' before dropping to the set idle speed (set the idle to 1000 rpm to start).

Correction:

* turn the pilot screws OUT 1/2 turn or so. If the pilot screws end up turned out very much more than three and one half turns total (stock is about 2 1/2 turns), you should use larger pilot jets (stock is #37.5).

The mixture is rich if:

* the plugs are excessively soot-ed up or fouled.

* the throttle is lightly 'blipped' and the idle speed drops below the set idle speed before rising up to the set speed.

Correction: turn pilot screws IN 1/2 turn.

 

Full Throttle - lower midrange:

Adjust the needle clip so that the engine will accept full throttle between about 2750 and 3250 rpm.

* The mixture is lean if there is a 'dry' and flat in this range.

Correction: raise the needle height (e.g. move clip down one groove).

* The mixture is rich if there is a 'wet' rhythmic, soggy spot in this range that gets worse as the engine heats up.

Correction: lower the needle height (e.g. move clip up one groove).

Full Throttle - upper midrange:

Set the needle height for the best power between about 4000 and 6000rpm. If the engine pulls better when cold but 'soft' when at operating temperature, it is too rich in the midrange and the needle should be lowered.

 

Jetting the carbs has been my continuing problem. Probably because I am trying to use 1985 carbs!.

What I can recommend is; Replace the needles on the bottom of the slides with Vmax parts.

Test ride. Make adjustments (see above). You might be happy leaving it alone . . .

Shims on the slide needles will raise the slide needles.

Edited November 17, 2014 by GaryZ