`85 Vmax runs best with pilot screws closed?

[RempageR1]

Hi,

I`ve been busy setting up my Vmax. After syncing the carbs, it was time for the pilot screws. I set them at a preset value of 2.5 turns out and started the bike and drove it around until it was warm.

Then I started to find the setting at which the engine runs the highest RPM at idle, which is all screws turned all the way in.

How can this be the best setting? Also, does turning the screws all the way in leanen or richen the mixture at closed throttle?

Thank you!

 

[mr.maxx]

all the way in will actually shut off the pilot jets.

turning them out will richen them.

go back to yure base setting....then set yure idle to 1100 rpm. run yure bike around and see how off idle performace is .....if it hesitates then back out each screw 1/4 turn at a time until yu get it running smooth.

after yu may want to re synch. if it wont idle at 2.5 turns than yu have plugged pilot jets.

 

[RempageR1]

all the way in will actually shut off the pilot jets.

turning them out will richen them.

go back to yure base setting....then set yure idle to 1100 rpm. run yure bike around and see how off idle performace is .....if it hesitates then back out each screw 1/4 turn at a time until yu get it running smooth.

after yu may want to re synch. if it wont idle at 2.5 turns than yu have plugged pilot jets.

Thank you for your reply.
So if I understand you correct all the way in is the leanest setting. I`ve checked the carbs, all jets are clean.

Could it be that the main jet is too big (or needles set too high), causing it to run best with all pilot screws closed?

I will try see if the Vmax still feels normal on throttle in this setting.

 

[mr.maxx]

Thank you for your reply.
So if I understand you correct all the way in is the leanest setting. I`ve checked the carbs, all jets are clean.

Could it be that the main jet is too big (or needles set too high), causing it to run best with all pilot screws closed?

I will try see if the Vmax still feels normal on throttle in this setting.

yes all the way in is leanest.

if it has adj needles than yes i suppose that could be an issue.
and yu would have to verify if the jets are stock too of course.

 

[robsplatf4]

If it doesnt die with the screws all the way seated they are worn and prob should be replaced.

 

[gamorg02]

yea thats essentially cutting all fuel at idle off. not sure what % of fuel goes thru the needle at that point but can't be much.

make 100% sure ur choke isn't left on too.

 

[RempageR1]

Just drove the bike to work as it is now and it ran just fine (choke was off for sure). When I bought this bike all pilot screws were closed as well (and screwed in tightly). I`ll first look into the pilot screws to see how worn they are.

 

[RempageR1]

Hi,

I checked my pilot screws and found no signs of wear on them, but did find out some strange things:

Some settings my Canadian bike should have and next to it what it is on my bike:
Pilot Jet #37.5 same
Pilot Air Jet No.1 #90 unknown
Pilot Air Jet No.2 #170 150 (Mikuni)
Main Jet #152.5 same
Needle Jet 5EZ50 5EZ44

So the needle jet is of a different type (looks like stock on pics but with five grooves to set the hight) but the thing that catches my attention is the 150 pilot air screw No.2. Could this mean a richer idle mixture, a source for my 'issues'?

Thanks!

 

[RempageR1]

What i`ve found:

My pilot air 2 jets are 150`s instead of the standard 170`s (see blue circle). This leads to a richer mixture at low throttle. The Vmax has two holes to add the pilot mixture (see red circles).

Due to the richer mixture seen in the top red circle, I do not need to add additional mixture and the pilot screws can remain closed.

 

[maleko89]

The "top" holes are bypass holes and mixture only comes out of those when you open the throttle. If you close all four mixture screws, bike should stall....unless you have a sync problem or your choke is on.