Carb tune.

[maleko89]

Purge jet #2.

 

[Clyde Porter IV]

Purge jet #2.

?

 

[Clyde Porter IV]

Purge jet #2.

How and what does that do

 

[Clyde Porter IV]

Would anyone advice doing a peeshooter cleaning even if the bike is responsive to throttle inputs?

 

[maleko89]

How and what does that do

It's part of the purge circuit which supplies a bit of air in front of and behind the slide to "monitor" pressure differential and open/close slide. the air has to go somewhere. Air from purge jet #1 (inner part of diaphragms ) and #2 (outer) exits out the mixture screw area. I included pics showing the top oval vent, bottom oval vent, purge jet #1, #2, passage way and where the "purge" air exits.

 

[maleko89]

Would anyone advice doing a peeshooter cleaning even if the bike is responsive to throttle inputs?

It wouldn't hurt but Peashooter doesn't always work and then need to take apart carbs to clean. Take a look at the purge jet #2 opening on the inside, past the o-ring. That and other holes are super tiny. Peashooter doesn't clean the purge jets.

 

[Fire-medic]

On the VMax, I just yank the carburetors and ultrasonically clean them. While stopgap cleaning measures may occasionally help, I've found that absent some ham-fisted botched 'rebuild' by a former owner or incompetent shop, the #1 issue is a plugged pilot jet, and no amount of peashooter/shotgun spritzes will always fix a blocked pilot jet.

Here's a pic of a stuck pilot jet I used a left-handed drill to remove/replace. No amount of red wand waving was gonna get this recalcitrant jet functional!





A single stainless steel strand from a shop brush fastened in a pin vise will remove hardened accretions.

 

[dannymax]

Cleaning the purge jet behind the o-ring can be done with a small wire...the one Mark indicates in his 3rd photo above can get a little trickier. But they need to be clear.

 

[Clyde Porter IV]

On the VMax, I just yank the carburetors and ultrasonically clean them. While stopgap cleaning measures may occasionally help, I've found that absent some ham-fisted botched 'rebuild' by a former owner or incompetent shop, the #1 issue is a plugged pilot jet, and no amount of peashooter/shotgun spritzes will always fix a blocked pilot jet.

Here's a pic of a stuck pilot jet I used a left-handed drill to remove/replace. No amount of red wand waving was gonna get this recalcitrant jet functional!

View attachment 82877

View attachment 82878View attachment 82879

A single stainless steel strand from a shop brush fastened in a pin vise will remove hardened accretions.

You guys are way way Way More knowledgeable about Carbs then I, if anything you guys taught me that I need to Study everyone’s work before I even attempt to do anything more then pull a Slide out that’s hung up. I will say I couldn’t believe the power I was missing and seemed not to know it. I’m guess that It’s been stuck for a week and half or 2 weeks. Me and my nephew was out riding he has an R6, by the way his daddy my brother in-law dropped dead instantly 3 months ago of a massive heart attack he was 48 if you could keep him and his brother in your prayers it mean the world. But we came off a red light both knowing it was for all the Marbles. It’s cool here so I came out at 3500rmp and wrapped the tach 1,2,,3 and 4th soon as I let out of it and got back to Sanity it spit popped and lurched until I pulled over and choked the Carb a minute or two it cleaned up. I pulled the breather and seen a Slide forward not moving to my input. Now it’s back to breaking the tire loose at 25 with just a quick twist. Sense all others are playing along should I pull them anyways and check out.

 

[Fire-medic]

Yes, spend time researching issues you want to know about, using the 'advanced search' (click on 'search' and then 'advanced search' and a couple words you want to read about).

The VMax had a great deal of torque for its time, and VBoost is a lot of fun. Unplugging the VBoost stepper motor connection, the round plug beneath the left air scoop, when you turn-on the ignition, and the VBoost cycles open (disconnect it now) and then closed, gives you that idle the H-D boys can't help themselves, they have to look at "what's than b-a-d idle coming-from?" However, for performance, the VBoost functioning normally is my favorite way to run it. I have a Dynojet Stage 7 jet kit, and I keep the VBoost operational, where the DJ kit says, "remove the VBoost butterflies." Not necessary, and it makes it harder to synch the carbs.

 

[James t]

Stock on my 85

 

[Ryce]

Hello; My carb question isn't directly related to the Max; I have another Bike ( 1965 Honda CL72 ) that I put a 250 Twin Star motor in because the original was fragged. It runs well, however when rolling off of the throttle, the engine tends to hold a high idle rpm ( about 3000 ) for about 45 secs before it falls down to the correct RPM. about 750 RPM. I have checked for air leaks and perhaps the throttle cable not returning all the way. That doesn't seem to be the problem . If I am decelerating say 3rd gear and ride the brake to pull the RPM down to about idle, the engine will continue idling just fine. I tried richening up the idle mixture and maybe that helped a bit. I was thinking of pulling the carb slide and machine about 1/2 mm from the cutaway area. The carb is from some unknow bike. I thought I would ask for some opinions on what do next before protentionally ruining the carb . Thanks in advance.

 

[Stephan]

Is it a single carb on the engine? What type of carb or carbs does it have? How do you set the idle speed normally? From your description I would say that something is not returning to its idle setting - be it slide, cable, butterfly linkage or butterfly shaft.