Jump to content

Who wants to tune my carbs?


JackImpact

Recommended Posts

14 minutes ago, JackImpact said:

Its been going pretty shit so far. 

eh don't fret, some people learn better by having someone there walking you through the steps.

I was ready to light my mower carb on fire and set it out to sea when I was trying to do it myself. My dad came over and helped walk me through it and picked it up finally

Link to comment
Share on other sites

13 minutes ago, wolfeman28 said:

I'd do it for free if you came up here. I have synch gauges and I use wideband to get spot on with the AFR.

Very grateful, but I dont own a truck and I wouldnt ride it that far haha.

Link to comment
Share on other sites

What carbs are on that bike, Mikuni BS cv's? They really aren't that hard to get right, you can be talked through it on here. Stock filters, stock exhaust? Usually you can just set the screws to stock settings, run a length of tube filled with heavy oil as a makeshift manometer, synch them at idle, and call it a day.

Link to comment
Share on other sites

26 minutes ago, wolfeman28 said:

What carbs are on that bike, Mikuni BS cv's? They really aren't that hard to get right, you can be talked through it on here. Stock filters, stock exhaust? Usually you can just set the screws to stock settings, run a length of tube filled with heavy oil as a makeshift manometer, synch them at idle, and call it a day.

I think they are both clogged and out of sync. They are on stock exhaust, the air filters on the carbs, I am not sure if they are stock replacement. If you want to add me on FB so I can quickly send you photos and videos of it I will. 

Link to comment
Share on other sites

Ok I'm going to post a reply to your PM here so others can help, and also if others need help in the future they can reference.

So you have Mikuni VMs and aftermarket filters. I'm going to guess they are VM 30's, do you by any chance know? Any idea what jets and needle are in them? If not, we can still work things out. From what I can see, the manifolds they used don't have nipples for hooking up a synch gauge. So that kinda stinks, but we can work around that too.

Take off filters, and set each carbs throttle height visually to the same height. The slide is adjusted up or down with a knob in the middle of the carb(on the other side of the pic you posted). Set them all the way down, then lift them up slightly so that they are just ever so slightly opened.

Turn your air screws in all the way. These are the screws that are closest to the air filter, you can see it in the pic you posted on the left. (Looks like its out pretty far). Turn it all the way in until you feel pressure slightly. Don't crank down on it, or you risk ruining the tip or breaking it off. Start tuning by backing it out counter clockwise 1/2 turn (180 deg). In your pic, it looks like they are out farther than they should be. Try to start the bike without giving it throttle. If it idles where it is, let it run for about a minute. Then you need to pull the plugs and we can go from there.

  • Upvote 1
Link to comment
Share on other sites

15 minutes ago, wolfeman28 said:

By the way, in the pic your enrichment(choke) is in the on position. Make sure its off when doing this, or your going to be fighting the tunning

 

So they should be flipped up? Also when you say adjust throttle height, could you draw an arrow to it? Is it the little thing at the top that a cable goes to the throttle?

Link to comment
Share on other sites

23 minutes ago, wolfeman28 said:

Ok I'm going to post a reply to your PM here so others can help, and also if others need help in the future they can reference.

So you have Mikuni VMs and aftermarket filters. I'm going to guess they are VM 30's, do you by any chance know? Any idea what jets and needle are in them? If not, we can still work things out. From what I can see, the manifolds they used don't have nipples for hooking up a synch gauge. So that kinda stinks, but we can work around that too.

Take off filters, and set each carbs throttle height visually to the same height. The slide is adjusted up or down with a knob in the middle of the carb(on the other side of the pic you posted). Set them all the way down, then lift them up slightly so that they are just ever so slightly opened.

Turn your air screws in all the way. These are the screws that are closest to the air filter, you can see it in the pic you posted on the left. (Looks like its out pretty far). Turn it all the way in until you feel pressure slightly. Don't crank down on it, or you risk ruining the tip or breaking it off. Start tuning by backing it out counter clockwise 1/2 turn (180 deg). In your pic, it looks like they are out farther than they should be. Try to start the bike without giving it throttle. If it idles where it is, let it run for about a minute. Then you need to pull the plugs and we can go from there.

What about the screw with the spring that affects the idle speed?

Link to comment
Share on other sites

The lever should be flipped up, so the plunger(brass) goes down. That would be the off position on both carbs.

The slide height adjustment is on the other side of the carb. If you go to the other carb on the left side of the bike, you should see it on that one. Its a knob directly in the center. That right side carb will be a PITA to get to. You can actually modify the carb to move the slide height adjuster to the other side to make it easy to get to, but I do believe you need to order a different slide to accommodate it. I have it circled below.

The adjustment on the top of the carb is used to eliminate slack in the cable. It should not be used to set idle. Once you get teh idle on both carbs proper, you adjust those top things to get the carbs to open at exactly the same time. We will get there :)
 

VMsync.jpg

Link to comment
Share on other sites

5 minutes ago, JackImpact said:

What about the screw with the spring that affects the idle speed?

That is the slide height adjustment for idle. That's what I'm referring to. Set them equal on both sides till they are barely showing the slide as open

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...