Should I rejet?

[EZRider76]

My bad, I was quoting the stock 26mm setting for the float.

"I have heard/read other people say that fuel will trickle/drip out the float bowl vent if they don't turn the fuel off on 2-Strokes."

If fuel drips or trickles out of any carby, not only 2 strokes, there is a possibility that the needle and seat assembly is not working correctly, because it has dirt or a varnish build up, or has been bastardised.

I hope not. I checked and chased the needle and seat earlier and blew threw it, YUM, it seemed ok and it the needle seated well. I will just have to keep tinkering, and figure out a way (or build a tool) to check my float levels. X(

As for the 26mm carb, yeah, I keep forgetting at times that this isn't a stock carb and the questions I ask are relative...and relatively a pain in the ass. I just hope I can dial it in soon, the riding season is here and I should be riding, not wrenching, it's not a Harley for crying out loud!

I am going to try the old tooth paste polishing trick on the seat and needle tomorrow after work. Then give it a shot. I know though, because I left the fuel on once by accident, that the fuel will drain out if you leave it turned on...hopefully that will change after I do some polishing tomorrow. I'll let you know.

 

[Blaaster]

I have not been inside a 28mm Mikuni but I am confused about the floats just sitting in the bowl.

Is there something missing that ties them together or what?

Or should you maybe just call me thick.

The only time I turn off my petcock is when I am working on the carby, and it has never leaked once.

 

[EZRider76]

If I call you thick, then I don't know what that means you get to call me. LOL If you look at this pic...

you see how they are on those little posts? The posts are the shiny silver rods, they are part of the float bowl. The copper/tarnished cylinder that is around the posts, those are part of the float itself. That is what lets them float up and down by fuel level. Then, in this pic...

see that thin plat that is at an angle from the gray part, that is the plate that the floats hit against and push up to shut the needle and seat. I know, very confusing...of course, I don't know much, so it all confuses me. Anyhow, if you look at the floats, they are kinda tapered going to the middle of the float bowl, that is kinda what hits the flapper is that tapered part of the float. There is nothing that links them together, they float independantly. I guess that makes it easier if you're side hilling or whatever??? IDK.

 

[EZRider76]

No no no, never mind...I'm tired and being an idiot...the copper pegs at the bottom of the float is what hits the plate...not the taper in the float....been a long weekend.

I will say this tho too, that long copper/tarnished pipe that sticks up from the bottom of the bowl, that is the bowl bent pipe, that will let fuel trickle out. I wish I had a good side pic, but I don't, but that pipe is just a bit taller than the gasket on the bowl...so the fuel flowing in is just barely higher than the gasket, that is why it is trickling out. I have thought about bending the little tab on the flapper that hits the needle just a whisker to see if that will keep fuel from trickling out, but I don't want to mess with it too much.

Hey, we are getting off track of my WOT issue. Any idea why it will spit and sputter at WOT (before I hit the "power band") in 1st thru 4th? I haven't been able to hit 5th or 6th yet, my yard isn't big enough.

 

[Blaaster]

Yup, the penny just dropped!

So they just flog around in there individually, with nothing to hold them together, or is there a guide on the posts?

 

[EZRider76]

Wait, what? The Penny just dropped? PM me that one if you would.

There is no specific guide on the posts, just the tubes in the floats themselves that lets the float move VERY freely up and down, but they are independent from each other....so free it feels like an ice cube hydroplaining on a kitchen counter top. Also, check above, you replied while I was editing my last post.

 

[Blaaster]

Have you been here.

http://www.mikuni.com/pdf/vmmanual.pdf

 

[EZRider76]

Have you been here.

http://www.mikuni.com/pdf/vmmanual.pdf

Does a Blaster go "Ring-a-ting-ting-ting-ting, Ring-a-ting-ting-ting-ting-ting-ting-ting" when you feather the throttle? 8-|

Sorry, couldn't resist. Yes, I've looked at that quite a bit, learning and trying to make sense of it all. I'm pretty familiar with it. The exploded view is a bit misleading, showing that flapper plate down there by the floats, but it should be up with the rod that holds the flapper plate to the posts that is in the top half of the carb.:-/

 

[Awk08]

yes....bend the little tab up towards the top of the carb, ever so slightly, that will allow that "plate" to push the float valve closed earlier, and lower that fuel level to below the "overflow tube"

 

[EZRider76]

yes....bend the little tab up towards the top of the carb, ever so slightly, that will allow that "plate" to push the float valve closed earlier, and lower that fuel level to below the "overflow tube"

That won't have any other effects on the carb? Could that change the AFR? I'm gonna clean/polish the seat first, then try that if it doesn't fix my problem.

 

[Blaaster]

Page 12 tells how to adjust float level. Fig 18, easy peasy!

 

[EZRider76]

Page 12 tells how to adjust float level. Fig 18, easy peasy!

Ooooohhhhhh!!!!!! :-[ I read that, but because I didn't think it was something I would need to do, I didn't really try to understand it. Um...ok, max green coming your way....lol...The Penny just dropped. I:I Maybe I will take the time to re-read that again. Now that I'm getting a little more hands on, it is starting to make a little more sense....soon it will make dollars.

 

[Blaaster]

That should stop the Blasty from guzzling gas! Ha Ha.

 

[EZRider76]

That should stop the Blasty from guzzling gas! Ha Ha.

Well, that just means there will be more for me to ride with. I:I

 

[Awk08]

the float level does effect all jetting ranges, thats why it should be adjusted to spec before any jetting is done, same as the pilot, will effect the needle and main jetting, and the needle will effect the main jetting
each circut effects the ones above it, as it is still flowing as the ones above come into play
for example...if the needle clip is dropped, richening the mids, it is still flowing that extra fuel as the main opens above 3/4 throttle, so the over all jetting is richer because of the added fuel the needle is flowing with the main

jet from bottom to top....
1 float level
2 pilot/airscrew
3 needle
4 main jet

 

[EZRider76]

Ok...man, now I will definitely have to refer back to that one, I think that brained my damage!!!! I will have to get that float into specs, then pay closer attention to everything else.

 

[EZRider76]

the float level does effect all jetting ranges, thats why it should be adjusted to spec before any jetting is done, same as the pilot, will effect the needle and main jetting, and the needle will effect the main jetting
each circut effects the ones above it, as it is still flowing as the ones above come into play
for example...if the needle clip is dropped, richening the mids, it is still flowing that extra fuel as the main opens above 3/4 throttle, so the over all jetting is richer because of the added fuel the needle is flowing with the main

jet from bottom to top....
1 float level
2 pilot/airscrew
3 needle
4 main jet

Ok, re-read this after an nice hefty helping of cat from the local "butcher shop". That all makes complete sense to me today. Last night, it was like I could see your fingers typing but there were no words on the screen.

So, looks like I'll be starting back at ground zero and tuning the carb tonight, starting with the float flapper. I know it is off, the tab is perfectly straight and like stated earlier, it's trickling fuel out the bowl vent. From there, I will put the #270 back in and take it for a trip around the yard a few times, see how it acts. If it keeps dogging at 1/2-WOT, I'll throw my biggest main in and run it. If that doesn't do the trick, seeing how I'm only running a #30 pilot, I'll throw my #35 in it...really wish I had a #32.5, but it is what it is, richer is better right? Right! By midnight I should have this slob tuned!!! B)

 

[Blaaster]

Two words, "plug chop"

 

[EZRider76]

Two words, "plug chop"

I know, I know, that is the preach. However, does it make sense to plug chop when it bogs at 1/2-WOT...seriously, I took it out on the road tonight and tried 5th and 6th...nothing, just choking and spitting and sputtering.

So, here is what I did tonight...I tinkered with everything. Now thinking back, I'm confused at what combinations I tried. I know when I changed the pilot to a 35, I had a hard time adjusting the idle, so I put the 30 back in. I moved the clip up and down one spot from middle, I don't think there was too much of a change. I started at a 270 main, then I went up to a 290 and it got worse, so I quickly changed to my 250 and it seemed to have a little more snap and ran just a little better, maybe started to cut out at 3/4 throttle? Then I ran out of light and had to call it quits. I even pulled the plug a few times to check for flooding and fouling, it seems like I am flooding it, but it didn't have a heavy fuel smell, but it was wet. Peeking at the ceramic close to the electrode, it was oily, but the plug wasn't black. I'm as frustrated as a midget in a dunk contest right now. I wish I thought ahead and took notes. X( The only thing I didn't do was change plugs and fuel. It has great flow of fuel though. AND, I fixed the float level....no more flooding out the vent tube. I:I So something went right.

 

[mjgnslngr]

I know, I know, that is the preach. However, does it make sense to plug chop when it bogs at 1/2-WOT...seriously, I took it out on the road tonight and tried 5th and 6th...nothing, just choking and spitting and sputtering.

So, here is what I did tonight...I tinkered with everything. Now thinking back, I'm confused at what combinations I tried. I know when I changed the pilot to a 35, I had a hard time adjusting the idle, so I put the 30 back in. I moved the clip up and down one spot from middle, I don't think there was too much of a change. I started at a 270 main, then I went up to a 290 and it got worse, so I quickly changed to my 250 and it seemed to have a little more snap and ran just a little better, maybe started to cut out at 3/4 throttle? Then I ran out of light and had to call it quits. I even pulled the plug a few times to check for flooding and fouling, it seems like I am flooding it, but it didn't have a heavy fuel smell, but it was wet. Peeking at the ceramic close to the electrode, it was oily, but the plug wasn't black. I'm as frustrated as a midget in a dunk contest right now. I wish I thought ahead and took notes. X( The only thing I didn't do was change plugs and fuel. It has great flow of fuel though. AND, I fixed the float level....no more flooding out the vent tube. I:I So something went right.

i feel for ya man, im suffering threw the same JETTING NIGHTMARE!!! 120 main jet in a keihin 28mm and its SOAKING the plug. i ordered a new size needle in hopes that it cures this crap. i should see it tomorrow or wed with any luck. did you ever change your needle size at all?