Drastically different spark plug readings

[Jim]

I measured the resting float height. These photos are only from the suspected carb that had carbon fouled plug. When I sighted down the floats they all seemed to sit at the same height, no tweaking on them.

The last photo shows a repair I did to the float which had a leak, I used a small amount of tank weld to repair the holes which worked well… but do you think that this could be causing some sort of issue?

Thanks again for your time and helpful knowledge.

Adding the weight of the epoxy will affect the float setting. You can compensate for it by using the sight tube method and adjust based on fuel level instead of float height.

I'll add that I've done the same in the past. My opinion is it's false economy... buy a new float.

 

[gggGary]

I replace any suspect floats cuz I HATE taking a carb off for the second or third time..........
Did you do another hot water dip test?

 

[Jim]

I replace any suspect floats cuz I HATE taking a carb off for the second or third time..........

Not to mention the long walk home when the float sinks and it won't quit pissin' gas out the overflow.

 

[Nifty650]

Adding the weight of the epoxy will affect the float setting. You can compensate for it by using the sight tube method and adjust based on fuel level instead of float height.

I'll add that I've done the same in the past. My opinion is it's false economy... buy a new float.

Thanks , I’ll replace float and report back. Might be a stupid question but I’m assuming the new floats will sit at the needed heighth of 24mm?

 

[gggGary]

new floats will sit at the needed heighth of 24mm

Nope, must be checked, expect some adjustment will be needed.

 

[Nifty650]

I replace any suspect floats cuz I HATE taking a carb off for the second or third time..........
Did you do another hot water dip test?

I’ve removed my carbs countless amount of times, so 2 or 3 more times until I can sleep right at night isn’t too bad as long as I get to the bottom of it! Now just to await parts..

Passed hot water test, both sets.

 

[Nifty650]

Nope, must be checked, expect some adjustment will be needed.

Alrighty. I’ll report back.

 

[jpdevol]

The spec'd float height also assumes genuine Mikuni VM24/171 floats. There are instances of some aftermarket copies not correctly adjusted at that height.

https://www.summitracing.com/parts/mku-vm24-171

 

[5twins]

Oh my, I see they've gone up .70, lol.

 

[Nifty650]

Okay everyone thank you all for your time and help! Looks like 5twins was correct about the needle emulsion tube Oring, it was drawing in fuel from the top causing right cylinder to run rich, replaced and on to the next.
Of course my questions aren’t over quite yet… the pictures I have posted are brand new plugs I put it at same time and went in a 200 mile ride yesterday, pulled em and they look pretty darn clean so I’m thinking I’m running lean but does anyone think these look normal or “healthy” reading?

 

[jpdevol]

IMO, those iridium thingies are hard to get a typical reading on. How does it perform; rolling on/off at various throttle openings?

 

[Nifty650]

IMO, those iridium thingies are hard to get a typical reading on. How does it perform; rolling on/off at various throttle openings?

It rode very well, so well that I didn’t want to go home! I can see how the reading would be a little more difficult to get from these style plugs but everyone says they read the tang and not the porcelain.
I am running the stock exhaust but I drilled out 6 holes to allow it to breathe a little more.

 

[5twins]

When reading plugs, what you also have to look at is the base of the porcelain down inside the plug. You want to see a ring of color down there, coming up maybe no more than 1/3 of the way. If the dark color covers up to half way or more, you're running a bit rich .....

The top side of your plugs look very nice so if you've got that color ring down inside, I'd say you're good.