Project My Fizzer

seems odd that some people are good with 10.5 above and some on the line , in theory why wouldn't they just make the line 10.5 higher

 

Consider that Mikuni carb was likely chosen from a number of candidates and wasn't produced specifically for the 250 Fizzer, so the float bowl casting line is just a reference

 

well that makes sense

 

i read somewhere the float on the 2kr is between 10-15 mm above not 100% on those numbers but it was variable

 

am i confused or is that chart saying its 10.5 mm below the line

 

Well to clarify for you guys, because I went through the precise same confusion, my bike was neglected, and not too badly actually, it was at least indoors.
It wasn't molested or tampered with and that was simple enough to tell from the condition of the screw and bolt heads.

Also my carbs were cleaned one after the other, so all parts when back into the exact carb they came out of.

Anyway, so when I measured my float heights they all measured up at 10.5mm above the line and all of the needle and seat valves worked properly upon first re-assembly.

Remember I was measuring what I had, and I drained and refilled each carb for each measurement.

Remember also that you're measuring from the bottom of the meniscus which in a piece of 4mm tube is quite pronounced.

I hope this eliminates some of the confusion. I know I went through it before I bit the bullet, made the jig and did the measurements.

peace out

 

i just used a ruler from the line to the fuel level , im pretty sure mine were all different
this only affects the carbs at some points
not knowing too much about carbs i cant say where and why i just know the end result and how to get away with it (at a loss of mileage if it floods of course )

 

You could set the fuel level to the line, however that would significantly alter the vacuum pressure needed to draw fuel. Not something I'd personally recommend.

However if you do, then I'd recommend doing an immediate set of plug chops at 1/4 throttle, 1/2 throttle, 3/4 throttle and full throttle.

Running lean will grenade an engine real quick.

Needle and seat valves not working needs to be fixed ASAP because you could end up with a hydrolock, so fix that first. BTW the float may have pinholes, so check that in hot water.

Again my observations were just of my carbs, which whilst filthy were untampered and unmolested.

I got the fuel height from one of he 3ln documents someone posted, which is for a later model with a frame starting 3ln-350101. The numbers tallied except for the starter jet which was 42.5 for the later models and 37.5 actually installed in mine.

My parts are due to arrive today, so with any luck I'll be able to actually ride it in the next few days and feel the state of tune, up till now, it's been revved in neutral, so the engine spools up and that's all I actually know.

BTW the float bowl breathers would be the overflows on these carbs if they were angled differently, so the fuel will go down into the engine via the pilot system first as that's the lower point.

peace out

 

Hi there mate, I had the exact issue you are having a while ago and this is how I got my bike going.
My issue with the bike not revving once warm was the valves. I'm not sure if you mentioned that you did your valves on this bike yet but once I adjusted them I no longer had the issue. Found that one intake valve had pretty much no gap, as soon as the engine got warm everything just got too tight.

I have the 3LN3 and found that the float hight on the model is an absolute bitch.
My floats are adjusted so low that it looks like the float valves dont even open.
I dont have the exact specs on my float height but please try this:

Check your valves gaps.
Lower your floats as low as they will go.