Carb woes!

[PaulD]

I’ve been attempting to sort these problems with my Kat again. My new compression tester has arrived and I’m getting some very strange readings? On the two outer cylinders I’m getting an identical 175psi which seems very high to me, the inner two are similar at 125psi (cold engine for this test) a dribble of oil in the inner two brings them up to 175psi so I’m guessing I’ve got sealing problems on these two. I’ve pulled the carbs off AGAIN! and renewed all the “O” rings plus I think I’ve sorted the #2 carbs flooding problems as the float needle seemed to be stuck but I’m still convinced the float height is wrong as the bike starts from cold without choke? I’ve ordered two of these https://rover.ebay.com/rover/0/0/0?mpre ... 2778152771
As I can’t find any m6 fine thread bolts and no one has a spare drain plug! So until they arrive can anyone tell me where I measure the float heights from as there are two possibilities either from the flat highest part of float or the step which is the start of the curved part.
I hope someone can help here as I’m rapidly loosing faith in my big Kat

[fossie]

To check float height , a ruler against the carb base gasket area, and the top at the height point , as in the flattest part where the float joins the mounting area. I know what I mean so maybe you can suss it!

I'm not convinced that float heights would lead to running rich on start up as in no choke. That sounds like pilot jet , or mixture to me. How did you get on with the carbs from eBay you were looking at.

[PaulD]

Ok, one of the reasons I’m thinking floats is the abundance of fuel in the plenum chamber. I’m sure I’ve seen somewhere you measure the heights from the curve of the float not the very top flat part but I can’t find it anywhere? Mine are measuring correct where you say Fossie. The float valves are sealing so that rules them out, I would bet against the pilots as they have been cleaned and cleaned again plus I’ve blown them through with my airline gawd knows how many times. Blix, the oil in the bores rules out head gaskets. Generally speaking if oil restores the pressures it’s a ring sealing problem if it’s a head gasket it looses pressure slowly. (I think lol)

[fossie]

Paul, your mechanical logic is what I would expect , so .......measuring the float height , if the gasket is in place minus 1 mm .

What we need is a set of carbs that we know are good and set up, to at fit to your bike, to see if all is well then, to rule out any other issues. Or prove iffy carb bank.
I personally don't have an 1100 , so no help here, But someone might be able to come to the rescue.
Even if it to send your carbs to them for t hem to check.

[pookie]

Carbs are a bit of a black art, I spent ages rebuilding mine with new viton o-rings and fuel line rubbers and the beggars still played up, in the end I got a local Polish bike mechanic to look at them, he sorted them out and three years later they are still performing perfectly, maybe you should bite the bullet and find a local Polish guy to look at them.

[PaulD]

Carbs are a bit of a black art, I spent ages rebuilding mine with new viton o-rings and fuel line rubbers and the beggars still played up, in the end I got a local Polish bike mechanic to look at them, he sorted them out and three years later they are still performing perfectly, maybe you should bite the bullet and find a local Polish guy to look at them.

Where are all the Polish guys when you want one
I’ve spent half my life farting about with two stroke carbs but these buggers have me beat?
I jury rigged a fuel level pipe from the drain plug and the fuel level seems to be spot on!
I’ve stripped and rebuilt them (again) with new Viton o rings, I’ve removed the jets and blown them out with compressed air and then flushed em out with carb cleaner. I’ve also re-set the air/fuel screws to 3 1/2 turns out and static balanced the butterflies, I’ll bolt them back on tomorrow and see what happens?
Fingers, toes and everything else crossed.

[pookie]

Same as you as regard two stroke carbs, I've owned a Kawasaki Kr-1 from new since 1989 and owned a selection of strokers before that, the main difference between the carbs is that the stroker ones are slide carbs and the diesel (sorry four strokes) are cv (constant velocity) the main change seems to be that cv carbs use engine compression to work whereas the slide type are simpler and draw the air and fuel by using a cable operated slide, as you have discovered the cv carbs are a real pain to set up compared to the slide type, especially 'cos there's usually four of 'em instead of one or two, and hurry up and find a Polish mechanic before Brexit sends them all back to Warsaw (this is more government bull because the main reason East Europeans are returning is because the weaker pound means they have less in their pockets to send back home) even though 90,000 more arrived in the UK than left last month!

[pop-up]

Anymore news on this. Following with interest.

[PaulD]

Unfortunately due to the feckkin awful weather I’ve been totally idle and done nothing. The carbs are off the bike AGAIN and I’ve bought a couple of fuel level gauges which turned up yesterday so I’ll check & adjust the levels and screw it all back together this weekend. If it still runs like a bag of spanner’s it will be having it’s very own Viking funeral!
I’m really regretting selling my Suzuki Kettle at the moment

[PaulD]

Well I finally got my a**e into gear and checked the fuel levels with my widget I bought from the states last night. Interestingly it showed two carbs with the float hight way too high and the other two slightly low? Using the widget I got one carb spot on and then measured the float hight with my vernier and found that the 22.4mm was bang on if measured from the top of the curve on the float and not the flat bit which is higher up! I’ve re-set all the floats to 22.4 from this datum then re-checked with the widget to confirm the fuel level on all four is now correct. One thing I meant to ask, my throttle slides seem to have a black coating which is peeling off in places on all four? Is this a standard Mikuni thing and do you think it will affect the running if I polish it all off?
Hopefully later on today I can bolt everything back together and she will run like a watch (or not)