Setting float Heights

[wildtapholer]

Excellent write up by Nurse Julie about setting float heights but does it make a difference if you just have your carbs horizontal and leveled out with a spirt level, like i watched on youtube, I ask this as when I changed the float valves because the carbs were overflowing, I just set them level. The springs in the new valves were a lot softer and I found I had to adjust all the floats considerably to 21mm, put back on bike they overflowed, not pouring just a constant drip, took off checked the levels then set at 22mm put back on still the carbs dripped down the overflow pipes, I had to settle on 23mm to get the carbs to stop dripping, it didn't help that one of the overflow pipes in the float bowls was fractured and took a lot of identifying only to find out later it is a common fault(hind sight is a great thing) I did consider putting the original float valves back in with just new rubbers any thoughts on that and would it affect tick over in my other thread.

[K2-K6]

Background is that the original Kehin brass components are, even now, extraordinarily accurate and consistent in their function. Hard to match in other words, and general site experience of new replacement often brings up concerns and difficulties when using them.

What change will the altered height have? Taking it a with the carbs upside down then the 23mm set will give a lowered fuel height when installed on the engine, is that the way you're describing?

If so, the reduced fuel height will make the vacuum from carb venturi pull less fuel through the idle jet at the same carb opening.  You may have to compensate by having the air screw setting further in to bring original equilibrium in mixture at that point.

[wildtapholer]

Yes the carbs were upside down, the only way to stop the fuel going down the over flow tubes was to set the height at 23mm as compromise. I had to assume the weaker springs in the float valves was having an effect on the heights and not cutting off the fuel correctly. I must have fitted and refitted after identifying the overflow fractured pipe 6 times and was getting ready to throw a wobbly over the over flow pipes dripping petrol because every time I took the carbs apart, the float bowl seal would expand and could not be reused, as I had another set I had to keep changing them around after the swelling had gone, if that makes sense .

[Nurse Julie]

You say the springs on the new valves are a lot softer, which I understand but that shouldn't make any difference to the setting of the float height levels. The spring will still be pushed in the same by the tang, closing the fuel flow. Have you made sure the valve spring seats are really pushed in as far as they will go so the little bracket that holds the seat in is perfectly flat to the casing?. If the seat is sitting proud, your float measurements will be out. If everything is in place correctly and your floats set at the correct height, the carbs will not leak.

[wildtapholer]

With the carbs upside down and the floats resting on the float valves, and because the springs were a lot softer, the floats were a lot lower, something like 20mm, so I had to bend the float tangs to get to the required height with the new valves, I'm tempted to rip it all apart and put the original float valves back in with new seals. When I originally stripped the carbs, I measured the float heights upside down to give me a starting point and one was a lot lower than the rest, not knowing what the height should have been at the time I set it to the height of the rest, I'm thinking that was the one with the fractured overflow pipe. I never checked if the valves were slightly smaller, but blowing down the petrol pipe and lowering each of the floats they sealed.

[wildtapholer]

That's it, I'm pulling the sodding carbs off AGAIN, I've watch umpteen video's of setting float heights and they all seem to contradict each other, every time I pull the carbs I'm marking the repainted engine cases and I really hope this is the last time, so this time I'll get the vacuum pump out as well and pressurise the carbs checking for leaks, I'm finding that, do it properly, do it once, yea right I've heard that somewhere before, I thought I was ready to go out for a test ride and shake down, maybe later.lol

[Nurse Julie]

If you stand the carbs up on their end like it shows on my guide, you can't go wrong. And if you still can't get them right after following my guide, then you haven't been following my guide 😁😁😁

[wildtapholer]

I feel like I'm chasing my tail, I watched all the vids, carb float bowls off at this point I used a vacuum gauge to check for any seals leaking and ended up using 2 of my old float valves, after I was happy with the test, I reset all the float levels, yes the carbs were end up with just the tang touching, all clamped back up bench test for fuel leaks bugger no 4 carb over flow, carbs apart again no 4 over flow leaking, changed the float bowl, clamped up again, petrol on, petrol everywhere, quick tap with screw driver and a shake all's well. Carbs back on bike and bike running but I think it's no 3 over flow drips a bit, not so much when running just if I leave the petrol turned on and not running, is this worth another carb strip.

[wildtapholer]

I did all that all on the bench before and after assembly, even using a vacuum gauge but you have to use some petrol or WD40 to get some sort of a seal, I can only assume the height on that bowl is slightly high unless I have another weeping float bowl over flow pipe.

[wildtapholer]

I'm still not happy, so I intend to pull the carbs apart again and use all the original brass work, recheck the float heights and check all float bowls again except for no4 I've already changed that, I'll just have to be really careful taking the rubber seals of the new brass wear when swopping them over.

[Nurse Julie]

I'm still not happy, so I intend to pull the carbs apart again and use all the original brass work, recheck the float heights and check all float bowls again except for no4 I've already changed that, I'll just have to be really careful taking the rubber seals of the new brass wear when swopping them over.

If you do tear any of the O rings, I have full sets of Viton O rings in stock for your carbs which I can get in the post to you 1st class for (hopefully) next day delivery.

[wildtapholer]

I might have already bought some from you if your ebay sellers name is julies9731, because I didn't fully split the carbs I only used the float valve and float body seals, when I tipped the carbs up they fell out after I removed the retaining screw so that's why I thought the carbs were over filling, how wrong I was.

[Nurse Julie]

I might have already bought some from you if your ebay sellers name is julies9731, because I didn't fully split the carbs I only used the float valve and float body seals, when I tipped the carbs up they fell out after I removed the retaining screw so that's why I thought the carbs were over filling, how wrong I was.

Indeed I am julies9731 😊😊😊