measuring float height

[Deleted]

hi, im trying to figure out the correct position to measure the height as stated in the haynes,do you measure the edge near the front or from the middle of the bowl,thanks again.

[ianboom]

Fist picture is the correct one, make sure you remove the gasket and keep the ruler off the raised lip on the casting!
Make sure it's right as I bent the tab on mine and melted a piston on the dyno!
Ianboom

[Deleted]

thanks ian,sorry about your bad luck, i put new thingos in it today and it seems to have made the float higher, its reading 22 and a half were the book says 21 give or take half a mill. this is a job for tomorrow, overhere the footy is about to start and it is beer oclock,i will have one for you, thanks again

[Deleted]

Mar 23, 2012 9:07:47 GMT 1 ianboom said:

Fist picture is the correct one, make sure you remove the gasket and keep the ruler off the raised lip on the casting!
Make sure it's right as I bent the tab on mine and melted a piston on the dyno!
Ianboom

Is that because you had it too high or too low? How did it cause the piston to melt?

[nikfubar]

Not sure if it's the same on these but on the PWK28s you also have to hold the carb at an angle so you make sure the weight of the float does not compress the spring in the needle valve which can give you a false reading

[Tone]

Yes, same on the Mikuni carbs. Hold the carb upside down and at an angle so the tang of the float is Just touching the needle valve but Not compressing the spring loaded tip and measure from the gasket face of the carb (with the gasket removed) to the highest point of the float (with the carb upside down) like in the first photo. Looking at the first photo it looks like the float height is too high which will result in a low fuel level in the float bowl causing a weak mixture. Float height on the LC and YPVS is 21mm + or - 0.5mm.
Tone

[ianboom]

Mar 23, 2012 21:16:42 GMT 1 @scruff said:

Mar 23, 2012 9:07:47 GMT 1 ianboom said:

Fist picture is the correct one, make sure you remove the gasket and keep the ruler off the raised lip on the casting!
Make sure it's right as I bent the tab on mine and melted a piston on the dyno!
Ianboom

Is that because you had it too high or too low? How did it cause the piston to melt?

The float height was too low, so there wasn't enough fuel in the bowl.

I was doing a full load dyno run, and the bowl must have run dry as the float height was that low it couldn't replenish the used fuel quick enough. If the float height had been ok, when the fuel height dipped, it wouldn't have been enough to starve the engine?!

Luckily, I hadn't nipped the barrel drain screw up and it started to leak, so we stopped the bike, to sort the leak, then it wouldn't start! If it hadn't of sprung a leak, i reckon more piston would have melted and I'd have shagged the bore/head.

I bent the tang on the float when I reassembled the carb after a main jet change

[arrow]

Mar 23, 2012 9:39:18 GMT 1 @ken007 said:

thanks ian,sorry about your bad luck, i put new thingos in it today and it seems to have made the float higher, its reading 22 and a half were the book says 21 give or take half a mill. this is a job for tomorrow, overhere the footy is about to start and it is beer oclock,i will have one for you, thanks again

Ken, what make were the float valves you put in ? Changing them should not in itself alter the float height.

[Deleted]

gday gary,they are the tour max repair kit from norbo, i may have been wrong cause i didnt measure them before but they seemed higher, i had only started the bike twice before i pulled it apart to restore (it was unrideable) so as far as performance goes i cant say , but what a job setting the float height, it was like trying to sink a putt on the golf course, just kept missing, ,to high,to low, to high, to low,this went on for half a game of footy, i thought the tang would snap off in the end. see ya