AIR FUEL mix screws

[makzy]

Well I'll start at the start ! i have 2 sets of carbs, both are the same but 1 has tin tops and the other has alloy, when i originally bought my bike it was running ok but not reg so i don't know how it really ran on the road, it sat for 5 yrs, when almost back on the road my brother decided he wanted my 120 mains and swaped me his 140's thinking mine might go a bit better with bigger jets! I'm wiser now!! when back on the road the bike seemed to run ok but obviously out of tune, I eventually found out i had a slightly bent inlet valve, and probs with first and second gears, along came engine no,2 same carbs went on  with all std jets, new diaphrams, cleaned, set up, vacuum tuned, color tuned, started well, idiled well, but was still rich from low right through to mid, when run at about 120, 130 for half an hr, plugs looked fine, good actually, but 2 days town riding and the plugs were black and fouled, tried needle settings by halves, float settings in 1mm incs, all with pretty much the same result, but I was also having trouble with rust powder from the tank getting through the filters and into the carbs, so there was 2 things workin against me so off came the tank and the carbs, tank taken apart, sandblasted, dents rolled out, welded back together, treated, painted, waiting for stickers to go on this week, Steptoe and I stripped both sets of carbs, boiled them and cleaned, them rebuilt with new kits, ( yeah yeah i know, not gen mikuni)  so thats where we are at the moment, as i said before the only difference between the old parts and new is the new pilots lacked the 4 small holes, havn't had the bike on the road yet, hopefully next weekend, !!!!!! then I'l run the bike for a week or 2 with this set of carbs then try the other set but i'll replace the new pilots with old ones and see how they go......will let ya know what happens, cheers

[petejw1966]

jat,
check the valve clearances, they can make a huge
difference if there out.

[excess.11]

Hey Steps/Maksy.....whats the latest update on where things are at and have been tried/investigated since last report
  ?

[Jonesy]

Yeah not a bad thought Bryan,
maybe Jumped one tooth on the cam chain sprocket, not enough to prevent it running but just badly? seems the carbys have been done to within an inch of there lives so time to look elsewhere?
Hey makzy you didnt happen to be doing anything in that area did you? but not run it until after playing with the carbs also.

just a thought

[AussiXS11G]

don't suppose it could be an ignition timing issue ?
seems unlikely but not discussed yet...

[Christian Raith]

Don't know what happened to my brain Pete 
Just getting old I guess

[excess.11]

Fit your carbs to Maksy s bike and see if they require to be adjusted the same as his.

[steptoe]

no choke probs,, checked and double checked that bit,, all closes off nicely

[excess.11]

An issue with the choke maybe?

[petejw1966]

i was just throwing some thoughts out,

i bought a kit a little while ago off ebay, cant remember the brand off hand,
the pilots were marked 42.5 ive got teeny weeny drill bits, the actual
size of the center hole was 50.0, u couldnt tell to look at it tho.

[steptoe]

K & L, the blue branded kits,,, japanese made  kit# 630
 we compared the sizes as we put it together, sizes said they were the same, that's as much as I can tell you, {not genuine mikuni} how much of your left arm do you need to give them

to be quite honest, it never occurred to me to take the air box off, it,s a new filter

nothing wrong with ignition, checked all that

sync'd before mix screwed

the engine doesn't pick up revs as it's adjusted now, idles nicely, runs quite sweet, starts easy runs smooth and revs quick and dies quick with a flick of the throttle

have just had a thought, having been over them meticulously, will get back to you

[petejw1966]

what brand of 'kits' did u use?

ive bought kits from os before and the pilots
were the wrong size.

does the bike run the same way with the air box
disconnected from the carbs?

[petejw1966]

100 percent 40's,, bells are 185

float heights should make it run lean,, but alas no, rich as,,

I know you spend a LOT of time on your carbs,, do you check the floats at the small step where the steel meets the plastic on the bowl, the highest spot or the bowl itself?

check the floats at the heighest part of the float,
the 40 pilots on our bikes have no side bleed holes.
hows the ignition system?  if its not working effeciently itll show
the plugs as fouling. 

but
if ur able to screw in the mixture screw til its lightly seated or a 1/4 turn out, and the engine
speed pics up then the pilot jets are to big are they genuine mikuni jets?
are the carbs synced when ur adjusting the mixture screws?

just for ur info,
the mixture screws adj fuel not air.

[steptoe]

100 percent 40's,, bells are 185

float heights should make it run lean,, but alas no, rich as,,

I know you spend a LOT of time on your carbs,, do you check the floats at the small step where the steel meets the plastic on the bowl, the highest spot or the bowl itself?

[makzy]

Well the jets are all std, float hight is within range, the only difference being the new pilot jets lacked the 4 small holes in the side! Opinions!!