raising needles in carb shims??

[jerry]

My new m750 from Bilbo is excellent ,, i have fitted some Sils and put the Piper airfilter box in bike is fine at 3500 and up revs but a bit flat between 2000 and 3500 revs air screws are out 4.5 tuns so I think just putting the needles in the carbs up a notch or a shim ? will richen up the mixture and take out the flat spot

i also changed the front sprocket from 14 to 15 as she was a bit frentic for me

the bike is lovely

[jerry]

I put the standard cans back on NO difference still crap at low revs lumpy with standard cans and original air filter fine above 3500 rpm will try adjusting airscrews again ,, will chack the jets in my other bikes size as thay are fine at all revs with sils fitted ,,

standard cans are not really much quieter ,, and bike is lumpy between 2k and 3k

took the plugs out they are lean even with standard cans 3 turns out on airscrews ????

[Flip]

Jerry, you're probably not getting a true plug reading if you just take them out- you need to clean them up and then do a proper plug chop under load at the revs/throttle opening it's running rough at.

This is quite a good reference to work out which direction you need to go in when changing jets/needle position.

https://i.postimg.cc/3JgvKLYP/carb-throttle-range-chart.jpg (https://postimages.org/)

[jerry]

I need help now because I bought this bike primarily for Kat to ride ,, she has tried it but cant get on with the low speed rough running around town ,, below 3500 its horrible ,even slipping the clutch it s lumpy and hesitant , also I have lightened the clutch for her but its still too heavy eevn with 4 nuts only ,

she does not feel confident riding it ,


I may drop the carbs from my M750 2000 in as they work perfect at low revs but the clutch problem ???

[jerry]

looking at mt M750 carbs the old ones which work perfectly at all revs even 2-3k and roars the bike to 125mph with perfect fueling has open air box and sils the main is 140 thats massive from a 900 ( normal is 132.5) the slow jet is 70 thats standard and needle is set at 4 its a dynajet needle

dont know yet whats in the new bike but its ok at anything above 3k with standard factory cans and airbox and according to Alf it probably needs the needle raising one notch to improve pilot and low circuit as the airscrews are out 4.5 turns and its still lean at low revs will have to get the carbs out and check

if Kat cant ride this bike i will have to sell it on again and get her something with Fuel injection and an ultralight clutch she is used to Yamaha MT07 or kawasaki ER650S

I like the bike its in nice nick and handles sweet and runs lovely for me except in town

[Flip]

Not wanting to state the obvious to you Jerry but I assume that the valves are within spec and the carbs are balanced properly?

As for the clutch I am not sure there is much more you can do with the earlier 'Pantah' based motors other than what you have already.

[Mr Gazza]

Re carbs... Can you get them in an ultra-sound cleaner?

Re clutch; how much meat is there round the slave cylinder bore? Would it be possible to bore it out for a bigger piston? pistons dead easy to make on a lathe, just need to decide a diameter and source the seals.

[jerry]

Put the airscrew 5 1/2 turns out ,, once warmed up and given a good thrash the bike is more stable running in 1-4 gear on part throttle , at revs less than 3000rpm , less lumpy smoother and less hesitant , more pleasant overall after 40mile run

so that means its too lean and needed richer ,, but 5.5 turns out means needle needs to be raised , with a shim or notch to richen things up then the airscrews can be wound in a turn or 2