one duff cylinder

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kickstart

kickstart

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I have a 71 750 that i recently bought, hasnt run for 25 years. Ive changed oils, etc. cleaned out the carbs (more than once on the lh side), changed ht leads, plugs, battery and cleaned most electrical connections. It has electronic igniton. It now starts on one cylinder then the left cuts in about 3 k revs. almost idles on the rh cylinder. valve clearances are good..... oil return good...
 
If there's sparks both sides, then the left chiming in as the revs rise does still suggest fuelling issue that side...
 
When you cleaned the carbs did you poke out the pilot jet bush ?
If not checkout
Bushman's carb tuning secrets
 
baz said:
When you cleaned the carbs did you poke out the pilot jet bush ?
If not checkout
Bushman's carb tuning secrets
Click to expand...
just drove down the road, first time its rolled on its own power. Did give me a good grin. i did put another plug along side the lh cylinder and it did spark like mad so i think that is ok. i agree and think its fuel, i put a carb cleaner down the air screw then using a compressor blew down the air screw with my finger over the pilot intake hole, i am sure looking down in the carb the small hole was blowing okay? i didnt know you can pop out the pilot jet? i will give that a go. all things point that way.
cheers
 
Pilot jets are only removable on the Premier Amals. Use a guitar string or I believe #71 drill bit.
 
1st...spend only a tiny bit of time making the old Amals work...no more than an hour.

2nd..remove the carbs, strip them of anything useful...screws especially...and toss them in the trash. It feels good to whack them with a ball peen a few times.

3rd spend the money to buy the overpriced replacement premier Amals and hope there are no flaws. Or buy a single Mikuni and save yourself all kinds of problems.
 
Cuppy said:
Thanks for correcting that now what size guitar string?
Click to expand...

It says in the Bushman's link...:

"Use a 5th String or “A” BW045 Med Bronze wound guitar
string with the windings removed."

...Not being a guitar player myself I must assume that to be correct.
 
kickstart said:
just drove down the road, first time its rolled on its own power. Did give me a good grin. i did put another plug along side the lh cylinder and it did spark like mad so i think that is ok. i agree and think its fuel, i put a carb cleaner down the air screw then using a compressor blew down the air screw with my finger over the pilot intake hole, i am sure looking down in the carb the small hole was blowing okay? i didnt know you can pop out the pilot jet? i will give that a go. all things point that way.
cheers
Click to expand...
You can not remove the pilot jet bush
Sometimes a hair from a wire brush will do the job
Or a nozzle cleaner
Or as already mentioned a guitar string
But the best way is to use a 16 thou drill bit glued into a wd 40 tube
With a drill bit you can pull the debris out instead of poking it in
 
L.A.B. said:
It says in the Bushman's link...:

"Use a 5th String or “A” BW045 Med Bronze wound guitar
string with the windings removed."

...Not being a guitar player myself I must assume that to be correct.
Click to expand...
Bit of a faff, removing the windings. I used (an unwound) top E, 0.010 with masses of carb cleaner. It did the job and still fine 4,000 miles later.

I now turn off my fuel tap before I reach home and run the carb dry as I get into my drive, I think that helps avoid stale ethanol content fuel gumming it up again. Was clean when I checked last service.
 
well, i had a spare carb off an A65 that was the same 930, so cleaned it, swapped all the bits and fitted that one. Like magic it started and runs, still haven't set it up properly... tomorrow with luck. May be getting it ultrasonically cleaned would do the trick? It did look tough to get the pilot body out. I recon that as it has sat for so long dust and all sorts have clogged it, a soak might even sort it. Many thanks,
 
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