Road rocket problems

[barry2]

Hi mates
This is a continuing problem Ive been having ,but will start afresh
Road Rocket w/- super engine was running too rich, was starting Ok  but was surging a bit, so  fitted a new needle/ needle  jet, still rich,  so dropped the needle a notch, now on the lowest /the first time I too it out was missing  at pilot / needle jet change over  but not all the time and ran well most of the time , but acc' missed a bit , Yesterday morning flooded the "Monoblock" but wouldn't start after good hard kicks , thinking too much fuel held the throttle about 1/2 open after 1 or 2 kicks it started rough/missing etc but but settled down to ok tickover, rode quite well but with acc' missing, went about 10 kms , stopped for about 1/2 hour, this time no flooding to start, still hard to to start till I opened throttle wide open then missing till settled down, went fine on the freeway from low down to flat out,, had the colourtune on it fine at tick over , i also took the plug leads off in turn each and cylinder ticked over fine on each cylinder , but sometimes the tick over is erratic but not always ,,, The engine is still running rich but not as bad
Been right thru the magneto plugs / leads / pick up / brushes etc great spark and no arcing at the points , I did take the slide block out before maybe I stuffed up w/- that, if it wasn't for the hard starting I could put up w/- it any thoughts P/S do they have a brush behind the points plate?  mine didn't I put one in ,, it didn't help
Barry

[ironhead]

Hi Barry.
Float level may be a bit high. If an engine idles good when cold it usually means its too rich.
Also maybe check the needle jet holding block, there should be a fibre washer under it. Make sure the small locating screw on the r/h side is not binding the block & stopping it seating properly.

[orabanda]

not so sure about the needle jet holding block requiring a fibre washer?
Although the parts list shows one, I have found the float level is usually too high. Removing the washer brings the level lower (to the level of the dimple on the outer cover).

Richard

[barry2]

Hi Mates
Thanks for the tips ,,I did check the fuel level, was spot on, going put the needle where it was ( correct  position)
Barry

[Swarfcut]

Bazza.. There is another carbon brush under the pan head slotted screw adjacent to the magneto name plate. This is the earth return between the armature and body. Worth checking as failure here can give all manner of erratic running. The later steel points backplate does not have its own  carbon brush and relies solely on this brush for the earth return. This is why some brass points plate have their own brush, some don't. Its a case of belt and braces, or just a belt. Not saying this is the answer, but something else to consider.

 Anything which alters the height of the needle jet in relation to the fuel level needs careful scrutiny. The jet block needs to be seated fully. Check the parts are the right ones for your carby, and the basic assembly is correct, as in the parts diagram, regarding the position of any sealing washers.

 Swarfy.

 

 

[ironhead]

G'day orabanda & swarfy.
Not the float needle, the jet block ( venturi) holder. It pushes out when the small locating screw on the r/h side &
big nut on the bottom of the main carby body is removed. This has a fibre washer & will cause richness if it doesn't seal properly.

[duTch]

 

.......This has a fibre washer & will cause richness if it doesn't seal properly....

 I'm fairly sure mine has a really thin paper gasket

[barry2]

Hi Thanks
for tips, already checked the other brush (ok) , did have trouble w/- the jet block, think I may have distorted it getting  it out, when I put the jet holder back it wouldn't seal  on account it wasn't square will look into  it, don't remember a gasket either
Barry

[Rocket Racer]

whats the provenance of the monoblock, might have a wrong needle or worn needle jet. check your float levels and consider getting a new correct needle and needle jet from amal, there are some dodgy non genuine jets and needles around that will cause pain.
Is the carb relatively new?  Has this problem been a constant?

[barry2]

Hi Mates
I think I have fixed it , it didn't have the thin paper gasket under the slide block and I was weaking to compensate, I'm going on a 80ks runs this am, will get back PM to tell how it went...., RE, the old needle jet I took out  had "Amal"  the same number on it and was chrome plated , had  about .010 thou' bigger  hole than the new one , I have a feeling  it wasn't genuine
all the best  Barry

[richard boys]

hi just rebuilt a 389 no gasket [ the thin one between the the jet block and housing] the rebuild kit i got had a note inside " thick rubber 'o' ring no gasket thin o ring paper gasket " the carb i rebuilt did look like no one had ever touched it since new no rounded or bured  screws nuts or flanges ; other 376 monoblocks i have had that paper gasket and they had large  "o" rings  ,