carb problem 2.5k idle

[kev edwards]

Have not done much until today, carbs have been put back to standard settings throughout bench set, new rubbers both sides, new Dyna-s fitted, new plugs and caps, valve clearances done, good compression, and 12v at the coils, it really took a lot to get it going jumped via car as battery is almost shot, still took a while firing up for about 2 seconds then dying this happened a few times, eventually fired up run on enricher for a couple of minutes, i then strobed in the Dyna, on both sides, running roughly idling between 9 and 1500, throttle pick up when blipped is instant, put on the vac testers and number three right down brought them all into sequence and the idle has gone right up to just over 2.5k idle screw right out, chokes all the way down, pilot screws tried in different positions, pull cable has slack and not sticking, WD sprayed around joints no change, i even put the old points plate back on to see if it was the Dyna but no change, every thing has been done by the numbers, can anyone shed some light as to what can be happening.

[z1bman]

you need to set the slide heights as per workshop manual

[kev edwards]

you need to set the slide heights as per workshop manual

I bench set them before they went back on.

[gray]

fuel height too low on 1 carb ? causing over lean mix and high revving?

[chrisNI]

Can you lower the tickover by dropping the slide adjuster screws on the top ignoring for the monument the vacuum balance? You seemed to have a better tickover when you strobed it, perhaps in balancing them you have chased the balance by pulling them all up? If it's not the slides it could be sucking air from somewhere else.

[ZedHead]

Probably a silly suggestion but I presume you have checked the throttle cables aren't to tight?

[kev edwards]

Out there again today to remove carbs and make the checks again, i thought i would turn it over on the kick and got a hissing from number 3 plug, checked for tightness and sprayed WD around it turned it over on the starter and it's blowing by i then checked all four and they are all blowing by with number three doing it badly, when i first got it i compression tested it and all were within upper limits with number three a little down, now i know why, so dependant on whether it can be repaired it looks like i may need another head.

[Stugill]

Buzzard (Dave) repaired my replacement Elr head. Two of the four spark plug threads were Fcuk'd, they had about half the thread they should have had. He made his own helicoil type thingys and made a cracking job of it.

I appreciate that he is miles from you, but just a thought.

Good luck.

Stu

[z1bman]

if it only requires heli coils you don't need to remove the head

[kev edwards]

Well today the head was removed,at some stage there has been some massive overheat in there even the alloy under one of the cam cap bearings has evidence of overheating, exhaust bearing shell lowers are black on the back and the surface like sandpaper, left side exhaust cam journals i could use as a file, one cam cap has had holes drilled to 8mm, one bolt has snapped off most holes have helicoils, 3 spark plug holes have been repaired badly and the remaining one is letting by, valve shafts exhaust side are polished almost black , a few of the valves are not seating properly, the head to to barrel locating dowels are shot and one is jammed in, one of the 6 mm head bolts is stripped, so the head is pretty much toast, i would chance my arm and say a PO has had a disaster with it, and thrown it back together and got it running after a fashion and i am the unlucky bugger sorting it out, i find it hard to believe they spent a huge amount of money on the rest of the bike and neglected the motor, looks like i am in the market for a complete head cams and valve gear included, i have made one inquiry and hopefully it will come through for me.

[ZedHead]

Speak to Buzzard. It might be salvageable