Starting problem, any ideas?

Ok, i think i've got the starting problem sussed out. Took the diaphragms and the choke mechanism out of the both of the carbies and it seems that the choke passage from the plunger to the diaphragm chamber (where the fuel leaks down to be ingested by the bike) is blocked on them both. I used air pressure and didn't quite manage to clear it, but i have at least identified *THE* reason why this thing is being such a bastard to start.

Sorry for drawing this thing out so much, appreciate the hints and suggestion, some have proven to be very helpful. Will let you know when i get this fugger operating.

forget that last comment, choke actually goes and vents directly into the throttle venturi. Still figuring out some minor quirks but its something to do with the choke circuit, i am certain of this. I used the compressed air & carby cleaner and blasted a few jets out. I guess its just a case now of frigging about until i find the magic combination (i also suspect that some bits like crossover tubes for breathing are missing, which doesn't help things).

btw awesome Mikuni bs series carb guide

issue sorted, thank FARK!!! I soaked the idle air & fuel jets as well as the main jets and the needle jets in carby cleaner for 48 hours, then cleaned them out with compressed air & fishin line. Assembled it all and the beastie fired up on the third go.

She sounds alright aside from possibly being in need of a balance. That aside i *think* she's ok. Finally i can get on with doing other things like focussing on sorting out various quirks im experiencing with the chassis and front suspension.

Thanks to every suggestion both good, bad & neka . It really really was helpfull and goes to show that even someone that has a reasonably fair idea about what they're doing and some mechanical inclination can be totally flummoxed by a recalcitrant set of f*#*$&$(@#*$&#$(@ing carbies.

Cheers again,
Mick-c, Gos, photomike, i owe you guys a few frickin beers.

p.s. for those interested the pilot jets were the cause, they kept clogging up when i cleaned them manually without actually soaking them. Once i got them soaked and all the varnish was dissolved, a quick couple of quirts of compressed air and abit of mucking with the fishing line and they were good as apples.

Good stuff Mike...I don't know about you but I got pretty sick of coming back from the garage stinking of fuel while I was sorting mine out. Now there's a whole range of other things you can get into, like chasing dodgy electrickery

exactly!!! Thats why i was quite happy to get it sorted, it was getting *VERY* demoralising to have the bastard continually not work properly.The only reason i didnt jump in and soak it in carby cleaner straight off is i didnt have a bottle of the stuff, i only had the aerosol stuff and it means i had to waste a heap of it spraying into a bottle to get enough to soak all the brass bits. Frugal i know, but i thought it was a bloody waste to do that to it. As it turns out spraying them and scrubbing them didnt cut it
Must have been some deeply caked on varnish.

Great news at last........give it a good kick in the guts every few days, just to make sure that everything is still OK !!

Great News Mike, glad to hear she kicked into life.

Note to self, any carbie issues, start by soaking entire thing in a bucket of carb cleaner

One carb still isn't quite running at idle, but im going to run a shitload of wynns through her with the rhs pot running super rich in the hopes that helps sort the problem (i.e. get SOME fuel through there & clean it out).

and yes, just a shame i couldnt find carby cleaner in a bottle, felt such a waste, even though i have a number of cans of the stuff.

Oh and remember to remove all rubber bits as you could kill them in the effort of cleaning the bastard up!

on parra road near burwood there is a tyre place, behind that is a carb place

about $30 to dip a set of carbs

cheers, good to know.