help needed! bike won't rev

Hi I own a '91' xlh 1200 which has been off the road for about 5 years, my bike fires up ok, but cuts out as soon as I put the choke in, I can rev the bike with the choke out, but if I push the choke in all the way, the engine cuts out. I can keep the engine running with the choke onlly about a quarter out, but then she won't rev, as soon as i open the throttle, the engine cuts out. I have replaced the diaphragms and cleaned the carb with carb cleaner (coz the float valve was sticking). Would really appreciate any suggestions/help to get her running, desperate to get biking again. thanks

[Phil]

Check for vacuum leaks, probably a huge one.

Originally Posted by Phild

Check for vacuum leaks, probably a huge one.

I agree, check your diaphram its probably perished

thanks for the replies guys. How do Icheck for a vacuum leak? and where is the most likely place for one to occur? I have replaced the diaphragm and the rubber sealing ring where carb joins t manifold.

[S.T.Chapman]

Take a good look, get it running and spray the inlet manifold with wd40 if its leaking it will smoke like hell or stall it.

[kiwidave]

when it is running with choke out, see if one of the pipes is cooler than the other. of if you can hold both mufflers after engine itself is hot.....

also see if there is any oil dripping out of exhaust port/s

oil could be contaminating one or both combustion chambers.......

had the very same symptoms myself. a week ago.

Excessive valve wear or failed seal/s...or bore wear.

[Phil]

Originally Posted by kiwidave

when it is running with choke out, see if one of the pipes is cooler than the other. of if you can hold both mufflers after engine itself is hot.....

also see if there is any oil dripping out of exhaust port/s

oil could be contaminating one or both combustion chambers.......

had the very same symptoms myself. a week ago.

Excessive valve wear or failed seal/s...or bore wear.

WHAT! You just fixed it!

[Hawkeye]

If the engine has not been run in 5 years i would think you have some crud in the float bowl.

The fuel would have evaporated first them moisture gets in and makes the alloy corrode with little white bits of crp, this then gets sucked in the jets.

remove float bowl, remove jets and blow out, do not stick anything in them to clean them. Wash the whole carb in petrol and reassemble being real careful with the diaphram.

I.ve stripped the carb down more than once and cleaned everything out, (getting pretty quick at the whole carb removal clean & refit thing now!), but I hadn't thought of corroded alloy, that.s interesting. So presumably these bits of corrosion may be dislodging and blocking things up again. I'll strip it again and clean everything out to see if this helps, although there are presumably many passageways that I cant reach. I rang a local carb specialist, and they reckon the only way to clean it properly is to put it in an 'ultrasonic bath', has anyone got any experience of this process?

Originally Posted by rocorn

I.ve stripped the carb down more than once and cleaned everything out, (getting pretty quick at the whole carb removal clean & refit thing now!), but I hadn't thought of corroded alloy, that.s interesting. So presumably these bits of corrosion may be dislodging and blocking things up again. I'll strip it again and clean everything out to see if this helps, although there are presumably many passageways that I cant reach. I rang a local carb specialist, and they reckon the only way to clean it properly is to put it in an 'ultrasonic bath', has anyone got any experience of this process?

yeah the ultrasonic bath uses ultrasound to clean any particles out of the carb in all the little crevices , tattooists use them to clean thier equipment before sterilisation, so do watch repairers to clean watches. I would have a real good look at the diapraghm again its very very easy to trap it on reassembly.