Bike revving high on startup

[Pea]

Hi All.

I have a motor Hispania Furia 59 bike, believed to be the AM6 engine with PHBN 12 Carb.

Bike has been stood for good year+, but it fired up fine the other month. Gone to start it up again this weekend and it wouldn’t go. Filled up with fresh fuel and tried it again but this time after a few kicks the overflow from the carb started leaking with fuel tap on.

I removed the carb and float bowl cover but didn’t do any extreme cleaning. Put it all back together and this time no overfill leak. After a few more kicks the bike started all be it a little rough but not bad for being left so long !

I cut it off and relocated the bike, upon starting it up again it seems to be revving extremely high at idle, so much so that I can only run it for a few seconds before having to kill it.

Initially thought it was the mixture screws but I hadn’t moved them since it was last running fine, or maybe the throttle cable being pulled.

I changed the screw positions but nothing major seemed to change and also reseated the throttle cable in the carb and checked for pulls etc but all good. I don’t think it’s the cable as when it’s revving high I can apply throttle and this changes - so if the cable was already on I’d not expect that.

Any idea on what could be the problem ? Is it worthwhile stripping down the carb and cleaning jets etc ?

One thing I did notice is it took some force removing the choke cable from the carb but this seemed to reseat back in fine, additionally I wouldn’t expect essesive revs I’d say the choke was fully on would I ?

I can upload a video of what occurs on start up if need be.

Any help appreciated !

Thanks.

[Riejufixing]

Can you see down it when you operate the throttle (not running)?

[jaffa90]

""" overflow from the carb started leaking with fuel tap on. """
This is your problem so you may have crap in the fuel supply stopping the float valve from shutting the fuel off at the correct level.
After sorting the carb fit an inline filter in between the tap and the carb to stop further crap from the tank & tap.

[Robby]

Check the choke first. It may be stuck fully on, seeing as it sounds that everything in the carb is a bit grotty from sitting for a year. Find where the choke cable fits onto the carb, it will be an arm or a plunger. Give it a wiggle and see if it snaps back into the closed position.

You may have also messed up fitting the throttle cable back on after removing the carb for cleaning, so it is always holding the throttle open a bit.

Finally, if it isn't an obvious thing, air leak. Most likely carb isn't properly seated in its rubber on the engine side or a hose clamp isn't tight, again from removing the carb to clean it out.

The stuck float would have just been from sitting for a year with stale fuel in it, something that stick a bit. Tend to free up with fresh petrol and use.

[Easy-X]

Having just cleaned a carb (badly, evidently) and getting similar results... I'd say give it another clean!
____________________
Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter