Hitchcocks Forum

Can anybody help ?
I have a 2009 Machismo bullet 500 and when on neutral gear or when I released on gas , the engine revolution (rpm) goes faster and faster .
I allready check for air leaks after the carburator but found nothing . Should I dismantle the carb or does it come from the Pulse Air Valve (PAV) ?
By the way I have no idea what the utility of this PAV ...

Thanks everybody.

You don't mention what carburettor you have but might I suggest taking a look at the technical notes on carbs?


Here's a link!

The PAV injects extra air into the exhaust to burn up unburnt fuel, emissions control. It should not affect the running of the motor, should not. Setting up a carb should be done with the motor hot but running an air cooled motor whilst static for 10 minutes or more will have it over heating. It does sound like the carb may have something stuck and needs cleaning. I might give it a squirt of carburettor cleaner before pulling it apart. Is the throttle cable too tight, there should be a little slack, left and right on the bars. Could be the slide is not dropping to its stop or the idle jet has adjusted itself.

If, as jefrs suggests, the slide is not returning to its stop, check for a damaged or snaqged throttle cable, make sure the outer cable outer is properly seated the throttle control or whatever adjuster might be provided at the other end. I have never used the CV Mikarb as fitted to the 500 Machismo, My Electra-X had the Dell'Orto conversion from new, but a mid-cable adjuster could slacken off, allowing the outer cable to snag and hold the throttle slide open, with much the same effect as you are experiencing. Easy to fix once the problem was identified.



Are you in India, by the way? The 500 Machismo was never sold here as an official import, though a few (very few!) were imported privately, the 350 Thunderbird and 350 Machismo were brought over in slightly greater numbers, though still as private imports.



A.

Thank you guys !
As you say I check again carefully and found the problem with my throttle gas cable. ouf , no need to dismantle the carb but I keep in mind the carb cleaner product , look to be usefull in future.
Thanks for the explanation of the PAV , understood , it was realy a mistery for me as I never saw it on other bikes.
Sorry for my english ...but I m french so I try my best.
I bought this Machismo 500 in 2009 (one of the last 25 made ) when I was working in India and rode in back to France in 2012 . It is really a nice bike .
Take care every one

Hi Enfield Pirate,
Funny is that I own too a Machismo 500, and that I'm french too... We arn't a lot around to own this model, I know one on witch I worked on nearby me. Where do you live ?
Claude

Enfield Pirat,



if you have not already seen this: http://www.royalenfieldlesite.fr/forum/



A.

If the throttle cable has become faulty the best thing to do is replace it. They do go out of adjustment but that can be re-adjusted; they always tighten and loosen with the turn of the steering (altering the cable run may improve this situation). Adjust to a couple of millimetres slack at the tightest position. They can be re-oiled but this is never satisfactory, they often rust inside. The british cables are better than the indian ones, they do not stretch as much, it is usually the outer that becomes a problem.

The slide is returned by a relatively weak spring, the cable must move freely, without resistance.



If this is the original 2009 cable then it is probably overdue for replacement. Clutch cable too; I once had a clutch so stiff that I grew calluses, until I replaced the cable - it's often something that goes unnoticed for a long while.

Hey Claude ,I m living near by Royan (Charente Maritime).

Enfield Pirate, here is my e-mail address, if you don't mind :
[email protected]. Hope to have news from you soon. 😁