Carb set up probs

[bazabod_downunder]

Need some insight or thoughts on current problem, setting up PWK copy on a rebuilt Muggy 186, variotronic ignition with a LTH reed valve with Scootrs expansion. It hasn't been roadworthied yet so only can ride it around a small carpark, last weekend seemed to be running sweet as although a little smokey. I've been messing around with it today & after changing jets, clip positions & pilot I'm back to where I was, but now when set to idle, when ridden & then stopped the revs race irratically & won't come down to idle, also from then it needs choke to start again. Bogging at low revs which seems to point to running lean. At the moment it has 40 pilot, 114 main JJH needle middle clip...any ideas?.....looking at ordering more pilots & needles

[dapper]

Firstly have you done the mods to the carb? There a threads on here about it. Also, the PWK can benefit from turning off the fuel before you stop and not turn fuel on again until she has started. I think what happens is that until the mods are done, when riding the floatbowl empties and then when you slow down/stop it suddenly fills and causes the engine to race when the fuwl gets back through.

[tarmac tickler]

do the mods like the man says,,, the main is way too small .. 145 and come down one at a time , pilot about right ,, make sure its not blocked,, dead small hole up the middle of it,, blow it through. good luck

[coaster]

It sounds like you may have an air leak, that pilot is too big so it SHOULD be boggy. My 186 muggy was running with a 38 and it didn't have a reed valve. The issue with not starting when warm isn't restricted to PWK's, PHBH and Jetex can do it too, it's due to spit back fuel collecting in the airhose. Also you'd need to be caning under load before the float bowl ran dry so I would doubt that you'd have that problem tootling round the car park. Worth bearing in mind when you get out on the road though.

[bazabod_downunder]

Dismantled carb, looked at the mods & it's like that already, ground off the float stops from the bottom of the bowl......checked for leaks, looked like oil had been blown out from the exhaust manifold, so took that off & put a new copper gasket on, put the carb back on with the biggest main I have (although that's not important right now) & the leanest pilot I have which is a 32, started ok, faffed around with the air screw, still seems to not come right back to idle after blipping the throttle....had to stop as neighbour came round to complain......thing that is bugging me & I have a bad feeling about, it was & still is a bit smoky which is pointing to drive seal leaking, I'm hoping I'm wrong as I put in all new seals/Bearings/hallite washer when rebuilding :O( muffled the exhaust & still ran a bit.....any other reliable way of checking without dismantle?

[Darrell Taylor]

use the choke to see if improvements are made at various throttle positions and if so richen up
is pwk 21 24 26 28 30 32 34 std or powerjet version
has the lth been fitted with boost port and window,s added to piston?

if 28 non powerjet try quarter to half turn out on mix screw and adjust the tickover /clip 2 needle/45 pilot/150 main as a start point

check the varitronic is set correctly as the smokey running condition can be too retarded related


or try doing a leakdown test

http://scooterotica.org/forum/viewtopic ... 27#p191602

[Yanker]

Is your 'float height' set correctly at 19mm ?

The floats run very close to the overflow tube. If the float carrier bracket is slightly bent on these, they can easily snag on it. Try to replace the float chamber with the carb upside-down and give it a shake to ensure the float is moving freely before re-installing.

[bazabod_downunder]

Yes, reset/checked the float on reassembly & could hear it rattling away...anyway as was cut short by tw@7 of a neighbour yesterday, got home earlier, kicked over second time had to pull the choke back a bit as it was going for it big stylie, let it warm right up, reset tick over & airflow screw, running sweet as a nut now??????? & blipping like a blippidy blip thing now :O)....however I realise I will have to make more adjustments later when it's running in & isn't so smoky now, so fingers crossed it was just a case of being a little bit rich......plus decided to invest in a JL3 at some point as it's as loud as now....thanks for all the tips.......Darrell it's 30mm non powerjet, will get a pilot & main sets from MB as this is only the beginning...timing is set to 19 degs