Aerox and Fog ped not firing :(

My son drove home in heavy fog the other night and now the ped won't start. He had complained of spluttering at half revs (going slow following me in my car) but everything was ok if he opened the throttle 80-100%. As we arrived home the ped stopped all together, I thought it would be the moisture getting past the air filter and into the carb.

Anyway I was out last night trying to get the thing started but would it go - would it hell. She's turning over but just won't fire, I've drained the carb in case there was any water in the float chamber, cleaned the air filter, checked the fuel feed (sucked on the vacuum and fuel splurted out the other pipe) and there is a spark. I'm at a loss as to what else could be wrong. Everything was fine before driving in the fog.

Would using the wrong 2 stroke oil cause the fuel/air/oil mixture not to fire? Son decided to buy some oil at a garage as the oil light came on, he bought 2 stroke oil for an outboard engine - obviously didn't read the fine print lol, although ti does state for all 2 stroke water cooled engines. That said he put the 'wrong' oil in about 100 miles ago and it was running fine till the fog.

Any ideas?

Cheers

Dave

 

Cheers MC, how would I go about checking for a dead choke or air leak? I read somewhere the choke is a wax filled tube that melts under electric current?

Thanks again.

 

the choke is just a valve on the carb that just lets more fuel in the carb for when the engine starts , if its a rox ul b able to see easily because its manual so its got a cable coming out from it , dont confuse it with the throttle which is in the middle. i dnt know what its like on other scoots all iv ever worked on is my aerox but itl b the same sort of thing just probably automatic , hope that helps

 

get a tin of WD40 and spray it round the cdi, HT coil, HT lead, spark plug and any other wiring connectors, it should cure your problem.

 

what he said

 

Still not sorted it yet although we are a bit nearer to the cause. I changed the plug to a brand new one but still no joy. I tried the old school way of putting a little fuel directly into the head (via the spark plug hole) the bike started, I stopped it straight away as not to cause any damage.

This kinda told me it is a problem with the carb or the reed valve, unfortunately the reeds are bolted in with those tamper proof allen bolts (little nipples in the middle) and I can't get hold of a tool to remove them locally.

I think I'll get some carb cleaner strip the carb and see if that helps.

As for the choke it's the automatic type - there may be a fault with it though. I've checked the 2 wires that go to the top of the unit and there was only about 1 volt going to the unit and that was only when I tried starting the ped - there wasn't any current when I turned the key which I thought there would be (pre heat the choke?).

Any more ideas?

Cheers

 

rightm its probably water in the jets blocking the fuel, to get the reeds out, get a small punch and knock the central pins down then use a normal torx bit or use mole grips to remove the bolts.

 

OK bought some Carb cleaner and a tool to get the reeds out. Stripped the carb and cleaned it, removed the reeds and cleaned them also but still no luck.

I am right in thinking if I have my thumb over the spark plug hole and it gets blown off then the compression is ok? I only ask as it's as if fuel isn't being drawn into the reed from the carb (no vacuum).

I've filled the float bowl and put fuel directly into the fuel nozzle pipe but when I try to start the bike (trying constantly over a 5 min period) the level in the nozzle doesn't drop.

I know nothing about engines (gimme a computer any day) but to me piston isn't creating a vacuum therefore the reeds aren't opening.

Is there any way to check the vacuum/reeds baring taking the head off?

Thanks again all

Ninja

 

ok this sounds incredibly like someone else i know....

is the scooter in question an aprilia sr 50??

 

no mate it's a stock Aerox 50 de-restricted via variator/Technigas exhaust.

Ninja

 

Hi ninja sorry im no help to help solving the problem but I was just curious of what sort of speeds your getting out of your rox

as my dad is thinking of full de restricting mine (std exhaust and variator and possibly jets)

thanks chris

 

With the Variator and exhaust he was getting about 50-55 - fast enough I say lol

Ninja

 

Here's a thing guys, could a semi crushed exhaust pipe be the cause? Son told me he went up a cerb and bottomed out, I just noticed the downpipe is about half the circumference it should be.

Hmmm I wonder.....sons gonna get a right bollocking if it turns out to be this, 3 nights working in a bloody freezing shed grrrrrr.

Ninja

 

Another update....

The ped still won't start, I borrowed a compression tester from the local motor shop and it was showing about 100psi but it was the rubber bung type so I couldn't get a snug fit, but if it's 100 with a 'leaking bung' then it would be 100+ with a proper snug fit one?

As I took breakdown cover out on it I called them out. They checked the very basics, spark, fuel etc (although I had to show him how the vacuum hose operated the fuel flow - didn't instill confidence lol). They took it to a garage where my son is doing his work experience, where they managed to get it running but only by using easy start fluid directly into the carb.

I've ordered another set of reeds as when I was working on it I removed the air filter and put my hand over the carb inlet and could feel a very light back pressure against my palm, am I right thinking there should be no back pressure else the carb is blowing fuel out rather than sucking it in or should there be a little back pressure for some reason.

The Aerox is an 06 plate so has the stock Gurtner PY-12 carb fitted with auto choke I really can't afford another new carb and eBay only have the Dell 'Orto carbs with manual choke, could I switch from one carb to the other even if it means rigging up a manual choke lever.

As always - any advice appreciated

Ninja