Compression and a pop from my exhaust?

Cut long story short my aerox ran out of fuel and I walked it to the peteol station. went to start my bike and it wouldn't start , and was chuckin compressed air of some sort and a pop from the exhaust .

Any ideas?.

 

possible you have fully drained the fuel system and it would need a good few kicks on the kickstarter to prime the whole system again, ie fill the pipes and filter then fill the carb and expel any air from the carbs float bowl.

check fuel filter incase running full dry has drawn some crap up into filter and clogged it up causing a no fuel flow to carb and fuel lines

 

Thanks dude, appreciate the fast response . whats causing the compression and pop from the exhaust ?. ive kicked loads but will try again later.

 

unscrew the carb bowl drain see if your getting a fuel flow. ie bike turned off unscrew and drain bowl, leave it unscrewed with a bottle of something to catch petrol then kick bike over a few times, it should drain right outta the bowl straight to the bottle, if this is not happening you got a blocakage somewhere.

compression pop could be the fuel is compressing and igniting itself due to the high compression ( but its very unusual unless you have a very fine set squishband producing a very high compression rate ).

pop plug out and check your getting constant spark , not an intermitant sparking ( spark only comes every three or four kicks, that could be producing the pop as its not burning fuel and getting a build up.

 

I've managed to get it started but whenever I let go of the throttle it dyea, revs up fine but when I take off the throttle it wants to die?

 

I've emptied the float bowl it had fuel. It's to dark to take apart the carb. but I believe ive sucked some shit up in the carb..I do have a 90dg air filter what points directlty to the ground which don't help.

I will clean the carb, jets tomorrow and flow the pipes through to check for dirt and build up...and will let you know tomorrow mate...

 

kk maybe look at a 45 degree rubber hose for that filter get it away from any possible dirt/water entering . or see if you can turn the airfilter in a way so its faces a better direction but is not getting any thrown near it by rear wheel

 

Yeah mate the weather here in Wiltshire is awful , so much rain and don't help not having under belly pannel...this sort of weather everything needs to be covered. hopefully ill have it sorted tomorrow buddy...

 

same here weather in norfolk is tipping it down , may wanna see if you can get a secondhand one fella will atleast help on keeping water out.
could also cut some vent slots in it to aid cooling if need be

 

I feel like a complete tool. bought Aeroc Evo Kit...bit sold the belly to a mate. ill do what you said just pick up a 2Hand one from ebay or summit .

Yeah cooling on 70s are a must have. they get ridiculously hot, but I always use the correct oil ratio, and coolants. but I was stupid to let my bike run empty , ive drawn all the shit from my tank..just gonna pull my vac tap out clean it, clean my lines, and carb...I'm 100% certain what u recommend will sort it.

 

be honest buddy nobodys gonna see a belly pan so even a stockers gonna be fine, use a dremmel and just carve out a couple venting slots but be sure to keep most of the strength still intact and im sure its gonna help you no end .

yeah give her a good clean out see if that helps, also pop that sparky just to be sure your still got a fire on that plug to

 

Get an airbox on it instead of the aftermarket filter thing.
You guys know nothing of rain, try living surrounded by mountains and close to the coast, it rains about 80% of the time here... Norfolk is funny, its not rain its sort of drive through clouds, really light rain that gets you soaked right? Im originally from the fens and know it well

 

**Update**

I Cleaned the carb, lines, flushed ny tank through a few times with some esso fuel and oil and flushed it through a funnel...couldnt believe the amount of shit that was in the tank mate, its shocking to think that shit can be drawn through .

Now on to my rollers...I put 3x 4.5g Rollers on one side and my old 3.5g 3x rollers on one side i lubricated the roller area with the supplied stuff...huge huge difference !!! but it still has that sluggish bit but that's because I only changed 3 new rollers. I'm sure when I replace all of them the bike will run

 

need to stagger rollers buddy otherwise you can cause damage to crank.

fit rollers like this 3.5 - 4.5 - 3.5 - 4.5 - 3.5 - 4.5 , this way as it spins the weights are distributed evenly around teh variator.
if you load one side with 4.5 and the other with 3.5 the variator can cause a wobble and this will transfer to the crank shaft causing very quick wear , the shaft to shear off and the bearings to take extreme wear to.

you will find with the staggered method the pickup is smoother and the rpm is to , as for tank crud thats what our inline filtering is capturing, in old bikes like honda cubs they never had filters fitted to the fuel taps and are prone to rusting in the tank, so even cub owners fit inline fuel filters to stop crud getting into carbs , just keep a spare one in the seat bucket if you notice the one fitted getting caked up its a quick swap over and your away again.

and try not to run dry again buddy on the fuel side , when my tank hits the red block mark i ride to the gas station and fill back up i never go below the red marker on tank gauge

overall roller weight : we can do some simple maths to give us the overall weight in the variator.

right now your 3.5 and 4.5 weights when added up eqauls 24g all in, now we devide this 24 by the six roller ramps and that final number is the overall weight , so for your set up using staggered 3.5 and 4.5 weights we get a overall variator weight of 4g

it means its like we have just put in 6x 4g rollers

so to caculate your variator overall weight we use this maths

3.5g x 3 = 10.5g
4.5g x 3 = 13.5g
13.5 + 10.5 = 24g
24 / 6 = 4g

 

Thanks for that buddy. should I stagger them out them like you said?

 

yes mate stagger them

so put in a 3.5g at the top then working round the clock face add a 4.5, then a 3.5 , then a 4.5, then a 3.5, then a 4.5
the variator will then bee full of the rollers and they will be in a staggered setting , this is how we fit differing weights of rollers and its a lot more better for the engine and crack having this balanced weighting .

you should feel it being a lot smoother in transition from low to high and high to low ratio. than it is now with bulked weights on either side.

trust me on this its a lot better for your scoots motor / crank and variator and belt wear

 

After running for while. when to kick and the 4th kick it started than died. 3rd kick it shot out air and a pop..so, pshhhhhh..pop.

 

check your sparking. possible the spark plug is not firing all the time (constant timing spark ) and during the break its not sparking its building up fuel then when it does spark it backfires.

check the magneto timing is set correct to .

 

How do I go about doing that and how do I check the sparking mate ?

 

empty the carb bowl so no fuel is in it at all , and pop off the vacuum pipe so pump wont work,
remove sparkplug and rest it onto either a metal part of frame or the cylinder and give the starter a whirl / kickstart. you should see a constant sparking on plug tip , if its only sparking now and again its possible a wonkey ht cap - ht lead - coil

magneto, remove the pump/fan on right side of motor casing to uncover the magneto bell, compress the kickstarter a couple times lightly to get piston to top dead center, now look at magneto theres a F mark and it should line up with a notch on the engines casing. if both these are aligned and the piston is around top dead center your timing is good.

grab your credit card, and slip it bewteen the pickup sensor and the little nub on the outer ring of the magneto ( line the nub up so its directly below pickup) you should just be able to slide credit card bewteen the space, if its all go the pickup gap is good and the timing is set correct.