Keeps oiling up, could it be?

hi.
My sons generic 50 keeps oiling up the plug and spitting oil out of the exhaust, and keeps bogging.

How likely is it the fuel mix oiler playing up, is this a common issue?

I have fitted a 19mm carb along with a big bore kit


You help would be greatly received

 

When you set the carb up did you jet it correctly, are you pre mixing, what mods you got buddy?.

Could be seal leak, to much oil, dodgey pump..

How long has it been happening and did it start doing what you said after installing the carb etc?.

 

After I completed the mods the bike has covered about 400 miles and it was working fine but it has just started having this issue.

 

Seal leak? Which one you referring to?

Many thanks

 

Hi mate, their be one on each side of the crank. If you take the variator out, electric start and behind there is the oil seal, one will behind the pump/air cooler as well. Crank seals basically

 

over oiling ,

oil pump been set a little to strong, has your son notice he is putting a lot more oil into scooter than before, like every few days he seems to be topping up oil res ?

the throttle and oil pump cable work together via a 1 into 2 cable design, when you draw back on the throttle the slide opens up but at this very same movement a small cable opens up the pump. as you have fitted a big bore and a larger carb you would need to recalibrate the oil meter feed , its possible its gone outta skew and is just loading up bike with a little to much oil . ( i know this as i had to have my oil pump recalibrated when a whole new cable fitment was made for my new larger bore carb ).

your scooters manual (service manual) should have the oil pump setup. and metering requirement from the oil pump. if your not sure and have no service manual a bike shop mech can calibrate it for you at a cost.

 

Thanks guys for your help

Would the crank seals affect the oiling up?

With regards to calibration of the oil feeder, do they often go out of sinc?

 

If the oil pump/feeder is out of calibration it will either under supply or over supply your oil or it won't supply any at all, like cowboy said check your manual to see how much it should supply, then check your pump to see what its chucking out.

Could be dodgey pump though if anything.

 

crank seals would see problems starting and running, motors an airpump so if its gotta air leak its gonna be a right pain to start and keep running.

oil pump would be more the problem i would have said , if your getting a lotta oil in you would notice this as a very smokey tail end when running, ie your fire up and shed loads of smoke come out the pipe and when your running its gonna be smokey. theres smokey and theres really smokey ( really smokey if often due to to much mixing oil ) , if its a watercooled machine smokey can also mean a water seal has gone ( top head gasket leaking )

very rare they can go outta sync but then more tend to just break and end up just pumping at max rate or just stop pumping oil and you end up with a heat seizure.

first off what jet size did you drop into the carb 80-90-100 between these for a 70cc bigbore more so the high 80's mid 90's ( race kits you tend to run up into the 100 size jets but some sport kits like a bigger jet size) , you could find your just a bit to rich with the jet size, that would show as a blackish dirt colour on the plug and it being wet ( ideal colour for plug is a chocolate brown ), that would say your running a bit to high on the jet size and would need to come down a little. another sign would be slugging on the throttle as your getting a lotta fuel but less air giving you an over rich mix and some bogging on the throttle.

 

It is running a 94 main as I wanted it to run a little richer knowing full well that it will be ridden flat out all the the time, hence wanting to oil the bore a little more I have dropped it down to 92 main but still seems no better.

I was thinking about disconnecting the oil feed and filling the tank with premix to see if I get the same problem, do you think this would be worth doing?

I was going to run some 40:1 in it to see

 

dropping out the oil pump feed and running a premix is ok to do.

would give you a better idea if that oil pump is the cause to being able to measure out oil and premix. thing is the son will he be ok carrying a shot of oil all the time for when he fills up the tank and not forget to add that shot of oil when filling up ?

only takes him to forget to premix and the bore is at risk if he is a wide open rider. but yeah premix is fine , i would pull the plug out and fit a new one then run a premix , take scoot out run it hard for 2-3 mins they turn off the scoot while running hard, pull the plug and look for that chocolate brown tinge to the plug ( the choco brown colour is a good sign the fuel mix is just right ).

and yep always good to air on the side of a little rich

 

Personally I wouldnt of run the 70 kit with a standard pump, even the ones what say (race pumps, uprated pumps) its bs. The standard pumps don't produce enough oil mix (which results in boom!!)

Bin the bottle and do pre mix, yeah its a risk but that way you know what oil your bike is getting .

Don't pre-mix while at the petrol station,the oil don't mix well with the petrol when just chucking it in the tank, so use jerry...all my friends do it and their regret it when there bore goes bang.

 

You haven't been premixing and using the oil pump have you?

 

i think OP should pop an image of that plug state so we can get a grasp on if this is just to rich, or its a oil system problem.
some plugs look oily when they are super wet due to the oil build up from all the fuel added.

and that dual premix and oil pump running would show as a very oily plug indeed, a few folks say to drop 20ml into the tank extra if your running just the stock oiler system on a 70 kit ( i think thats about right between 20ml and 30ml ? )

 

Never premixed on my zip, only during the running in period; and it ate plugs for the first 300 miles because of the fouling.