Engine parts

Dont mistake the idle screw with being a fuel air mix screw. Idle screw adjusts the throttle setting by basically adjusting the throttle connection at the carb end to add tension and rev higher, same as twisting the throttle handle on a little. Once its revving nice and steady at tick over then adjust air fuel mix screw so its revs at the highest possible level, turn just quarter screw each time. You will reach a point where when you turn right it dies a little and when you then turn left it dies a little, then you know you have reached optimum setting. Once this rev level is found then readjust your idle screw to sit at 1000 - 1500 rpm idle or whatever your book says.
If the air fuel mix screw makes no difference then its time to check your jettings and needle setting.
Plug looks very rich.
Let the forum know what carb you have and what main jet you have fitted.

 

Re oiling your sponge filter, many people wash and dry the sponge then spray some filter oil on. This is a very sticky oil that traps fine dust. If you are running rich then avoid oiling for now as it will restrict air flow. Try running the bike with no air filter, this will increase air flow and if its runs better then good indicator that the carbs too rich.

 

Yeah what does that mean when it's running rich, I know the spark plug was due to be changed as at my last service they said so.

My plan of action is to replace the spark plug in a few days, change the filter, drain the oil and add some new oil too it.

Anything else to do? And will do what you said about checking it, I take it that is why I can't get top end speed.

 

I only did that way as it said to do it like that in the manual lol

 

Defo the idle screw as it revs higher one way revs lower the other way and have set it just below when the wheel starts spinning as some guides say to do like that

 

The carburetor is a fuel and air mixer. Air comes through the air filter and fuel through the fuel line where it sits in a small float bowl much like a toilet cistern. Jets hang down into the bowl. As the air flows across the top of the jet it sucks up fuel and the fuel air mix enters the engine where the piston squeezes it to high pressure and spark plug ignites it. If the jet is too large then the fuel being sucked up is too much and therefore is a fuel rich mix. The problem then means that it either wets the plug so it cant spark or the plug fires and combusts the fuel air mix but not all of ghe fuel burns, this results in a sooty residue which coats the plug and piston. Inefficient firing and often too much fuel to fire properly.
A fuel lean condition is where not enough fuel mixes which results in very hot combustion and a lack of oil from the two stroke mix - result is burnt pistons.
Best is slightly too rich to keep piston cool but not so rich it fouls the plug.
Hope that helps

 

Question:
Part of the service on any car/bike/lawnmower/anything with an engine and spark plug, requires that the plug be changed as part of the service and it's costs.
Why didn't they change the plug then instead of telling you its due to be changed?????

 

Because then they can invite you back in for a plug change for £60.

 

Ahh okay so you think getting the carb cleaned would be a good idea

 

Good question lol and I have no idea but won't go back to them for sure.

 

Cleaning the carb is always worth doing but more importantly is working out whats wrong with your fuel mix. You can clean your ar$€ but it wont cure your dodgy stomach.
You need to replace the plug, run it awhile then check it for black soot or running issues to see if it is still rich. Meanwhile Check the specs for your carb to see what size main jet you should run then increase the size by one increment. Read up on google about tuning your air fuel mix on the carb , tune it and try it all again.

 

here we go scott ,have a watch on this video about the idle and mixture screws found on a scooter, it will give you an idea what your looking at and doing. videos are great for gleaming knowledge and seeing how things work

 

I will have a look cheers is there any carb cleaning that you can add to the fuel I have seen a similar thing from America but not over here

 

I usually strip mine down and soak in redex but carb cleaner spray is great as long as you remove and avoid all rubber gasket bits as it rots the rubber. Adding fuel additives to your fuel tank can dislodge particles which clog the jets so i avoid them personally.

 

you mean seafoam.

depends on the age of bike and other likely hoods, but usually a carb clean entails , blowing out the main jet and pilot jet ports with compressed air same goes with choke port. then we tend to have a good old toothbrush and a dribble of petrol to put into the bottom bowl of the carb and scrub it out a bit we then throw that old scrubbed fuel away and rebuild the carb back up.

places like your scooter shop will put the carb in a ultrasonic cleaner machine and charge you a small fortune, so its usually having a friend who has some carb cleaning expericance to sit with you and show you how to do it, doing it yourself or having a motorcycle savy friend / relative/ dad/uncle is better and costs nothing but a cuppa tea and a chatter you also learn about your bike to at the same time going from a total novice to knowing a little about what you need to do if things go wrong again.

 

Your right there lol wish I had one as I am a quick learner and would be happy to do all the repairs my self, my bike is over 20 years old but was going to buy one, stick it in the fuel tank and see if it does anything I suppose no harm done, and I do wish I had the confidence to remove the carb but not feeling it lol

 

Carb stripping and rebuild is fun, just a puzzle of pieces. Take photos at every stage so you can refer back to what goes where afterwards. You learn one helluva lot from a good carb session and its actually very rewarding when you piece it back together. Do it over old tupperware or trays or large sheets of white paper as the odd tiny washer or clip may drop. Remember the lower bowl is full of fuel which will happily run up your forearm without warning !! Take it slow, be methodical and look it over each time you remove a piece to remind yourself where it came from .

 

I wish I was more confident lol I would rather let someone who knows what there doing and watch them I would then learn the process or if I had a old engine to muck about with lol

I think what has happened wasn't down to me but more I was going to happen anyway and it chose now to do it lol

 

I am such a dum ass thought my bike was registered in 1997 but it was registered in 2007 making it only 10 years old not 20 years plus lol doh

 

Scooter been to the garage and they have said carbs were dirty and had water in it, been sonic cleaned and adjusted so is now a happy scooter pick it up Monday morning, also had a new air filter and spark plug.