4 stroke scooters

[piglet]

Does anyone on here know anything about 4 stroke scooters?
sons scooter looses power at about 15 - 20 mph and won't pick up. have changed spark plug, cleaned the carb, checked the rollers these are all fine any other idea's as to what the problem may be.

[pyro]

make sure theres no loose plastic under the seat blocking the air intake, I did this once on a 400/4 with a leaking seat, over 3000 revs it sucked the plastic into the intake.....

[Yambabe]

My other half is a scooter mechanic by trade. What make/model is it?

[piglet]

It's a Taishan sport but think it has a Honda cp50 engine.

[Yambabe]

Have you had it any faster than this at all? Is it restricted (in which case it will only do about 28mph anyway)? How many miles has it done?

His first thought is that there may be a step in the variator that it can't get past but you should be able to see that if you've had the rollers out?

[piglet]

It has been faster he has had it up to 40mph,and it has been derestricted.
It was running fine but no power now.

[pyro]

What colour is the plug? Sounds like fuel.

[piglet]

Had thought of that one but have cleaned the carb and put a new plug in it.made no difference, rollers are fine to. :confused:

[John Hopkins]

Had thought of that one but have cleaned the carb and put a new plug in it.made no difference, rollers are fine to. :confused:

My son had a similar problem with his two stroke turned out to be the centrifugal drive unit or it could just be the belt if the engine still runs but there is no drive!..although the belts don't usually go unless there's a reason!.. for under £400 you can get a new Sukida on ebay..It could cost you more than that for repairs to yours at your local friendly bike repair shop!..John

[pyro]

Had thought of that one but have cleaned the carb and put a new plug in it.made no difference, rollers are fine to. :confused:

so what colour is the plug? Is the throttle opening fully? if you raise the rear wheel off the ground does it run up to speed freely?

[piglet]

so what colour is the plug? Is the throttle opening fully? if you raise the rear wheel off the ground does it run up to speed freely?

plug has black sooty stuff on it, yes throttle open fully and if rear wheel off ground runs upto speed freely.

[piglet]

Thanks everyone for their idea's but have solved the problem by putting another carb on it , now runs fine. Cheers Guys an Gals xx :D

[wurzel]

I believe it is the same engine as is in Baotian's and a colleague here had one. Same problem, turned out to be crack in the rubber inlet manifold as it has a 90 degree bend in it but has to support the entire weight of the carb.

[Crofty]

black and sooty? running rich mate, either too much fuel or too little air

[Crofty]

Thanks everyone for their idea's but have solved the problem by putting another carb on it , now runs fine. Cheers Guys an Gals xx :D
Opps! looks like i joined the party a little late there. glad you've got it sorted though