Scooter jerking at full throttle?

**rag_angelo** · 30th May 2008, 20:34

Hi all scooterers, just got my first scooter today

so im a big noob on scooters.

I got a 2006 Benzhou YY50QT. What are users' thoughts of these scooters? It looks like all the Chinese ones (the ones that all look the same but just named/branded differently).

Problem...
It's just ticked over 900kms. It goes good, but on full throtle, it starts jerking and feels like its hitting a seed/rev cut..
Sometimes, at full throtle, it goes to about 35kms and starts doing the above problem.

I'm currently reading things on derestricting but I'd like to get this problem fixed first before doing any mods.

Ane help or tips on the above problem or modding would be real great.

Thanks heaps

**R6_kid:Me** · 30th May 2008, 20:57

its hit top speed?

**Romeo** · 30th May 2008, 21:03

It's not a 2-stroke is it

?

**rag_angelo** · 30th May 2008, 21:10

its speedo goes upto 60, lol , but i got it to just over 60 with just playing around with the throtle, trying not to do it open (or whatever) the throtle fully.. Most of the time though, it maxs out at 40 (with just about 3/4 throtle) and if i full throtle it, it jerks back n forth between 35-40km/h. was told before that this cruised at 50 and max 70+ downhill

its a 4 stroke..hehe..

previous owner said he hadn't riden it in a few months and reckons it could be "stale fuel" or something with the carb.? ive used up most of the previous tank and filled up but its still the same..think its possible it could be any of those?

thanks

**Dave Lobster** · 30th May 2008, 22:21

Are you sure it's not just shit?

**CookMySock** · 30th May 2008, 22:37

Originally Posted by rag_angelo

previous owner said he hadn't riden it in a few months and reckons it could be "stale fuel"

yep. Very likely. Just keep riding it and see if it clears up.

Welcome to the world of two wheels, and to KB.

DB

**rag_angelo** · 31st May 2008, 00:43

Originally Posted by DangerousBastard

yep. Very likely. Just keep riding it and see if it clears up.

Welcome to the world of two wheels, and to KB.

DB

cool. I'll give it a good ride and see what happens in the next tank..
will update on the next tank. Other suggestions or thoughts would be great too

.hehehe

Thanks

**davereid** · 31st May 2008, 09:24

It could be fuel starving. This happens a lot on chinese scooters.

1) They have a vacuum operated fuel tap. Often the vacuum line is tied so tightly to the frame that the fuel tap never pens properly.

2) Same thing, but due to compressed fuel line.

3) Dodgy spark plug cap. They seem to be made of a plastic that breaks when it gets hot, and the spark plug cap is never-after a good fit.

Take the seat off, and remove the body work.

Go over the bike carefully. Look for all the things above, lose wiring plugs, relays that haven't been fasten to the frame, just that kind of thing.

Drain the petrol as well from the carb - in case there is a bit of water in there. That often causes the problem you describe, as at high RPM, the engines goes very lean.

Welcome to two wheels.

**rag_angelo** · 31st May 2008, 18:03

Originally Posted by davereid

It could be fuel starving. This happens a lot on chinese scooters.

1) They have a vacuum operated fuel tap. Often the vacuum line is tied so tightly to the frame that the fuel tap never pens properly.

2) Same thing, but due to compressed fuel line.

3) Dodgy spark plug cap. They seem to be made of a plastic that breaks when it gets hot, and the spark plug cap is never-after a good fit.

Take the seat off, and remove the body work.

Go over the bike carefully. Look for all the things above, lose wiring plugs, relays that haven't been fasten to the frame, just that kind of thing.

Drain the petrol as well from the carb - in case there is a bit of water in there. That often causes the problem you describe, as at high RPM, the engines goes very lean.

Welcome to two wheels.

Cool, thanks for that. I'll try those out too.

I had a friend look at my scooter, whos got a similar scooter, and he thinks its something to do with the clutch slipping or its not going into gear at high throtle or somethin..were not sure though. possible?

Thanks for the greetings - 2 wheels are fun.

**skidMark** · 31st May 2008, 18:05

Originally Posted by rag_angelo

Ane help or tips on the above problem or modding would be real great.

Thanks heaps

It's jerking?

Take your hand off it.

**Pogo2** · 31st May 2008, 21:02

Originally Posted by skidMark

It's jerking?

Take your hand off it.

and it looks like Skidmark took the advantage!

**rag_angelo** · 2nd June 2008, 17:06

Originally Posted by davereid

It could be fuel starving. This happens a lot on chinese scooters.

1) They have a vacuum operated fuel tap. Often the vacuum line is tied so tightly to the frame that the fuel tap never pens properly.

2) Same thing, but due to compressed fuel line.

3) Dodgy spark plug cap. They seem to be made of a plastic that breaks when it gets hot, and the spark plug cap is never-after a good fit.

Take the seat off, and remove the body work.

Go over the bike carefully. Look for all the things above, lose wiring plugs, relays that haven't been fasten to the frame, just that kind of thing.

Drain the petrol as well from the carb - in case there is a bit of water in there. That often causes the problem you describe, as at high RPM, the engines goes very lean.

Welcome to two wheels.

Just did the above. First checked for wires and if all plugs are in place. Then checked and cleaned and tested the sparkplug (spark looked a bit weak though) then drained and checked the carb. Took it for another ride and it doesnt feel as hesitant at full throttle as before so it made a small difference.

Should I change the sparkplug and see if theres any difference? If so, what sparkplug do youz recommend? Direct replacement or iridiums or any others?