Scooter jerking at full throttle?

[rag_angelo]

Hi all scooterers, just got my first scooter today :2thumbsup 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]

its hit top speed?

[Romeo]

It's not a <acronym title="You have to put OIL in them!">2-stroke</acronym> is it :p?

[rag_angelo]

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]

Are you sure it's not just shit? :blink:

[CookMySock]

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]

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 :scooter: .hehehe


Thanks

[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.

[rag_angelo]

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. :2thumbsup

[skidMark]

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

Thanks heaps

It's jerking?

Take your hand off it.:buggerd:

[Pogo2]

It's jerking?

Take your hand off it.:buggerd:

and it looks like Skidmark took the advantage!

[rag_angelo]

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?

[davereid]

The original spark plug is TORCH brand, and they err are not really that good. See if you can get an NGK equivalent, about $8.

[skidMark]

and it looks like Skidmark took the advantage!

I can do it again if ya like?

[MisterD]

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?

Worn variator rollers can cause some wierd behaviour alright...but at 900k's, that's not very likely.

[rag_angelo]

Worn variator rollers can cause some wierd behaviour alright...but at 900k's, that's not very likely.

Sorry for being a noob but what are rollers? I want to derestrict my scooter after I get this problem fixed and I've been looking over some posts. Heaps say something about rollers and get lighter rollers and all that. What / where exactly are they and what are they for?

[Sparky221]

Sorry for being a noob but what are rollers? I want to derestrict my scooter after I get this problem fixed and I've been looking over some posts. Heaps say something about rollers and get lighter rollers and all that. What / where exactly are they and what are they for?

Have a read through this:

http://www.flexistentialist.org/blog/archives/2003/10/27/cvt-basics-constant-variable-transmissions

[rag_angelo]

Just to update on this, it was the carb that was playing up. I got a 'performance' carb today and also bought a little pod. Goes good now :done: . No jerking or anything now. Accel is the greatest but did 60 on flat pretty easy on a short road, should do more on longer roads!. Sounds really deep with the pod too :2guns: