Honda X8r 50 Lack of power on the road.

[supan1]

Honda X8r 50cc
So awhile ago i was on my mopped coming back home with my gf on the back , all of a sudden I heard and felt a little bang, like something popped or broke.
when i got home me and my dad mechanic started to take it apart and found other problems such as the clutch being worn out and the starter being broken.
We adjusted everything as usual , new clutch , new starter and we have a new carburate ready to put in (got it because it was cheap)

While the mopped is on its centre stand the wheel and the whole machanims sounds great ( even better after new parts) but as soon as i hope on it and go for a test drive i cant go higher then 25km/h even downhill id only go 30 ish...for reference i used to go at a steady 60km/h and a 65 downhill. But this speed difference is very noticable .. i did 10k km on it last year and everything was worn down...we still cant find the cause of the lack of power while im on it.

[aeroxbud]

I would start with the CVT. If you have been regularly taking a passenger, it will be under a lot of strain.
You should be able to find a minimum belt width in the manual. But if not it's usually only about 1mm of wear is acceptable.
CVT inspection video here.

[supan1]

The belt is fine ..idk how to explain it when i sit on the bike to move off it takes a bit of time to ramp up to speed but after the little accident when im on it driving around it doesnt go past 25km/h could it be that when im sitting on it something moves or is under more tension. I dont know how to explain it.

[aeroxbud]

Did you take the CVT apart? That is what controls your gearing.
Perhaps a roller got flipped round and it's stopping the ramp plate from opening.
If the bike sounds great it's likely to be CVT related. Either the variator or torque drive.

[supan1]

we took the cvt apart...my father says it could be resolved but the new clutch have to driven out a bit but it doesnt feel like thats the problem. imma keep updating here

[aeroxbud]

Do the marker pen test. Take the CVT cover off and draw a thick line across the variator face. It should go from inside where the boss is to the outer edge.
Once you take it for a run. It should be obvious if the variator is moving correctly, as the belt will rub the pen away.

[supan1]

Ill give that a go thanks!

[supan1]

SOOO the CVT seems to be fine and we are at the stage where we took off the cylinder and my dad did a compression test? I think he said that sorry to not be fully knowledgeable on this matter , from what I read its supposed to be 12psi and we had 5psi...so look at the cylinder and piston and they are slightly worn so we are looking to buy a new set.

A question about that ...how legal and illegal is it to increase the cc off the mopped and turn it up to like 70cc? From what I understand I would have to state that in papers and in insurance etc. But would that be a good move? We did put in a carburetor which is not for the exact model but the parameters are good. We can adjust the fuel air oil mixture to match the new bigger cylinder. Right?

[aeroxbud]

If you are in the U.K. It's a mine field. You need to notify the insurance company. But if over 16 it's not such a problem.
When I looked at changing my old bike on the log book it opens a can of worms. Anything bigger than 50cc has different regulations. Even stuff like the lights are a different specification.
If you ever want to change it legally back to a 50cc, the DVLA make it very, very hard.
They don't mind changing a vehicle to a bigger displacement. But don't like reducing it.

[supan1]

You mean if I am over 16? I mean I use this mopped to get to university through town and occasionally i go for a 30-40min drive to my girlfriend that lives a bit outside the city. I never seen anyone stop a mopped and Its not for anything like going around racing or anything. My dad believe it would run better on 70cc.

[geoffh]

70 kits are great but might not solve your problem,it does sound like a CVT problem,my best shot would be that you changed the belt and its the wrong size .

Geoff

[supan1]

We checked the belt..maybe we are missing something but it does seem to be working as it should. Too invested in it to give up!...and the bike is great..One day i will sell it after i fix up the body work a bit more but its a fantastic little thing

[supan1]

So we are at the closing stage of changing and recalibrating some parts , the new cylinder 70cc is on but just got to adjust the fuel intake. in the mean time we noticed that the cdi is slightly damaged. And have not noticed that before. How important is the CDI. Just asking out of curiosity the bike should be on the road soon, we are waiting for a new exhaust gasket as they sent us a wrong size with the cylinder.....!

[aeroxbud]

Without the CDI it won't work.