X8R engine racing at start up and other issues

Time for an update, took it out for a test ride today.

Good things, it's not screaming anymore with the new cable and it doesn't over oil.

It does though still cut out at full throttle.


Thinking about this and doing a bit of research I'm wondering if it dies because it hits the rev limiter in the CDI?

The effect is like having a misfire. It then stops and restarts again.

The scooter is currently capable of over 40 mph. It dies at around 43-44 mph.

I'm not really keen to de-restrict the scooter further for now as my son is only 16. (so I don't want to mod the CDI or put on an upgraded one to remove the misfire if this is what causes it).

It made me wonder if the previous owner must have changed the variator else it simply wouldn't be possible for the scooter to go to almost 45 mph? If so I'm guessing a very simple fix to the engine cutting out would be to go back to the standard variator and hence it could not the rev to the limiter. It will go along all day at 40 mph no trouble at all right now.

Trouble is I'm struggling to find a complete standard variator (Drive Pulley Assembly) on ebay or elsewhere.

Any thoughts on going backwards and re-restricting the scooter to solve the cutting out problem but putting in an original variator? (i.e. is it likely the rev limited is the issue and would this be an easy fix??)

If anyone has a standard variator assembly available for an SZX50X (X8R-X) I would be interested if this seems like a way to go.

 

That cutting out you describe is the rev limiter cutting the spark at 43-44mph. Does my head in as most hondas it comes in at a speed the vehicle can easily attain and intrudes when one is having a relaxing drive

It isnt doing any harm but unfortunately will always happen unless the cdi is changed for one with no rev limiter.

If you were to put in an originl variator it would still hit the rev limiter, except it would do it at 30mph instead of 44

 

Down jet the carb so it's not getting as much fuel at full throttle.
Or, restrict the slide from opening all the way, a couple of washers on top of the slide should do it.
Or.........you may be able to bypass the speed sensor........not too sure about this one, but thought i'd throw it in there just in case

 

no speed sensor on these, once it runs out of gearing on the variator it just revs up a bit and limiter comes in at 9000ish rpm from memory.

 

Hi guys

Today's news!

I kept on digging around and found that there are two limiter settings in the CDI

A standard one of 7500 rpm

And one set for 9,250 rpm

To remove the standard 7500 limit involved digging into the rubber back of the CDI and cutting a wire/staple thing.


This has worked and cured the problem.

The Scooter though now does 50 mph down hills


Though I was initially reluctant to go this route, the problem was that the engine didn't just hit the limiter before, it actually cut-out and stopped running, so one was left with coasting to the side of the road and restarting the engine.


One more questions for now, is it normal for the scooters to rev quite high when cold?

That seems to be the last issue that starting from cold it revs a lot and the rear wheel will start to turn. Once warmed up it will return to a good tick-over.

 

that means the choke is working normally, totally normal

 

Cheers Steve, been a bit of a learning curve for me with these twist and go scooters, I changed the autochoke for a new one whilst doing the carb strip as the resistance was miles off the book figures I had, so good to know it is working normally.

 

I've had a go at setting the mixture screw as it seemed to be eating petrol at an alarming rate. That has had a knock on effect as revs are now lower when first starting from cold. It seemed to rev away a bit before until the autochoke operated. Now it will start off at quite low revs and increase steadily as it warms up.

Thanks to all for the help and encouragement to get it all sorted out. Went out with my son at the weekend and it ran really well with no problems I was feeling really bad about before when he took it out for the first time after the CBT and it smoked like crazy then the engine cut-out within the first 2 miles of riding. So really glad all is now OK.

Just have the MOT coming up soon. Should be OK though with a new front tyre and some brake pads.