Poor Running Mini Moto

[Banshee2400]

Hi Guys

Right guys

I've just brought a Mini Moto off a mate and its running quite poor at the moment

First of all could someone tell me what engine size it is and what make if possible

Secondly I have a problem when it's running, the running in generally quite lumpy and if i rev it more than half throttle it dies and stalls, i'm quite competent and know my way round most mechanical things so is there any advice you could offer me to sort it

It sounds like it overfueling as anything more than half revs and it dies , I've heard there is a fuel regulator screw somewhere on the actual throttle body but I can't seem to find this to turn it down

Here is a pic of the bike (and before you ask, yes I'm replacing the fairing


Cheers
Banshee

[FERRINO]

Hi Banshee, you have bought yourself a bog standard Mk2 Cag. These are just mass produced Chinese bikes made by any different number of factories in China, so they don't have a 'make' as such.

It will most likely be a 49cc, but may be 47cc version (there really isn't much difference in performance between the 2).

I've had loads and loads of these non-running things brought to me by my neighbours kids and their friends over the years. I always perform the following operations and not once yet (touch wood) have they failed to run properly afterwards.

1) Remove the Carb and clean "thoroughly"! - paying particular attention to unblocking the main jet - This is the single biggest problem with these bikes.
2) Set the gap properly between the flywheel and the coil pickup (as close as possible without touching).
3) Throw the rubbish Chinese spark plug in the bin and replace it with an NGK BM6A (I think from memory)
4) Make sure there is a small hole drilled in the top of the plastic fuel cap (to avoid vacuum build up restricting the fuel flow)
5) Make sure you are running 50:1 fuel mixture. The mixing bottle supplied with these will give you a 25:1 mix and will choke it to death

If it still doesn't want to rev properly after all that - take the air filter off and try it without it - if it runs properly without it, then your filter is clogged up with crud.

If you need any more help on any of the above, have a look at this thread which describes things a little better:-

http://www.minimotoclub.co.uk/vb/showthread.php?t=51617

Hope you get it running properly dude!

Cheers
Tony

[Banshee2400]

Brilliant Advice Cheers Terrino

I have compoleted steps 1,4 and 5 and the bike seems to now be running somewhat better however still does the same, it idles fine now at one constant RPM and I can also hold the throttle fully open now and it will rev away happily but sometimes it does go to die but as long as you come off the revs and give it a minute it will come back, however I still want to address this

I am going to gp to the Car Spares shop by me later on today as they stock every single NGK Spark Plug ever made

I don't understand Tip No 2 though ???
Could you please explain in more detail what I have to do here

Cheers
Banshee

[FERRINO]

Glad to hear it's starting to get there Banshee

To set the coil gap you need to remove the pull start. The coil will have 2 screws holding it - loosen these (but don't remove) and lift the coil unit up slightly. Fit a thin piece of card or a few sheets of paper (people use different things) in the gap between the flywheel and the coil pickups and lower the coil down, push it agains the card and re-tighten the screws. Pull the piece of card out and turn the flywheel by hand just to be sure it isn't catching on the coil pick-ups and re-fit the pullstart.

Also, did you try it with the air filter off?

Cheers
Tony

[Banshee2400]

Ok so I have now followed all of you steps and now the Mini Moto start only when applying a little bit of revs and will run sweet then, you can hold the throttle wide open and it will happily sit there revving away at its maximum, however it will no longer just sit there and idle any more and just cuts out

This is a really strange one, this is with the air filter off by the way and the spark plug I replaced the cheap one with was an NGK BM6A 5921

HELP !!!!!

Cheers
Banshee

[FERRINO]

Ok so I have now followed all of you steps and now the Mini Moto start only when applying a little bit of revs and will run sweet then, you can hold the throttle wide open and it will happily sit there revving away at its maximum, however it will no longer just sit there and idle any more and just cuts out

This is a really strange one, this is with the air filter off by the way and the spark plug I replaced the cheap one with was an NGK BM6A 5921

HELP !!!!!

Cheers
Banshee

Mmmm - ok so the coil is now set right - the plug is a decent one (set to about 0.5mm gap?). Does suggest the carb again to me.

When you cleaned the carb out, you did unscrew and remove the brass main jet fully from the carb and run a piece of wire through it to properly clear the hole didn't you?

I only ask because on that link that I put in my first reply - the guy was insistant that he had cleaned the carb properly. But it turned out on the third time he tried, that actually he hadn't and a chunk of crud fell out of the main jet, have a read through it just in case :-

http://www.minimotoclub.co.uk/vb/showthread.php?t=51617

I apologise if you have really properly cleaned the main jet - but it's always worth triple checking as it's usually the cause erratic running and stalling etc.

Also, I assume that you have adjusted the tick-over screw on the side of the carb?

Cheers
Tony

[DMR]

Give it a good run to clear the engine..............dont rely to heavily on it ideling for prolonged periods............needs a good run and even then it probably wont idle for long...................doesnt matter.

[Banshee2400]

When you cleaned the carb out, you did unscrew and remove the brass main jet fully from the carb and run a piece of wire through it to properly clear the hole didn't you?

I didn't do that actually , I'll give that a try !!!!
I took the jet out but I didn't actually run a piece of wire through it, I thoroughly sprayed it with Carb Cleaner however but, yeah that might not have got the crap out

Also, I assume that you have adjusted the tick-over screw on the side of the carb?

I have attempted to adjust this before cleaning the carb and it would adjust the tick over, but since cleaning the carb out this has had no effect , if I can definatly point the finger at the carb I may just get a new one

Also, I started it again today and it was belting out a lot of smoke and actually started spitting flames PMSL

I take it the fuel is either to rich, or there is unburnt fuel entering the system ??

Cheers
Banshee

[Banshee2400]

Ok so I've borrowed a Carb from my mate and the thing ran like a dream !!!!!
I've just ordered a new carb for £7 so its all gravy

I took a video on my camera but i've left my USB cable for it at work , I'll upload it tomorrow morning when its running

Is there a section on here for Progress threads ?????, I'm going to start one

Also I'm about to order some new plastics for it as well and alos thinking of an uprated sports clutch and a K&N Air Filter

Cheers
Banshee

[FERRINO]

Ok so I've borrowed a Carb from my mate and the thing ran like a dream !!!!!
I've just ordered a new carb for £7 so its all gravy

I took a video on my camera but i've left my USB cable for it at work , I'll upload it tomorrow morning when its running

Is there a section on here for Progress threads ?????, I'm going to start one

Also I'm about to order some new plastics for it as well and alos thinking of an uprated sports clutch and a K&N Air Filter

Cheers
Banshee

Ah nice one (it's always something to do with the crappy carb's on these bikes)

You probably could have got yours running nicely by cleaning out your carb properly and checking the jet size - but as you say it's not worth the time or agro for £7 is it

Glad to hear you will be up and running soon anyway - It would probably be best to start a new thread about your progress with the bike in the 'air cooled imports' section really.

Tbh I wouldn't waste your time with one of those uprated 2 shoe clutches on Ebay. The pad material is made of cheese and the springs are way too strong for the air cooled engine - you will burn them out within minutes (I tried them when I had a cag, even fitted some genuine polini shoes to it but it still didn't work properly).

The k&n style air filters are ok - just don't believe too much of the hype about them flowing so much more air that you have to up your jetting - they aren't that good lol.

You really would be best just getting it running nicely as standard and learning to ride the wheels off it, then upgrading to a genuine bike (most people on here have been down the same route at the begining and wasted cash trying to hop up cags and would advise the same).

Look forward to hearing your progress anyway

Cheers
Tony

[ady1306]

here ya go mate should help you no end...



yeah yeah yeah i know, but how could i not do it....

[Banshee2400]

here ya go mate should help you no end...



yeah yeah yeah i know, but how could i not do it....

I can't believe you would tell em to throw it in the bin
HARSH !!!!!!!
It was only £40, just a little project for me when I get bored

[Banshee2400]

OK guys, I'm really really stuck now
I've tried everything;

Carb - Cleaner than a chefs knife set
Spark Plug - New and correctly spaced
Coil Pickup - As close to coils as possible without touching
Fuel Filter - Clean

and it still does this;


I think its overfueling, I've left it with a mate over the weekend who knows a bit about them so we'll see what he makes of it, but does anyone have any more ideas ???

ooooo, I've adjusted the Idle Screw also, this had no effect either

[Banshee2400]

BUMP

Any ideas ???

[FERRINO]

"Ok so I've borrowed a Carb from my mate and the thing ran like a dream !!!!!
I've just ordered a new carb for £7 so its all gravy "


So it's still not running properly with the new carb fitted then?

I thought it ran great with your mates carb fitted, or is it still your old one whilst you're waiting for the new one to arrive?

The only other thing to check really would be the reeds. If you remove the carb and black plastic manifold you should find a 2 petal reed. If it's standard it will be thin sheet metal, if it's been 'uprated' then it will be a fibre composite type material. It's quite common for reeds to split or not seal properly (or have a piece broken off) - which will cause erratic running and difficult starting usually. Might be worth a look?