I've got a 2019 Beta 4T that I've had for a while, but don't get on with it anywhere near as well as I'd hoped.

It's not as docile as I expected (yes, I'm at the old duffer end of the sportsman class standard of rider 😁) nor very easy to start when hot, and runs very rich.

So, I took the carb off, and gave it to my local dealer to check that everything was right - jetting, needle, float height etc. to be sure.

I refitted the carb, and it started second kick, then as soon as warm put the choke in, and stood back listening to how nicely it ticked over.

Then out of the blue there was a loud 'clunk' from the engine as it stopped running, and now the it won't turn over at all. I can't move the kick start at all, with it having a very solid feel to it.

If the difficulty getting the carb off is anything to go by, it's probably a job for a qualified mechanic, but was wondering it this is something anyone else has experienced with this particular bike before I give up,  and get expert help???

Here is a suggestion.  drain the oil to check for anything odd in the oil         if nothing take the spark plug out        have a look in the spark plug hole       next put the bike in 5th (top) gear          try to pull the bike backward       you only want to turn the engine a very small amount        once the engine has turned over backward a small amount        try to look into the spark plug hole       next take off the water pump cover and make sure the impeller in intact       next I would have a look in the clutch side cover              I would not suggest trying to start the bike until you find the problem

what has happened seems odd     GOOD LUCK

Were you missing any small parts like a bolt or screw when you reinstalled the carb?  The fact that something like this occurred right after having the carb off suggests that something could have gotten into the intake port when the carb was removed.  

Edited December 25, 20223 yr by mcman56
correct

Does the shifter shift? 

When a 4stroke has a problem it has one! somethings in the way? try rolling the bike backwards in gear, would that free the jam? If it does lets troubleshoot?  "i'll guess valves? I know very little of Beta 4t"

When I took the carb off, I put a bung of clean paper in the manifold to stop anything getting in there, and removed it when I reffited it.

I've tried putting it in top (it seems to click go through all the gears fine) and turning the back wheel, but can't feel the slightest movement in either direction. 

The only thing different I can think I did was put Aspen ethanol free petrol in it, because didn't think I'd be using it for a while, and it's not easy to drain any fuel due to the tap design, and difficult to access  float bowl drain screw - who thought tucking the screw behind the exhaust where you can't get a screwdriver at it a good idea I wonder??

Just for info when you get the engine sorted.  It makes a huge difference to how docile the bike is if you fit an amal 80/200 slow throttle. Straight swap but make sure the cable nipple on cam on carb is in the rearmost of the two possible holes. 

As I had a bit of time on my hands today, decided to have a slightly deeper look.

I took the clutch side case off, to look at the kick start mechanism (which seemed OK...) but put a spanner on the crankshaft nut to see if I could move the piston at all, and heard a slight mechanical noise from somewhere behind the clutch, and also saw the basket turn slightly at the same time. 

The kick start can now be pressed down by hand, but haven't tried starting it due to not having the any oil until tomorrow.

So, it looks like when it stalled, it kicked back and jammed something in the kick start mechanisim. 

Time will tell I suppose.....

Thanks for all the suggestions, and will definitely do the slow action throttle mod

Before you attempt to start it, take out the plug and turn it over multiple times. Either kick it over, or roll it along in gear. Just in case it locks again. (It seems a little implausible that it would lock once, then free itself and never have a problem again.)

13 hours ago, trapezeartist said:

Before you attempt to start it, take out the plug and turn it over multiple times. Either kick it over, or roll it along in gear. Just in case it locks again. (It seems a little implausible that it would lock once, then free itself and never have a problem again.)

I agree. And think I'll worry that the same thing is going to happen everytime I use it, if I don't find out why it happened this time.

Maybe it's just time to go back to a two stroke........

has anyone else used the Amal 80/200 throttle ? if so how do you like it  Thanks  Geeman 

Not the Amal throttle but a fast (white) Domino. I found it to be too slow. Original is much better

 

On 12/29/2022 at 1:17 PM, geeman said:

has anyone else used the Amal 80/200 throttle ? if so how do you like it  Thanks  Geeman 

I put one on mine when I had the 4T a few years ago. Definitely an improvement (for me).