Gokart MZ 250

[Desertduler]

And of course the Main jet, this controls the air fuel mixture from around 3/4 throttle to wide open or W.F.O. as I call it, as you can see this main jet is a 270 so the higher the number the larger the hole (richer) get this one wrong and this one will burn the engine down in a hurry if it is too small for the engines needs.

 

[Desertduler]

Ahh ok , thank you for the explanation . I do have some experience with small 2strokes but big ones are a new thing to both me and karte

p.s - this applies to reed-valve induction 2strokes as well ?

Yes indeed!

 

[karte_m0lim]

thanks again for your answers ...

I think I know what the problem/s is /are ...

first, when I cleaned carb first time, I wasn't sure which jet goes where , cose I have two jet with same thread, one for main emulsion tube and second for choke.. one in size 60 and second 100.. I put bigger on main emulsion tube , and smaller on choke emulsion tube..

second, i spoke with @newb and I recall, as engine was wet and I didn't have spark, I used spark plug from gx140 to test spark and , I think, i leave that spar plug on this engine ..

anyway, few pics below (first cleaning and user manual) ..

 

[Desertduler]

thanks again for your answers ...

I think I know what the problem/s is /are ...

first, when I cleaned carb first time, I wasn't sure which jet goes where , cose I have two jet with same thread, one for main emulsion tube and second for choke.. one in size 60 and second 100.. I put bigger on main emulsion tube , and smaller on choke emulsion tube..

second, i spoke with @newb and I recall, as engine was wet and I didn't have spark, I used spark plug from gx140 to test spark and , I think, i leave that spar plug on this engine ..

anyway, few pics below (first cleaning and user manual) ..

You may have just solved your rich running condition, now you have learned something, good job, but I would use the correct heat range of spark plug for your engine or you could come up with other problems with your engine by not using the correct spark plug, it matters indeed! Please post another video with the kart going with the correct main jet in place. I am sure that you will see a big improvement in engine performance.

 

[karte_m0lim]

If you have time to watch my previos videos in this thread, basicly my first fireup, I think engine run better then. ..

What do you think?

 

[Desertduler]

If you have time to watch my previos videos in this thread, basicly my first fireup, I think engine run better then. ..

What do you think?

In the earlier videos the engine is not warmed up and the engine is not under a load (driving) so it is hard to tell how the jetting is. Another test run on the same road that you drove your kart in the later posted video would be the best test and then compare the performance then.

 

[karte_m0lim]

Yeah.... Not sure if I can do that before monday

 

[Desertduler]

Yeah.... Not sure if I can do that before monday

That is not a problem, when ever you can, your kart ought to move out pretty good with that 250 on it

 

[karte_m0lim]

Hi ..

didn't tested anything having problems with clutch , it's spinning on shaft ..

also some parts here are worn out so ordered new ones ..

still waiting for push bearing hopefully will be her e in day or two ..

but, polishing on clutch and shaft are needed first ..

 

[Desertduler]

Wow, the crankshaft and inner clutch bushing are destroyed, it looks to me like the transmission has been ran with low oil causing the inner clutch bushing to seize to the crankshaft therefore not letting the clutch disengage, in picture #3 to the far left it looks like someone made that slotted washer by hand? The crankshaft is ruined and you will have to split the cases apart in order to replace it which is not a big deal if you can get the parts.

 

[karte_m0lim]

Yeah...

Maybe I didnt have to buy engine few days after I blew up old one but..

 

[karte_m0lim]

it is been a while since last update...

lots of things happens, mostly bad...

so lets start:

- fixed clutch
- fixed kick starter
- still problems with too rich mixture
- then carb started to leaking
- ordered new carb but couldn't fit so additional work needed
- reduced gear ratio from 18:20 to 18:28 to cut top speed to 90km/h
- while setting up new carb and testing how engine run, connection rod bearing stuck
- now need to open whole engine, see what is damaged and decide, fix it or leave it
- anyway, when it was running it was wooohooo... but was too short

 

[karte_m0lim]

Current state...

 

[landuse]

Wow. Thats a lot of pieces . I hope you know how to put it all back together. Are the problems sorted out now?

 

[karte_m0lim]

No and no

I need some new parts but it looks like that is cheaper ro buy whole old motorcycle...

So.. I do not know what to do now..