Mmb80 not running good

SAT

Well-Known Member
#21
So I took everything apart, I haven't done anything yet besides change the spark plug but I was wondering how I'm supposed to clean the tank? It seems pretty clean and I changed the gas which was dirty and im going to install a filter. I am also going to take the carb apart.
I removed ours, shook the residual fuel out. Added some clean solvent, shook it a bunch. We have several of those remote grabbers, like for picking-up lost bolts from behind the workbench. Clamped onto a few shotgun cleaning patches and wiped it clean. There are several YouTube videos out there with the variations. We replaced the entire fuel line with ethanol resistant hose and a new filter. And bought a new carburetor. The new carbs have the fuel fitting facing up and that took some engineering fir the fuel line.
 

SAT

Well-Known Member
#22
I removed ours, shook the residual fuel out. Added some clean solvent, shook it a bunch. We have several of those remote grabbers, like for picking-up lost bolts from behind the workbench. Clamped onto a few shotgun cleaning patches and wiped it clean. There are several YouTube videos out there with the variations. We replaced the entire fuel line with ethanol resistant hose and a new filter. And bought a new carburetor. The new carbs have the fuel fitting facing up and that took some engineering fir the fuel line.
For the fuel line support...
 

I74

Well-Known Member
#30
How's the gaskets between the carb & head ??
If those are torn or in bad shape,, they could wreck havoc on how it runs …...
 
#32
Ok so I put the clutch on and it doesnt bobble the rpms anymore so its smooth in that way but when you go from 0 to 100 percent throttle it stalls for a sec and then revs up. Also when your coming down from 100 percent throttle to 0 percent it dies. Does this sound like a pilot jet problem?

Also how do I lube the clutch? The original clutch you would lube at a certain place. Can I do the same or do I have to take it apart and lube?
Also I would like more torque than speed as it already goes 33mph and I don't want to buy a $100 jackshaft or have a larger rear sprocket but im wondering if I could get maybe a 10 or 9 or 8 tooth sprocket for the front? the least teeth I could find stock was 11. Is this even possible?
 

SAT

Well-Known Member
#33
I would:
Replace the carb
Lube the clutch with one drop of 30 wt oil, on the oil lite bushing, every few hours of run time.
Buy the HRM jackshaft kit.
We like ours.
I believe your bike is a MM-80b
 

Attachments

#34
I would:
Replace the carb
Lube the clutch with one drop of 30 wt oil, on the oil lite bushing, every few hours of run time.
Buy the HRM jackshaft kit.
We like ours.
I believe your bike is a MM-80b
Where can I get a new carb? I've looked every where and only found one for 25 dollars!
Ok not sure where the bushing is but I'll try and find it.
For the price of the jackshaft I would just as well get a predator.
I'm curious would this work as a jackshaft? 1565981281514.png A cvt backplate?
 
#39
Cool, has anybody tried this? Is the frame big enough?
All I am saying is that style of plate can be a jackshaft, in that it will work correctly to hold the shaft and gears, as long as it is properly reinforced like the Comet style back plate.
Whether or not that will fit your bike I have no idea. That is something you will have to figure out for yourself.
 
#40
Using a Comet style backing plate is often times easier than making an actual long jackshaft that goes across the width of the bike. But clearance can be an issue because of the size of the plate.
But don’t forget, if you are not using a driven and driver from the CVT, you could trim quite a bit from the rearward portion of the plate, since instead of a 6 in driven you will be using smaller sprockets.
Don’t forget about a cover, you’ll need that to keep your leg from getting chewed up.

Maybe a predator would be easier in the long run
 

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