Would adding a reed and windowed piston do much on a ported motor? (zeda 80)

[extremeodd]

Razor edges will do that round them out really good next time so the rings will ramp up into the piston seat instead of ramming flat into the side of your jug. Don't worry about dropping your transfers as much as widening them more grinding toward your intake side and just widen your exhaust and it should be solid if you want some more simple fuel/air flow i done it a few weeks ago works great i copied the work that cr machine does with his exhaust port

Surprisingly ZMS didn't razor edge them and if you look close they have a nice little bevel to them. I'm thinking that despite being overall fairly rich that I have an intermittent fueling issue where it leans out or something at a specific area. I've noticed when cruising that sometimes it'll suddenly 4 Stroke and when I give it even 5 to 10% more throttle it suddenly takes off hard.

This failure happened after my 2nd 1/4 mile WOT pull from 2k rpm after getting the motor nice and warmed up for a mile first. I'd bet any money if I was riding it like a civilized human being and not a maniac it wouldn't of went bang.

Whatever the cause, I'm going to crack the motor in half and try to clean the crap out of the crank and see if I can get away with not replacing any bearings. If I can, then I'm going to clean up where the jug broke (the skirt of the jug also broke too on the intake side, huge freaking chunk. Look at the last picture) and try throwing a new piston in it. Hopefully, that will sorta work if I'm super gentle with it since I'll be ordering a ZMS ported zeda 80 and they typically take a few weeks to ship as they port them to order. I honestly can't be bothered doing a full rebuild when a decent ready to go motor can be had for $130 or so.

 

[Lukesky36]

move your needle up too a leaner notch if it 4 strokes good luck on it though

 

[extremeodd]

So I've managed to get the entire motor tore down without any real issues and the bottom end is basically perfect with the exception of one of the crank bearings. Since the crank and clutch shaft bearings are the same size, I'm going to trade them and put the bad bearing/s on the clutch shaft for later replacing. My thought process is, the clutch shaft can be removed far easier than the crank and by putting the bad bearings on the clutch shaft, they will survive longer than on the crankshaft with the current damage as the clutch shaft isn't always loaded with the motor running.

Essentially $15-20 is going to get this back on the road and a future $30-50 will get it back to 100%. Got a replacement piston on order from Amazon and I'll be running up to harbor freight for a cheap rotary tool and some bits to clean up the rough edges of my jug so I can reuse it. I cannot say it enough, I bloody love the simplicity of these motors. With literally $25 in tools and $15 in parts, I'll have this thing running again after such a catastrophic failure.

 

[extremeodd]

Hooray! Throwing a new piston fixed my issues. Surprisingly even with that big chunk out of the transfer, she feels 100% normal. I've yet to run it hard as I'm deathly afraid of breaking it again but shes handed a 70% pull to 6k rpm without issue and did a couple of out of gear redline revs without a problem.

Thank god for the simplicity of these 1950s russian designed motors.

 

[FurryOnTheInside]

LATVIAN

 

[extremeodd]

Oh, yeah, that's right. I forgot there is something wrong with my freaking clutch shaft. It gets stuck engaged for whatever reason and literally smacking the flower nut with a hammer or wrench a few times will free it up to engage/disengage again. Screw it, I'll ride carrying a damned spanner and just smack it at stop lights so I can bump start it again.

EDIT: I should ask. The bar that is between the bucking bar and metal ball that actuates the clutch: Is it supposed to be flat at both ends or is one end supposed to have a divot that fits the ball?

 

[FurryOnTheInside]

Oh, yeah, that's right. I forgot there is something wrong with my freaking clutch shaft. It gets stuck engaged for whatever reason and literally smacking the flower nut with a hammer or wrench a few times will free it up to engage/disengage again. Screw it, I'll ride carrying a damned spanner and just smack it at stop lights so I can bump start it again.

EDIT: I should ask. The bar that is between the bucking bar and metal ball that actuates the clutch: Is it supposed to be flat at both ends or is one end supposed to have a divot that fits the ball?

Well, that bar is the bucking bar, it sits between the clutch actuating cam and the ball, and it should be flat at both ends. You can turn it around I think. Apply lots of grease regularly to help prevent a divot being worn into it.

 

[extremeodd]

Ah, my mistake on terminology. Until the new bar/cam/ball comes in (yay Amazon Prime, only $3 shipped) I've flipped the bar over, its already starting to have some issues with the cam digging into it (the divot was DEEP) but it seems to be behaving somewhat better. Riding with the wrench isn't as needed but I've noticed it still needs the occasional 'whack' to start working right again.

Pulled the muffler off and ran it a bit harder today and everything seems to be mint. However, after this experience, I'm going to be building an e-bike when funding permits. Gas is fun and all, but I want something that is dead reliable and save the fun bike for the weekend.

 

[gary55]

Oh, yeah, that's right. I forgot there is something wrong with my freaking clutch shaft. It gets stuck engaged for whatever reason and literally smacking the flower nut with a hammer or wrench a few times will free it up to engage/disengage again. Screw it, I'll ride carrying a damned spanner and just smack it at stop lights so I can bump start it again.

EDIT: I should ask. The bar that is between the bucking bar and metal ball that actuates the clutch: Is it supposed to be flat at both ends or is one end supposed to have a divot that fits the ball?

Some are flat, some are slightly dished like the Zeda I'm building right now, And I know I've seen them dimpled, but can't remember if it was always after wear or dimpled when new.
View media item 61952

 

[Spare_Parts]

Cut up a 5/16" or 8mm drill bit for the bucking bar. No more dimples!

Every new bar I have seen is flat.