A3 motor shudder at gear change

Fresh A3 rebuild, new Rito rod 12mm pin and piston, Airsal 44mm broken in from previous 10mm pin setup, VM20 jetted like everyone elses, Techno Circuit, stock gearing (26/22)

The only difference is I replaced the old clutch/rubberized cork pads with an A3 clutch that seems to have much stiffer material pads almost ceramic like. The old rubberized cork pads started falling apart.

Anyway, motor trembles at gear change when cold. Seems to go away after warming up. What's happening here?

Re: A3 motor shudder at gear change

did you check/replace the 'sprag clip' question mark clippy thing? that will cause it for sure.

having the clutch shoes out of balance can cause it

sometimes new clutches do that as they break in

the clearances/shims could be jacked up.

Re: A3 motor shudder at gear change

Dmitry K. /

what sprang clip you referring to? I hadn't taken replacement clutch apart; it seemed in good condition.

PagesfromTomosA3spareparts.jpg

Where would you place any 0.1mm shims? I didn't see any place for them; all parts are pretty tight fitting.

O one other thing: I used liquid gasket material in place of paper between the crank cases. Why should this affect the clutch operation?

Re: A3 motor shudder at gear change

nah by you asking, i'm gonna guess that is probably the issue.

its on the freewheel cluster. its a little question mark lookin' spring clippy deal, it preloads the freewheel rollers so they dont slam back and forth when it shifts from 1st to second gear

the tomos doesn't have 'shims' per se like the ZA50 does, but #6, 10, and 17 are washers which control the spacing of clutch parts, and the #7 bushing. I'm not sure if they have different thicknesses. the cover spacing does affect float, but not as much because the nut on the end locks down the clutches on the shaft instead of the ZA where the float is controlled by the case depth.

Re: A3 motor shudder at gear change

Dmitry K. /

you mean the spring item 8 on drawing?

PagesfromTomosA3spareparts.jpg

Re: A3 motor shudder at gear change

Mine does the same thing and ive been wondering about this for a while...Im running a thicker oil and it better but still

Re: A3 motor shudder at gear change

Dmitry K. /

I'm using ATF type F per manual. Took apart up clutch side completely: no damage from all the shaking and all parts are where they should be and looking good. Whatever burnt 1/2 tank riding it today.

Re: A3 motor shudder at gear change

Yeah that's the one, #8, best replace it or you're gonna be sorry, eventually the freewheel cracks and it spits out the gear teeth

Re: A3 motor shudder at gear change

I put the sprag clip in mine AND replaced the gearset because the previous owner cracked it and it still shudders...

Re: A3 motor shudder at gear change

Dmitry K. /

Where to get these springs? Treats doesn't have them.

That's so strange because my a3 clutch looks brand new, the pads are unworn. Pads are ceramic I think and engage very hard as opposed to rubberized cork ones that hat had gone bad.

How to explain the fact that the shudder disappears after riding and some gear shifting?

Re: A3 motor shudder at gear change

The shudder I am experiencing never goes away. I got my clips from a local guy but he got them from treats or 1977

Re: A3 motor shudder at gear change

i don't bother with the sprag. 1000s of kitted miles.

Re: A3 motor shudder at gear change

ephraim zimbalist jr /

liquid gasket makes it thinner...shims should be snug to cover

Re: A3 motor shudder at gear change

Mixing gear lube and type f fixed this problem, this allows clutches to slip, and engage smoothly in my mind, instead of harsh clutch engagement

Re: A3 motor shudder at gear change

mit mortso Wrote:

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> i don't bother with the sprag. 1000s of kitted

> miles.

eh one of those agree to disagree kinda things.

when i bought out the moped shop in north carolina there was a box of probably 20 sets of gear clusters, all cracked freewheels and chipped teeth. seen the missing sprag do that on at least two occasions combined with the shuddering issue.

or whatever...

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