How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Hey y'all.

There's not a lot of info on this so I figured fuck it.. ima archive the procedure and my overall thoughts about it.

First off.

Why do you wanna put aftermarket Tomos springs in za50 stock clutches?

Great question, I mean the treats clutches exist and they rip dicks. We all know this. However, idk if you're a za50 nerd but there's hella cases of the treat clutches failing and grenading all of your precious za50 internals. Ouch.

Storytime!!

I had both 1st / 2nd gear treat clutches. 4.5k springs in first and mild 2k springs in second. The 2nd gear felt a lot like a stock flipped clutch but man that 4.5k ripped hella hard. Like it woke the bike the fuck up. After maybe.. 50 miles I broke a clutch cable and said FUCK IT. IMA INSPECT THE TRANNY. well.. guess what? The stock chain links in the treat clutches already had a lot of play. An uncomfortable amount. I coulda grenaded my tranny. Scary!!! So I said FUCK IT, ima tune those stock clutches and reduce potential damage to my precious za.

Alright let's get started!!!!

First off, get that clutch out.

You'll notice the stock chain links aren't particularly serviceable. I opted to do what moped luau did. Ditch the stock chain links and replace with masterlinks.

Take a angle grinder to those links and take em all out. Be careful!! Don't damage that previous clutch.

Now that it's all apart we gotta decide what Tomos spring were gonna rip. I opted for the yellow springs. They're significantly stiffer / beefier than the stock 1st gear spring. The blue spring was a hair stiffer than stock but I opted for yellow in hopes of getting some serious changes in clutch stall. You'll also notice that aftermarket Tomos springs are significantly longer than puch springs. Weird huh? Well they work. I guess. *shrug*

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright now that we've chosen a spring. Let's slap that bad boy in.

I chose the visegrip / screwdriver method to install the spring. You can also use a tapered tube type thing to install the springs.. but I didn't have too much luck with that. I'll add a picture of the tool I made for shits and giggles

Make sure you get some needle nose pliers and secure those ends together. You don't want that shit poopin loose.

But yeah, putting the spring in wasn't too bad. Maybe the red spring would be more challenging but I didn't have too much trouble with the yellow.

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright. The next battle were gonna face is puttin some masterlinks in. I dunno what goddamn size chain is stock. Looks like some bicycle size. Definitely not 415 or 420. You could try to match the size of the stock ones I suppose.

I opted to do what moped luau did. Drilled all the holes out with a 5/32 " drill bit. Fits a 420 master link. Kinda on the tight side though. Wiggle that drill bit around a hair. Hahah.

Alright here's another curveball. The 420 master links are a little wideeeeee. I got the chain breaker out and made em a hair more narrow. I left the long end hangin out the back.

I did a test fit and found out that the long ends out the back touched the 2nd gear clutch a hair. I got the angle grinder out again and gave the excess links a little haircut. They no longer touched. I additionally made a small shim out of a pedal Peugeot shaft shim with the center slightly enlatlrged. I simply put it on top of the stock spacer between the two clutches.

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

The 420 master link rubbed a tad on the top not allowing the securing nut to tighten properly. I got the dremel out and gave the top portion of the master links a tinyyyyyyyy haircut. It cleared the nut properly now.

Alright now slam all that shit back together. I dunno if you wanna make a shim like me but if you did... for the love of fucking God make sure the securing nut sits all the way down so the clutchbell doesn't rub on it. That would fuck up everythinggggggg.

Alright boom. That's all I got. Have fun and be safe. The yellow spring in 1st ended up being a bit less than the 4.5k springs in treat clutch but definitely a significant increase in clutch slip over the stock unmodified 1st gear clutch.

I haven't touched my second gear yet. Probabky will fuck with it later. Should be the same yeah?

Alright I'm out. God bless.

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Nice write up.

I like red first blue second.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright I'm gonna keep the ball rollin' y'all.

Maybe it was a manic episode but I decided to take apart a 2hp 2nd gear stock clutch so I could compare the spring to others. As most of you know, the 2hp 2nd gear has the stiffy spring. Compared to the 1hp that is. Mine came with two blue dots on it from the factory.

Anyway here it is compared to the stock 1st gear spring. The 2nd gear one is slightly longer and significantly more stiff. In terms of tension it is about equal to a aftermarket blue Tomos spring. Keep in mind this is just me pulling on it. No science here.

So for the sake of making it simple... stock 2hp 2nd gear has a stock spring equivalent to a blue. So you could add a blue spring to a 1hp clutch to essentially mirror a 2hp. Pretty cool.

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

DrGeorgeTompson (Alan) /

Following to absorb knowledge about ZA50 coilynoodles

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos spri

Overpriced Parts /

My one hp clutches slip like a 2 hp and with polini reed kit 19mm phbg and 4 pedal reed, it’s wheelie city on take off and 1-2 shift even with custom 21x31 gears so like I said before most za50s have there own personalities!

How I tune clutches on my za50s isn’t to change clutches springs but to change clutches to ones that slip good and since I’ve had about 50 za50 engines it wasn’t hard to do but my lo mi 78 1 hp maxi II has stock clutches!

When I’m done my bikes I have full and part throttle kickdown like a Chevy Powerglide transmission but my 1 hp maxi II already had super slippy wonderful 1hp clutches to begin with !

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos spri

Interesting Ken. I have noticed that with ZAs and thought it is just my imagination, that this one shifts or takes off better then the other. But I only messed with a handful. You got 10Xs on me.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos spri

Jonathan Feldman /

> Ken Roff Wrote:

> -------------------------------------------------------

> My one hp clutches slip like a 2 hp and with polini reed kit 19mm phbg

> and 4 pedal reed, it’s wheelie city on take off and 1-2 shift even with

> custom 21x31 gears so like I said before most za50s have there own

> personalities!

>

> How I tune clutches on my za50s isn’t to change clutches springs but to

> o change clutches to ones that slip good and since I’ve had about 50

> za50 engines it wasn’t hard to do but my lo mi 78 1 hp maxi II has stock

> clutches!

>

> When I’m done my bikes I have full and part throttle kickdown like a

> a Chevy Powerglide transmission but my 1 hp maxi II already had super

> slippy wonderful 1hp clutches to begin with !

Yeah you got some real good za50 posts. My favorite thing about a " tuned " za ( you know what i mean ) is when you slow down and go around a corner and blip the throttle and it downshifts. So fun.

This is my first za50 so I'm mega newbie. The stock clutch stall wasn't horrible by any means but I wanted a tad more slip to help overcome not being 100% tuned perfectly / excessive blowback/ blah blah blah. You know what I mean.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright so I went back in and flipped the masterlinks around. Multiple people had concern that the way I had it.. might be prone to throwing a clip.

Here's the new position.

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Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Good . The open end of the clip should ALWAYS follow the closed end .

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

not sure if it really matters but i like to put the spring joint in the middle of a shoe.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

> pat splat Wrote:

> -------------------------------------------------------

> not sure if it really matters but i like to put the spring joint in the

> middle of a shoe.

Hmmmm. I have been rippin it with how it was set up in the last pic. Seems to be operating just dandy.

Interesting point though, legit never had that cross my mind at all.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

I use a socket and a punch to push the pins out of the stock links instead of cutting them off.

Do the clutch/spring work, then hammer the links back on to the pins. I've NEVER had a pin or a link come loose.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

how do your guys' pads hold up? so far thats really the only problem i've had is the linings getting chewed up.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

> Graham Motzing Wrote:

> -------------------------------------------------------

> how do your guys' pads hold up? so far thats really the only problem

> i've had is the linings getting chewed up.

I'm new to the za50 life so I'm not sure I can judge how my pads are doin' long term. I got maybe 100 miles on it since I was inside the transmission fuckin around.

Gonna keep rippin' it for maybe another 100 - 200 miles then pull it apart and inspect how everythings holdin up.

Definitely gonna throw a yellow spring in second gear. MAYBE put in a red in first gear.. but that's probably pushing it.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

yeah seems to me like the key to life on these bad boys is to let them shift nice and easy like, the big gears are cast iron and it doens't take much bangin' around to get them to chunk off teeth.

clean oil, keep everything nice and tight so it doesn't slam around.... put a lot of miles on ZA bikes over the years and they hold up pretty good but i also treat them pretty easy peasy and save my performance breakin' stuff builds for e50's and french bikes. i'd like a higher 1-2 transition myself but not if it comes at the expense of clutch life. my polini has about 3k on it and starting to show some damage but those clutches weren't the best when i put them in either, so tough to say.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright y'all I'm back. Unfortunately no cool pics or groundbreaking discoveries.

But I did some thinking...

Ok so yesterday I rode treats Jack's za50 cobra. Big dick airsal 46mm with treat clutch in first and stock clutch in second with red tomos spring.

It was FAST for sure but I noticed something. At ( what I believe was 20/38 gears ) it did the traditional za50 shift around maybe 23 / 25 mph but after it shifted... it slipped like crazyyyy before engaging into second.

I was like woah! All this nutty clutch spring shit didn't actually extend first gear length at all but rather just gave a butt load of clutch slip before second. I wasn't too sure how I felt about it. On my stock clutch first gear with yellow springs / stock flipped 2hp second gear... when it shifts it's immediately in second gear. No weird slippage. I kinda liked that more.

Ok so OBVIOUSLY I know stock 2hp second gear clutch is a world different than red spring stock second gear clutch. So maybe my stock second gear clutch with yellow spring wouldn't slip as much going into second. But it really got me thinking that maybe stiff springs in second doesn't actually extend first gear but just controls how much slip occurs when entering second.

SO I DID SOME MORE THINKING... How does a za50 shift / what dictates when a za50 actually shifts? Does anyone know? I really want to understand the system.

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Blaine- The artist formerly known as Plumber Crack "(OFMC)" /

The rpm of 2nd gear clutch to overcome the clutch spring is what determines the “shift”. Those high 20/38 sprockets will move that shifing point to a higher speed as well as lengthen the period of slip, relative to speed.(edited)

Re: How to: rebuilding za50 stock clutches with aftermarket Tomos springs

Jonathan Feldman /

Alright I'm back at it again.

I grenaded my rear wheel on a Oakland pothole so that took me outta the game for a hot bit but I've still been fuckin with the za50.

I've been getting consistent shifts around 20-24 mph with 0w20 and stock 2hp second gear flipped. However I wanna get more in the 25-30 mph range.

I chose to put a yellow spring in second gear stock clutch. I haven't been able to run it yet due to wheel troubles but I got the second gear clutch ready to party. Some things I noticed include.

1. Guess what? 410 links don't fit. They fit the stock non drilled holes but they are way too short. Doesn't even reach the other side of the clutch. Bummer. I was really hoping 410 was gonna be the magic size. The stock links are almost like 410 but longgggg extendo. If anyone knows what size it might be.. PLEASE speak up.

2. I chose to run the masterlink clip side on the opposite side that I originally did on first gear. So.. triangle side has the master link clip side.. not the spring side.

3. I had to massage the master link clip a tinyyyyy bit to get them to fit in nicely. It was kinda a shitshow trying to find the best fitting master link clip. Some had more play than others.. I ended up going through a bunch to find the best ones. I'm getting pretty sick of the master links. To be honest they're starting to feel like a whole 'nother failure point being added to the already questionable za50 transmission. I'm gonna search for a appropriate chain breaker that will allow me to use normal 415 Chain.. hmmm.

Yeah.. things to ponder. Ima update when the 2nd gear yellow spring is in and how it changes the shift point from what I'm at currently.

Xoxo y'all

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