Puch Z50 engine - Recommend me a kit

Russell Cosham /

Hi guys,

I'm in the process of rebuilding a Puch Z50 engine, new bearings/seals & full roller bearing crankshaft etc. I'm now looking for a 65-70cc cylinder kit to buy for it, to be used with the dellorto 19 phbg carb and Tecno estoril pipe i've already got.

Bacially what i'm asking is, what kit do you guys recommend? I was thinking a Metrakit 65 or possibly a Tomos reed kit?

I've already got an E50 engine'd Maxi with an Airsal 65cc kit, 15mm Bing, RS cigar pipe, 18x45 gearing etc that's a nice 45mph bike. I've also built in the past another E50 (DMP 70cc, tecno boss, 14mm Bing) and a Tomos A3 (Airsal 65cc reed kit, VM20, tecno circuit).

I'm looking for something different to what i've had but nothing too extreme.

Re: Puch Z50 engine - Recommend me a kit

Probably Fred /

I’d run what you’re used to running but otherwise maybe a 64cc polini kit, 15 mm bing 20-21x35-36 gears

Re: Puch Z50 engine - Recommend me a kit

This is a bad ass kit on a za50 if you take the time to set it up.

https://www.doscycles.com/products/puch-dos-45mm-70cc-reed-kit?variant=40859899599

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Re: Puch Z50 engine - Recommend me a kit

Russell Cosham /

Thanks for the recommendations so far.

Although it's NOT a ZA50 I'm building, it's a Z50 2 speed manual shift.

Re: Puch Z50 engine - Recommend me a kit

Dirty30 Dillon /

If it were me, I would go with the 46mm Airsal, enjoy a grunty mid-range monster that can actually pull through some tall gearing to get the most from the manual 2spd. This will help avoid the issues people have had with peaky setups on the Z50 and the clutch spring slipping

Re: Puch Z50 engine - Recommend me a kit

> Dirty30 Dillon wrote:

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

> If it were me, I would go with the 46mm Airsal, enjoy a grunty mid-range

> monster that can actually pull through some tall gearing to get the most

> from the manual 2spd. This will help avoid the issues people have had

> with peaky setups on the Z50 and the clutch spring slipping

I was going to say the same. The 46 airsal is the best bang for your buck and you do not need to open the cases up! I’ve ran em in stock cases and they still rip! Got about 4 setups currently running it and they are all sold fun 50+ bikes.

Re: Puch Z50 engine - Recommend me a kit

Z 50 can take the puch hero 65cc kit that treats sells. It has massive transfers which will match up to the z50 very nicely. Probably the best matched kit for that engine available right now.

Re: Puch Z50 engine - Recommend me a kit

Russell Cosham /

46mm Airsal aka the 72cc kit?

I don't know about not case matching or the Z50 having big transfers, mine has stock E50 sized ones with not much metal around them.

Re: Puch Z50 engine - Recommend me a kit

Dirty30 Dillon /

> Russell Cosham wrote:

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

> I don't know about not case matching or the Z50 having big transfers,

> mine has stock E50 sized ones with not much metal around them.

I was going to say, AFAIK the Z50 has normal sized transfers

Re: Puch Z50 engine - Recommend me a kit

I think Jackerz is saying that you can still get a lot of performance out of the 46 Airsal without matching the transfers.

Re: Puch Z50 engine - Recommend me a kit

Russell Cosham /

I would have to case match though, its like doing a half a job otherwise.

The only thing that puts me off the Airsal 72cc is the cylinder skirt cracking issue.

Re: Puch Z50 engine - Recommend me a kit

todd amundson /

I got this Hero 65 kit set up to run AV10 reeds. It’s clean.

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Re: Puch Z50 engine - Recommend me a kit

Z50 clutches are very small and very weak, they don’t hold up to very much power at all. You may want to look into getting a stiffer spring for the clutch or maybe even getting the upgraded mv50 3 plate basket.

Re: Puch Z50 engine - Recommend me a kit

Russell Cosham /

> Daniel '' wrote:

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

> Z50 clutches are very small and very weak, they don’t hold up to very

> much power at all. You may want to look into getting a stiffer spring

> for the clutch or maybe even getting the upgraded mv50 3 plate basket.

Yep that did cross my mind, i've seen the upgraded clutch springs but was unsure of what to go for? Thanks for the tip on the mv50 clutch i didn't know that.

I'm thinking a lower revving torquey cylinder is the way to go, rather than a high revving one. I'm not keen on the Airsal 72cc kit thats been recommended due to issues with the cylinder skirt cracking, anyone tried the new MK65 kits or can anyone recommend something else?

Re: Puch Z50 engine - Recommend me a kit

Sander Mulder /

I would go for the normal athena 45mm, good quality nicasil, piston is ok. Not too fast, good for z50

Mk65 with nicasil is also a good option, good torque and good quality

Re: Puch Z50 engine - Recommend me a kit

The clutch thing was the problem I had with my Sachs 2 speed Athena 80. You would think 2 speed would do better with a narrow power band but it was worse because there is no slip, and when it hits the pipe it just spins the clutch.

If you tried to slip the clutch by hand into the power band it would just never grab.

I think something like the small reed Athena might be the best case low end torque and you can build them to have a really flat power band. I haven't run the aluminum mk65 but if it's anything like the old one I'm sure it would be great as well.

Re: Puch Z50 engine - Recommend me a kit

The z clutches are even smaller surface area than sachs, tbh they’re kind of a joke. I was trying to build mine to do 50 in first like rodneys 74/74 za, but it was so much load and so big of a gear drop that when I went to shift into 2nd I didn’t have the clutch all the way released and that was enough to smoke my 2 disc with the metrakit spring. If I’m being honest the z50 is not very fun when it’s set up tame, the only cool thing is easily clutch dump wheelies at 10mph. A stock hi torque e50 maxi with a pipe eats it’s lunch.

Re: Puch Z50 engine - Recommend me a kit

Russell Cosham /

> Daniel '' wrote:

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

> The z clutches are even smaller surface area than sachs, tbh they’re

> kind of a joke. I was trying to build mine to do 50 in first like

> rodneys 74/74 za, but it was so much load and so big of a gear drop that

> when I went to shift into 2nd I didn’t have the clutch all the way

> released and that was enough to smoke my 2 disc with the metrakit

> spring. If I’m being honest the z50 is not very fun when it’s set up

> tame, the only cool thing is easily clutch dump wheelies at 10mph. A

> stock hi torque e50 maxi with a pipe eats it’s lunch.

I'm starting to wonder whether buying a new roller crank, bearings and seals for this engine was worth it now lol

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