Best Crank for LML Reed Valve

Hi all,

My cases are beyond repair... I'm thinking of getting the LML reed valve crankcases as they are reasonably priced and i hear they can offer better performance.

Would my current Mazzucchelli cut crank work well with the reed valve (with its extended intake timing), or do you NEED to have a full circle crank? I haven't had it long, so would prefer to use it if I could.

Any help appreciated.



i'm not 100% sure about the performance... mine are still stock cylinders and cranks. i do know i found in all the research i've done shows that most people upgrade the crank when they rebuild their stella (LML) engines. part of the reason is because the stock cranks seem to have had some reliability issues, but i believe they are getting more performance too. seems to offer a lot of info on the stella/LML engines. i plan on going with a race crank when it comes time for a rebuild. just check on the SIP site to see if the crankshaft will work with a LML star dlx / via toscana / star /stella / belladonna rv 150 2t and you should be fine.  i also upgraded my reed block with a "ggr hot reed" on one of my stellas.  (google it and you can find more info on it.) it's a carbon fiber single reed to replace the stock metal reed. it seems to improve the power a bit and it feels like the throttle responds faster. SIP seems to offer the LML cases in auto mix ( for si carbs) and w/o auto mix - neither of them seems to come with the LML reed valve block. and it seems like they only seem to sell w/o auto mix reed valve block... so you might have to search the internet for the LML reed valve block for the one for injected engines if you are running a si carb. sells them but they are often out of stock. or maybe you should try to email or call SIP to find out exactly what the LML cases come with (i'm kinda going by what the photos show.) or if they offer the auto mix reed valve block. (i can't find it on the SIP website even though the item description for item  40311000 says they also stock the original block. i hope this was helpful and not to confusing.

electricsun... you are right about the side ports on the pinasco. i pulled out my pinasco kit and an old LML kit i have and the LML side ports are bigger (longer). i think it will still work because people definitely do run the pinasco kit just bolted on to the LML cases, so don't let that keep you away from the LML cases. as you said, you just won't "be getting the best out of this set up."

my genuine stellas are relabeled LML stars with LML reed valve engines and they don't come stock with a full circle crank so you don't NEED a full circle crank. 

Thanks for the reply Heggie,

Are cranks in reed valve engines different in any way though  e.g., are the crank webs smaller or shaped differently to accommodate the reed?

I have a standard PX crank which I could use but I'm wondering whether a race crank would perform any better in a reed engine or would it make no difference at all.


You don't need a full circle crank. I'm running a Worb5 60 mil crank in mine. Works perfectly.

Heggie, you're a diamond!

I understand exactly what you mean re. non auto lube reed block - it's a really good point and one that I'd overlooked. I guess you mean this < >

The reed valve thing is all new to me – the main thing that made me consider it is that the LML '5-port' reed valve cases are almost half the price of a Piaggio rotary engine and they can use a SI24 carb. But I've also noticed that the transfers are too big for my Pinasco alloy 177 (better suited for a Malossi 166) and this may cause issues also.

I'm not too sure now [*-)]

Thanks once again

having to buy a reed block will raise the price some, but it should still end up being less then vespa cases.

as for the transfers... from all that i've read the way i understand it is that stock LML cases are a close match ( cases to cylinder kit. ) to a 166cc malossi kit. and to get the most performance they would need to be made a bit bigger for a 177cc pinasco or polini kit. (thought it should still work o.k. without making then bigger.) you should definitely double check that, but i'm pretty sure.

it is also my understanding that LML cases aren't '5-port' but the LML cylinders are.

how do you like the pinasco kit? i've read some good things about it. i bought the alloy version and i'll put that in when it comes time for a rebuild. i'm thinking i might go with a pinasco crankshaft at that time too. and a 24/24 T5 SI carb. i've already rebuilt the clutch from a stock 21tooth to a 22tooth to give it a bit of an upgear without having to split the case... i really like it, just one tooth size up makes a noticeable difference. (a bigger difference then i thought it would.)

let me know which way you end up going.

Heggie… your point regarding the reed block is one that I overlooked. I didn't notice the one available was non-autolube, so thanks for pointing that out!

The side ports on my Pinasco alloy 177 cylinder (although bigger than stock vespa 125/150) are much smaller it seems than the transfers on this reed valve LML case, which I believe is ported to fit the so called "5-port" LML cylinder. I don't want to do any work on the cylinder to match, so I'm convinced I wouldn't be getting the best out of this set up.

The pinasco alloy kit is great btw, plenty of low down power and I highly recommend this if you want a good tourer and not a screamer, but can still take a fair hammering. I had considered an up geared clutch myself, but don't want to sacrifice the ease of getting up hills.