Pinasco plus 60mm crank

I recently fitted a Pinasco 215 to my px200. 60mm maz crank and sito plus exhaust, standard carb

I had previously been running a standard top end, witha 1.5mm packer under the barrel to compensate for the 60mm crank.

I DID NOT use this packer with the pinasco because it seemed OK without it, ie, clearing ports nicely and squish around 1.5mm

Timing with standard barrrel fitted was 23 btc. That is also what Pinasco recommend, but I found the scoot would pink badly with that timing and not rev out.

I changed to 19 Btc, and that was much better, but the engine still got hot very quickly and started pinking again after 10 minutes on the motorway.

I tried every combination of jets, right up to a 150, but no joy. I even used a 0.7mm head gasket to try and lower compression, no good.

Somewhere along the line the kit has now got too hot and damaged the nicasil lining. I may be able to recover it for short duration racing, but it will never tour.

When the kit was running well it was bloody great, and I am considering getting another one, but can anyone tell me how you set these things up with a 60mm crank so they don’t blow?

Cheers

hello,

yes you can modofy the standard head to be used with 60mm stroke, but it is something that has to be done by a professional.
I am sure Andy worbl from worb5 scooterparts will be able to do it for something around 25 - 30 euro. Write him an e-mail at the addres I left in the topic MIKUNI PETROL PUMP posted today.
If you travel alot in double, I will prefer having torque too. Maybe also for the Pinasco kit too, you will want the head modified to accept longstroke.[:roll:]

Thanks again Curare. I’ve polished the nicasil back and hope to be able to reuse the kit, at least for round town riding. Worth a try.

In the meantime I am going to refit the standard barrel and head. I’ll use the packet this time, but can you tell me, is there a modification I can make to the standard head which will allow me to use the 60mm crank and a smaller base packer (or no packer at all?) I ride 2-up a lot and need the torque.

I have a T5 top gear but do not want to fit it just yet as I don’t have time right now to split the cases.

Cheers

Thanks for the info Curare. Strange though, with a 1.5mm base gasket this combo will have well over 3mm of squish clearance?

I’ve since found out this is the way PInasco made them… oh well, you live and you learn!

Must say though that before the kit siezed it certainly had great compression and went very fast!

…if you prefer torque, insted of 1,5mm base gasket , you will need somebody to work the head to be used with longstroke. Worb5 does it for about 25euro. Maybe SIP they do it too.-[H]

Is 1-1.5 mm squish clearance okay for the head with a standard base gasket? The improved torque of the 60mm crank and no thick base gasket sounds like the hot set up to me. It will enable me to run the standard 4th gear for touring. If I reshape the combustion pocket to add a few cc, then the compression will come down. Is this the right way to do it?

hello,

just remember to consider the option of having the head worked to be capable of working with longstroke. This option will give more torque then base gasket but less high rpm power.
It depends how you like your engine and your gearing. If you use base gasket get a short forth.
[H]

I have a question about this same set up. The Vespa Doctor recommended a Pinasco kit with the 60mm Mazzuchelli crank, a SIP exhaust, 24/24 Dellorto with 135 main, 190 air, BE4, and 18 BTDC timing. Here are my questions:

  1. Am I better off machining the head to accept the 60mm crank? If so, what should my squish clearance be and how many CC’s should the head be to get 130 PSI?

  2. If I run the 1.5mm base gasket, do I need to do anything to the standard Pinasco head? Cost is not a factor, so if I can make it better I will.

  3. Is there anything that should be done to the „out of the box“ Mazzuchelli 60mm crank before I put it in the engine?

  4. Will the Pinasco kit fit in an electric start PX200EFL? I know there is some minor grinding of the fins involved, is there anything else?

  5. This is a newbie to two stroke question - do you balance the piston, crank, flywheel assembly like a normal car engine? What components get balanced and what balance factor do you ask the shop to balance them to?

  6. Is there anything else you would recommend adding to this engine while I am in there, like a SIP clutch release bearing, higher quality engine bearings, etc, etc?

hello,

unfortunately you didn’t use a 1,5mm base or head gasket…
you have too. You are changing the stroke and what was enough space to cope with piston expansion after heating won’t be enough anymore. Not merely a question of compression.
So the problems you had were the problems you should have had.
I personally like the use of the base 1,5mm gasket with this combination. The time about 21 or 20.
It is a very reliable combination. For the next time…
[H]

hello,

if you use base gasket, no head mod. required.
For the barrel to work with the flywheel, yes you have to cut few mm of the last two fins.
As far as for the balance yes you balance the flywheel , and the cranckshaft. Sometimes even the original one are not well balanced. In sip catalogue you can find fine balanced crank.
24/24 and the set up you refer it is good, in my one though I use 20 ignition with no problem. 18 in my engine made me loose too much on mid. You have to try.
If you can buy a renforced (with outside welded ring) clutch do it. Not too expensive and you will be more protected; even though with this set up wouldn’t be necessary.
Sip exhaust very good with this set up.
Other choices: RZ right hand, it will give you little more low, more mid power but less high and over rev.
RZ 2000, very very similar to SIP in this set up.
If you go for a PK flywheel you will loose electric start but gain something… but in this set up I wouldn’t boder.[H]