M232 quattrini setup

[stuart]

Hello GSF. I've just installed a M232 on my PX. I have match ported the cylinder to the cases and am running standard ignition (have kytronic unit too) currently set to 24deg and curve 7, SI24/24 carb with drilled out float chamber passage 2mm, SIP #4 slide and DRT #7 float chamber top lid, 160/BE3/132, 55/160, SIP XL. My issues are that it is a little stuttery at light throttle and it hasn't the power that I would have thought it should have. Can anyone tell me what I should be looking for or see anything obviously wrong with my set up? My thought would be timing but not sure...thanks in advance.

[Motorhead]

there is a topic for that quattrini q232/q242 largeframe, have a look =>

 

 

Bearbeitet 3. November 2016 von Motorhead

[MaRi]

what is the timing of your rotary valve?

[stuart]

there was no instructions with kit so rotary pad was left standard

 

[MaRi]

well, this might be one reason your missing performance...

 

One option:

Leaf it the way it is and be happy with the performance the engine has right now and get a little more into the Carburetor setting,

 

Or:

Drill the the rotary valve the way it should be and getting into the Carburetor jetting any way, but with more power, I guess. 

 

 

 

[stuart]

That's great MaRi, thanks for the reply.

 

I'm happy to rip apart the motor again to do the rotary valve but I guess I need some specs as to how much I need to take off? Quattrini had no instructions with the kit so rather than hack away unknowingly, I stuck to stock.

[Truls221]

what is the exhaust system ?

 

how do you identify that the jetting, and especially the main jet is correct?

 

if it doesnt have the Power you expect would suggest to look over the jetting..

 

if the jetting is ok, you can go further with the inlet..

 

 

for the inlet timing such open 120 deg and closing 65 deg would be good.

I suggest you determine how much to mill, based on your current measurements...

 

you can also mark the sealing Surface on the crank with a pen, an mill until you have 1 mm left of sealing Surface to either side

 

 

 

 

 

 

[stuart]

Thanks for the reply Truls221.

 

I'm running a SIP XL.

 

The jetting is good...I've just been on a 300km/h trip last weekend and it performed well except for that little stutter at light throttle.

 

Looking back on the weekend, it does just keep up with well tuned Malossi 210s but going up long hills, it'll leave them for dead.

 

I will look into doing the rotary pad. 

 

Is there anyone on GSF who is running a similar setup that would share their specs?

 

[PolifkaRudl]

Keep in mind that with the Quattrini crankshaft you have already with a stock inlet valve a inlet-timing of 125° before TDC / 60° after TDC, which is good in combination with an si24 carb.

Quattrini does mention in the Italian text of the kit that reworking of the inlet is not required. 

With the conservative si24 carburetor your setup may work more harmonic with a torquier box exhaust like the SIP road "non XL" or LTH box or Big Box Touring, but that is a question of personal preference...

[stuart]

PolifkaRudl....That's great advice, thank you. What about ignition timing? Any advice on that?

 

[PolifkaRudl]

I made the experience ignition timing is not a huge determinator for engine performance, but a huge one for safe operation.

With static ignition I would start off at 18° and gradually increase until it starts knocking and then go back again.

Quattrini recommends in the text Vespatronic 26° at 1500 rpm. I remember Kytronic has a curve reproducing the Vespatronic curve?

Bearbeitet 3. November 2016 von PolifkaRudl

[stuart]

Fantastic. I will start at 18deg and work towards the recommended...and yes, kytronic has a vespatronic curve...7 from memory.

 

Thank you guys.

[stuart]

PolifkaRudl, are you running a CHT?

[PolifkaRudl]

CHT?

[stuart]

Cylinder head temperature

 

[PolifkaRudl]

No I don't, I like it simplistic on a Vespa

And they are slowly reacting, especially when used just with a spark plug adapter and not threaded into the head metal

[stuart]

I understand. They are a helpful tool for setting up a motor and also I find them a good tool for highway riding as to keep a check on the motor, especially in Australia where summer can be quite hot.

 

[Nick Knatterton]

So you are running the engine with an airfilter and hose towards the frame?

 

Have you every tried a few meters without filter or with removed hose?

 

Maybe an SI intake could support you at light trottle https://www.lambretta-teile.de/Inlet-trumpet-LTH-for-Dellorto-Si-2424-Vespa-PX  or

https://www.lambretta-teile.de/Air-filter-inlet-bellmouth-Polini-Venturi-for-Dellorto-Si2424-carbs-Vespa-PX-Sprint

but take care, you go leaner without filter or without hose or with inlet trumpet.

Bearbeitet 4. November 2016 von Nick Knatterton

[stuart]

Yes Nick.

Standard air filter and air bellows.

I have tried the polini venturi and pinasco carb box lid but I think I need to get it all running smoothly first before I delve into more performance bits!

[Nick Knatterton]

Of course, just wanted to know if it feels better at low RPM´s when running without filter etc.

[MaRi]

By the way, i did check my notes about the rotation valve I made for my motor.

It's 57/122° in my case (Original PX 200 casing, 60mm Quattrini crank).

That's not too bad for your setup, if it is in that range as well.