Malossi 46.5 RPM?

[maciekTopic starterBerichten: 12]

Hi Guys, I am wondering about Your tuning experiences with this kit. What kind of RPM does it like, where should I expect the power band to be with a Simonini Proline? Any pipe that would pair with it better?

I thought the Estoril I originally was using since before variating the bike was keeping the RPMs down, but I’m not getting much more out of the Proline, though it did want more jet (92!). Only leak is seeping at the exhaust clamp, hard to seal that up completely..anyway it’s good at WOT and the plug looks just right.

modified stock cases: http://vespa-ciao.nl/forums.php?m=posts&q=34468
Malossi 46.5, lower transfer ports widened to match piston windows, piston windows cleaned up.
Simonini Proline
Dellorto 13.13, 92 jet, very rich idle.
Malossi clone filter (very porous black foam).
Malossi vario, 5.7 gr LeoVince weights (16.3mm diameter in stead of 15.9 Malossi)
Treats clutch (https://www.treatland.tv/vespa-rear-variator-clutch-assembly-p/vespa-rear-variator-clutch.htm)
9.5:1 gears

Thanks,
~M

[hansiebModeratorBerichten: 10922]

Not to much people on this forum are driving this cilinder. Check for opinions -> [url]forums.php?m=posts&q=15321[/url]

What are you willing to get, Topspeed or maximum torque?
About the jet, i think a 92 is way to much.
With a speedengine and a 46mm cilinder you normally go for 72-74 jet.

[maciekTopic starterBerichten: 12]

Thanks, I thought 92 is very big as well, probably compensating for the exhaust leak, I found no others, and I did put the proline on without any sealant (just to see if simonini did any better job on the clamp then polini or tecno). It does run pretty well at WOT and the plug-chop looks just right, just very rich at idle.

I was originally set up for torque, 12.25:1 gears and estoril, top crank cut to malossi specs, and just the intake and mild port match done on the case, running jets in the mid 70s and topping out around 65km/h, 70 on a good day, 7-8k rpm… Then I had an unfortunate accident where the clutch blew up and put a hole in my foot (http://www.mopedarmy.com/forums/read.php?1,2715103,2718946) and broke the transmission cover around the bicycle-mode button. I took a break from this bike.

Meanwhile I decided that since I had to re-build another transmission I’d try taller gears and maybe get to 80km/h+. When I finally got the bike back together with new clutch, trans, and gears, I cracked my variator on something (still don’t know when/what, having too much fun) which bent the crank, which promptly snapped. So, over the winter I ported the cases close to the maximum, transfers and boosts all the way down to the crank lobes, and used an anticipato crank. I tried the biggest jet I had first, an 82. It four-stroked at idle (time to shave the slide), but still seemed lean at WOT, plug chop confirmed. Hitting 75km/h and only 6-7k rpm max, and the vario is not tuned in and variating fully yet. This is according to a TinyTach which I’m starting to doubt.

I figured 80s, but I got up to 98 just in case. I also finally got the proline so I installed that.

I tried the 80 first, lost power and top speed, felt lean but i did a chop anyway and it confirmed it, 90 was better and faster, but still looked lean. 98 felt rich, four stroking up most of the throttle, but would clear out at WOT. 94 was fastest so afar so I chopped and it looked a bit rich, so I went with the 92 and essentially got back to where I was with the estoril.

80s seems more reasonable with this much case work at sea-level…I’ll try some sealant and hopefully it will help.
I also tried lightening up the vario weights which got me a few more rpm and about the same top speed. I have heavier I might try, but I need to get/make some lighter ones, seems more likely it may be variating too early.

[ritzeBijdragerBerichten: 3421]

Hey, i drove that cilinder, on a reedvalve 19 mm with vario. I drove 2 different pipes; a custom hi rpm pipe, and a gianelly city power

With the hi rpm pipe i messured 9250 rpm at 82 km/h and it started at about 7500 rpm

The gianelly was a lot different, it started at 6000/6500 and went on to aprox 7500/8000 kmh with hi torque

My jets were also very big (92) and it ran a little rich.
Check ritze perso for pictures and tuning how i did it

Perso
http://www.vespa-ciao.nl/forums.php?m=posts&q=18884&d=400

De budget beun tjoener: geen geld is te duur of het werkt nog niet
Link naar Mijn collectie / Projecten.

[maciekTopic starterBerichten: 12]

Thank You! That is exactly the kind of information I needed. Seems not many on either side of the pond run this cylinder, at least not people that bother to use a tach ;). I have to get some sleep before work, but I can’t wait to try some things tomorrow.
~M

[hansiebModeratorBerichten: 10922]

@ritze

He has a 13/13 with a 92 jet. You were driving a rv with 19mm carb..

[ritzeBijdragerBerichten: 3421]

At hans i know his jet is very big for a 13/13 carb so we know for sure that he have a leak problem.

92 on a 19 mm is kind of normal but it is on the bigger side haha

De budget beun tjoener: geen geld is te duur of het werkt nog niet
Link naar Mijn collectie / Projecten.

[maciekTopic starterBerichten: 12]

I hope You all are having a good summer!

I broke the sub-frame on my bike, while the engine was out to install the re-inforced replacement I changed the seal. It did seem to help, as I downjetted from 88 to 84 and my head temps stayed around 350F/175C. I also put a notch in the slide to lean the idle to a reasonable mix and dropped the rollers down to 4.7gr. Did half the rally this way and all looked good so I went down to an 82. It runs great, peaking around 400F/205C and approaching that magic 80km/h mark at a bit over 7k RPM. Still seems kind of low, so I’m thinking to try some lighter weighs and the 100mm rear pulleys, see how high of an rpm it will pull through and still variate fully. Hopefully the 9.5:1 final gearing is not too high.

Also, maybe you guys have some input on rotary-valve intake timings for this thread: http://www.mopedarmy.com/forums/read.php?7,3509334

Peace,
~M

[MartinoModeratorBerichten: 7384]

I’m still amazed. An 84 jet in any setup which contains only a 13/13 SHA carburettor looks way to big. You found out not that many people here in Europe drives these cylinders on resembled setups. It is offcourse not without any reason. People don’t get good performance and the quality of the cast iron Malossi Cylinder is not very good.
It’s rather cheap though for a big bore. 😉

That said i’ll have some experience and worked on an engine as followed; Speed Engine, Olympia race crank(Don’t remember the exact timing) 46,5mm Malossi, 13/13 @ 74 jet and a Malossi powerfilter. Even the 74 jet was a little too rich and when running the engine for a short period off time on idle, will cause too what we call “fattening up the sparkplug”.So we should have tried a 72, but never got the time to do this.This was build in a Piaggio Si with also an variated setup. 1:10,5 rf, 100mm pulleys. It was performing very well and flies off from a standing start, but it will top at max 70km/h. This is in an enviroment with sea-level/climate conditions. Isn’t it always regarding the Netherlands. 😉

First and foremost. Forget about the Tecno Estoril. This pipe is rubbish performancewise. The Proline should be much better, but may not be the best for your setup. The top rated pipes we tried where Proma Circuit and Proma Cannon.

As we found out. We also had some leaking problems at first. Keep a close look at the lower right transfer.
There is only a little bit of flesh or space for any gasket to stick on. Even in some cases you can see light go through. I could only imagine with Piaggio cases this could be a problem aswell. Make sure this is tightened and sealed with maybe any extra liquid gasket. It can also explain the need for high jetting.

As for any crankcutting and timings. I would not go into that now. It shall only fill the entire post with text.
Too many variables and contradicting theories only to conclude perfomance is not predicted this way in the real world.

Edit: I’ve edited an photo of this Malossi cylinder problem. You can zoom in for a closer look.

Link naar Mijn collectie / Projecten.

[Gebruiker]

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