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Post by paulwaite on Sept 10, 2015 12:22:37 GMT
This is the standard 24/24 carb with a 130 main jet being the only difference to the stock carb, ie with a BE3 mixer. Before I had the Malossi tuned, it ran well with a great plug colour. Since then the barrel ports have been tweaked, I have changed exhaust from a Sito plus to the BGM big Box and set up Ky-Tronik ignition.
In this form, it runs great with plenty of pull and feels right and the tickover sounds and feels right.
But just done plug chop at 1/2 throttle and its probably just a bit too lean. So to richen up this low end, do I change the mixer tube to a BE4, or should I be looking at something else in the jetting zone.
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Post by henri on Sept 10, 2015 15:46:43 GMT
were have ya mapped the k-tronic to or is it on stock settings , i think it was vespaco went through atomiser chops on his rally mallosi 210 recently ,will look for thread ,have only found 1 atomiser chart online ,an dont trust it ,its here ,http://lmlocgb.co.uk/phpBB3/viewtopic.php?f=5&t=1707,H
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Post by henri on Sept 11, 2015 6:53:13 GMT
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Post by vespasco on Sept 11, 2015 16:36:13 GMT
Yeh thats the one!! Here....  To avoid confusion, the BE6 is quite different from the more common BE3,1,5 & 4 and can not be easily compared to others and is actually leaner than most other atomizers. I firmly believe that the atomizer order as above is correct (ignore the BE6) for the 1/4 + throttle/ 4000rpm range. I have a malossi 210, with a PM evo pipe, autolube si24 and am running a 130mj so id say youre not far out. Although Im not so sure if the cases have matched on mine and dont imagine ay porting work was done either. Are you sure its at 1/2 throttle? The only real/easy way to tell is marking the throttle/grip/handlebars. |
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Post by paulwaite on Sept 14, 2015 13:03:59 GMT
Hi Henri The table below gave me some idea on the mapping for my tweaked 210 malossi with standard up jetted carb and BGM BigBox exhaust  So my original mapping was as below, using curve 8 and that's when I got the slightly lean plug chop.  Then I had a re-think that my setup may not be a street racer. Although I have a tweaked further malossi cylinder, I still had the standard carb, but upjetted to 130. Also, although the BGM BigBox may be an improvement over the Sito plus, its still not a big expansion pipe. So over the weekend, I changed to the map below, running on curve 7. Initial chops upto 1/2 throttle look better, but I'm still in the dabbling mode. But thanks to you and Vespasco for the head up on Vespa atomizers, all interesting reading that I have stored for later.  |
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Post by henri on Sept 14, 2015 15:11:37 GMT
i'd agree ,unless youve really tweaked the barrel n port timings/inlet stick on a 7 curve ,an if me i think i'd be tempted to try it static timed to 22 rather than 24 , the extra retard might shave a % of a bhp off ,not much really, but would make engine run cooler ,counteracting a slight leanish mix in mid range , H
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Post by paulwaite on Oct 13, 2015 12:19:41 GMT
Just to give an update for all interested or those who want to know.
Following on from setting Curve 7 and still in the experimental mode, I drilled out the airbox as shown in the sticky. The 7mm hole above the main jet was there already, so it was just the 5mm hole over the pilot jet. Then I thought I would just see what main jet that I had installed. Thought it was a 130 one, but turned out to be a 125 main jet that I ran with this Malossi engine before had the ports tweaked. Anyway, put in a 130 main jet and did the plug chops with perfect results. Although the 3/4 plus throttle range in 3rd gear was a bit hairy when it came to ignition off and clutch in.
Now since drilling out the air box and the 130 main, the scooter pulls great, with plenty of torque and acceleration, without having to find a power band. To date, I'm a lammy person, but must say, I'm impressed with the smoothness of this Vespa engine, albeit I seem to have the Malossi rattle, which worried me until someone told me it was normal.
Will get it dynod over the next few weeks to give me the confidence that I have got the jetting correct.
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Post by henri on Oct 13, 2015 15:34:27 GMT
mallosi slap , as in piston slap, they dont use low-expansion ali for pistons so cold bore/piston clearances are larger , should get better an pretty much disappear as engine comes up to temp .thats normal . H
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Post by vespasco on Oct 13, 2015 17:49:11 GMT
Out of interest, what porting mods' did you do?
Id also be tempted to first set static timing at around 18° and then set the carb. Then set the Kytronic up to curve 7 or 6 if you can.
If you really want to test the main jet, try at WOT for a few minutes. Scared of being too lean? Go oversize on the main jet and work down.
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Post by paulwaite on Oct 14, 2015 12:15:17 GMT
Gave my Malossi barrel and piston to Mick Abbey (http://mickabbeytuning.co.uk/) to tune for a fast road touring, so I can't tell you precisely what he did, other than match the piston and stroke to the ports, raise the exhaust port to suit and smooth of the transfer ports. Now I hadn't used this Malossi engine for around 4 years, but comparing it now, with how I remember it, there is a marked improvement. This improvement is better acceleration, a smooth power curve right from low down revs upwards. And although I have the T5 final gear fitted, the top end (ie in 4th, still has loads of torque).
In respect of the Ky-Tronik and just to avoid any confusion, this is what I've done. If you have a look at the table above, I have set the static timing to 24 degrees and set the curve to 7. So when you kickstart the engine, it starts at 15 degrees to ease starting the rises to 24 degrees over the rev range shown to make the burning of fuel and therefore performance more efficient. Then as the revs build up, it advances the ignition to help in cooling. Or are am I misinterpreting what you suggested?
Over the years I've had M Tech and other boxes, but I'm impressed with the Ky-Tronik.
All the best
Paul
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