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Post by unreliablesc on Aug 27, 2007 20:33:24 GMT
I have put some miles on my bolt-on polini motor now, and have to say I'm very disappointed. It's painfully slow. Almost slower than a SS180.
I have never tried a std. et3 so i don't know what to expect, but it it rides like this:
revs to 65kph on the vespa speedo in 2nd, 75 in 3rd and 85 in 4th. if i have a long straight road i can just keep up with the cars in the 80kph limit (50 mph)
bottom line; it has no power in higher revs, seems to peak at 65kph on the speedo in 3rd.
setup: bolt-on polini with Mazz racing crank, PK ignition, Polini Left exhaust and 19mm carb and reed. nothing is ported. Primmy gearing
Main jet 100 / 45 idle. plug looks spot on.
no air-leaks, new bearings and seals
does anyone have a similar setup? how does it ride?
and one more thing. at first i ran it with a crappy old 19/19 carb with a 82 mainjet, but the carb was so crappy that i had to bin it, thats why i fitted the reed, a mate had a new 19.19 Polini carb/reed kit. Why did i have to go up to a 100 main when i swapped out the carb for a new 19.19?
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Post by Juan on Aug 27, 2007 21:51:51 GMT
Bolt ons are never great,always match the transfers.However,that does sound stupidly slow.
I don't really understand the science too well but the jetting has something to do with the larger surface area opened for the reed and the more constant delivary of fuel.I know that I've not explained that well at all and someone will clarify this for you with a far better explaination.
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Post by breezer on Aug 28, 2007 4:57:37 GMT
That sounds EXACTLY like mine.
polini (rotary) kit, transfers matched, mazz crank, pk ignition, pk 125 gearing, 24 carb, leo vince pipe.
The bike will probably go faster, but has a tendency to jump out of the higher gears when it hits the power band. I think I need a stronger spring.
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Post by smallyshane on Aug 28, 2007 8:03:14 GMT
I run the Rotary setup (with matched casings, kind of (one side is smoothed and the other is kind of jagged)) maz crank (with rod lightened and smoothed) PM pipe and 24mm Delly, this scoot goes off the clock on an 80mph speedo (probably not 80, but can pass cars on the dual carriage way), very surprised to hear you can only just reach 50mph with a similar setup... I would match the casings if I were you and see what difference that makes, but would be surprised if it would be that much... maybe try looking at the carb like Juan suggests.. (I quite like the 24mm delly, easy to get new jets etc, and quite easy to setup!! and not too expensive either..)
good luck
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Post by unreliablesc on Aug 28, 2007 14:34:57 GMT
I know that matching the cases should help, I built this engine in a hurry as i didn't have a scooter on the road. I will match it later.
It's not ported for the reed, so it's basically a rotary setup.
I just cant believe how much slower it is than the polini motor I had in the cutdown (rest in peace), (same kit and exhaust, malossi reed, OKO 24mm, matched an ported for the reed). That motor would leave a PX200 in the dust, and rev to a genuine 100kph with V90 gearing)
I guess strobing the ignition timing wouldn't hurt. 16deg for a polini?
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Post by smallyshane on Aug 28, 2007 14:50:42 GMT
16deg sounds right to me.
Your carb can breath properly can't it? I have had problems with my air filter that stopped me from revving past about 5500... good clean and way we went again..
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Post by unreliablesc on Aug 28, 2007 15:23:27 GMT
No problem with the air. ran it without a filter for a while just to make sure. 16deg sounds right to me. Your carb can breath properly can't it? I have had problems with my air filter that stopped me from revving past about 5500... good clean and way we went again.. |
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Post by MiNiKiN on Aug 28, 2007 20:34:37 GMT
For me the main jet seems to be way too big. try a 95 or even a 92. My Polini double induction with no matching and everything standard did 100 to 105 kph. a polini single should at least do between 90 to 100, depending on you being lucky with the barrel quality (YES, they differ a lot in timings). ignition timing: I would try 18 to 19deg (listen for pinking and retard if necessary). BTW: 85kph is only 6000rpm  Standard Et3s do 85 to 90kph. |
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Post by unreliablesc on Aug 29, 2007 14:13:29 GMT
For me the main jet seems to be way too big. try a 95 or even a 92. . Depending on you being lucky with the barrel quality (YES, they differ a lot in timings). ignition timing: I would try 18 to 19deg (listen for pinking and retard if necessary). BTW: 85kph is only 6000rpm Standard Et3s do 85 to 90kph. I could try a 95, but the plug looks nice and tan with the 100. I set the timing with a strobe firs and se how that helps. It's the same barrel i had on the cutdown, and back then I would rev to 8000. I still revs to about 8000 in 2nd, but doesn't have much power above 6000 |
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Post by Juan on Aug 29, 2007 19:03:51 GMT
I'd be looking at the inlet,sounds restricted to me which is why you need such a large jet.Same as Marcus I'd be thinking low-mid 90's.It's either the inlet itself or that a 19 on a RV is too small for the 130.
Just guessing as I've never run a RV with a 19/19 on a 130 or anything else.
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Post by MiNiKiN on Aug 30, 2007 0:53:35 GMT
I did not realise you got a reed assembly. That in fact is suboptimal as you "over-control" by using a rotary and a reed in series. either/or is my 2 pennies worth. but try jetting first.
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Post by unreliablesc on Aug 30, 2007 18:24:14 GMT
Problem solved!!!
Had to turn the stator about 1cm anti-clockwise...
Plug is a little bit dark, so I'll take another look at the jetting this weekend.
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Post by MiNiKiN on Aug 30, 2007 18:55:57 GMT
Would you mind to also adjust the ignition timing properly. What you state ("...about 1 cm...") scares me death. You know that Millimetres can decide about life or death of your cylinder . |
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Post by unreliablesc on Aug 30, 2007 19:40:33 GMT
Sorry I wasn't completly clear, don't be scared. I sat it at 18 degrees using a strobe, ("...about 1 cm...") was just to visualise how far off it was. Previosly it was set according to the marks on the stator. Would you mind to also adjust the ignition timing properly. What you state ("...about 1 cm...") scares me death. You know that Millimetres can decide about life or death of your cylinder . |
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Post by unreliablesc on Aug 30, 2007 19:47:41 GMT
One more thing, I noticed something weird while setting the timing.
On idle it advances to 16 degrees, and just above idle it retards to 18, and stays there through the rest of the rev range.
Is this normal, or a sign of something about to blow?
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Standard Et3s do 85 to 90kph.