Web moped2.org




Date: Wed, 07 Jun 2000 11:48:59
Subject: Re: moped tuning
From: Hans Hartman
Reply to author   Post followup (list members only)   Back to index   Subscribe to the mailing list   Unsubscribe from the list  

Hello Ludo,
At 09:16 7-6-00 -0700, you wrote:
>A little question: are there any persons on the list that are tuning/racing
>their mopeds? Because I am really into tuning mopeds, I have a Honda Pa50
>that I am tuning, still needs some perfection but it already goes about 110
>km km/h. So if anybody has suggestions, comments or questions (like the
>nitro-thing) let me know... Specs of my Pa50 (when finished) -70cc liquid
>cooled (with waterpump) -21 mm carb with special air-intake -motor insides

Is that Polini kit NR. 119.0028?
If so, what did you pay for this kit? I understand the pump is an extra?

>are totally polished -"Ninja" exhaust -tuned vario-matic -carbon Reed
>valves -Frame is totally re-cut (much lower than standard) and reinforced
>-Oil springs (back

You seem to have the lot.
As an extra, you might reduce the crankshaft chamber's volume by adding a
piece of metal (alloy) under in the sump (between the two crankshaft
counterweights). This results in a better (higher) under-pressure in your
engine, this increases the performance a bit.

Be sure that the 21-mm carb gets enough air, if in doubt you could fit
Polini's air power box.
When you start adjusting the carburettor settings, begin with a too large
main jet, and work your way down with smaller jets by trial and error.

I believe there was a special end-ratio kit for the PA50 too, you'd have
too check the Polini-site for that.
What alterations did you do to your variomatic system? Did you replace the
centrifugal clutch spring's (3) with heavier springs (+40 percent)? Which
weight rollers did you use?

I discovered an edge on my primary pulley, which restricted the belt
further down. After we've machined that one off, the end speed was a bit
faster (from 45 to 55 KM)
We did not remove the edge entirely, because a lot of pulley axles were
broken in the old days.
I do know Belgium used other pulleys, but I am not sure the edge is on your
model too.
Does your model have the six-roller version or the three-roller clutch?

The Polini kit and the expansion type exhaust you use, will shift the
maximum torque from 5000 Rpm to 8000 Rpm, you must adjust the clutches
accordingly.

I am going to fit my PA50 with an electronic ignition unit for the Honda
PX, as far as I can see right now, everything fits.
When you use an electronic ignition, you can discard the flywheel, and use
a battery ignition instead. This will cause your PA to howl to it's 8000
(or more) rev's quicker, thus improving acceleration.
Of course, you don't want to do that when you're going to use it on daily
bases, because the moped stops when the battery is empty of course.
In moped races in the Netherlands this modification is common practice, as
all modern scooters and mopeds have electronic ignition.

This however is not the reason I want use the electronic ignition. I just
want to get rid of those contact-breakers, and like to experiment a bit.

How do you measure your speed? Over here everybody uses these bicycle
computers, which are really accurate when the set-up is done right.

Hope this helps,

Hans Hartman

Reply to author   Post followup (list members only)   Back to index   Subscribe to the mailing list   Unsubscribe from the list  



Forums at Moped2.org Privacy policy
Moped2.org Home My other sites

Home   Contact
Wikipedia Affiliate Button