Cleaning up a P2 barrel

[stonerosesmod]

Hi all,

Just had to split the casings on my standard P2 engine due to a knackered clutch oil seal.While I'm waiting for a new one I cleaned up the flash and polished the inlet port of the casing.Is there anything I can do with the barrel ports to improve flow? Nothing excessive,just wondered if I can do anything myself to improve things?

[GeorgeS]

Many years ago Sticky did an article in Scootering about adjusting P200 barrels & I tried it on one I had at the time and it transformed it in to something that would easily sit at 70mph with more in reserve. Essentially you bolt down the barrel without the head on and check how much the piston obstructs the transfer ports at BDC, which I found to be 3mm. You then check the squish which I found to be 1mm too excessive. You pack up the barrel by the first measurement (I made 3 gaskets out of 1mm ally) and file down the windows on the piston. You'll then need to have the top of the barrel shortened by the figure of your two measurements added together (4mm in my case), so you'll need someone with a lathe.

Perhaps more than you want to do, but I'd though I'd mention it as the way it transformed my scooter was amazing (also repeated it on a friends with similar results) with standard carbs and exhausts. With the extended exhaust port timing I found these standard barrels are more like Malossi 210's & have a power band, quite amazing. I had a Kegra T200 (T5 body, P200 engine) with an 85mph speedo and the needle disappeared around the back of the display. I realise it wouldn't have been accurate but it was certainly much more fun that it was as standard.

I've got scans of the article but perhaps there's a copyright consideration that means I should not post them here, but I can probably get them two you if you're interested (or at least tell you the year/month of the publication).

Cheers,
George.

[rosscla]

It would be good if you could quote the issue.

I think there was also an article on how do the HB 'stage 4' tune in one of the issues too.

[GeorgeS]

The articles where run Oct, Nov and Dec 1994. Like I said, I've got them scanned in PDF format but I guess I'd be reproducing them 'without permission' if sharing publicly but perhaps I can share them individually on request? Not sure of the copyright issues on something over 20 years old.

[drunkmunkey6969]

The articles where run Oct, Nov and Dec 1994. Like I said, I've got them scanned in PDF format but I guess I'd be reproducing them 'without permission' if sharing publicly but perhaps I can share them individually on request? Not sure of the copyright issues on something over 20 years old.

Please do not share them here, copyright is a minefield.

[sean brady scooters]

widening the exhaust port by a few mm seems to help things

[stonerosesmod]

Thanks for the replies,I had a HB stage 4 on my old P2 which went very well and i recon that will be the way to go when funds allow again.Ill probably just clean out the sharp edges on the ports for now,give the bore a quick hone and fit new rings.

[railfancwb]

Don't know how old this thread is - the post date does not include YY (hint, hint).

So if the PDF offer is still available I would like a copy.

mrb37211 at yahoo dot com

Thanks!

[rosscla]

I don't know what you're using to view the forum but the post date is right next to your name .

[OzOAP]

If you're going to widen the exhaust port I would use a SIP piston. Exact copy of std P2 piston but with thinner, better quality rings.
Someone on here says they got over 30hp out of a P2 barrel. CBA to search for thread.