Riva 7 ports cylinder Superjet
- Thread starter Shnapsou
- Start date
- Location
- Charlotte, NC
I'm sure it would be a great cylinder for closed course power wise, however it should definitely be inspected and checked regarding deck height and all of your port timings as it could possibly be a stroker cylinder or require some crazy concoction to work. Such as custom domes, or rod length and even pistons. These things will be very hard to tell without measuring everything. If that is above your ability, then I'd send it to an experienced engine builder and have them look at it and tell you what it needs.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
These were very popular race motors back in the late 90's Pro Mod days
I built a Ton of them! (as shown in my Avatar pic!)
Most all were +8m Long rod x 81.75mm Flat Top pistons
Which made 799.89cc Or fit perfectly into the 800cc rule at the time.
They were avail in both PV & Non-PV versions
Most all were run with the then R&D Dry Pipes, Total Loss, and 220# plus compressions
They were a Handful to ride!
As time went on, they became popular with the freeride / Freestyle crowd, and several strokes, and bore sizes became options
Anyway, Feel free to contact me directly for information on getting this going. Most parts are still available, except maybe sleeves?
Those would probably need to be made to order.
ski ya, Paul
I built a Ton of them! (as shown in my Avatar pic!)
Most all were +8m Long rod x 81.75mm Flat Top pistons
Which made 799.89cc Or fit perfectly into the 800cc rule at the time.
They were avail in both PV & Non-PV versions
Most all were run with the then R&D Dry Pipes, Total Loss, and 220# plus compressions
They were a Handful to ride!
As time went on, they became popular with the freeride / Freestyle crowd, and several strokes, and bore sizes became options
Anyway, Feel free to contact me directly for information on getting this going. Most parts are still available, except maybe sleeves?
Those would probably need to be made to order.
ski ya, Paul
waxhead
wannabe backflipper
- Location
- gold coast
I machined an 8mm down to a 6mm and got the port timing spot on as well by where I machined. Its brutal, I love these cylinder and own three of them
- Location
- Illinois
Aside from the name on the cylinder and PV bosses, and sleeves, what kind of differences are there between say a Riva, R&d, and the unbranded Dasa (Lamey) cylinder?
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
They are all the same...............
- Location
- Northern Cali
ABLE Has a 7 port Billet cylinder also from the same time period i believe
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
Think he thinking of SS 800 limit. I remember at 2006 or 2008 APBA Nationals. Was talking with Pat Bogart. He said Chuckie built him a pissed off sub 800cc DASA. Said they took it right up to the limit!!!!!!
The early Mod class with oem cyls was 785 as I remember it? When they started allowing aftermarket cyls it went to 800? Now im second guessing myself also? I keep log books on all that stuff and what I have built.
when I get back from PCB races on Monday, Ill dig it out and confirm
P
waxhead
wannabe backflipper
- Location
- gold coast
waxhead
wannabe backflipper
- Location
- gold coast
Heading towards the square bore. Such a better combination than the big bore we see these days
I know near the end of MotoGP two stroke era all the 125/250 and 500 motors were square. Most 125’s are 54/54 today. I read the SAE paper Honda did after the end of the era and the data suggest most metrics (BMEP) the square bore produced the best results. I think every mfg that competed at the high level of Motorsport (MotoGP) was square. There paper is a good read. Honda releases a few real good papers on their two strokes at the end
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
What you talking about Willis?
Ok. Maybe a better way (layman’s) to say what I think the data suggest is.
For a given displacement (cc) (class rules) a square bore produces best results. The point would end when piston speeds get to high for the length of stroke for a large displacement. The port windows can flow more volume with a square bore for a given volume than a large bore smaller stroke. Does that help?