Question: Why was the biggest two-stroke bike 500cc?

**vifferman** · 17th July 2008, 09:08

Originally Posted by nudedaytona

I don't recall seeing any holes like that in the cylinder I recently took off.

The only hole I can remember seeing was the exhaust hole. There were holes in the cylinder head, but they seemed to be for coolant to flow around on the outside of the cylinder.

The pic is of a piston-ported two stroke (the piston covers/uncovers the ports). There were also two-strokes with disc valves, which had a spinning disc with holes in it.

**rogson** · 17th July 2008, 09:24

Link to Maico 760 article in my original post (#7) fixed.

Specs I've seen for current 685cc LC model are 82HP, 101kg - bloody hell!

**BIHB@0610** · 17th July 2008, 10:19

Originally Posted by sidecar bob

Check out this weapon!!!
Kenny Roberts' TZ750 dirt track racer.
http://www.motorcyclemuseum.org/classics/bike.asp?id=42

Kenny once said "They dont pay me enough to ride that thing"

Who taught you your ferocious "advanced googling" skills Bob? I'm mightily impressed

**James Deuce** · 17th July 2008, 10:27

Must be a 4 stroke RS250 then.

The inside of an RGV250 looks like this, so your RS must too.

The Junkers JU86D used by the Luftwaffe for High Altitude Recon (46,000ft in 1940!) was powered by the Junkers Jumo 205C a vertically opposed 2 stroke diesel.

http://www.dundee.ac.uk/museum/mecheng/3001.htm

**nudedaytona** · 17th July 2008, 10:41

Oh yeah, I remember those holes now.

So what would be easier, boring cylinder out or changing the ports.

**James Deuce** · 17th July 2008, 10:44

There's plenty of info in making porting changes to RGVs. All of which are a bit dodgy.

I know there is a 300cc kit out there for RS250s. You should do some digging on that because the end result will be better than having a go with a riffler file.

The best thing you could possibly do is talk to this guy. The 465cc kit in my RG400 had RG500 and GSXR750 riders really scratching their heads.

http://www.stanstephens.com/rgv.htm

**imdying** · 17th July 2008, 11:14

Long story short, the biggest ones available were the biggest they could make whilst still be elligible for racing. When the sizes for the classes got smaller, so did the Win on Sunday Sell on Monday bikes.

**Grub** · 17th July 2008, 11:22

Originally Posted by MVnut

..... what's wrong with the handling....you ever ridden one ??

Ahem ... have you? These bikes were lethal. The frame flexed so much that the geometry of the bike would change several times in a corner. Yes, they were the Falcon GTHO of the bike world ... they killed people. Oh ... and they sounded GREAT!

**imdying** · 17th July 2008, 11:36

Originally Posted by Grub

Ahem ... have you?

Given that it's already Thursday, then yes, MVNut has probably ridden his one this week

**Grub** · 17th July 2008, 11:38

Originally Posted by imdying

Given that it's already Thursday, then yes, MVNut has probably ridden his one this week

He's got one? He rides it? He's alive? He's mad!

**Choco** · 17th July 2008, 12:04

Originally Posted by MVnut

Disc brake front on all H2s..... what's wrong with the handling....you ever ridden one ??

Only repeating what i've been told (dont shoot the messenger)

**Badjelly** · 17th July 2008, 12:14

Originally Posted by ChocolateWheels

Kawasaki 750 triple 'widow maker'.
My old man got to ride one once, scared the shits out of him!
That bike was the fasting thing on the road at the time and had drum brakes front and rear

crap handling too!

Originally Posted by MVnut

Disc brake front on all H2s..... what's wrong with the handling....you ever ridden one ??

The 500 (H-1 aka Mach III) came out before the 750 (H-2 aka Mach IV) and originally had drum brakes. The 500 was the one that first got the scary reputation.

**Mikkel** · 17th July 2008, 12:34

Originally Posted by Grub

He's got one? He rides it? He's alive? He's mad!

If you only knew...

He's not that mad though.

**Grub** · 17th July 2008, 12:57

Originally Posted by Mikkel

If you only knew...

Got a bit of an idea, I doubled the owner to work for 6 months on Mach III (drum brake) since he'd lost his licence on it .....

He flies 747's for Air NZ now ... kinda worrying really