I'm going to have another go at F3

[Mental Trousers]

Aprilia 550 would have to be the least fragile I reacon.

Ummm, no. Have a look through the Aprilia forums or talk to anyone who's raced one. They're fucken rockets but they're a really high maintenance engine. The early ones had plenty that needed to be done to them. Issues were; blowing oil seal between engine pump & g/box pump, sticky rear decompresser, heads not torqued correctly, stator/rotor bolts coming loose, blowing starter motors (they are really small & burn out if run for ages, updated ECU map lets them run for 6 secs at a time). But the big one - they used an orange sealant (if you can call it that) between the cases and this will eventually fail, mixing coolant and oil followed by a rooted engine. Later models use a black sealant (threebond, yamaha sealabnt etc), a smart move is to split the cases and do it before it fails. Some bikes have gone for ages and other died quickly, If the cases are done, the service intervals are no different to any other bike, just depends on what you using it for.

[crazy man]

There's an engine builder in Auckland who made a screamer R450. Went ok, but when it failed he dropped a slug as a temporary measure till he got another screamer done. Triple went so much better, he has stuck with it.

Two stroke might be the way to go...if you can get through a season without a dnf of course.

l look at the triple as been l cheap competitve bike but not the best. intresting to have a poll on all f3 bikes and see what people think is the best to have

[Mental Trousers]

There's an engine builder in Auckland who made a screamer R450. Went ok, but when it failed he dropped a slug as a temporary measure till he got another screamer done. Triple went so much better, he has stuck with it.

Two stroke might be the way to go...if you can get through a season without a dnf of course.

That was Greg Percival. Originally he had a new shorter stroke crank made and used longer conrods. Unfortunately that engine never got anywhere near making peak power because the stroke was so short it needed to do 22,000rpm to flow enough air. So he built another engine as a 3 cylinder and removed the piston and conrod. But he's had a lot of trouble getting it right cos it suffers from a vibration in the crank which gets so bad it whacks the crank speed sensor and stops dead. Although at Hampton Downs they did something more than that cos the crank cases were actually split. I think Chris Osbourne finally got around to removing the piston and conrod from his. However, it's been a whole heap more reliable.

I reckon the way to do it is how Ducati made the Super Mono. They took a twin and lopped a cylinder off but left the conrod in place. Instead of the piston it bolted to an arm, the end of which is a similar weight to the other piston. In the pic below you can see the conrod at the top of the pic attached to the arm.

From Neil Spalding, http://www.superbikeplanet.com/thumper.htm

Ducati applied this very same engineering, literally, with their Supermono, a racebike that was produced in a limited run of 67 units between 1993 and 1995. The bike was literally an 888cc L-Twin with one bored-and-stroked cylinder that yielded 572cc. Both con-rods were still present, but the "vertical" cylinder and head were lopped off and replaced by a pivoting counter-balancer weight

[Mental Trousers]

l look at the triple as been l cheap competitve bike but not the best. intresting to have a poll on all f3 bikes and see what people think is the best to have

I'd love to do one properly. Pull the piston and replace it as above. Pull the cylinder liner, machine any excess weight out of the cylinder area and head (without weakening them of course) blocking or diverting oil and coolant galleries as needed. Make a custom exhaust (this is where just about all of the current triples are losing power cos a 4-2-1 exhaust has the 4th cylinder scavenging the 3th cylinder so they're not filling the 3rd cylinder properly).

A good solid 600 can put out a reliable 130hp without going pop. Three quarters of that is 97.5hp.

[koba]

Hahahaha, be a funny betting pool. Won't be who wins, but Will I crash before the stroker blows up.

Eh? Gimpy = Jason Easton = Aprilia 550 in tiny Rs sized thing.

[Shorty_925]

A good solid 600 can put out a reliable 130hp without going pop. Three quarters of that is 97.5hp.

Whats the power to weight like after dropping the cylinder to compared to a standard 600?

[Mental Trousers]

Whats the power to weight like after dropping the cylinder to compared to a standard 600?

Less power same weight more grip. What do you mean??

[GSVR]

Ummm, no. Have a look through the Aprilia forums or talk to anyone who's raced one. They're fucken rockets but they're a really high maintenance engine. The early ones had plenty that needed to be done to them. Issues were; blowing oil seal between engine pump & g/box pump, sticky rear decompresser, heads not torqued correctly, stator/rotor bolts coming loose, blowing starter motors (they are really small & burn out if run for ages, updated ECU map lets them run for 6 secs at a time). But the big one - they used an orange sealant (if you can call it that) between the cases and this will eventually fail, mixing coolant and oil followed by a rooted engine. Later models use a black sealant (threebond, yamaha sealabnt etc), a smart move is to split the cases and do it before it fails. Some bikes have gone for ages and other died quickly, If the cases are done, the service intervals are no different to any other bike, just depends on what you using it for.

My definition of fragile is different to yours maybe.

I'm saying its it less fragile because its less likely to have the cases break or fail, throw a rod, drop a valve, etc. Real issues.

Have to get Gimpy in here to tell how many motors he lunched in the years hes been running them.
To my knowlege his main issues were blown head gaskets and overheating. Both have been overcome.

[Drew]

Eh? Gimpy = Jason Easton = Aprilia 550 in tiny Rs sized thing.

Oh right. I thought it was the 400 two stroke thing he was talking about.

[Grumph]

Ummm, no. Have a look through the Aprilia forums or talk to anyone who's raced one. They're fucken rockets but they're a really high maintenance engine. The early ones had plenty that needed to be done to them. Issues were; blowing oil seal between engine pump & g/box pump, sticky rear decompresser, heads not torqued correctly, stator/rotor bolts coming loose, blowing starter motors (they are really small & burn out if run for ages, updated ECU map lets them run for 6 secs at a time). But the big one - they used an orange sealant (if you can call it that) between the cases and this will eventually fail, mixing coolant and oil followed by a rooted engine. Later models use a black sealant (threebond, yamaha sealabnt etc), a smart move is to split the cases and do it before it fails. Some bikes have gone for ages and other died quickly, If the cases are done, the service intervals are no different to any other bike, just depends on what you using it for.

All this used to be normal Italian...you guys have been spoiled in the last few years as Ducati has finally got it's act together. Nothing I see there which can't be sorted by a competent engineer.

[wharfy]

All this used to be normal Italian...you guys have been spoiled in the last few years as Ducati has finally got it's act together. Nothing I see there which can't be sorted by a competent engineer.

Yeah used to be normal - however for the sort of money you have to hand over for a bike now days there is no excuse for the factory to not get it right (or fuckin close).

[wharfy]

Make a custom exhaust (this is where just about all of the current triples are losing power cos a 4-2-1 exhaust has the 4th cylinder scavenging the 3th cylinder so they're not filling the 3rd cylinder properly).

A good solid 600 can put out a reliable 130hp without going pop. Three quarters of that is 97.5hp.

How about diverting the exhaust from the unused cylinder into the air box - supercharger !!!