High performance two-stroke mods...

[4skindiver]

Hi, a bit off topic but I thought you guys would know where to point me.

Im looking at creating a chainsaw from a 2-stroke 250cc singly cyl bike engine, for competitions, demos etc.

I need to find a company that specialises in high performance tuning for 2-stroke engines.

Im not talking your basic "widen the exhaust port with a dremmel, bigger muffler" etc, but a company with enough knowledge and all the tools (mills, lathes, TIG welding, balancing etc etc) to get the engine screaming. Custom crank, piston, bridge porting, wider bigger transfers, carb work (will be running race fuel / alcohol etc).

The engine will never be run for more than 30 seconds (each cut should take a few seconds only)

Hopefully, this perfect tuning company can also assist with the manufacture of brackets, handles, engineering concepts etc.

Does such a company exist? Auckland would be perfect, but travel is no problem if im dealing with the best.

Thanks!

[WRT]

Can't help with the tuning side, but I'd imagine you'd need to allow for more than 30 secs running. I'm assuming your talking an MX engine (2/, 250cc single), in which case they don't run well when cold and are prone to cold-seizing if not warmed up properly.

[4skindiver]

Can't help with the tuning side, but I'd imagine you'd need to allow for more than 30 secs running. I'm assuming your talking an MX engine (2/, 250cc single), in which case they don't run well when cold and are prone to cold-seizing if not warmed up properly.

hmmm... a good point when considering a std 2/ setup! definately a warm 2/ is needed.

however, ideally, some of the bikesaw setups I have seen overseas use carbon composite pistons (US$500 ea) and ceramic rings. As these do not expand at anywhere near the rate of alloy, finer tolerences are used in piston / ring / bore clearances, so compression is at almost optimum from cold.

I would be looking at an air cooled setup (less weight) and grinding the fins down so it heats up quicker. So in short, a rebuild will be done often as bikesaw racing is murder on moving parts!

I'm really hoping such an experiend company exists in NZ! I've found so many experts on 4 strokes, but mention 2/ and everone seems to run a mile!

No pressure, you guys are my last hope

[koba]

Yeah, drag volkswagens are often built so they are "warm" almost as soon as ya start them and if you run them longer than the startup and trip down the quarter they will sieze up!
This sounds like absolutley MENTAL sport if you need more than the power from a standard 2stroke 250! I don't think I can help past saying "I know the tuners are out there"

I would love to know more about these saws and the sport in general...

Good shit too.

[4skindiver]

Yeah, drag volkswagens are often built so they are "warm" almost as soon as ya start them and if you run them longer than the startup and trip down the quarter they will sieze up!
This sounds like absolutley MENTAL sport if you need more than the power from a standard 2stroke 250! I don't think I can help past saying "I know the tuners are out there"

I would love to know more about these saws and the sport in general...

Good shit too.

www.racesaws.com

check out the pics posted by my good man dennis cahoon. some good video links too. old dennis is nucking futs. i could get him to build one for me (his saws hold a few world records) but it would be nice to throw it all in the old buggers face and say "ha f****** ha us kiwis are better!!!"

kinda like the worlds fastest indian, but im no burt monroe. all I know is saws

[WRT]

I would be looking at an air cooled setup (less weight) and grinding the fins down so it heats up quicker.

Air cooled is not used for much with any sort of performance these days. I did a quick search on http://www.motorbikes.be/en/ for 2 stroke air cooled in the last 10 years and came up with SFA. There's the Jawa 350 cc, which is only 23 hp. Compare that with a modern 250cc water cooled mx which is good for around 70hp.

A Suzuki Bergman 250 air cooled came up, but doesn't say how much it produces. Could be worth a look, but being a scooter they will have designed it for long maintenance schedules rather than outright grunt so I'm picking it will be fairly tame.

I reckon you'd be best to go for water cooled, even if you dont attach much of a cooling system to it. There is also more likely to be performance parts readily available for a modern mx engine.

[koba]

www.racesaws.com

check out the pics posted by my good man dennis cahoon. some good video links too. old dennis is nucking futs. i could get him to build one for me (his saws hold a few world records) but it would be nice to throw it all in the old buggers face and say "ha f****** ha us kiwis are better!!!"

kinda like the worlds fastest indian, but im no burt monroe. all I know is saws

That is sooo farken cool!

[4skindiver]

Air cooled is not used for much with any sort of performance these days.

Oh sorry, I left that part out... and you are right, all the modern stuff is w/c, thanks! The plan was to find a w/c engine, and take the cooling system off to end up with an air cooled saw. I'd grind out the water jackets also to try and reduce the weight.

Thanks for the link! i'll need to spend some time looking around...

[speedpro]

Pete Sales at Total Motorcycles down Palmerston north way has been building good 2-strokes for ages. Him or his son can fabricate just about anything and their workmanship is superb. In my opinion the best 2-stroke man in NZ is Wobbly. PM me and I'll forage out his contact details. He has contacts that can do all the fabrication as well. He's Tauranga way. For me, keeping it as North as possible whilst still getting the BEST job done I'd get Wobbly to design and do the porting and Jim Steadman to do all fabrication. Jim lives in a tin shed with a lathe, mill, and a few welders. He's built his own 750cc V3 2-stroke which is wicked fast and his workmanship is also brilliant.

[4skindiver]

Pete Sales at Total Motorcycles down Palmerston north way has been building good 2-strokes for ages. Him or his son can fabricate just about anything and their workmanship is superb. In my opinion the best 2-stroke man in NZ is Wobbly. PM me and I'll forage out his contact details. He has contacts that can do all the fabrication as well. He's Tauranga way. For me, keeping it as North as possible whilst still getting the BEST job done I'd get Wobbly to design and do the porting and Jim Steadman to do all fabrication. Jim lives in a tin shed with a lathe, mill, and a few welders. He's built his own 750cc V3 2-stroke which is wicked fast and his workmanship is also brilliant.

Hey thanks mate! Have sent you a PM