Aircooled big bore 2 stroke

[Pony]

The past few days I have been gathering as much info for my street build as I can. I am balls deep into an off topic bike I am choppin, so my CR project is in the parts gathering phase. Therefore very little pictures as of now and just trying to get as much info so I can build what I really want from the get go.

So I am wanting the best air cooled big bore single platform to put into my street project. so all other workable problems aside (countershaft/kick/pipe side) Where does this leave me?

1984 CR500. Easiest to fit into my chassis/setup. Good power, 5 speed, parts are not too hard to find. From what I understand more of a lowend torque/short shift type motor. Is it that far off to think that this could be moved around a bit with porting and a pipe design not comprimised by fitting into an offroad platform?

KTM 495. The more research I do the more I am intrigued by this motor. I really like the idea of putting this motor in my bike for the cool factor and the power. I have not seen specs side by side but seems to put out more hp than the CR, but not a lot more. Also seems like this platform has more potential for modification. Saw that 100hp honda was planning or running a CR rod in this motor. Does this motor have a lot of reliability problems? Would it be stupid to peice one of these motors together?

I have seen some sand drag guys run custom intakes with dual carb setups. Whats the deal with that? How would that affect the power range and would a bike not running alky ect ever be able to benifit for something like this?

Any other motors come to mind? I Just wanted to get ya'lls opinions on the pros and cons of these motors (any any other that might fit the bill) in one place. not the bike as a whole, not really interested in usable MX style torque, more wide open midrange and up type power. I just want to make a radical and fun 2 stroke machine. I dont wanna throw practicality totally out the window but its not too high on the list. I searched and didnt find anything like this.

[NightBiker07]

The past few days I have been gathering as much info for my street build as I can. I am balls deep into an off topic bike I am choppin, so my CR project is in the parts gathering phase. Therefore very little pictures as of now and just trying to get as much info so I can build what I really want from the get go.

So I am wanting the best air cooled big bore single platform to put into my street project. so all other workable problems aside (countershaft/kick/pipe side) Where does this leave me?

1984 CR500. Easiest to fit into my chassis/setup. Good power, 5 speed, parts are not too hard to find. From what I understand more of a lowend torque/short shift type motor. Is it that far off to think that this could be moved around a bit with porting and a pipe design not comprimised by fitting into an offroad platform?

KTM 495. The more research I do the more I am intrigued by this motor. I really like the idea of putting this motor in my bike for the cool factor and the power. I have not seen specs side by side but seems to put out more hp than the CR, but not a lot more. Also seems like this platform has more potential for modification. Saw that 100hp honda was planning or running a CR rod in this motor. Does this motor have a lot of reliability problems? Would it be stupid to peice one of these motors together?

I have seen some sand drag guys run custom intakes with dual carb setups. Whats the deal with that? How would that affect the power range and would a bike not running alky ect ever be able to benifit for something like this?

Any other motors come to mind? I Just wanted to get ya'lls opinions on the pros and cons of these motors (any any other that might fit the bill) in one place. not the bike as a whole, not really interested in usable MX style torque, more wide open midrange and up type power. I just want to make a radical and fun 2 stroke machine. I dont wanna throw practicality totally out the window but its not too high on the list. I searched and didnt find anything like this.

Your best bet is going to be to build something you can get parts for relatively easily. if a stupid little part breaks, and its hard to find you could be not riding your bike for months.

contact a couple porting/motor guys on the options for the air cooled 500 as far as porting and other mods to make the bike run better all around.

I know the Yamaha 490 had massive detonation and tuning issues that was remedied by headwork, and "if" I remember correct,y the air cooled 500 was a nightmare as well until some work was done to fix the issues.

Denny at Flotek Performance should be able to help, he seems to have a lot of experience with the old air cooled motors.

[Pony]

Thanks for the reply! I have been leaning towards towards the CR more because of the reason you stated. I was looking into a yz490 just because they seem to be cheaper, but the 4 speed kinda turned my away. The idea behind this bike was to kinda build with what I could round up and make into a cool high horsepower bar hoppin type scoot. I am not racing it, and a motor with a few quirks such as the cr and the yz's pinging would be a fun project to be able to tune on and learn more about 2 stroke tuning/porting/carburation ect. So I guess part availibility would be pretty important for what i am wanting.

Anyone else? I am sure some of you guys have some ideas thats you have wanted to see but the practicality of keeping the bike good for what you need it for holds you back.

[Roostius_Maximus]

run a wet bottomend, better parts, make the finner top fit. hillclimb guys were doing it

[Pony]

Killer idea! I assume that the finned topend is a fairly close fit? And what do the hillclimb guys benifit from running the aircooled cyl/head? I guees no raditors to crush would be the main reason?

[Roostius_Maximus]

ya, there were a few bikes out there like that, bolt strait into the chassis then

[NightBiker07]

run a wet bottomend, better parts, make the finner top fit. hillclimb guys were doing it

wet bottom end?

[2strokekyle]

Wet=liquid cooled