300EX Woods Machine

[Tecate]

Anyone ever put a twostroke 250 in a 250X/300EX chassis before? I see the expansion chamber running into frame rails.

I have a 250 motor that runs strong and I know I can get a 300EX chassis for cheap to use as trail machine. Think the 300EX would handle 40+ hp?

[Creech52]

I had a friend that put a R motor in a mojave frame, worked ok, alittle short for that kind of power. I think he used a stock ATC pipe. I dont see why it wouldnt work, its not gonna be a great handling race bike or anything but would work on the trails given the 300EX's short wheel base and good handling manners.

[Tecate]

I've heard of Tecate motors in Mojaves before, bet it was a real flyer.

I just want a play bike, something to fart around on in the pits and rough trails. Needs to be small like the 300EX so my g/f can handle it too.

[Raptor350_Rider]

Yea I rather have a Yamaha Raptor 350 in stead 'cause there betta and faster !!! ~GET A YAMEYA

[300exOH]

I would think that with the short wheelbase of the 300ex and the power of the 250R motor you're going to end up staring at sky the second you hit the power band. You'll probably need a lengthened swingarm at the very least plus some good suspension to handle the speeds it would be capable of. IMO the R motor is too much for the 300 frame. It can barely handle what the built 300ex engines w/330 kits can deliver even when the frame is gusseted. It would be interesting to ride though.

[Tecate]

Originally posted by Raptor350_Rider
Yea I rather have a Yamaha Raptor 350 in stead 'cause there betta and faster !!! ~GET A YAMEYA

I don't want the 300 fourstroke motor that will come in it. My 250 Tecate stays with 660's on top end, that will be the "motor" I'm using. I want the 300EX "chassis" because its small and has great suspension and loads of chassis upgrades via the aftermarket.

It'll need an extended swingarm, theres no doubt but it won't be stretched any more then 2 inches.

I'm building a KX 500 powered trike at the moment and theres only a +2 on that thing.

[Creech52]

If you know how to ride I dont think the short wheel base is an issue, I mean alot of bikes are light in the front you just have to know how to ride a bike like that, and whats wrong with 60mph wheelies across a field. I dont think youll have any strength issues with the frame, as long as the motor was designed for a quad and is counter balanced it should be fine, just make sure you mount it to all the motors mounting points, and do a little gusseting to the frame. A motors power really doesnt have much to do with frame damage, its more due to riding. If you think about it in car terms, most cars are either two long rails with a few cross members, or 4 short rails connected by sheet metal (sub frames) and with a good motor they will twist, however putting in a roll cage eliminates alot of twist, along with boxing the frame. Now take a look at a quad chassis, box or round tubing, and its basically like a main frame with a roll cage around the motor, therefore flex shouldnt be very bad with most sport quad or trike motors.

[300exOH]

Originally posted by Creech52
If you know how to ride I dont think the short wheel base is an issue, I mean alot of bikes are light in the front you just have to know how to ride a bike like that, and whats wrong with 60mph wheelies across a field. I dont think youll have any strength issues with the frame, as long as the motor was designed for a quad and is counter balanced it should be fine, just make sure you mount it to all the motors mounting points, and do a little gusseting to the frame. A motors power really doesnt have much to do with frame damage, its more due to riding. If you think about it in car terms, most cars are either two long rails with a few cross members, or 4 short rails connected by sheet metal (sub frames) and with a good motor they will twist, however putting in a roll cage eliminates alot of twist, along with boxing the frame. Now take a look at a quad chassis, box or round tubing, and its basically like a main frame with a roll cage around the motor, therefore flex shouldnt be very bad with most sport quad or trike motors.

I just meant that the frame is built for an engine that's only capable of about 55 mph. With the 250r engine the thing will be able to go 70+ mph and launch much higher off of jumps than with the stock motor. Also he mentioned something about his girlfriend riding the quad too. I think a 250r engine on a 300 frame will be hard for most ladies to handle. I can bet that if ridden hard enough a 300ex frame with a 250r motor will snap sooner or later even if its gusseted. I'm not saying it won't work...I just want to warn that it may not hold up for long. If you do build the hybrid make sure the frame is gusseted well and check it for stress cracks often.

[Tecate]

The Tecate has no counterbalancer, though I'm not too concerned about frame fatigue. If it breaks I'll fix it, simple as that.

Short wheelbase doesn't concern me. The trike I ride is short and always wants to come up when it finds traction.

It'll be a play quad, doesn't have to be perfect. The motor I have is rated at 37hp stock. I've got a good port job by CWR, Vforce II reeds, DG exhaust and a 38mm Mikuni TMX on it so far. Its no slouch.

[300exOH]

Originally posted by Tecate
If it breaks I'll fix it, simple as that.

Short wheelbase doesn't concern me. The trike I ride is short and always wants to come up when it finds traction.

Good plan. As long as you check the frame now and then it should be okay. I guess if you are used to trikes the light front end won't be a problem. lol Sounds like it will be a sweet project.