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Discussion Starter #1
Hi, guys, new to the site.

I'm starting a 2-stroke super moto build using an Aprilia SXV and a Yamaha RZ350 engine. The build is still in the planning stages, but yesterday I went ahead and ordered the Aprilia SXV frame, subframe, swingarm, rear shock, shock linkage, front forks, lower triple, upper triple nut, front and rear axles, rear wheel spacers, and rear swingarm adjusting blocks.

That should get me started on the engine conversion. The engine swap doesn't look easy, but if I'm not happy with the outcome, I'm going to use the RZ350 frame, and modify the Aprilia parts to fit. That way, I'll only be out the money and time I spend on the Aprilia frame.

Here is a custom motard using the RZ350 frame and engine with CRF450R bodywork:







Here is the bike that inspired me to build a 2-stroke super moto bike. This bike has a custom frame, and uses the RZ350 engine:

 

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Sounds like a cool project, someone on here is doing a bike with a banshee motor.

One question though, why the sxv frame? It seems like it'd be more expensive to acquire, and they are V-twins, so the frame will need more modifications. Other bikes using singles seem like they'd be less work to modify, like the examples you showed.
 

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^ I was thinking the same thing. Why not use a yamaha WRX frame? Then you'd have a yamaha when you're finished, rather than a mutt.

Either way, it sounds like a sweet project and I wish you luck with it...
 

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Discussion Starter #4
Sounds like a cool project, someone on here is doing a bike with a banshee motor.

One question though, why the sxv frame? It seems like it'd be more expensive to acquire, and they are V-twins, so the frame will need more modifications. Other bikes using singles seem like they'd be less work to modify, like the examples you showed.
The others have already been done, and I'd like to do something original. I think the Aprilia frame and swingarm are straight-up exotic, compared to those bikes. Also, I don't usually like doing things the easy way. ;)

The Banshee engine is okay for the dirt, but I wouldn't use it for a street application. All modern 2-stroke engines for the road or track (not dirt) use some type of valve (usually on the exhaust port), which adds power lower in the RPM band and smooths out the delivery of power. The Banshee engine doesn't have a power valve system.
 

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but everything can be modified im sure you know of duncan racing and trinity racing. trinity built my last motor for my banshee and tuned it to my exact request, then i had bills motocross development make custom pipes to suit my needs. i think it will be a bad ass bike good luck,
 

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The others have already been done, and I'd like to do something original. I think the Aprilia frame and swingarm are straight-up exotic, compared to those bikes. Also, I don't usually like doing things the easy way. ;)

The Banshee engine is okay for the dirt, but I wouldn't use it for a street application. All modern 2-stroke engines for the road or track (not dirt) use some type of valve (usually on the exhaust port), which adds power lower in the RPM band and smooths out the delivery of power. The Banshee engine doesn't have a power valve system.
:clap: :thumbup:
Makes sense, i can't wait to see the result. And you're right, the SXV is a sexy frame and swingarm to use. If you're going that route why not step up and make a custom frame out of any frame? Maybe use a single sided swingarm like the black dream? A guy on here made a cr500 with a single sided swingarm, which is sexy. I'll try to find it for you. (not saying what you should or shouldn't do, just giving a possible idea).

edit: found the single sides cr500.
http://supermotojunkie.com/showthread.php?t=70549
 

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Discussion Starter #7
:clap: :thumbup:
Makes sense, i can't wait to see the result. And you're right, the SXV is a sexy frame and swingarm to use. If you're going that route why not step up and make a custom frame out of any frame? Maybe use a single sided swingarm like the black dream? A guy on here made a cr500 with a single sided swingarm, which is sexy. I'll try to find it for you. (not saying what you should or shouldn't do, just giving a possible idea).

edit: found the single sides cr500.
http://supermotojunkie.com/showthread.php?t=70549
A one-off custom frame would be very cool, but there is no way it would perform as well as a factory frame, unless it was seriously overbuilt and HEAVY. One of my biggest fears is that I'll spend a lot of money on the build - and then the bike won't perform well. I think keeping the factory frame and suspension will pay off in the long run. I'll still be doing a lot of custom work, so it won't look like any other SXRZ. :D

I'm currently working on another 2-stroke build, and I could throw up a couple of pics, if you guys want to see some of my work. Not a motard, though.


{Not putting down anyone's project!! Just stating my reasons for choosing a different path:}

I thought about using a CR500 engine, as well. It's got good displacement, good power, and is relatively lightweight. The problem is, I've talked to several guys that have actually done it, and every person said the same thing- "Too much vibration for a street bike! So much that you won't want to ride the bike very long."

I also love the look of single-sided swingarms. What I don't love is that they are heavier than conventional swingarms and don't perform as well. I do have an NS400R that will be getting a custom SSS, but that bike will be more show than go (mostly because engine parts are almost impossible to get).
 

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my pants are happy :)
good thing about using the RZ engine instead of the banshee is the oil pump
no pre mixing :D
man ur living my dream :)
 

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Discussion Starter #9
my pants are happy :)
good thing about using the RZ engine instead of the banshee is the oil pump
no pre mixing :D
man ur living my dream :)
Actually, I prefer to premix. Most likely this motard will premix, too. Not sure, though.

Here's the clutch side casing from my other project bike. Notice there's no oil pump. It's an RZ engine, but this side casing is for a Banshee. I might do a custom dry clutch (on the other bike), and the casing will probably be polished, not blue. Designed my own featherweight oil cap, too. :)





 

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Discussion Starter #13
im sure you have already noticed that in a sxv/rxv frame....the motor is a stressed member of the frame...how do you plan to compensate?
By installing a brace that will go from the inside of one engine mount - over the intakes - to the inside of the other engine mount. The brace can either bolt onto whatever is left of the mounts after I cut them down, or welded to the aluminum frame itself.

I talked to a great fabricator about welding the cast aluminum frame. He has a lot of experience doing it and says that motorcycle castings in general, weld very well and that these frame pieces should be no problem.

There will also be drop-down brackets from the steel part of the frame to the front engine mounts on the RZ engine. I thought it might be cool to triangulate the brackets to the outside of the front mounts on the Aprilia frame. The brackets would probably be perfect for mounting a radiator, which could also brace the engine mounting brackets in the middle.

I know, I suck at photoshop! After I drew these brackets, I realized it might be better to use straight lines like the frame and swingarm.

 

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Discussion Starter #15
Best of all it will probably street legal because the frame tells if it is an offroad or on road bike, maybe im wrong.
Actually, it's the engine that tells if it's an offroad bike or on road bike. If I have a legal engine, I can put any frame on it, but If I have a legal frame - the engine still has to meet the EPA standards (for California).

The SRX engine wouldn't be street legal in California, But the '09RXV engine might be legal - not sure. The RZ350 engine that I'm using is from a bike that's not California legal, but I got it registered a few years ago when the regulations weren't so tight. So, the engine (and the entire bike it's on now) is registered and plated. :) Originally,I imported the bike from Canada.

The bike is definitely going to be street legal. It will still have the same RZ350 licence plate and engine but with a different frame. The Aprilia frame I bought is fully titled, as well.
 

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Discussion Starter #16
Made a profile template of the RZ engine, grabbed my measuring tools and drove to the Aprilia dealer almost every day for a week. I calculated that it's going to be a bitch to transplant the RZ engine into the SXV frame. :headscrat





Someone that read about my project sent me this pic and said he thinks the RZ frame is the better way to go. If I had access to an SXV frame with no engine and an RZ engine, I might have chose not to do it! :lol:

 

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Discussion Starter #18
I shouldn't have any issues with this bike being legal. The RZ350 is in my name, and is already registered and plated. The DMV doesn't know I'm turning the RZ into a motard. Later, I can have the bike inspected with the new frame. The DMV and CHP don't care if you change the frame, as long as you legally purchase the frame and have a title for it, which I will. It's the engine that the DMV and CHP don't want modified.

Another thing I could do is chop the head tube off the RZ frame (the VIN is on the head tube), modify it, and transplant it onto the Aprilia frame. Then, It's really a modified RZ350 frame - even though the head tube is the only piece that's original. The VIN number remains unmodified and matches the engine VIN. I could also weld over the numbers on the Aprilia frame and stamp the RZ VIN into the Aprilia head tube - and just say that I transplanted the RZ head tube onto the frame - but that wouldn't be kosher. ;)
 
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