Not for sure this is in the right place but I'm sure I will be told if it isn't. This is a thread started because I could not find any Information on the web showing what I am going to do. This is a 90 something Polaris sportsman 4x4 300cc or so that the engine was blown on. The trans and running gear seems to be fine so I looked for an engine to make this thing go. What I found is a honda cb1 400cc inline 4 cylinder. This engine is capable of about 14,500 rpms has a six speed tranny and was a fun little bike till it was wrecked. Sad that the bike got wrecked but I got an engine for the 4x4 anyway so it all works out. Here is what I have got so far: Streched the bottom of the frame 12" to fit the engine in and a couple engine mounts welded in. Not bad for an afternoons worth of work. Lots more to be done though. What I want is for it to look as close to normal as possible and the 4 wheel drive will still be usable. This quad is all time 4 wheel drive with hi/lo/reverse plus now 6 speed tranny. I want it to be able to crawl in 1st and low. and cruise way to fast in 6th and hi. In hi I plan on never probably taking it out of 3rd or maybe 4th. The atv originally had a cvt set up. This is a great design but It doesnt easily work with what I am doing so I have a plan to put a sprocket on the transmission shaft and driving it via chain just like the motorcycle did only instead of powering the rear wheel of the motorcycle it will power the atv's tranmission.
Today I finished getting the engine mounts welded in and finished welding the top frame back together. Installed clutch lever and thumb throttle(which may be changed to twist throttle ie: motorcycle style).
Looks pretty cool with that honda motor in there. How do you think the frame will hold after being extended 12 inches? Good luck with it, want to see what it looks like when its done.
I used 3/4 inch solid steel for the inserts on the frame then 1" squre thick wall to extend the frame the engine is also a stressed meber type so the engine actually becomes part of the frame. I think it will hold up nice. I don't know how it will do on log crossing though with an extra foot between the wheels.
Well I got the wiring sorted on saturday. The thing started right up. I need to work on the carbs because 1 is pouring out gas but all in all it is working to be a pretty easy build. I got the shifter mounted and it works like it is supporsed to hi lo and reverse. welded up the exhaust. and got the front 4x4 hubs wired so that it can be locked into 4 wheel drive at anytime. Mainly all that is left is the cooling system chains and sprockets and stretching the body and paint. I am thinking black bedliner.
Got some more done but things are slowing down. I have to get 2 520 idler sprockets 1 for a tensioner and 1 for the front chain to clear the engine. I need to get one more sprocket for the transmission I just have to figure out how many teeth. I have started on the body. I have the lock in hubs working a key switch and a push button start. I hooked up the shifting mechanism to the motorcycle trans the other day. Mainly all I have left are the sprockets, body work front brakes and a fuel tank. I already have the cooling system plumbed and filled and cooling fan works perfect. Not much left just gotta bite the bullet and atually spend something on it. chassis will be done with at most $100 more dollars. All in all I dont have hardly anything in this build and I hope it impresses me. If not I'm sure someone will want it.
Finished my first trial of sprocket ratio. on my new hub that my friend down the road machined for me. It worked but way to slow...back to the drawing board....
The project is still on going I just havent had much time. I picked up a little vw beetle started on it, now I picked up a gs1100 powered sand dragster atv with full aluminum frame. Soon as i get it going I'm going to try to get back to the polaris/honda.
This is pretty cool. Pretty interested cause I got a sportsman 400 2 stroke and I have little interest in rebuilding the motor so down the road it may be a possibility. What kind of welder are you using? I always wonder when I see engine swaps because I assume a mig would work best and that a stick welder (arc) would have problems with burn through. I am a competent welder but definitely no expert.
sportsman 4X4 motorcycle engine swap
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