[1985Aspencade]

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Well, I like tinkering around with stuff, be it electronic, mechanical, or construction related, which I do for a living.

Ive had this idea in my head for a while now and it has finally started. I have an old dirtbike and was going to transplant the engine and everything into an ATV. Well thanks to craigslist I picked up an ATV the other day for the low low price of absolutly FREE. A polaris 400 4x4, the engine was blown and taken apart and then allowed to sit and rust up to the point of no repair.

I decided however to NOT put the dirtbike engine in it, instead Ive been looking at something along the lines of a CB 750 engine/gearbox. Ive acutally been dealing with a guy who has one, but ill just have to get the carbs and all the wiring elsewhere.

The only problem I have with doing it that way is Im by far no expert so I need to find out what all I need electronic wise to make this work. I know the obvious stuff like getting the wiring harness to plug everything into, getting the coils to get spark, but thats about where I get dumfounded. :?

Id like to be able to transplant everything over to the ATV, plug it all in where it goes, hook up the battery and fire her up. Now I know this isnt like a 2 day project or anything, cuz Ill have to fix up the stuff on the ATV too. Id like to be able to use some factory controls off the CB as well, maybee just mount them on the bars if the wiring will reach.

Hope to get pics too if this rain will let up. Oh and sorry bout the book I just wrote but I just wanted to share. :waving:

 

[OnaWingAndaPrayer]

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sounds to me a like an interesting project . May it go smoothly for you .

 

[Guest]

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Yea i hope it all works out.
Keep us informed on how ita going.
Good luck

 

[wayler]

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A lot of ifs in that project. But good luck, sounds interesting.

 

[CaptainMidnight85]

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A buddy had a XS650 engine in one years ago. It was a Suzuki Quad-Runner if I remember correctly. Sprocket alignment would be my primary concern.[flash=425,344]http://www.youtube.com/v/n_SUJlYXb9Y&feature=related&hl=en&fs=1[/flash]

 

[cldryder]

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heres a few suggestions from someone thats done a few "projects":

A I-4 750 is a large and relatively heavy engine for a 4X4. you might be a lot happier with a 750 (or smaller) twin or a 2 stroke snowmobile engine. many many things will be easier with a smaller engine. 2 cyl exhaust also much easier. air cooled also much easier.

if you use too heavy of an engine you won't like the poor performance from the overloaded suspension.

A carbed engine with points or CDI is relatively self contained electrically vs. more current bikes. a hot wire to the coils and simple rectifier/voltage regulator for the alternator output and you're good to go.

+1 on the comment re sprocket alignment. the smaller the engine the easier this will be to do.

re: buying an engine with no carbs; obviously you can't hear it run. At least do a compression check. engines that sit with no carbs tend to have rusted rings.

suggest you shop around for a running rat bike (they can often be had for $100- $200. you'll know then engine runs and you'll get a lot of parts that could be useful to boot.

a 400cc or larger 2 stroke snowmobile engine will be light, small, and simple particualrly if you buy an old enough one that its air cooled.

 

[gronk99]

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a CB750 should'nt have anything in way of electronics.
But way heavier + torquier = seems like overdriving suspension and rear axle.

That said - heavier springs, reinforcing on the axle housing, gentle on clutch = might live quite a while.

 

[PAF1047]

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i was thinking about doing that with a snowmobile then you even have a good chance to even to get reverse

 

[CaptainMidnight85]

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PAF1047 wrote:

i was thinking about doing that with a snowmobile then you even have a good chance to even to get reverse

How is that?

 

[Wingle]

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I think the 750 would be overkill, Sure you would have lots of challenges fitting the bigger engine in the frame and modifying the exhaust, sprockets and gearing, but it wouldn't be much good for anything really. Too much grunt and spinning wheels is no good in the rough. It would also make it a bit too heavy to shift. I had a motocrosser on the road, it was useless. First and second were gone zip zip and into third and forth. It would be similar with the 750 first few gears would be useless and you would have to clutch it after that!

 

[dirt devil]

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I know a guy that has a Busa engine in a banshee, and NOS. He sand drags it.



Way to damn fast for my old butt.

 

[1985Aspencade]

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how about a Honda Magna v45. Local small time car lot has one for sale. It looks a little bit rough cosmetically. Ive only looked at it though, havent been able to talk to anyone about it or start/test it or anyting.

Ive had the thought of just parting out the polaris and using the money to rebuild my other atv and just drop the streetbike/atv hybrid at the moment. Id like to build a rat rod type cycle too and Im thinking that magna would be a good candidate since it needs work anyways and I need to find a winter project for sure..... decisions decisions........:baffled:

 

[Wingnumberone]

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As a previous SOHC CB750 pilot - I feel comfortable saying that any project involving one of these engines is worthwhile. You did listen to the video, didn't you ?



Those drag pipes sound exquisite on a blippy,little, tire-frying freak like that. They will absolutely split your skull within a few hours at highway speed - FYI



As long as you won't be doing an awful lot of jumping - the extra weight won't hurt much. Great engine.

 

[1985Aspencade]

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I wont be jumping it at all probobly. If so very rarely. I have another ATV that I use to trail ride, jump, play in the mud and all that. This is just a project to mess around with and ride from time to time.

This project may be pushed back though, I had a guy offer me some $$$ for the atv donor frame I got and since I got it for free Im thinking of taking the cash and put it into a bike fund. I might be picking up a 70s or 80s Honda to fix up and ride next season.