Hh250 motor swap, 440 liquifire sled engine, questions
 

Hey guys,

Ok so I've upgraded my hh250 and still not getting the performance I would like out of it! Big bore 300cc kit, ported and polished head, dr pulley hit clutch and variator, digital adjustable CDI, and a new gear set ( prior owner trashed the low gear) and its got great torque, but only hitting about 35-38mph.

So...

My buddie has a 77 John Derre 440 liquifire sled that hasn't been fired up in 20 years barn kept that I was planning to use as a motor swap. But I don't want to lose the reverse with the buggy. I've been browsing around the forums the last few days and not finding what I'm looking for.

What do you guys think about cutting the motor off the gear box of the cf250 and attaching the 440 to the gear box? Do you think it would be able to handle the tourqe of the 440? I know it would be much easier to connect the jackshaft of the sled by chain to the buggys jackshaft, but then I lose reverse.

I was thinking of running a sprocket off the cf250 gearbox with chain to a jackshaft to hit the sled motor, I would be using the sleds clutch and driven clutch to a jackshaft, the said jackshaft to the clutch location on the cf250 gearbox.

I've read a lot on guys using gearboxes from atv's for the f/r , but not sure what type of gear boxes to look for in that instance.

Any thoughts or help would be appreciated!!!

Thanks guys
Dan

Or do you think I could use a gearbox like this and sell my cf250 motor gearbox combo?

https://www.ebay.com/itm/POLARIS-SCR...dYPh5Z&vxp=mtr

Thanks again guys
Dan

Thats the route id go as theres no point in cutting the cfmoto up since the sled cvt is different....Does it have a cvt? Mostly polaris atvs have the separate gearbox. In fact i have a polaris F/N/R box id trade you for your 250 as i have no use for it since ive decided its to big for the space i have in my 400cc swap. Pm me if interested. I dont understand why you was toping out in the 30's as my HammerHead 250ss would run in the 40s and over 50 with only 120 psi compression after i cut it inhalf and put the complete rear of the HH250 on a crossfire 150 frame. See my build thread for more on that.

Hello king,

I appreciate the offer! I had a lot of troubles getting top end speed out of the buggy hence why I was doing so many upgrades, the last thing I did, I thought for sure would fix it (rear jackshaft bearing was pretty much siezed up) but even new bearings didn't help. I've looked up Polaris gear boxes on eBay they go from $200-300 used, I've dumped over 1k into upgrades I'd be losing a lot in a swap!

The sled dose have CVT on it just no reverse, where me and my buddy ride ( his farm 600acres) there are trails and tight spots where I would like reverse.

Just getting some opinions, I don't really want to chop the cf250 but was thinking about it if I couldn't find any other reasonable, cost efficient options

Dan

Wow that is alot you got in that lol but yes you definitely want reverse.....I almost refuse to drive one without reverse nowa days. How is the sled motor set up on the output side? How much hp doe it have? Im goin to use a 150cc external reverse box on my 400cc swap as soon as i get the shaft made....I have pics of the shaft im wanting to have made in my build thread.

Well I got the whole John Deere liquifire sled, right off the motor is the clutch belt drive to the driven pulley, I haven't pulled things apart yet, but behind the driven pulley looks like a 2' shaft with a brake disk attached then I lose sight down below the sled from there. It's a 440cc liquid cooled two stroke.

Do you think that 150cc gearbox you have will put up the tourqe of the 400cc motor that your using?

Ive seen it used with the same motor before so i think it will. These 150 reverse boxes are whats called a planetary gearset so they should be pretty stout. I may be intrested in getting the track off the sled from you. Me and a buddy are wanting to try and build a set of matt tracks from scratch and i think sled tracks would be the place to start.

That seems high for the Polaris gearbox. I got one locally for $50 from a guy that parts bikes out. He said there wasn't much demand for the 2wd ones and has scrapped them for pennies in the past to clear out his storage.

See if you can find a local atv riders club. Most of those guys have old bikes they just about give parts away to get rid of them. I just picked up 4 new tires on rims that fit my buggy for $25. They were take offs to install bigger mud tires and custom rims.