GTS Hammer Head gets a Ninja EX250F motor

[metalstudman1]

I bought a used HH GTS - CFMoto250 for $250.- (99% complete & not all rusted) a little expensive but figuring I could get it to function with parts I already have. Typical used Chinese buggy though: not running,rotting seats, been rolled,wiring hacked up,bald tires,dirty carb,ect... I didn't realize just the CVT cover that was missing would be nearly impossible to find-new or used. After searching for parts for months with no success I decided to just re-power it with something I already have that's water-cooled.I have '83 Honda VFR700 & '03 VF750 (both V-4's). Pulled the motor out of the HH & sold it cheap the next day. While brainstorming how to wedge one of the HUGE/HEAVY(175lbs.) Honda V-4's in it a 2005 Kawasaki Ninja EX250 bike came up for sale w/171 actual miles on it for $500. That's about what I'd need to spend on the big Honda motors to function.
I contacted him to verify the info as it only had 1 pic with the ad showing no front fairing,cracked front fender,broke turn signal, everything else looks near new only it's very dusty. My guess was -It got laid down @ slow speed & scared the first time rider. I was close- it got pawned after it was laid down for many years. Someone has tried to start it over the last 16yrs - they stripped every screw on the carb bowls & used starter fluid to start it. The last pic shows what starter fluid sprayed in the air inlet on a CV carb does to the diaphragm instead of spraying in the butterfly opening. It's not getting started on the bike now -it's new so little doubt about it running.This motor seems ideal-it has double the HP of the CFMoto250, double the torque & rev's up around 14,000rpm vs the CFMoto's 6,000rpm. This should make it a dirt/mud slinger The Kawasaki EX250's are a dime a dozen, proven reliability & get 50-70 MPG. Parts are readily available & affordable. It should push this buggy around very well without applying extreme forces over it's intended design.I haven't weighed the motor yet but it can't be much heavier than the CFMoto if any. I just have to pull the motor out of the bike to get the build underway.Pic's show what I started with. Hopefully this build will provide some info that others could use if they decide to re-power their buggy.

[metalstudman1]

Got the motor pulled from the bike & started the process of seeing what it'll take to fit in the Hammerhead. I dangled the motor in the engine compartment and started cutting obstructions out of the way-CFMoto engine mounts ,floor shifter supports,ect.... I figured I'd show my inexpensive engine hoist - $50. HF winch, boat winch base bolted to the floor with a spare battery to power it. I use this to pull buggies up my ramps into the elevated shop as I don't have the muscle to man handle them anymore by myself, it lifts motors pretty easily too.
I cut 2 of the horizontal supports from the center-behind the seat area (to be re-welded later) to ease positioning of the motor.My criteria is as low as possible for center-of gravity & dodge any maintenance items. The only thing I had to manipulate around was the sway arm and the engines oil filter/drain plug. Those 2 items dictated the front to rear position. The HH shifter arm brackets got cut off and moved/used for motor mounts on the new motor (exisiting shifter won't work on this type motor). I confirmed that the exhaust would fit & be serviceable later, that meant I need to lower one of the horizontal tubes removed earlier but shouldn't effect the structure. I work alone -as you can see I have lots of helpers- clamps, adjustable bungie cords. I used a 3/8" nylon rope thru the engine mounts to ease leveling the engine by just sliding the rope in the "S" hook/engine mounts.Engine only weighs 94 lbs. FYI- document the position of the replacement engine before removal(if it's not out already) to know how to set it in the buggy- see if the manufacturers name is level or find a surface you can level- this will ensure the floats in the carb will be correct when you're done.I did set the seats I intend on using (new take-off's from a Polaris slingshot to verify clearances from engine & exhaust- It's close ! may need a heat shield.

[metalstudman1]

I got 2 of the 3 motor mounts completed-there was actually a lot of fabrication involved with this front mount for it to be strong and clear of all the items to fit later.Better to take your time and try to think about everything assembled & access to these items when creating the mounts-Motor is supported on it's own now.(doesn't mean I won't have to pull the engine later) The first pic's show a notch I created so I can remove the front mount bolt without any special tools. The next pic is the original engine mounts I demo-ed to be re-used on the engine front supports. There are radiator tubes that run down the frame behind the seats so I flattened my round tube engine mount for their clearances. Next pic is the finished portion of the frame @ the front of the engine with the lowering of the bottom tube for exhaust clearances. I doubt these mod's changed the original design any.The pic of the level shows that the engine sprocket is plumb. Next pic is an overhead shot for you to see how it fits in the engine compartment. The last pic is of the original engine support that I'll modify to complete my 3rd motor mount tomorrow-it amazingly lets the air-cleaners fit thru the opening in the middle.It will have to be moved forward so the mounting studs need to move also.So far no waste or the need to buy anything Everything appears to be fitting well with no conflicts-time will tell!

[metalstudman1]

Didn't get much done today. I did get the re-movable motor mount modified and installed.It turned out perfect for this motor by simply stretching it and relocating the tabs & mounting studs. Now comes the brainstorming a transmission location & mounts- this should be similar to my "real" Frankenbuggy set-up I made back in 2011 (Polaris tranny/gearcase to have reverse) I'll have to convert the secondary belt drive pulley to #520/530 chain drive.I'm also contemplating just tearing a bad tranny/gearcase apart and see if I can make a reverse drive that works the same as a jackshaft unit with just 2 support bearings to save space.

[metalstudman1]

I'm checking with a machine shop about tooling my transmission parts so I can build a custom F/N/R box. There's not enough space (width between sprockets) or reasonable way to spread them out for a Polaris tranny/gearbox to fit.I have a reverse unit for a GY6 but don't trust it for the long haul. Since this motor is new, I won't be changing the engine out anytime soon so I'd rather spend a few bucks to get it durable. If I had a bigger shop I'd have already bought a lathe & done it myself.

[metalstudman1]

I got my new carb parts today, rebuilt them and I have NEW carb's again.It's progress Currently I'm having to replace my air compressors as they both failed a couple of days apart from each other. You don't realize how much they're needed till you don't have them as I'm spoiled being able to blast dirty/rusty material & parts.Hopefully I'll get that issue resolved in a day or two & back to fabricating again.

[metalstudman1]

I know this off topic-I bought an older compressor (oldies but goodies) for $400. Took me ALL day to get it off my truck & in the spot I placed it outside my shop & create a foundation to support it (by myself & some brain farts) I had no clue it was that BIG (2,000lbs +/-)
It took 5 & 1/2 mins to fill a 200+ gal. tank to 250psi -now that's a compressor I still have to spend another day plumbing & wiring it in permanently, but that should solve my air issues for awhile.

[metalstudman1]

Currently still plumbing in my air drying system on the compressor (the time spent here will pay off later). I'll get back to the fun stuff soon!

[metalstudman1]

Update: I figured I'd pull the HH in the shop since it's been setting for almost a year. I needed to come up with a reverse for this and in the last year I ended up with 3 more Polaris ATV's with gear cases suitable for this build. I needed to figure out how to get the spacing of the sprockets to work. I only had 4"+/- between the motor sprocket and the IRS sprocket. Scratched my head for several hrs & came up with a way to extend the engine sprocket out enough to fit a Polaris 250/325 tranny in the space available (needed 2-3/4" more). Could have made jack shafts but that seemed too busy back there with all the supports! This is the method I came up with-see the pic's.

For clarification purposes-The drive chain from the motor is #520 to match the Polaris type sprockets (stock Kawasaki used 520)both drive sprockets are stock Polaris. I made my shaft extension out of an old gear case shaft with the Z-22 O.D. spline.The chain guard for the Kawasaki had 2 un-used raised bosses on the interior side that I took advantage of to secure the shaft extension bearing with a fairly simple bracket. I then demo-ed a warped Polaris driven pulley for the splined shaft for the output sprocket, turned it down on the lathe to slide a left-over #530 x 15t sprocket from a Suzuki 650 motor. I aligned it with the IRS sprocket and welded it in place. Of course everything is non-destructive to the tranny & Kawasaki motor if I ever need to go back and use them for what there were designed for. The chain cover is less than $20. on Ebay to replace-shaft is custom but totally serviceable if I need to replace something.
I'm waiting on some 1/2 links to come in-I ordered them with the #530 chain I ordered & they don't fit, the Ebay supplier used a different manufacturer for the links just to satisfy my order not knowing they wouldn't work with different makers of chains. I'll continue with other stuff-pipes/muffler,CV boot servicing, wiring it and verify that my drive train works. Tons of other stuff to do but these items dictate whether to continue spending $$$

[metalstudman1]

Well I got everything associated with the motor completed! went to fire it up & NOTHING. As I tried to fire it up I notice smoke coming from the crankcase vent, it scared me because if for some reason fuel had bled into the oil I could have a BOMB!!!!When it acted like it wanted to fire up but didn't I started checking for spark,fuel & then compression. Very little compression (about 90 psi in cylinder #1 and nothing in cylinder #2.Thought maybe the rings cracked from sitting so many years. Tore it down to find out why-now I know why it never got picked up from the pawn shop. A huge hole in the piston (cylinder #2)These motors don't have a rev limiter- I bet when the person dumped it they held the throttle wide open for a while & it melted the piston and quit running-so pawn it & get whatever you can out of a new (171mi) bike. Got parts ordered to see if I can get it running again. The one motor I bought that I shouldn't had any issues with!!!! It's still a new motor.Parts are CHEAP!!!If all else fails I have a Kawasaki EN450 bike w/15,000 miles on it I can use- it has 50hp versus the EX250 w/33 - 45hp (depending on where you look) that's still double the CFMoto 250 motor that came in it (I sold it for $250) The buggy's cost is now at about $700. If it runs it'll still be a very cheap Hammerhead GTS.

[metalstudman1]

Sorry for the LONG delay. I built another buggy for a friend-Kinroad 150 with a Honda TRX200 total teardown,sandblast,paint and restore to new condition & then I broke 5 ribs w/ a collasped lung.I ended up rebuilding the top end of the Kawasaki motor with Ebay used parts (about $125.) It runs like new!!! starts right up!!. Here's a vid. of it running & the drive train working.I made sure the important stuff was working before moving forward with seats,shifter,wiring the new dash,ect... still a couple of weeks before driving it-I can't move very well/fast-still healing but still moving forward with the build.
https://youtu.be/iL3u00S633I

[metalstudman1]

I got some work done since my gearing calculations were WAY off, started with about a 3:1 ratio which is usually a good starting point for low end & speed. I've got it down to nearly 4:1 with the new sprockets coming first of the week-I hope that's low enough as I couldn't get it to move without dying out with my first set up. I channeled the rear sprocket area for a 50t+ sprocket. If you've ever changed a chain on a hammerhead 250 you can barely get the chain on with the stock 39t.Got the drivers seat in, widened the frame by 4" on just that side (all day project). Got the shifter/clutch in and re-used the stock F-N-R shifter for my Polaris tranny with a gator shifter cable. I'll get a video of it soon for reference purposes.

[metalstudman1]

Haven't been able to get on here- here's a short vid of the finished project.
https://youtu.be/AG0cfxkt014

[metalstudman1]

Here's another video
https://youtu.be/jXdPzpjfDNw

[metalstudman1]

Another video from this outing
https://youtu.be/jXdPzpjfDNw

[metalstudman1]

This build has proved to be reliable and fun to drive
https://youtu.be/vLYuoCeRkuM