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Hi all,

I have embarked on a project that I think will be a match made in heaven. I have done quite a bit of armchair research and believe that a 87-'09 500cc Ninja/EX 500/GPZ500 engine would be almost the ideal candidate for the Mojo chassis. Now before all the naysayers chime in let me be the first to say that this project will not be for the faint of heart and nor will the result. I am a skilled CNC machinist/welder/fabricator/engine builder so as far as making it happen that is covered. I know that weight will invariably increase and I also don't want to lose reverse. However I will trade reverse for a sixth gear and electric start :) Also it would seem that these 500cc engines are basically two Mojave engines put together (they even use the same pistons, valves, springs etc...) Now here's the best part--they produce 50+hp rev to 11,500 rpm and the parts are friggin cheap compared to the gouging you get when trying to get a Mojo part. I'm fed up with my son's Mojo engine and that is what spurred this on. So I will document, and share as I go if there's interest. I do and will need some help along the way I'm sure. In fact I could use some help locating a complete '90 and up 500 Ninja parts bike for relatively cheap. Also does anyone know the overall height of these powerplants. Will be posting pics soon. Any thoughts? Bring on the comments good or bad. J.Rob
 

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Do you still have the Mojo Motor? I am in need of some small parts from one. If you have it and want to sell some of it let me know please. Thanks Pm me
 

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It's been done before, but I don't know much about what's involved with the swap. I'm sure if you search here and other sites, you can at least find some pictures.

Keep us posted, I have a soft spot in my heart for street bike powered quads. It's one of the things on my mile long wish list. If I get about $1 million saved, that will cover about half of what I want.
 

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Discussion Starter · #4 · (Edited)
It hadn't occured to me before but I guess I could sell the Mojo's 250 off. I was actually in the process of seriously doing it up (ported cyl head, Wiseco piston, larger stainless header pipe etc...) In fact I purchased a second cylinder head which I have had on and off the flowbench numerous times. I could use a set of cam caps so I could finish that head, it will also have +1mm KibbleWhite intake valves. These little heads can really flow some air+ I picked up over 20 cfm which I figure should be worth almost 6 hp and maybe 1000 more useable RPM. I also bought a second cylinder jug which is powdercoated black and is +1mm O.S. with a new Wiseco piston. The intent was to yank the stock engine, mount it to my Superflow 902 dyno and baseline it. Then swap out the cylinder head and piston, head pipe and re-test to see what it worth. However the cylinder head I purchased off of E-bag was sold to me without cam caps which renders the head useless until I can find some caps :mad:. So what this all means is if anyone wants to sell me some cam caps so I can finish the head I could then sell a very nicely ported cylinder head, cylinder jug with piston, as well as the whole other stock Mojo engine or just part it out as well. The prices will be very reasonable as I am one of those types that hates to see things that I've invested in just sit there. I would be happy to get what I paid for these items--just a fair buck. The stock Mojo engine actually ran really really well until the intake valves started to eat themselves up. It still runs but is not as powerful as it once was and is a total bitch to start. PM me or just post if you have cam caps or just want more info. You can see some more here see engine building www.skmfx.com J.Rob
 

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Pm sent on some Mojo Motor Parts. Let me know what you want for them. Thanks :tup:
 

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A buddy of mine did this and was a strong runner and based it off the Mojave 500 dirtwheels had back in I believe was 2000. Pretty much it was fab up new mounts and modify the gastank (we used a heat gun after the tank had all gas vapors out of it) and custom make an exhaust and we used an aftermarket radiator. If you send me your email I ill see if I can find the article and send it to you.
 

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i too want to try that i just recently aquired 2 mojaves neither runnin but i think i can take the 2 motors and make one one frame is green and the other is grey i thought about either a 250 or a 500 ninja motor to go on it with true duel exhaust and a 1into2 carb
 

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:)i did the ex250 swap and it is wicked fast!!!! and 450 just cant keep up and it looks stock:D

Is it nice and tourqey i know the 250's have about 45 or so hp and i was just wondering how it was in the woods and that would be badass if it would outrun all the 450's lol and the 250 will keep the weight down v/s's the 500 and you would still have almost 100mph top speed to.


Nikkih
 

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The streetbike motors have taller gearing so dont expect brutal boost out the hole unless you have say 12/50 t sprocket combos.The 500 would be the better bet,a 250 twin will be all top end.I think they were rated for 28hp or so,seen in mags a while back.
 

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The streetbike motors have taller gearing so dont expect brutal boost out the hole unless you have say 12/50 t sprocket combos.The 500 would be the better bet,a 250 twin will be all top end.I think they were rated for 28hp or so,seen in mags a while back.

All the research ive did says the 250's have from 40-bout 50 and the 500's have bout 60
 

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I have recently completed an EX250 swap. Runs well and will keep up with my buddies kfx700. The only trouble Ive run into is the gearing. I'm using the stock ninja front sprocket (15tooth) with the Mojave rear sprocket (43 tooth). Needs some more gear. No torque out of the hole and never shift out of third. Anybody have any thoughts on gearing? I will post up some pics when I get a chance.
 

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Smaller front sprocket and bigger rear sprocket. Trial and error til it feels right. If you feel that it's way WAY off, take a big swing at it and try 12/45
 

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i hate to tell u but i tried all diff. sprocket and u will just spin im now running the stock ninja front sprocket and a 33 on the back and its a sand runner
 

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500 mojave engine swap

Hi all,

I have embarked on a project that I think will be a match made in heaven. I have done quite a bit of armchair research and believe that a 87-'09 500cc Ninja/EX 500/GPZ500 engine would be almost the ideal candidate for the Mojo chassis. Now before all the naysayers chime in let me be the first to say that this project will not be for the faint of heart and nor will the result. I am a skilled CNC machinist/welder/fabricator/engine builder so as far as making it happen that is covered. I know that weight will invariably increase and I also don't want to lose reverse. However I will trade reverse for a sixth gear and electric start :) Also it would seem that these 500cc engines are basically two Mojave engines put together (they even use the same pistons, valves, springs etc...) Now here's the best part--they produce 50+hp rev to 11,500 rpm and the parts are friggin cheap compared to the gouging you get when trying to get a Mojo part. I'm fed up with my son's Mojo engine and that is what spurred this on. So I will document, and share as I go if there's interest. I do and will need some help along the way I'm sure. In fact I could use some help locating a complete '90 and up 500 Ninja parts bike for relatively cheap. Also does anyone know the overall height of these powerplants. Will be posting pics soon. Any thoughts? Bring on the comments good or bad. J.Rob
currently doing the same thing and it works cut away the front lower motor mount from the frame and the middle front mount that connect both sides at the bottom and goes up to the middle frame that holds the upper a arms it will look like a t when it is cut the 500 also mounts between the swing arm that's where you start from it fits and with a few washers on either side to line up the chain and sprockets that's the most important thing the bolt size is different so you will have to make bushings once you get the back bolt done then use a jack and lift the front until it has enough space for the carbs and fresh air intake and box the oil filter will be between the lower frame where it narrows to connect to the lower a arms also it is easier to remove the valve cover to put the motor in and oil pan first you must remove the skid plate and it bolting brackets flush with the frame for the oil pan to fit between the lower rails hope this helps get you started in the wright direction get er done
 
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