project KTMito

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

i might as well start the thread now then.

yes it a Mito KTM frankenbike.

so kind of sheer fortune meant that this project is a goer.

on ebay the other day i saw a KTM LC4 640 engine and though, yeah that looks good but the sprocket is on the wrong side to the Mito (which i already have) so i also found an aprilia RS125 front and rear end.

so me and chris-red went to pick it all up and had a go at bolting it together, bearing in mind i hadnt measured anything or investigated wheather or not this would work.

the RS125 swing arm fits in the Mito frame with around half inch of play. the swing arm wraps around the rear mount of the KTM engine like it was designed to fit it. Like a glove (in an ace ventura voice) and the engine also sits within the frame with small gap between what i think is possibly a water pump housing and the inside of the frame. the RS125 front end we put on just to see how it all looked.

so heres some pics adter about 2 hours work

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

the problems i will be facing are

-carb hits the top frame crossmember
-most likely a custom exhaust
-mounting the rear shock
-lots of wiring!!

main problem looks like the rear shock. the RS125 and Mito have a linkage type shock, so on the swing arm the mount isnt visable from the top so cant bolt a shock in from above and because its a frame and swing arm off different bikes, it might not be easy to recreate a linkage. i think the swing arm it too far forward to have enough space. maybe.

as for the carb, the top crossmember is welded. so i can get that redesigned and moved and at the same time possibly redesign the rear shock mounting. not sure if i can move the carb around and change the intake track as it will have to have bends in it which i dont want really.

from the pictures it looks like the frame is too high in the middle. not sure how much it can drop as the left hanger mount touches when its lowered. so either cut it off and mount the hanger elsewhere or leave it high. but that means higher centre of gravity.

as for looks, im thinking of a naked style, black and gold possibly. might even go for renthal bar but we'll see.

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

I don;t thing the exhaust or wiring will be a problem you have the full KTM loom, and the exhaust isn't far of fitting stock.

The rear shock will be the biggest problem followed by mounting the carb.
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Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

your the problem Chris Middle Finger

hmmmnz · Super Spammer Joined: 22 Aug 2006 Karma :

thats pretty damn good,
i wouldnt even call those problems,
just tiny little hick ups,

karma for both you 2 bitches Thumbs Up

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Frost · World Chat Champion Joined: 26 May 2004 Karma :

Maybe moving the engine forwards will get you some carb space?

https://cdn.bikechatforums.com/files/img_0447__small_.jpg

Even Seth Rogen is impressed.

mad4it028 · World Chat Champion Joined: 04 Jul 2006 Karma :

can you not slant the engine forward enough to make room for the carb?
which will also lower the center of gravety or does the engine have to sit bolt upright?
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steven_191 · Nearly there... Joined: 31 May 2009 Karma :

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

Also I need to try to keep the engine level. For the oil level and for the carb. If it's not at the right angle I'm not sure how it will affect fueling.

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

Because of the swing arm/frame combination I'm considering a custom swing arm. I've seen a few tubular types online which look good.

Does anyone know of any good engineering or bike shops in Essex that are worth contacting?

Tim.. · World Chat Champion Joined: 11 Oct 2006 Karma :

Is putting the Aprilia wheel etc into the Mito swingarm not an option?
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KDub · Renault 5 Driver Joined: 04 Sep 2010 Karma :

Why would you want to lower the centre of gravity? It's better to leave it high.

Get ready for some propper engineering maths, taken from the book on Motorcycle Design and Technology:

(I'm going to use emoticons instead of real symbols though)

"There is only one precise angle of inclination that allows you to maintain your balance at any particular speed when cornering."

tan Very Happy

= v^2 / (R^2 x g)

Where Very Happy

is the lean angle, v is the velocity, R is the radius of the corner, and g is gravity (taken to be 9.81m/s^2, just use 9.81).

Of course in that equation there's no mention of the height of the centre of gravity, but you'll need the resullt of that equation for this one:

sin(

) = (t x sin Very Happy

) / h - t

Where

is a substitute for the symbol delta which means "the change in", t is the radius of the tyre (so a 160 size tyre has a radius of 80mm or 0.08m, there are further refinements to this, but I haven't learnt them yet), h is the height of the centre of gravity, and Very Happy

is the result of the first equation.

Once you've got both answers just add them together and you'll find out the lean angle required for any given corner radius at any given speed.

You'll need to use SI units throughout, as in metres and metres per second.

So anyway the point of all this is that a bigger value for the height of the centre of gravity results in a smaller change in lean angle, which means you can go faster around corners.

It also proves that skinny tyres are the way forwards, anyone "upgrading" to a 180 section tyre from anything smaller is just kidding themselves. Especially on small bikes. The only time you need a wider tyre is when you're prepared to sacrifice mid corner speed for traction on acceleration.

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

KDub,,,

That's excellent. I'm not going to try and move the centre of gravity at all. The engine is going where it fits and where it's straight and square. One question I had was about tires actually. I was wondering what it is that goes into the choice? I think the mito has a 110/60 or 120/60 or something.

So in short and without too much maths with faces instead of symbols, what's your advice on the setup? And when u say inclination, are you talking about the angle of the bike and it's other angles etc. If you look at my picture it looks like the swing arm pivot is too high but because of the shape of the frame if the 'suspension' (bit of wood) compressed the high point touches the frame. So I need to drop the front down of not have much suspension travel or have a high bike???

KDub · Renault 5 Driver Joined: 04 Sep 2010 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

I was going to tell you I planned to put my maths a-level to use and work out the geometry of the standard Mito then we could try to keep the same/similar geometries.

Also surely lower CoG is better on a bike?

Someone should move this to S&T too.

JMC and Metchamex do swingarms, it won't be cheap mind.
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

KDub · Renault 5 Driver Joined: 04 Sep 2010 Karma :

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

The RS swingarm was definately shorter, I'm pretty sure it was by 50 something mm. I vote we just cut bits off till it fits. Laughing

Have you got your helicoil kit yet?
____________________
Well, you know what they say. If you want to save the world, you have to push a few old ladies down the stairs.
Skudd:- Perhaps she just thinks you are a window licker and is being nice just in case she becomes another Jill Dando.
WANTED:- Fujinon (Fuji) M42 (Screw on) lenses, let me know if you have anything.

steven_191 · Nearly there... Joined: 31 May 2009 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

MaybeGuy · Super Spammer Joined: 12 Mar 2007 Karma :

i predict a fail unless you modify the frame crossbar around the carb.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!! Mr. Green

Kickstart wrote: Hi I tend to agree with Matt. All the best Keith