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Big bore kit

3K views 18 replies 6 participants last post by  flash 
#1 ·
Is there a big bore kit available for the 450. I've got this idea of putting a little turbo (IHI RHB32) on the bike (to thoroughly scare some sports bikes) but I need a few more cubes to do it. I thought of putting the 510 crank in but if I can get a big bore kit that might just give me enough with less expense.
Flash man
:2hard
 
#3 ·
turbo ?!?! i was goingto recoment the 510 setup since there is only a little ole Thumper can do.. You can just go all out I guess as in port work, up the comp on the chambers rather than the turbo.. I don't know but it sounds like a granade to me.. I my self might go the 510 way in the future.. with only 32 miles on the motor :D I'm a long ways bro...
 
#4 ·
I know I'll have to de-compress and change ignition curve, probebly inject it as well as put stainless valves in and maybe change the cam timing to get less overlap in the cams or change cams fullstop. and I know it will cost bucks 5 to 6k but I love motards and I hate being beaten by road bikes anywhere!!! :bringiton
BTW My 450 has done 5000km's and I'm doing the work when it's in need of a rebuild. so it's still a ways off yet but I'm accumulating the bits as we speak just so I'm ready to roll.
 
#5 ·
I've seen one one other turboed 'tard and it was for sale on ebay.

Depending on your boost, you'd probably want to run compression at around 8:1.

You want to be able to easily adjust waste-gate pressure. I don't see the need for FI—especially when carfbs are so much easier to fiddle with. You'd want to use the smallest turbo you could get your hands on and you'd want to either be proficient at welding yourself or know how to run a cad program (then you could post cad drawings on the web and take bids on the manufactured bits you'd need to have made).

You wouldn't need much for an intercooler because 'tards are not high rpm engines but you'd still want your intake charge to be less than 180°F.
 
#6 ·
I used to make turbo manifolds for cars! I can mig tig and hardface weld!(even titanium)
I would like to get a form of intercooling (maybe as simple as water injection) just for longevity. I will try the carb option first just for ease, but I'm not delusional about it. If I use the slightly larger turbo I will be able to leave the compression up a little higher as long as I decide keep the boost down to a moderate level around the 6 to 10 psi this is a broad range I know but it will require a little testing since no one seems to have any ideas about a small single cylinder engine.
I was hoping to hide the turbo a little but in playing with the set up a bit I think it's going to be obvious to look at :headscrat
 
#7 ·
I hear you on the larger turbo thing but I'm thinking that too large a turbo would spin up too late. I'm thinking about Honda's ill-fate 650 turbo that spun up in the last 1,000 rpm and was useless.

I'm thinking you'd mount the turbo on the side of the engine and then plumb it into your carb but the turbo XR I saw had the turbo mounted right belind the carb. The XR didn't have a provision for cooling the intake charge though but it did use a carb and the owner boasted 100hp.
 
#8 ·
I'll sort the sizing out so that the turbo comes in in the later half of the revs definatly not the last 1000!! :thumbup:
100hp was going to be my target as well but I'm not going to risk reliability of the motor if I can't get there. I don't want to increase the engine speed at all in fact it would be nice if I can reduce where peak power is. :headscrat
With the carby I have heard that on boost it can suck the throttle slide and cause it to jam creating very notchy movement.
There was a guy here in OZ that I have been trying to find who had this happen to his KTM525exc. I don't know whether he ever got around this or not. He said that when he goes round the outside of the R1s etc going on to the straight at Phillip Island I'ts hard to control the throttle, it's so notchy that you can't be smooth and I end up smoking the rear tyre!!! :bowdown:
Ever since hearing that I knew that I had to have a wistle on the smar.
 
#11 ·
Flash

Not sure if you have a KTM but

If you do you could consider doing the 540 kit
which is barrel and piston without change of crank or Rod.

that will give you more Cubes

but nowhere near 100hp

i am considering doing either 525 or 540 kit on my KTM 450 EXC (03)
 
#12 ·
Hi John
I've got a husky 450. I'd love to be able to get a kit to increase the capacity. Then I could put an even bigger turbo on!! :lol:
I've been thinking about a 510 crank but I've been told that it would be at least a 2k Au exercise to do that alone (parts?) That would go along way to my turbo set up. I'm still looking at the idea but at that cost I don't gain enough. I'm now trying to find out how much thickness there is in the barrel so I can just get a piston made then bore and replate it.
I don't know whether this is an option yet.
Flash
 
#17 ·
The 450's are pretty hot from the factory but you can still do the usual exhaust, cams, jetting, headwork and increase the capacity. These will give you an improvment at a fair cost. Now if you spend a little more with a turbo, you get a lot more.
The other plus is a hot natural motor is not going to be as reliable as a mild turbo motor just take the Jap performance cars for example. A mild turbo motor will still out perform a hot natural motor and is usually easier to use as well.
 
#18 ·
Hi Flash,

Interesting project, my normal way is go nos, but this time i will be building up a t'bo something, maybe a te610, 525exc, 640lc4, 650burg, xr650, not sure yet, looking for someone with the "right" bike that will trade in my soon to be "stock" ZX12R. Check out the current edition of "Rapid" mag and you will see what I mean.

Cubes are good but not the be-end all, my mates at www.sandrpro.com do a 250cc road bike and got it to rip!
Neverless, I prefer to go into turbo land with as many cubes as I can get.
Water cooling is a good option, a small tank = small fuel range on bike, or maybe no cooling is required considering low boost levels, only so much hp can be delivered through the frame before the bike goes ass over tit anyway.
Maybe use nos to cool the charge?

The great thing about doing this on a single cylinder is there is only 1 cylinder to blow, how good is that!!

Some more pics.....

NOS Rob
ps, where abouts in oz are you?
 
#19 ·
I'd go the te610, or the LC4. Water cooled turbos don't run as hot and don't heat up to much when you turn them off. I'm trying to find an efficient but small intercooler otherwise water injection may have to do. (keep the inlet charge COOL = less engine wear) I'd like NOS but not the weight, I want to keep the weight down as much as possible. It does see the track and a little dirt too. My next lot of investigations is to find out how to put an oil cooler on it!!
I'm in sunny Melbourne
Like those photo's to keep em comming!!
Ash
 
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