Can I stick a bigger engine in my bike?

[pyrocam]

Alot of people ask me if its a 400 or a 600, now that its time to upgrade and I have mint fairings. why not put a bigger engine in instead of selling it? or get something like this

http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Parts-accessories/Engine-drive-train/auction-89440002.htm

and put my stuff on.

any reason why not?
Would I be best to put a 600 in my chassis or put my tank and fairings on a 600?

Cheers in advance

[bugjuice]

a 600 wouldn't fit in the 250 frame without heavy mods. The 400 might slide in a treat tho.. with a bit of persuasion. I wouldn't buy a heap like that and put your good stuff on it, be a waste..

[Deviant Esq]

Mint bike mate, too tidy to go butchering it up by trying to biff a larger motor in it. Hell, if you were to sell that, being probably the most popular 4 stroke 250, you'd probably sell it for more privately than a dealer would ask for a CBR400RR. Just not worth butchering. Keep or sell.

My $0.02

[avgas]

what deviant said. sell the 250 for $4K then buy a 400/600 for 2K

[Colapop]

If you wanna spend the money on it go for it. It may cost a few more bucks than you thought but that's entirely up to you. It's not like people haven't built their own bikes before.... OCC, Billy Lane all started somewhere. It just depends on whether you want to spend money on it.

[vifferman]

I had a CB250RS with an XR500 engine in it. Didn't do it myself - inherited it like that. Good for wheelies.

[Cibby]

pyro, you could get like a ridculous price for your 250, like $6,000 - $7,000 or more if you found the right idiot,,

that woudl be more than enough to upgrade quite nicely and then you dont have to fark around trying to sort your bikes out and become bikeless for a while.

Good luc :)

[idleidolidyll]

The thing is, a really tidy 250 is probably worth more than a similar 400 or even a 600 sometimes.
The learner licence thing is the driver of that situation.

Before doing a motor swap then (which would mean re VIN ing the bike or riding illegally), I'd have a bit of a scout around and figure out how much you could sell your bike for and how much a bigger bike is gonna cost: you might be surprised.

The cost of swapping motors might be about $1000 to $1500, consider the trade up option first but if you still want to do it, get the advice of someone who has done it before first.

[idleidolidyll]

I had a CB250RS with an XR500 engine in it. Didn't do it myself - inherited it like that. Good for wheelies.

that's a great concept and one done by lots of bikers.

A really good handling 250 rolling chassis with a 500-650cc 4 stroke single motor is a very cool thing.

[James Deuce]

It's a $5000 bike as it stands now. If you've got $20k minimum, go for it as Col says.

CB250RS with XR500 in it is cheating. It bolts straight in, after a couple of bashes with a hammer.

I doubt that a CBR400 engine would fit, and the CBR400 chassis parts are better than the CBR250's anyway.

[imdying]

A friend built a nice CBR400 triarm with a 600 motor, worked out pretty good. The others are right though, sell it for heaps and buy something else... you'll still have sad suspension and brakes if you put a bigger motor in it.

[vifferman]

CB250RS with XT500 in it is cheating. It bolts straight in, after a couple of bashes with a hammer.



Not quite.
The lower engine case/crankcase is externally identical, so that's no problem. The engine's a lot taller, so the top motor mount has to go, and the tank needs a "cut'n'shut" job done on its underside. Also, the carb's bigger. I think mine had the wrong carb on it, as I had perpetual fuelling issues, despite several idle/main jet changes. Ideally, a compact flat-slide Mikuni, or later dual-carb model or summat to replace the Keihin would've done the trick.
Custom pipes are also a good idea - mine had Cycleworks dual megaphones and sounded awesome.

[James Deuce]

that's a great concept and one done by lots of bikers.

A really good handling 250 rolling chassis with a 500-650cc 4 stroke single motor is a very cool thing.

The Cagiva Mito is coming out with a 500cc single in it this year.

My kind of bike.

[James Deuce]

Not quite.
The lower engine case/crankcase is externally identical, so that's no problem. The engine's a lot taller, so the top motor mount has to go, and the tank needs a "cut'n'shut" job done on its underside. Also, the carb's bigger. I think mine had the wrong carb on it, as I had perpetual fuelling issues, despite several idle/main jet changes. Ideally, a compact flat-slide Mikuni, or later dual-carb model or summat to replace the Keihin would've done the trick.
Custom pipes are also a good idea - mine had Cycleworks dual megaphones and sounded awesome.

Yeah. Hammer and a hacksaw and some bondy then.

[idleidolidyll]

The Cagiva Mito is coming out with a 500cc single in it this year.

My kind of bike.


excellent! kinda like an updated Gilera Saturno

[terbang]

Shoehorned a GSX1100 engine into a GSX 750 a few years back. Went well.

[xwhatsit]

I had a CB250RS with an XR500 engine in it. Didn't do it myself - inherited it like that. Good for wheelies.

:drool: :drool: :drool: :drool:

And here I am throwing money at my recalcitrant 250 lump...

[Buddha#81]

:drool: :drool: :drool: :drool:

And here I am throwing money at my recalcitrant 250 lump...

try and find a good 500cc motor though.

[xwhatsit]

try and find a good 500cc motor though.

Yeah, and as you said, the chassis isn't really designed for that much grunt.

Which is actually relevant to the thread -- is the bike going to still handle and be as beautifully balanced with a bigger lump it wasn't designed for?