GSF250 Bandit Mods

[Danboy]

It's a "Cycleworks" I think. No idea about model. Send him a PM. If yours is a 98 model then it's a newer model than Wasps or my other halfs. Nice looking bike

Cool. I'll PM him now. Taa.

[FROSTY:Me]

dude 150s are easier to get than you think--a lot of motards are running 150's for racing.
DO NOT overtire it--it will feel terrible.
Personally what I would do is rip out all the EC gear get a freeer muffler and then get the bike jetted and tuned -run it up on a dyno.
Maybee you might wanna change cam timing a smidgen to suit performance instead of Emission laws
Im not talking major stuff-should all cost less than 500
Suspension wise Id start with a simple old fashioned service then get someone like Shaun Harris to set it up for you.That might be all you need

[Danboy]

dude 150s are easier to get than you think--a lot of motards are running 150's for racing.
DO NOT overtire it--it will feel terrible.
Personally what I would do is rip out all the EC gear get a freeer muffler and then get the bike jetted and tuned -run it up on a dyno.
Maybee you might wanna change cam timing a smidgen to suit performance instead of Emission laws
Im not talking major stuff-should all cost less than 500
Suspension wise Id start with a simple old fashioned service then get someone like Shaun Harris to set it up for you.That might be all you need

Cool, that sounds like the plan then. EC gear, Muffler, jetted and tuned on a dyno. Sweet.
Found some tyres...like the look and reviews for the new Avon Storm-ST's. AV55-17-110/70 front $220 - AV56-17-150/70 Rear $276

[FROSTY:Me]

Save yaself a shitloada greif--give Shaun a yeodle---he can sort that stuff for ya and the long term cost will be lower

[Danboy]

Save yaself a shitloada greif--give Shaun a yeodle---he can sort that stuff for ya and the long term cost will be lower

And Shaun is?....

[FROSTY:Me]

go to members list--type in shaun --see what happens
er un Shaun -um some fulla Shaun Harris- dunno if ya heard of him--virtual unknown

[boman]

I am running a 150-60r17 Pirelli Diablo rear and a 110 70r17 front. The bike handles awesome. No problems or unprdictabilities from these at all. I was spoilt for choice in a tyre. Metzler Bridgestones Pirelli ---- depends on what i wanted. My tyre have just done 3000 kms, and are going to need replacing within the nxt 2000kms.

[Danboy]

go to members list--type in shaun --see what happens
er un Shaun -um some fulla Shaun Harris- dunno if ya heard of him--virtual unknown

Ah THAT Shaun...haha. Nah never heard of him. Yep found his profile, I'll get ahold of him and see what he can do. Is he all ok now after his crash at the Isle of Man?

[FROSTY:Me]

ask him yaself--hes getting there

[James Deuce]

Everybody will tell you the usual story -- don't bother. Too expensive, really small gains for heaps of money and potentially blowing it up. It's already making 40-odd-hp. They'll tell you to save your money and buy a bigger bike. Don't let that stop you though, I wouldn't fiddle with the motor, but I'm sure some money spent on better suspension would certainly get it moving faster, and maybe some cosmetic fun can be had.

Don't worry about engine performance. There is very little that you can do that you would notice without spending big money. He's being sarcastic, but he owns an old single that WILL respond to basic flow work. Your bike won't. All you can do in the less than $500 range will make it harder to ride.

Through the thinly veiled sarcasm is a truth though.

Spend money on Steering Head bearings and Swingarm bearings/bushes, wheel bearings, and suspension before you spend on anything else. You will make the biggest gains in outright speed and handling right there. Oversize tyres are for custom cruisers.

Paint and Brightwork are easy to fix up, but make sure you go for factory colours and decals. A fancy custom paint job will reduce the value of your bike, because most crusties like me just look at it and see a tasteless attempt to hide accident damage. Maintaining a bike's authenticity on the other hand will garner respect from old crusties like me.

Above all do NOT over-capitalise on your bike. Replacing bearings, bushes, and moving parts is maintenance. Anodising it all metallic blue is expensive frippery that you will NOT get back when you sell it. The Bandit will be worth the same as any other Bandit. It will just have blue anodised bits on it.

[Danboy]

/snip........................................

Above all do NOT over-capitalise on your bike. Replacing bearings, bushes, and moving parts is maintenance. Anodising it all metallic blue is expensive frippery that you will NOT get back when you sell it. The Bandit will be worth the same as any other Bandit. It will just have blue anodised bits on it.

Ok, that's cool. Lets just clear some things up though.
I'm not interested in changing the looks of the bike or "blinging" anything.
I've raced karts and cars throughout my life and was rebuilding 2 strokes from the age of 8 and modding them from about 13. However, small capacity 4 strokes are a new thing to me.
I like the idea of sorting the handling, because that appeals to my competition background, but I also like the idea of small engines packing big punch and bringing it to the larger guys(yes it does happen).
Anyone that says that an engine from factory is already as powerful and/or efficient as it can possibly be is simply ignorant(in the nice way, not the insulting way ). Otherwise, factories themselves wouldn't revise and improve on the same engine each model release, and people wouldn't have been modifying their own engines from the earliest of times to gain more power/get a better sound/acheive more kudos.
I'm not interested in modifying simply for the sake of modifying, nor have I mentioned anywhere that there was a budget. I simply wanted to know what was available.
But thanks for the solid advice so far anyway.

Dan.

[Danboy]

Also, nice old school Katana on your profile Jim. Always loved those. Looks like a minter too! Sweet.

[xwhatsit]

Anyone that says that an engine from factory is already as powerful and/or efficient as it can possibly be is simply ignorant(in the nice way, not the insulting way ). Otherwise, factories themselves wouldn't revise and improve on the same engine each model release, and people wouldn't have been modifying their own engines from the earliest of times to gain more power/get a better sound/acheive more kudos.

Unfortunately that's where for all practical purposes you're a bit wrong there. 250cc straight-four technology pretty much peaked with the CBR250RR back in the early 90s; 45hp, 18,000rpm. Your engine is from the same era, from the GSXR250 from late 80s/early 90s.

Stories float around about people who hotted up their CBR250s -- a far more reliable and solidly built engine than the GSXR250 lump, of which horror stories abound -- to 60, 65hp or so. Some versions of the story they had turbos and the like. In none of the stories did the engine successfully complete a Rusty Nuts Grand Challenge.

For sure, you could probably get 50 peak hp out of that engine. However it would all be right in one blurt, about 1000rpm before the red-line, and would make it an absolute dog if you ever tried stopping and starting in traffic, or in fact rode it anywhere other than a racetrack. It would also probably shit itself in a major way within the mileage of an oil change.

Those motors are really highly worked, straight from the factory.

[James Deuce]

Anyone that says that an engine from factory is already as powerful and/or efficient as it can possibly be is simply ignorant(in the nice way, not the insulting way ). Otherwise, factories themselves wouldn't revise and improve on the same engine each model release, and people wouldn't have been modifying their own engines from the earliest of times to gain more power/get a better sound/acheive more kudos.
I'm not interested in modifying simply for the sake of modifying, nor have I mentioned anywhere that there was a budget. I simply wanted to know what was available.
But thanks for the solid advice so far anyway.

Dan.

Motorcycles are quite different to cars. The manufacturers operate in a low volume market and the difference between one model being a sales success and another being looked at as second best is often a gnat's whisker on a piece of marketing bumpf.

I guarantee you will get a pleasant surprise if you ever tear that Bandit engine down. It will look like the head has been ported and polished, the included valve angle will leave you wondering how they did that, and tolerances, even after years of (ab)use will probably be miles better than anything you'd see from a car manufacturer until very recently. There are plenty of tales of motorcycle engine tuners pulling engines apart and being left very little to do.

Small capacity Japanese bikes, including my 400 Katana, are limited in engine performance by two things; Japanese regulations regarding power output and metallurgy. 400s were limited to 53HP down from a previous limit of 59HP. I think 250s went from 45 down to 40 around, or just after the same time. There's no point improving 4 stroke engine technology when you can achieve the regulated engine power figures with 80s and 90s technology. In fact the manufacturers probably breathed a sigh of relief because they didn't have to go particularly high tech to keep engine output on the boil in a competitve market. My 400 Katana will pull cleanly from 4000rpm right through to 12500. The Bandit 250s I've ridden will do the same from about 5500 rpm. When the focus came off peak power, the bike manufacturers went for improved power delivery, which vastly more useful on the road than a 60hp 250 that lasts for 5000 kms between tear downs (50 hours for Aprilia's SVX550 in 70Hp trim - modern engine, modern metallurgy) and won't leave the lights on a slight incline without 12000rpm and masses of clutch slipping.

Small capacity four strokes in 60s GP racing were pulling between 12000 and 20000rpm rev ceilings but they had 7 to 20 speed gearboxes to cope with the 100-1000rpm wide power bands.

There are little tiny turbos and screw type superchargers out there, but you'll have to be able to manufacture your own manifolds and have access to a dyno to make sure you have it breathing efficiently across the usable rev range. I'm not ignorant about automotive manufacturing techniques having worked in the industry, but I think most motorcycle engines leave the factory in a much better state than you think, especially the small capacity ones. I do think that the law of diminishing returns is in effect the moment you crack one of those little gems open for the express purpose of "making more power".

[Danboy]

Cool! Thanks guys, I am humbled by your knowledge of the industry..
That answers my original question perfectly. Basically there's nothing interally worth doing, because it's already been done.
Ported and polished from factory sounds good. You certainly don't get that with cars, (or Karts for that matter, even though some of those are motorcycle powered) and I would always have to do all that kind of work myself, along with changing cams, valve sizes and quality of internals etc.
So, that brings me back to the bolt-on extras such as muffler, etc. That will suffice. (Until I get the NOS system that's available for $900 ) I'M KIDDING!
WIll do the suspension too I think. Bearings and the like, get it handling well.
Thanks heaps.

D.