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Discussion Starter · #1 ·
Hi,

recently bought a K100RS which has been converted into a cafe racer, just the basics so far realy.

I've got an idea of what I'd like to do but can't find the info on if it will work or be worth it.
I'd like to update the front end, Forks and brakes, I've seen a couple of pictures of bikes with S1000RR forks and discs, or also GSXR, what do I need to take into account when looking for these? Will they fit? what else will I need to consider/buy.

Thanks, and sorry for jumping right in with my first post
 

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I will jump in to save you before you get flamed.
Please read the new members read here first post.

The k100 is a mighty fine bike for its era. Changing the front end for a modern usd setup will overwhelm the primitive frame technology and more than likely alter the geometry of the steering to dangerous numbers. Do you know about rake and trail and how it effectsstabilityand handling? Its something that is a basic and essential thing to learn if you are going to be doing front end swaps.
People who put these set ups on are going for a look and not performance.

On top of this no fork swap of this nature is easy or worthwhile especially in monetary terms.

Plus these front ends come from somewhere and that generally is stolen bikes that are broken down and sold.

A lot of the guys on here race bikes so in general this forum is about the racer not the cafe part of cafe racers.

Upgrade your existing forks through tried and tested methods like upraded springs, cartridge emulators and a general rebuild. Chuck a brace on and have done with it.
Upgrade the rear shick to match and you will have a fun bike to ride, which is the whole point.

Post a pic of the bike so we can see what we are working with.
 

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Discussion Starter · #3 ·
I will jump in to save you before you get flamed.
Please read the new members read here first post.

The k100 is a mighty fine bike for its era. Changing the front end for a modern usd setup will overwhelm the primitive frame technology and more than likely alter the geometry of the steering to dangerous numbers. Do you know about rake and trail and how it effectsstabilityand handling? Its something that is a basic and essential thing to learn if you are going to be doing front end swaps.
People who put these set ups on are going for a look and not performance.

On top of this no fork swap of this nature is easy or worthwhile especially in monetary terms.

Plus these front ends come from somewhere and that generally is stolen bikes that are broken down and sold.

A lot of the guys on here race bikes so in general this forum is about the racer not the cafe part of cafe racers.

Upgrade your existing forks through tried and tested methods like upraded springs, cartridge emulators and a general rebuild. Chuck a brace on and have done with it.
Upgrade the rear shick to match and you will have a fun bike to ride, which is the whole point.

Post a pic of the bike so we can see what we are working with.

Thanks for the reply, I'll take a look through the new members sections, was on a quick break during nightshift so thought I'd do a quick post whilst it was on my mind.

I love the feel of the bike as it is, don't want to ruin it, instead improve it, both its performance and aesthetics. so back to the drawing board, really like the look of the gold on black.

Picture of the bike before I got it, first bike of this style I've had and enjoying it so far. looking to improve the bike first and foremost and put my own stamp on it.

104638
 

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Awesome!

So i see a few really good things.
- somebody has taken the time to put braided lines on the front brakes.
-it has an airbox. Thus ensures that the engine will actually run properly throughout the rev range. Don't be tempted to get rid of it for pod filters.
  • it has a front fender albeit cut down. Keep this but also look at aftermarket fork braces to stiffen the front end.
  • its a big heavy bike and it still has decent width handlebars to help you steer that boat. I wouldn't recommend clipons especially without putting on corresponding rearsets.

I would say that the plate location is a little chopperesque.
Installing a small rear fender and mounting the plate there will have both an aesthetic and practical improvement by keeping crap off of your back.

It hasn't fallen into too many cliché pitfalls that most cafe racer builds do. So your not a million miles off a winner.
Sometimes the advice here will come accross as blunt but there is a lot of two wheeled experience to draw from if you have thick enough skin.

As the bike rides at the moment what is it that you don't like?
I would focus on these at first to improve the experience.
 

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K100 forks are 41.3 diameter, Ohlins rsu's are 43mm
still not plug and play but a whole lot closer to it and they are impressive performers.

 

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Bike is fuel injected, it's not fussy about what air cleaners are on it but mice do love to nest on top of the engine and the fuel pumps run hot as **** make sure you keep lots of fuel in the tank, that helps.
 

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Discussion Starter · #7 ·
Awesome!

So i see a few really good things.
- somebody has taken the time to put braided lines on the front brakes.
-it has an airbox. Thus ensures that the engine will actually run properly throughout the rev range. Don't be tempted to get rid of it for pod filters.
  • it has a front fender albeit cut down. Keep this but also look at aftermarket fork braces to stiffen the front end.
  • its a big heavy bike and it still has decent width handlebars to help you steer that boat. I wouldn't recommend clipons especially without putting on corresponding rearsets.

I would say that the plate location is a little chopperesque.
Installing a small rear fender and mounting the plate there will have both an aesthetic and practical improvement by keeping crap off of your back.

It hasn't fallen into too many cliché pitfalls that most cafe racer builds do. So your not a million miles off a winner.
Sometimes the advice here will come accross as blunt but there is a lot of two wheeled experience to draw from if you have thick enough skin.

As the bike rides at the moment what is it that you don't like?
I would focus on these at first to improve the experience.
Thanks for that, some really useful points highlighted there. the previous owner has done a great job in my opinion.

Nothing i don't like about the bike, just looking to build on it, if I can. I'd like the brakes improved and my thinking was two birds one stone with a modern front.

Rear sets are something else I've been considering.

Thanks for taking the time
 

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Discussion Starter · #8 ·
K100 forks are 41.3 diameter, Ohlins rsu's are 43mm
still not plug and play but a whole lot closer to it and they are impressive performers.

Thanks, i think the black and gold go really well together. Just don't want to make it worse to ride as that will spoil it a bit.
 

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Discussion Starter · #9 ·
Bike is fuel injected, it's not fussy about what air cleaners are on it but mice do love to nest on top of the engine and the fuel pumps run hot as **** make sure you keep lots of fuel in the tank, that helps.
Brilliant, never would have considered mice being an issue, thankfully they are not really a problem round here.

Air cleaners? Do you mean filters?

Thanks
 

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Yes to air filters = air cleaners,
pods on CV carbs is a disaster but the K100 was one of the first ever fuel injection bikes. Not recommending you change the air box particularly.
Those forks I posted would be a suspension performance upgrade and the brake bracket is suited to modern callipers. and your tire selection sucks by the way.

You can save a lot of money by running lawn tractor batteries instead of motorcycle batteries at twice the price, the terminals just need to be moved to the opposite sides.

Don't use the side stand.
 

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what happened to the centre stand, that doesn't look stock.

K100RS came with flat bars that would suit the bike perfect.
 

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Discussion Starter · #13 ·
Yes to air filters = air cleaners,
pods on CV carbs is a disaster but the K100 was one of the first ever fuel injection bikes. Not recommending you change the air box particularly.
Those forks I posted would be a suspension performance upgrade and the brake bracket is suited to modern callipers. and your tire selection sucks by the way.

You can save a lot of money by running lawn tractor batteries instead of motorcycle batteries at twice the price, the terminals just need to be moved to the opposite sides.

Don't use the side stand.

Not sure, what's happening in thae pic with the centre stand, I don't tend to use the side stand unless stopping for short periods, I use the centre stand for the rest of the time, I noticed a slightl oil leak when using the side stand, which dripped onto the exhaust and created lots of smoke.

Not sure which route to go down with tyres, they won't be getting changed until they are ready to be. I was temptedto change to air filters, but I quite like how the bike looks without filters sticking out the side.
 

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Discussion Starter · #14 ·
Looks like the bracket I rest my feet on, has been cut off your bike by a previous owner.
Too bad, that would have made a good bracket.

K100RS came with flat bars that would suit the bike perfect
Also this is the RS, have the handle bars been changed? it's 1986 model

View side onto the bike
104639


Cheers for all the input, fairly new to motorbikes, and a complete novice when it comes to this style of bike
 

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Centre stand on mine has curved legs at the bottom to make it easier to put it on the stand, I thought all K bikes were the same, possibly not. Side stand will allow engine oil to leak down into the inverted cylinders when the bike is leaning over. That results in smoke on startup and messes up your engine over time.

... it smoked after you took those photos, guaranteed.
 

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Is your rear disc as worn as it looks from here?
thar was because at some time in its life somebody didn't change the brake fluid frequently enough and the brake was stuck on for a while, ask me how I know.
 

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the airbox has an air flow meter inside it. if you remove the airbox and put pods on the throttle bodies there's no airflow meter and she no go mate.

4 piston calipers from k1100/r1100 should go straight on for some more caliper.
 
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