As I was dismantling Shirley's backend I started thinking...

**Conquiztador** · 6th January 2010, 19:46

Shirley, my K100, that was to be a temporary solution while I complete one of my projects, has become my ride. And for 8 months she has performed w/o any issues. Last week she developed a oil leak from the final drive (shaft drive) and so her rear end becam more slippery that normally, so I happily stripped her bum and sorted that.

But as I was playing with her rear bits I started thinking: She gives 90hp at 8000rpm. Not bad for a 24yo girl. And the motor is bullet proof. Has anyone umphed these K100's up,? As you would think that there is heaps more to squeeze. Sadly I am a old fashioned biker that knows re carbies, porting, stroking an so on, but the electronic stuff is outside my knowledge. Also the fuel injection is like girl talk to me (know it is happening, but...).

I have some plans for her when my other ride is on the road: drop motor 1 - 1 1/2 inch, wider back tyre, new backend, faering etc. But started to wonder re the HP's. Any advise is appreciated.

**Kickaha** · 6th January 2010, 21:50

Turbo it...

**Conquiztador** · 6th January 2010, 21:59

And when you think that a old Z100 has 85 Hp, a sportster has 65, and older CB's promise 85, then she is OK. Considering that normally you have the K100's run in at 80k's (indicates a design that is made to keep going and not for performance). So I have decided to scare her up to a little more. Would love to have a wheelstanding K100!

**Conquiztador** · 6th January 2010, 22:08

Turbo is an option. But if I am to add mechanical stuff I will opt for a supercharger. Like their logic more. And perhaps some nitro for the strip...

**Motu** · 6th January 2010, 22:43

I've never owned a bike with 90hp,so don't know what the problem is....Is it the 2 valve or 4 valve? Losing a shit load of weight would be the easiest way.The header pipes always look a bit puny to me,put on a weird set of headers a couple of sizes up...but that will kill a bit of bottom end.I'd stay with the fuel injection,I've spent too many years playing with carbs to find anything wrong with injectors.There was a thread on ADVrider a while back where a guy wanted to run a carb on a K75 - most said he was nuts,but we figured an SU would be the way to go,so easy to do.How about a couple of DCOE's hanging out the side?

**BMWST?** · 6th January 2010, 22:56

get a 4 valve head,and ease the breathing and exhaust.I dont know if slightly larger injectors would be required then or not.

**pete376403** · 6th January 2010, 23:01

Turbo would be a bit easier than supercharging (where would you drive the supercharger from, for a start?) If it is a 2 valve motor the FI uses an air flow sensor (swinging flap IIRC) so it *should* respond to the increased air flow without too much shagging about. Dunno about the 4V ones.
The K motors are solid, although not indestructible. A friend had one that had been well grenaded at manfield - at least two rods through the block. Welded up ok though. Automotive type clutch so easy to upgrade, gearbox is by Getrag (make of race car gearboxes, should have a bit of tolerance for more power)

**Conquiztador** · 6th January 2010, 23:14

Originally Posted by Motu

I've never owned a bike with 90hp,so don't know what the problem is....Is it the 2 valve or 4 valve? Losing a shit load of weight would be the easiest way.The header pipes always look a bit puny to me,put on a weird set of headers a couple of sizes up...but that will kill a bit of bottom end.I'd stay with the fuel injection,I've spent too many years playing with carbs to find anything wrong with injectors.There was a thread on ADVrider a while back where a guy wanted to run a carb on a K75 - most said he was nuts,but we figured an SU would be the way to go,so easy to do.How about a couple of DCOE's hanging out the side?

As mentioned, she is OK as she is, but you wonder re a machine that is so bullet proof. Is there more?

Would not touch the injectors. I understand that you can get new chips that map the injection. But even so, I am sure there is more...