Q: Hi guys. I’ve just bought a mint condition Kawasaki z1000 (2017 model), with only 3,000km on the clocks. I love the bike to bits but want more from it, so I thought I’d ask your opinion first before I empty my wallet.

What sort of horsepower does the stock bike make on your Dynojet dyno and what can I do to get more and, if so how much more? I’d also like to fit a quickshifter if that’s possible?

I’ve already been told that Racetech (locally made pipe), make a single silencer conversion to get rid of those ridiculous twin and hefty standard pipes.

Looking forward to what you guys have to say and urgently please, as I’d like to get on with the modifications before summer returns.

Jay Collins.

A: OK Jay let’s urgently respond. A stock z1000 makes around 118hp at the wheel. If you take away those silencers and fit a loud ‘straight-through’ single silencer conversion you’ll certainly have to change the fueling delivery using a Power Commander or similar, like Rapid Bike for example. Make sure the person who installs it knows what he/she is doing or it might run even worse and lose power output?

If set correctly you might get as much as nine or ten horsepower because the stock silencers are very restrictive. Either of the fueling systems mentioned above have quickshifter facilities, maybe using a separate unit but of the same brand. It’s best to install this at the same time as fueling as it’ll involve some wiring alterations.

However this will not be a cheap exercise and will probably cost you well over 10k by the time you’ve finished with new exhausts and stuff. Have a great summer either way Jay.

Q; I know you guys only deal with ‘real’ motorbikes but I thought I’d ask a question about my Jonway scooter, if that’s OK?

It’s covered 12,000km with no problems and I always service it myself because it’s very easy to do. But now it just doesn’t want to pull off without a good push from my legs. I’ve cleaned out the carb’ and made sure the vacuum fuel pump is working correctly, and now I’m stuck, hence the letter.

Any idea on what to look for next because once the scooter is on the move it runs fine, well perhaps a little flat at the top end?

Mitch

A: This is an easy one to cure and we don’t mind you asking questions regarding any form of two-wheeled transport.

It’s a simple case of replacing the six rollers inside the primary clutch. Just take off the cover and undo the center nut (might need an air-gun there), and pull off the clutch assembly. Buy six new rollers (about R150), and rebuild, simple. If the clutch assembly is badly worn, including the sleeve it sits on replace the whole unit for around R800. Then everything will return to normal. You might as well replace the drive belt at the same time if it’s not been done since new, around R300?

Q: I’ve had my BWS for five years now with no problems at all and, it’s still the best scooter ever made, even though Yamaha has stopped making them now.

Recently a ‘pop’ noise came from the engine and it locked the back wheel, which obviously means it’s seized! I had no idea why until I discovered the main jet was blocked with some sticky stuff, which is congealed fuel, I presume.

So I took off the head and barrel to discover the piston had a hole in it but the crankshaft assembly was covered and sprayed in aluminium debris, great!

The reason I’m writing is, I’ve asked many people how, or should I, clean out this mess. Some say just wash it out with petrol and rebuild the top end, others say split the crankcases and rebuilt the entire motor with new bearings and con-rod assembly. So what do you recommend?

Stuart.

A: We’ve seen riders blow up these engines whilst racing, and they just wash the engine out with petrol and ‘stick’ a new piston in, which isn’t really ideal for longevity.

If you use it a lot one way is to take out the whole rear end/engine and wash the engine/crankcase out with paraffin. We’d recommend removing the two crank seals and fitting new ones afterwards so you can get inside the bearings and finally wash out with petrol. Keep doing this until no debris comes out and rebuild with new parts and gaskets, then you should be good to go.

Q: Hi guys. I own a 1999 Kawasaki ZX-6R that is now sitting with 65,000km on the clocks. I’ve had it for over seven years now and it’s never given me any problems at all and it gets serviced at the correct intervals. Mainly because I can’t afford a new ZX-10 and it’s my only form of transport to get to work and play with at the weekends. Hopefully I’ll win the lottery soon and have a new ZX-10RR in my garage!

My reason for writing this though is that I recently went on a long run with my friends and did a spot of top speed dicing, which was great until the next day. When I started the bike I could hear a knocking noise coming from the engine but I’m not really sure where it’s from. I had to ride the bike to work, I have no choice, and the noise didn’t get any worse and did not affect the performance.

So, I’m afraid to ask, but do you have any ideas on what is wrong and, I’m not too keen to strip the motor etc? Any advice will be superb and thanks again.

Mike.

A; I’m afraid it’s very bad news Mike! It’s either the small-end bearing on the piston side or, more than likely the big-end bearing on the crankshaft. These bikes/model are quite prone to this with high mileage and constant high revving.

You WILL have to strip the motor and remove the crankshaft to inspect it correctly, and check the piston pin and it’s bearing as well. If you keep riding it will eventually throw a ‘rod’ out of the motor and destroy the entire engine.

So either go for the repair after pricing, or try and source another engine? Preferably from a bike that’s been crashed, why you ask? Well the engine was obviously running at the time of the accident so you know it works, hopefully not with the same problem though.