Q: Hi guys. I’ve recently acquired a 1984 Kawasaki GPz1100, the one with the first-Uni-Trak rear swing-arm. I’ve gone through everything and the bike runs surprisingly well except for one major problem, it seems to be quite ‘wobbly’ in a straight line and especially at relatively slow speeds.

It has new tyres (Bridgestone), new steering head bearings, new swing-arm bearings and new chain and sprockets; the bike has covered just over 70,000km. I also checked the wheel bearings while the wheels were out having new tyres fitted and, they felt nice and smooth to turn so nothing wrong there.

I did have one of these in the 80s and can’t remember it being like this on the road, so any added information will be greatly appreciated, and thanks for the best site in SA too; I’m on it every day.

Wayne.

A: It seems like you’ve gone through everything already but I’m concerned about those wheel bearings. Firstly don’t forget that they are probably over 30 years old! So instead of just turning them inside the wheels I would most certainly knock them out and wash them, then I believe you’ll discover a whole different picture, because I’ve already replaced many in the past on similar bikes.

Yes, they may feel smooth to turn but once removed they’ll definitely have sideways play and sound like a babies rattle when you shake them from side to side, I’ll guarantee!

So buy new ones with a dust seal on each side, three at the rear and, two at the front, not too expensive either. Just take them to a bearing specialist and they’ll match them up because they’re nothing out of the ordinary.

If there’s a couple of millimeters of sideways float in the bearing you can imagine how much movement they’ll transmit by the time it gets to the end of the tyre? That should cure your problem I’m sure.

Q: I recently purchased a Bajaj Pulsar from my boss for a good price to commute with. I’ve done two oil changes in a rather short space of time because the bike had been standing with a flat battery for a while.

A few people have told me that engine cleaner is not such a bright idea and to rather use a good oil that has cleaning properties. Now I’ve decided to change the oil filter and spark plug as well.

So I was wondering if you could tell me where would I be able to get the correct oil filter for this bike, because I don't want to take out the old filter before I have the correct size/type replacement part ready to fit.

Regards.

Tertius

A: First of all use any good quality motorcycle oil that has, as you say, a cleaning agent and additive for the wet clutch as well. A good bet is any of the Motul range as they specialize in this department. Go to www.ampsa.co.za to locate your local Motul dealer.

As far as getting parts, like the filter you require for any Bajaj, go to www.jonway.co.za for contact details, as they are the SA importers for Bajaj motorcycles. And it is a wise choice to get the parts first of all, well done.

Q: I have a Honda VFR800 VTEC, 2002 model, with 35,000km on the clock that has started to vibrate above the VTEC threshold after a day on a go-kart track. There were a few visits to the rev-limiter but no violent downshifts. These vibrations are noticeable in the seat, hands and feet between 7,000 to 8,500 rpm but seem to go away above and below this, there were no vibrations before the track day.

The bike has a ‘slip-on’ silencer and the PAIR, snorkel and flapper valve modifications done by PO otherwise, as far as I know, it’s stock.

So, any ideas what could cause this and where should I start to look while trying to fix this?

Regards Toby

A: This is a difficult one without having the bike in front of us. But first take off the air-box lid and have a good look inside to see if anything has come loose, seeing as mods have been made in there already.

It might be one cylinder has begun to give problems that would certainly cause vibration problems due to the imbalance this would cause, so perhaps a compression test might be a good start. You might want to check to see if the throttle bodies have gone out of sync as well, but that would possibly mean a visit to a Honda dealer.

We’ve also heard of voltage problems with this bike so make sure the battery is healthy as well?

Hope these pointers help and maybe have a check around various forums around the Internet world to see if anyone has similar issues?

Q: I was recently at a National superbike race and got talking to some of the guys who race the BMW S1000RR, mainly because I have one.

They told me that they tend to change the cam timing on their race bikes, but cannot change the actual camshaft itself. I did ask them if it makes any difference to performance but all I got was raised eyebrows and pathetic grins.

So, could you guys tell me the benefits of doing this and is it really worth fiddling around with mine, I only use my bike on the road for fast breakfast runs? Looking forward to your response seeing as you seem to know everything around these matters.

Piet.

A: As a rule, if you change the cam timing of the stock cams, it doesn’t really make any more horsepower or maybe a few depending on where they’re set. What it does do is move the power around depending on the track. So, for example, you may achieve more midrange or a bit more top-end and then possibly lose out on the stock mid-range settings. The original camshaft is what BMW believe to be the perfect compromise to begin with.

So, if I were you, I’d just leave the factory settings alone for road riding and spend your money on something else instead. Hope that clarifies thing for you?