Motorcycle Tuning Articles

Dobeck/Techlusion TFL
VTR1000 Article
VTR Tuning Tips
CBR900 Hot Up
Hornet 600 Dynojet Kit
ZX9R Performance
ZX6R Performance
ZRX1100 Performance
XJR1300 Big Bore
GSXR1000 Hot-up
Suspension Setup

Dirtbike Parts and Performance Motocross Parts, Performance and Tuning
Chain Adjustment
Never adjust your drive chain so it has less than 25-30 mm of vertical movement. If it is tight it will stretch and wear very quickly, put undue load on wheel bearings and swingarm bearings, in the worst cases the chain brakes and puts a hole in the crankcases or wears out gearbox bearings and shafts. If in doubt give it more free play not less.

Fact or Fiction?
Carbon fibre mufflers out-perform alloy or steel mufflers.
The answer of course is fiction. The only reason for the use of carbon on mufflers is to reduce weight. Carbon fibre is used in many areas on race bikes, purely for its strength and light weight.

Tyre Repairs
Have you ever gone to throw a leg over your favourite mount and head for the hills only to find you have a flat tyre? Worse still, it set you back $300.00 and has only done 1000 km.

Well, thank God for tubeless tyres. Not only did it not deflate in one miliisecond going through that 150 km plus sweeper last night, but it can be repaired cheaply and safely. There are special plugs available to repair the new generation of tyres as long as the puncture is a clean hole and not a big gaping slash. Even the tyre rating doesn't drop much, and I have seen some very game and probably broke enthusiasts use them on ride days without tasting disaster ( I don't recommend trying that one though).

Another thing to be aware of with radial tubeless tyres is that the PSI rating is normally much higher, eg 36 psi in the front and 40 psi in the rear is a fairly common rating.

Spark Plugs

I'm sure that many of you at some stage have been given the sales pitch on the horse power advantages of fitting brand X spark plugs. Take this as a warning: don't be fooled. My own personal experience with motorcycles would indicate that this line of approach can be very misleading.

In fact one manufacturer who we'll not name has been pushing this point very strongly and I am yet to see any proof behind this statement. I'm not saying that they are wrong, I just haven't seen any indication that they are right. One thing is certain though, we've had some problems with them. They have been the cause of many a misfire and they have a nasty habit of breaking in two when trying to remove them, resulting in many frustrating hours for us and many dollars for the customer.

Set out below is a guide to help you avoid all these problems and select the correct plug for your bike. Sometimes you can use alternative plugs, but you need to have an understanding of what the number on the plug means to ensure you're not stepping outside the limits of your engine's requirements. So the 1st rule is always go with the manufacturer's recommendations. The second rule is if you have any doubt give us a bloody call and save yourselves a lot of agro.

We recommend and use NGK plugs so the following explanations are applicable to NGK only.

The 1st letter prefix refers to the thread type and socket hexagon size. They range from 14mm thread down to 8 mm on the little 4 cylinder 250 imports.

The 2nd and 3rd letter prefix is the construction feature. eg P for projected insulator nose, R for resistor type. The first number refers to the heat range. This is probably the most important code because it refers to the operating heat range and means that if you get it wrong serious damage to the engine is eminent. With NGK plugs the higher the number the colder the plug. Racing engines use cold plugs because they generate so much heat. If you have a fowling problem, common on two strokes, using a hotter plug can sometimes cure it. But if you're off to P.I. for a ride day you need to put that colder plug back in it. Also note that on other brands the heat range works the opposite, 5 is colder than 7 not hotter eg, Champion plugs.

The next suffix letter is for thread reach, which is also where you can come unstuck because if you choose a plug with a thread reach that's too long then it puts an interesting impression in the top of the piston, if it's too short then it won't reach inside the combustion chamber.

The next letter is again for construction features, eg P for platinum ground electrode, GV for racing plugs made of nickel alloy and centre electrode made of precious metals, S for copper core electrode etc, etc. Sometimes there is another number at the end meaning the plug gap which it is set at.

The following is a common motorcycle plug number:
Explanation, 12mm thread 18mm plug socket, P for projected electrode, R for resistor, heat range 9, E for 19mm thread reach, A for specials and 9 for .9mm plug gap.

And there you have it, clear as mud, eh?. Don't worry if you're confused;  as I said earlier the manufacturer has done all the hard work, so if you stick to their recommendations you can't go wrong. If it's for a seriously modified engine then your engine builder should know what you need to use.

Shell Optimax

The response to our last newsletter on fuel has been quite surprising, so I thought I would put in some answers to commonly asked questions which have been supplied to us by Shell for your benefit. You can also go to and send in your feedback.

Optimax is suitable for all engines designed to run on unleaded petrol. The design of the cooling system should have no influence on the suitability of the fuel used. Carburetor fed engines may need adjustment towards a leaner mixture but fuel injected engines with lamda sensors adjust to the higher density and are generally less sensitive to the fuel density changes.

Rich running
When a bike is not tuned correctly to handle the high density of Optimax it may result in rich running. Not all bikes are effected, but carbureted bikes are more likely to suffer from running too rich, especially if they are used around town in stop-start situations. Some of the ways to overcome the bike running too rich include changing the plug to a slightly hotter grade (always consult the engine manufacturer), reducing the jet size on the carburetor, changing the carburetor needle, or a combination of the above. This will help the bike run well on Optimax and allow the rider the benefits of the high octane fuel—more power, especially at the high end and an advanced fuel additive to maximize engine cleanliness.

Scott Oiler

This thing has got to be one of the best products you’ll ever add to your bike, both in terms of maintenance and money saved. What they do is provide a constant flow of oil to the final drive chain, meaning it never runs dry. Like any moving part where there is friction there’s wear, so when your chain is dry it wears extremely quickly. Think of it this way, how long would your engine last with 1 ltr of oil when it holds 4 ltr’s, or with no oil at all. Either way - not very long. Chains are no different, they require a constant supply of oil to keep everything well lubricated and thus prevent excessive wear, maintain smoothness and comfort while not putting unnecessary load on wheel bearings and gearbox’s, thus improving fuel consumption. 

I have customers who were replacing chains and sprockets every 18-20,000km, who are now clocking up well over 40,000km. One guy reckons he’ll get a least 50,000km out of this lot. At $195.00 for the oiler he is well and truly ahead. 

Of course if you need someone to fit it for you then allow another $80.00, and you're still ahead. :)

Performance Tuning.

Our inventory of machinery includes a flow bench which is used to measure the performance of cylinder heads. In conjunction with the dyno we are able to test all performance packages before releasing them on the market to ensure the best all round rear wheel horsepower suitable for the road or track. We have found this to be a very difficult task as most products we have tested don't perform to our high standards.

User friendly road-going horsepower is our aim, as shown in AMCN and Streetbike Magazine tests on various bikes, including our Bimota SB6 which produces 155HP at the rear wheel and yet is still very sociable and forgiving. You might also care to read the ZX9R Hot-up article.

Dirty Filters

Air filters are important, but I must say this is a little bit ridiculous. In case you don't recognise it, it's a stock filter out of GSXR1000 with 24000 km on the clock. A bit more time on maintance and a little less on polishing wouldn't go amiss here. Don't let your filter get like this - clean it, or replace it if it's not re-usable. 

GSXR1000 Air Filter

And this one's even worse, if possible!


Suzuki Bandit Air Filter


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