Spannerman – July 2014

Date 14.7.2014

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  • Motorcycle Trader

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Letters this month: (MT #283)

– Life expectancy of chains & sprockets – 2004 Suzuki DR650 (‘Chain Claim’)
– What causes bikes to backfire (‘Bang’)
– DIY replacing bushes on a 1975 Suzuki GT185 (‘Nice Bush’)
– Time to buy a new bike, which one? (‘Choosing a Bike’)

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Spannerman’s soapbox

As you’ll read elsewhere in this issue, we’ve had a KTM 1190 Adventure R as a test bike recently. It’s a fine bit of kit and a very sophisticated interpretation of the big adventure-tourer concept.

I got it at the tail-end of the loan period and noticed how noisy it was on a trailing throttle at low revs in the higher gears. The noise was largely chain rattle. The KTM’s chain runs through a series of channels and only has to be slightly loose to bang on the plastic guides. Nobody else probably noticed as nobody else rides as slowly as I do.

Adjusting the chain was slightly more complicated than I’d imagined. To its credit, the KTM has a reasonably comprehensive tool kit under its seat. This includes a variation of a ring spanner that fits the rear axle nut and an extension tube so you can exert the appropriate torque. This was the first time the nut had been undone in the field and the stock toolkit item wasn’t up to the task, requiring the use of a ubiquitous 12-inch shifter.

While attending to the task of pulling the axle back a little, I noticed, for the first time, a sticker saying the chain should have between 40-45mm slack to be at its proper tension. This is more than you’d expect for conventional road bikes but it allows for the dual-purpose of the KTM in that, in parts of its life, it’s likely to be in mid-air before being fully stretched on its landing.

It also means, of course, that in normal use the chain will appear to be loose. I went for the lower setting but it still snatches a little and bangs on the plastic rails. If the engine wasn’t so quiet, you probably wouldn’t notice it…

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CHAIN CLAIM

I currently ride an ’04 Suzuki DR650 which is my hack bike. I have several others, some of which I keep in a bedroom in my house.

The DR650 has 73,000km on it and it still has the original chain and sprockets. I’m hoping I can get to 100,000km and set some kind of record.

I bought the bike brand new and have mainly used it as a commuter.

I oil the chain every 100km and don’t labour the engine in high gears. Third is 40-70km/h, fourth is 70-90 and fifth is left for over 90km/h.

Usually, I ride around town in third gear which whines but it’s been doing that since new. I’ve noticed letters here which complained about it so I figure it’s a fault with the bike.

Can I make a couple of suggestions to improve MT? I don’t want to know about horsepower at the crankshaft as I don’t ride the bike around on the crankshaft. Similarly, I don’t ride the bike around dry so dry weight isn’t useful either – weight should be stated with the bike with all fluids.

I’ve also noticed a reduction in the number of bikes for sale in the magazine compared with a few years ago. I’ve been buying MT for three years and have owned about 35 bikes. I’m not on the ’net so I rely on you. Thanks for a generally great mag.

John,
West Coast

Jeez, 73,000km from the original chain and sprockets! That could already be a world record, John. For larger capacity bikes, the life expectancy of an O or X-ring chain is usually somewhere between 25,000-35,000km.

The proper advice is to change chains and sprockets at the same time but poor people (probably everyone reading this, including myself) usually opt for new sprockets with every second chain.

Your riding technique (not loading the chain by being in the wrong gear) would certainly be helping chain life but lubricating the chain is another issue.

Let’s be honest here – cleaning drive chains is a pain in the arse and most of us either don’t do it at all or don’t do it properly. Best practice is to clean the chain once a month (depending on conditions – dirt riding needs more chain maintenance) with kero and a toothbrush.

It’s tedious but this is probably why i-pods were invented.

Once the chain is clean, it should be lightly lubricated. Pressure-pack cans with ‘anti-fling’ have their place but what lubricants that stick on the chain usually do is attract road grit which, combined with the lubricant, turns into a grinding paste.

Again, it’s a pain in the arse, but ‘lightly lubricated’ means wiping the clean chain with a thin coating of oil (the same oil you use in the engine is fine). Wet a rag with the oil and hold it around the lower part of the chain while you manually rotate the wheel.

Never try this while the engine is running with the bike on its centrestand and a gear engaged.

It’s a shortcut to rotating the wheel but it can so easily go wrong at the cost of fingers.

With a clean 0-ring chain, there’s already lubricant inside the links doing its job. The wet outside chain reduces heat and assists the parts of the chain not already being lubricated to slide easily.

Importantly, a slightly wet chain doesn’t hold grit from the road and that will extend its life.

Chains which aren’t cleaned but are regularly and liberally coated in spray lubricant will last half as long.

It’s a dirty business so buy a box of disposable rubber gloves from your local hardware store.

Regarding your suggestions for improvement, John, all manufacturers quote crankshaft horsepower as rear wheel horsepower can’t be measured as consistently. Crankshaft horsepower is comparing

apples with apples. As a rule of thumb, chain final drives will absorb somewhere between 5 and 10 per cent of crankshaft horsepower and shafts will absorb between 10 and 15 per cent.

Similarly, wet weight can be misleading. An otherwise light dual purpose bike can appear elephantine if it has a 25-litre tank full of fuel while it’s heavier competition will weigh in less if it has a 12L tank.

You’ll be interested to read that in the days when the major players were competing with each other on weight, Suzuki used to determine its dry weight figure by weighing every single component of the bike separately. Such was its dedication that it weighed drive chains without the lubricant between the 0-rings. Now that’s dry…

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BANG

I know I shouldn’t be asking this, but do you know how those riders who can make their bike’s backfire do it? I watched it happen in the shopping strip in Gosford on the weekend and it started every car alarm in the area. Hilarious!

Mich Thomas,
email

Aha, Mitch… Keep the throttle open, hit the kill switch, wait for a second and then turn the engine on again. Sometimes it doesn’t work, depending on the cycle of the engine, but, mostly, you’ll ignite mixture while the exhaust valves are open and you’ll hear what actually goes on inside an engine’s combustion chamber. Loud, isn’t it?

You can see why the authorities like proper ignition timing and mufflers.

A word to the wise, though: on modern bikes the practice risks damaging, if not destroying, the catalytic converter.

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NICE BUSH

I have recently acquired a 1975 Suzuki GT185 in really good condition. It’s kind of a barn find in that it has lived up the back of a bloke’s garage for about 20 years. Appearance-wise, it’s excellent and I’m not going to restore it – just clean it up. It’s surprisingly quick for such a small bike but it blows a bit of smoke. This is the first time I’ve ever had anything to do with a two-stroke but the internet tells me they all did that. The speedo says it’s done just 18,000km.

Why I’m writing is that I went over the bike before I bought it using an article I clipped out of MT years ago on how to check a used bike.

If I cup my hand around the outside of the rear tyre and push from side-to-side, I can feel movement in the swinging arm. I can’t feel it when I’m riding but I can definitely feel it when the bike is stationary. There’s enough movement to alter the tension on the chain.

You said that this would probably be the swingarm bushes. Is replacing them something I could do myself? What kind of bushes are they? Any idea where I could get the right type?

Rob James,
Vic

Sounds like you’ve correctly diagnosed the problem, Rob. GT185s and lots of other small capacity bikes from the time used ‘Silentbloc’ bushes. These are made from two steel sleeves with a ring of rubber in the middle. Silentbloc bushes fell out of fashion as bikes became bigger and more powerful but they’re very well suited to bikes the size of your GT as they absorb lots of the rocking movement associated with the function of swingarms.

I had a quick look on eBay and original Suzuki parts for your bike are available from the UK for $32 a set with nine bucks postage – bargain.

Can you fit them yourself? Certainly you should have a go. You need to remove the rear wheel and disconnect (and remove) the drum brake which is attached to the swingarm. Then you need to unbolt the shock absorbers from where they attach to the swingarm.

You’ll then be able to move the swingarm up and down and you’ll see where it’s mounted to the frame. Undo the nut on the end of the pivot bolt (pin) which runs from one side of the swingarm to the other and remove the bolt.

I love sentences like that in workshop manuals – 25 words that have the potential to frustrate home mechanics for hours. On many older bikes, the nut is very difficult to dislodge. Use plenty of WD40 and make sure the socket you use fits perfectly. The longer the lever on the socket wrench, the greater the torque applied. Feel free to attempt to tighten the bolt slightly as well as try to loosen it. Once the bond between the threads is broken, the WD40 can do its work.

The drama isn’t over. The pivot bolt can also be seized. Put a piece of wood at the threaded end and give it a good belting with a hammer. As my old mate, Mr Smith, used to say, “Never use force – just use a bigger hammer!”

Given the low mileage of your bike and the fact that it’s been out of the weather, chances are you’ll have no problems getting the pivot bolt (pin) out.

Then grab the two ends of the swingarm and gently rock it out from between the mounting lugs.

Depending on the wear, the original bushes can often be removed by hand but if not, you can tap them out using a hammer and a drift.

Oh yes, the smoke. A bit is okay but a lot means the crankshaft seals have dried out while the bike has been resting and are leaking. This is probably something you can’t repair yourself but if the rest of the bike is as good as you say, it would be worth the investment.

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CHOOSING A BIKE

I never thought it would come to this. I finally have enough money to actually buy a new bike. It took until I was 56 but that’s not the point – now I have to make a decision. When I was broke, I wanted everything. That was fine because I could never have my desires fulfilled. Now I can have at least one desire fulfilled but I suddenly have to live with what I choose.

I got by on second-hand Japanese bikes which, incidentally, I loved. I’ve had 14 in 30 years and have lots of great stories to tell about all of them. Probably the best was the first: a Honda K2 750. I’ve been reading MT for long enough for you not to have to go through the normal, “we want to find our first bike and our first girlfriend” amateur psychology routine but I accept I’d probably be disappointed (except with the girlfriend – she liked sex as much as she liked breathing).

At 56, I’m torn between being sensible (all-purpose, comfortable bike which is reliable) and passionate (bike of my dreams where I’m still a player and able to lap Phillip Island under 1.40).

Options torturing me include the BMW S 1000 RR, MV Agusta F4 1000, Suzuki’s new V-Strom 1000 (love the price) and the KTM 1190 Adventure. See the problem?

Reilly Scott,
email

Oh yes, Reilly, I see the problem. What’s this thing about ‘new’ though? What is it about ‘new’ that you want – virginal, warranty, status, cutting edge?

Clearly, courtesy of your first girlfriend, ‘virginal’ isn’t an issue for you, but presuming you have around thirty-large to spend, does it have to be one bike?

As your temporary psychotherapist, I detect you want something from the past, something fast, something comfortable and something that will give you street cred. That can actually be four bikes, not one.

Puds Four Parts can probably fix you up with a very nice single-cam Honda Four for around $8000. That’s the past taken care of and it’s an absolute investment. Don’t come back to me in 10 years and tell me you should have bought one.

These days, ‘fast’ is never about the bike – it’s about the ability of the rider. Cam Donald on a mid-90s Fireblade would be faster than all of us if we were on an Augusta F4. Spend what you save on the bike on advanced riding courses.

Off-road? Enter to win our Suzuki DR650 competition package in this issue but if that doesn’t work, find a low-kilometre Suzuki DL650 from around 2003 onwards.

For proper street cred, buy a classic or start a café racer project. Café racers and customs are the new black.

New bikes are, of course, cool but they tie up a lot of money.

 

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If you’d like some help, write to:

Spannerman,
c/o Motorcycle Trader,
Locked bag 12, Oakleigh
VIC 3166

or email mct@bauertrader.com.au

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