Advice: Tech talk

Motorcycle Trader's legendary "Spannerman" addresses all your technical woes

SOAPBOX

I'm fighting fires on two fronts at the moment. Jim Anka wrote in last year asking why his Honda Deauville 700 would run fine on either Shell or BP unleaded, but to get the same engine response from other brands (including Caltex) he had to run on premium unleaded. He's been in touch again asking if my silence on the issue was because "the fuel companies have got to you". I wish!

Fuel quality is an ongoing issue for all riders. Many of us would have noticed that our bikes occasionally ping (suffer pre-ignition) from certain batches of fuel often from the same outlet. Motorcycle Trader is a national magazine and the issues can differ from state to state and region to region. I am on the case, Jim, but what I say needs to be right for everyone, not just you.

The other fire front involves lead replacement additives. Stephen Foster wrote recently regarding his use of the Nulon lead replacement additive in his Ducati 750GT. My usual advice in this area is to use Valvemaster, as I know it meets the relevant Australian standard. Nulon claims this as well and has weighed into the debate with a letter from Chris Pascoe, Operations Director for Nulon Products Australia Pty Ltd. Recent correspondence from both Stephen and Chris has been headed "without prejudice" and "confidential - not for reprint" suggesting lawyers aren't that far away.

As always, MT seeks only the truth and we're currently investigating how we can test the treat rates of the samples we've acquired of a number of the lead replacement additives currently on the market. This could take a while so don't hold your breath. Be assured, though, lawyers or no lawyers, we'll tell you what we find out…

A BIGGER SHED
I have just gone through a pick-up stage and, as a result, have added three bikes to the stable. One is a 1979 GS1000S in very good, original (except for a four-into-one exhaust system) condition. The other two bikes are a 1978 Honda CB750F2 in good, standard condition and a 1977 Honda CB750F1 with a big-bore kit. It's a bit tatty but will be turned into a café racer.

They all came with a truckload of spare parts except for the exhausts. What do you think is a reasonable agreed value for the Suzuki for insurance purposes? Do you know of anyone who can supply exhaust systems for the two Hondas? I've sourced many new and old parts from the web but I haven't come across any four-into-one or four-into-two exhaust systems.
Bob Forster, cyberfosters@bigpond.com

Spannerman: As with all things old Honda Four, Bob, contact Andrew at Pud's Four Parts. His shop is in Yarram in Victoria and his telephone number is (03) 5182 5704. He has brand new original exhaust pipes for the K series fours (350, 500 and 750) and he has aftermarket four-into-one systems for the F1 and F2 models. Don't expect them to be cheap, though -- and that's not Pud's fault.

ETERNAL YOUTH
My wife and I are in our 50s. We're fit, intelligent and still possessing good reflexes and concentration. We spent the year of 2004 backpacking around the world, so we don't mind a bit of a challenge. We would now like to learn to ride motorcycles, having never ridden before. As expected, we have received mixed reviews from those who believe we have a death wish to others who have wished us luck.

We commence our NSW pre-learner's course soon, but I have booked us into a Queensland QRide course with AMA to provide extra tuition before we commit to a bike (we live on the border). Others tell us to get a cheapy to start with, but AMA believes that after we complete its competency-based course we should be competent enough to climb aboard a better bike. We have both fallen in love with the new Honda VT400 Shadow. What are your thoughts on the most sensible way of attacking our new challenge?
Garry and Michelle Sutton, msg_50@hotmail.com

My job isn't to convince you to start riding, Garry and Michelle. There is risk involved and it's a decision you have to make yourselves. The risk doesn't come from your age - clearly you're both more than physically capable of picking up the skills necessary to ride well. The risk comes from inexperience in roadcraft and that you'll be sharing the road with largely incompetent drivers. Many argue, of course, that a risk-averse life isn't really worth living and you won't be the first in your age group to have been seduced by the pleasure of riding.

ANCIENT WISDOM
Just read the letter titled "Clunk factory" in issue #228 and would like to make comment. Your response was good, but I think it left out a few important points. I agree with you that the loose chain/clutch adjustment might account for most of this guy's problems, but the clunk into first gear from a stationary position can be caused by other issues.

I believe that the real problem from clunky, stationary, first gear engages is that the majority of riders these days just slam the gear lever down at the get-go (and usually rev the engine just before they do it!). So often I see this heavy foot, heavy fist approach at the light with the rider's foot coming off the footpeg and slamming down on the gear lever instead of keeping the foot on the peg (the foot in-step resting on the peg) and gently applying pressure to the gear lever with your toes without any revs.

I also think that most "modern" (read young) riders do not understand the workings of a bike's crashbox set-up. Cars now have all-synchro manual transmissions or more likely automatics, and don't understand how motorcycle gearboxes have to work. As an old biker and one used to older 'boxes as well as modern ones, I was taught as a kid that when engaging first gear from stationary to always push/roll the bike forward slightly and let the lever delicately engage the first gear. This allows the gears/chain/wheel to engage together rather than fighting each other. I know this isn't always feasible, but it does help, especially with modern bikes with higher outputs, larger 'boxes and larger chains.

The other problem is the higher idle revs on most bikes these days. It's usually around 1000rpm. If you lower the idle revs to around 800 or under (but not low enough to encourage stalling), it makes the stationary shift to first like a proverbial knife through butter.

There is a trade-off here between lower idle revs to avoid the first gear clunk and higher revs to help avoid back wheel lock-up on down changes. A perfect balance here is hard to obtain. I haven't ridden a bike with a slipper clutch - maybe that would help.

Higher idle revs can also be an issue for first to second and second to third change-ups, especially with the usually large gaps between the ratios on first and second. Higher up the gears, the ratios are closer and this helps with smoother changes.

The letter writer also mentions that "if I rev the engine slightly before each down change, I can usually get a clean gear selection". Wow - this should always be normal practice as bike gearboxes don't have synchromesh.

I know I've waffled a bit here, but it does get up me when I see and hear people banging into first gear at the lights. It always makes me cringe but I feel a bit better now that I've vented.

David Bancell, davidb@myinbox.net.au

Glad you're feeling better, David. Your comments on idle speed are right on the money, but it's how things are now and you might just have to get used to clunking or, perhaps, invest in ear plugs. I share your cringe when I witness or hear a lack of mechanical sympathy, but it's everywhere now. My own children don't know how to check the oil in their Camrys and I'm scared to die because nobody will then know how to start the lawn mower. Here's something to cheer you up: my old mate Lance, rider of the legendary Mantis, got 193,000km from the original front brake pads on his Mitsubishi Magna. That's what I call mechanical sensitivity. The trouble is you, me and Lance are all the same age. We can't live forever and, one day, the world will have forgotten that men, once, could change silently from neutral to first at the traffic lights…

SAVED
After much research I have recently identified an old "barn find" - a bike my father used to ride in South Australia - as a 1964 Yamaha 125 YA-6. I have managed to buy a workshop manual for the bike from the internet and, while many parts are still available, very little is known about the bike. Can you shed some light on it?
Brodie Smith, shortrocket1@hotmail.com

Geez, a YA-6. Yamaha's first bike was a YA-1 which was a 125 single based (as was the BSA Bantam) on the German DKW RT125. The YA-6 was a development of this bike, but included an astounding system where a pump mixed the two-stroke oil automatically into the combustion mixture so you didn't have to do it yourself at the garage.

Australia has a special place in the history of Yamaha in that Milledge Yamaha in Victoria was the first distributor of Yamaha bikes outside of Japan. They came here before they went anywhere else in the world. If your father was a South Australian, Brodie, he would have had no option but to buy the YA-6 from Pitman's in Adelaide and he would have been among its first Yamaha customers as it didn't start with Yamaha until 1964.

BACK FROM THE BRINK
I am seeking your advice on some steps I could take to restore my ride to its former glory. I am the proud owner of a wonderful but neglected '85 model Kawasaki Z1300 with 97,000km on its clock. It's the fuel injected model and has been a trusty steed since purchase in '94. Unfortunately, due to circumstances beyond my control (as usual, work and family) the bike was parked up and not started for four years.

I can handle things like fork seals, fuel lines and the like, but my brother saw a website that was insistent that the cam chain tensioner needed to be changed, preferably with a stronger one from another Kawasaki model, before cranking it over.

Is this really necessary? What would fit from another model? What would you see as my priorities to get the bike running smoothly down the open road again? Hopefully, your insights might help other wayward riders out there looking at their old bikes in the shed and wondering what the first step should be.
Kevin Notting, kevlea.notting@bigpond.com

Step one, Kevin, is a good, external clean. Next, remove the plugs and squirt a little engine oil down each cylinder. Then take the valve covers off and squirt a little oil around the valve stems. All good? Now turn the engine over by hand (a long spanner on the bolt at the end of the crankshaft - it should be fairly easy to do with the spark plugs removed). What you're checking is that all the valves open and close. One of the problems with leaving engines unused for any length of time is that valves can stick. If you try to start the engine with a valve stuck open, a piston will hit it, bend it and major surgery will be required.

IT'S SPECIAL
I have a 1979 Yamaha XS650 Special. The bike had been sitting for eight years after it was mostly restored before I got it. After I finished putting it together I sent it off to a mechanic I know who races vintage bikes - he knows a thing or two.

When I got it back, the bike was running sweet and it was easy to start. It sounded tight and I was told the top end had been reconditioned. After a while it developed a sound I would describe like a loose cam chain. It became hard to start and very fuely. Once it backfired while I was trying to start it and now it won't start at all - not a hint of life except for the spark which seems okay. I'm not sure what direction I should take from here as the bike was running well, if only for a short time. It still has all the original electrical components, although the wiring harness has been replaced. Any help would be appreciated.
Chris Roach, candjroach05@mysoul.com.au

You need to take the methodical approach, Chris - one thing at a time. I'd start with the ignition timing because the symptoms you describe could easily be related to this. Timing correct? Valve timing would be next as the symptoms also sound a little like the cam chain jumping a tooth or two on the cam sprocket. If both these things shape up well (and you haven't bent any valves as a result of faulty cam timing), strip and service the carbs to ensure they're working properly. If you have fuel, spark and all the valves are closed on the compression stroke, you'll get action.

V-FLAWED
I have an old 1982 Honda VF750 Sports (a shaftie) which has sat in the shed for years. I crank it up and take it for a quick ride every three to six months as I work away a lot and can't pay it much attention. I'm constantly amazed at how reliable it's been considering the lack of care it receives. Oil, filters and plugs are all I've ever done.

I'm curious about the model's history. I know it was the beginning of the VFR range but how was it considered in its day? Is it ever going to be collectable?
Chris McIntrye, marmac08@bigpond.com

You won't read this in any official Honda history, Chris, but my view has always been that Honda had its eye off the ball in the late '70s and early '80s when it was more focused on developing its car range. The twin-cam 750, 900 and, eventually, the CB1100F which replaced the venerable single cam Honda 750 Four weren't competitive with the products from Suzuki, Kawasaki or Yamaha. When word got out about a new V-four engine, the motorcycle world held its breath. The empire was striking back.

Advice: Tech talk

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