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1. Lubricants
At a minimum, SR engines should get a 20W40. Shell Helix 20W50 got a couple of raves but also a few negative comments based on how bad Shell XMO was when it was released and some negative experiences with Shell Advance.
Out of left field, Motul 3100/3000 was praised by resident wrecker, Andy Bremner, and there was general agreement that Penrite HPR 30 (or 40 or 50 for that matter, depending on whether it’s summer or winter) was a reliable performer. Spannerman likes Castrol GP but there was some criticism of this product related to experiences of foaming.
Almost nobody thought synthetic oils had any real advantages for SR engines. Oil change periods also varied with the lowest being 2000km and the highest being never – although that particular bike features a constant loss lubrication system meaning any oil in it is almost always fresh. There were some raps for 5000km although all agreed it depends on how you use your bike. If you ride flat out in hot conditions or if you just make short trips without the engine ever really reaching its normal operating temperature, change the oil closer to the 2000km end of the spectrum.
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2. Petrol
Petrol
There are over 100 members of the SR500 Club and every bike engine is in a slightly different state of tune. There was a consensus view that lead replacement petrol (LRP) was crap – basically standard unleaded with the addition of some valve-seat lubricants which, unlike lead, don’t combust well. The result is harder starting and rougher cold idling but, for low compression engines, there wasn’t much evidence of pinging when the engine was at its normal operating temperature.
Everyone loves the premium unleadeds. Mobil 8000 works well for me.
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3. Tyres
There were a surprising number of 18-inch front wheels fitted to bikes whose owners were participating in this discussion. This gives a bigger range of tyre choices. Dunlop K81-style TT100 Roadmasters are probably the stickiest but not everyone would be happy with 3500 – 5000km from a rear tyre.
Metzeler ME33 fronts were a favourite and Bridgestone Battlax BT45s were promoted as offering good grip and a service life of up to 15,000km.
Another long laster with good, all-round performance was the Barracutta range.
Avon Supervenoms were recommended for 18-inch combinations.
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4. Stators
Early model stators can advance themselves and burn pistons. Later models can be retro-fitted and are more reliable
Stators and rotors are matched, meaning swapping them around between bikes will give unreliable results.
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5. Roadside repairs
If you have a drum-brake rear end, the length of the actuating rod is exactly the length of the rear shocks, meaning if you brake a shock on a trip you can limp home without a rear brake but also without the rear wheel wearing through the mudguard.
If you break a throttle cable, you can limp home by replacing it with the throttle return cable.
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6. Tappet adjusters
THE PORSCHE OPTION
SR owners can improve the performance of their engines, reduce mechanical noise and claim a relationship with Porsche engineering for less than $100. Here’s how…
Valve clearances for the SR engine are set by simple screw adjusters with lock-nuts. While this system is simple and effective, it has some disadvantages. The contact patch on the adjusters is relatively small and, even with properly set clearances, the top of the valve stem is pounded without mercy in use.
The adjusters used in Porsche engines (p/n 90110537002) have a flexible cap at the end of the adjuster which fills up with oil and and keeps the adjuster in constant contact with the top of the valve stem. This means no tappet noise and minimal hard contact between the adjuster and the valve. Fitting the Porsche adjusters does require a bit of machining work but no precision is required. You can do it with an angle grinder, a hacksaw and an old school ruler.
The Porsche adjuster is a bit longer than the stock adjuster so you need to cut the top off it so it’s the same length. Use the same hacksaw to then cut a slot into the top of the adjuster so you can turn it with a screwdriver. You then need to grind about 4mm off the end of the follower where the adjuster is located. The reason precision isn’t necessary here is that all fine adjustments are made by the adjuster itself when it’s in place.
It’s important to note, though, that, unlike the stock item, you need to fit the adjuster to the follower before you put the followers back into the head. The stock items can be screwed in and out with the followers fitted but the cap on the end of the Porsche adjuster prevents this. It’s no big deal as you had to remove the follower anyway to do the small bit of grinding. In case the amount of metal you take off the follower concerns you, the Club president’s bike has run this modification for around seven years without complications.
One last thing to consider is the follower itself. The followers fitted to the very late model SR400s from Japan have different oil passageways for lubrication and would seem to offer better protection and lubrication at the camshaft end. While the top end is apart, it might be worth considering a swap.
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