Mike's Suzuki RE-5A

The RE-5A is the black motorcycle in the foreground, that's an Allis Chalmers forklift behind it if you are having trouble figuring out which is which.

What's an RE-5?

The Suzuki RE-5 was the first truly mass-produced Wankel rotary engine motorcycle. It is a single rotor, 500cc vacuum staged peripheral port engine that puts out 65hp at 6500rpm and 55 lbs/ft of torque at 3500. Empty weight is just over 510lbs.

My bike is slightly modified and lightened. Power is estimated at 75hp (based on increased fuel consumption over stock) and empty weight is down to around 440lbs.

So what's the difference in an RE-5 and an RE-5A?

The RE-5 was first offered to the public in 1975 and had some wild styling features. The instrument cluster was a chrome cylinder with a green tinted clear plastic cover which flipped down and locked with the ignition key. It also had a cylindrical tail light and spherical turn signals. The engine was equipped with a complex vacuum operated system that fired the spark plug twice at low rpms for improved performance and reduced emissions. It also featured an automatic chain oiling system, which was basically a constant oil leak.

The RE-5A was the final model produced in 1976, and was simplified and much improved. The wild styling gave way to a more conventional instrument cluster, tail light and turn signals borrowed from the two-cycle, three-cylinder GT-750 (also known as the "Water Buffalo"). The dual firing ignition system was discarded (it suffered no reduced performance) and the chain oiler was blocked off.

Is it a good bike?

Compared to modern bikes, the RE-5 is slow, heavy, crude handling, quirky, and it is extremely hard to find parts for it. That said, it is a very capable highway bike (except for that narrow seat!) that can run for hours on end in any kind of weather thanks to its water cooling system.

Wait, I had an RE-5 and it didn't have one of those on it!

My bike is not stock to cure some of the quirks, but all modifications have been done so as not to be irreversable and all the original parts are safely stashed away.

The first problem I attacked was the original exhaust system. It is nice and quiet, but it weighs about 45lbs and tends to fall off about once a year. This is due to the finned aluminum exhaust manifold that is used to split the exhaust into two streams for the dual mufflers. The great difference in thermal expansion causes the studs that hold the pipes onto the manifold to loosen, then it blows an exhaust gasket. Finally, the studs wallow out the holes and they have to be heli-coiled and the process starts again.

After a few times of this, I went down to Kirk Racing, a company here in town that builds headers for many afermarket companies, and had them weld up a 1 3/4" stainless header. A Supertrapp megaphone capped it off for an all up weight of around 5lbs. Performance was much improved after rejetting the carb, but it is LOUD. I spend a lot of time riding alone or stay in the rear if riding with a group.

Where possible, I have also replaced all the rubber cooling hoses with some braided steel lines I scavenged at local thrift stores and a surplus industrial supply house. That only leaves the connection from the radiator filler to the radiator to be replaced every couple of years. This piece can be cut out of the return hose for a VW Golf Diesel and only costs about $11US.

I currently run Mobil 1 synthetic in the engine, tractor type hydraulic oil in the gearbox, and usually Shell 10-W30 in the oil injection tank. Synthetic should not be used in the oil injection tank as it doesn't burn very cleanly in the engine, and should never be used in the transmission as it will ruin the clutches. The oil filter is interchangeable with one for a Toyota Starlet and the Suzuki Swift and Samurai.

I have a installed a small windscreen and a set of low, flat aftermarket handlebars as the original bars were so high it made long high speed riding very tiring especially without the windscreen. The improved accelleration with the added power of the header and greatly reduced weight also made hanging onto the original bars a challenge at times! I have removed the electric starter (they burn out pretty quickly anyway) and the centerstand for further weight reduction.

Then how do you start it?

The RE-5 is VERY difficult to kick-start, until you get the hang of it. The problem is that the engine fires every time the crank makes one turn, so you can't get it at the bottom of the exhaust stroke and get a running start like you can with a British twin or Harley. Endless fun can be had by letting your biker buddies have a try at kicking it. The victim delivers an earth crunching kick, only to have the kick-start lever remain motionless and then slowly ease to the bottom of its travel.

The technique is to get at the top of the compression stroke and then give it a smooth push, not a sharp kick, using all your weight as well as a good pull on the bars to help out. If it doesn't start in two or three kicks, cold, or one hot, it is about to foul a plug or is flooded. Always carry a spare plug and wrench under the seat!

Spark Plugs

The plug used in the RE-5A is the NGK A9EFP. It was made by NGK for Suzuki, specifically for the RE-5 and fits nothing else on the earth. Your Suzuki dealer doesn't have them, NGK doesn't have them, the only place on earth that does is Rotary Recycle, and they aren't cheap. $35 plus US. You might get lucky and find a stash of five or six long-forgotten plugs in some god forsaken corner of a desk drawer in an old Suzuki repair shop. If so you can get out at about half price. Sam Costanza of Rotary Recycle has usually been there first, though.

Other Parts

The good news is that the spark plugs are the only bad news. Rotary Recycle has about everything else you could possibly need and Sam's prices are very reasonable. If Sam doesn't have it, though, you are in real trouble. Get a parts bike or two. Rotary Recycle is at this link. Rotary Recycle

BEWARE!!!!

If you do indeed own an RE-5A, or are considering buying one there are some definite do's and don'ts.

Do keep it up and take care of it. These bikes have already hit bottom and will certainly become an excellent investment. They are very rare in good running condition, and still fairly affordable at this time. They are not for everyone, but if you want something truly unique the RE-5 certainly fits the bill. Every fuel stop will take you longer than you expect due to curious onlookers.

Don't use synthetic oil in the oil injection tank or the transmission for the reasons stated above. Don't use automotive motor oil in the transmission as it will also ruin the clutch discs.

Do learn to work on it yourself. The RE-5 is a very different machine from the standpoint of its engine and supporting systems, but otherwise it is just a typical 1970s vintage Japanese bike. There is probably noone nearby that knows any more than you do about the RE-5 at this time, unless you can find a mechanic that worked on them when they were new. Buy a manual, be very careful, and ask a very good mechanic (experienced motorcycle, auto, or better yet an aircraft mechanic due to the great understanding of complex systems) if you hit a snag.

Don't drag race! Yeah, it's dangerous on the street, but more importantly, second gear is very weak in the RE-5, a good hard first -second shift off the light will snap a tooth off the gear...ask me how I know.

Don't ride with a loose chain. It will pile up in the drive sprocket cover and break it. It will also eat the beautiful stock aluminum driven sprocket. (I didn't do that one, but I have seen the results.)

Don't run it hot. If it springs a water leak, park it immediately. Overheating is the one thing the rotary is totally intolerant of. It will not stop running, but it will ruin the plating on the inside of the rotor housing in minutes. Then you have to buy a new engine.

Of course, make sure it has oil in it, too. There are three oil capacities to be aware of.

The engine oil sump must be checked with the bike level, otherwise it will run out all over the place when you unscrew the filler/dipstick...again, ask me how I know.

The transmission has no level indication, so if you develop a transmission leak, fix it right away and refill the transmission to the proper quantity.

The oil injection tank is to lubricate the internal engine seals that take the place of piston rings. It should be filled with a high grade 10-W30 motor oil and there is a light on the panel to tell you if it is low. Don't let it run out or you will get a bubble in the line, which will cause the injection pump to air lock and stop delivering metered oil to the carb. You will be buying a new engine if that happens.

If anyone has questions, feel free to contact me at... micallahan@worldnet.att.net
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