"Yamaha SZR660" thread in "Motorbike Chat"
Here's a review of our first (of three!) Yamaha SZR660 written back in early 2001 Engine - 4 stroke, SOHC Liquid cooled 5 valve single. ...

Here's a review of our first (of three!) Yamaha SZR660 written back in early 2001

Engine - 4 stroke, SOHC Liquid cooled 5 valve single. Bore x Stroke - 100 x 84mm
Displacement - 659cc
Compression Ratio - 9.2 :1
Lubrication - Dry sump
Ignition - TCI (Digital)
Starter - Electric
Transmission - 5-speed
Final Drive - 'O'-ring sealed chain
Dimensions (LxWxH) - 2,049 x 740 x 1,140 mm
Wheelbase - 1410mm
Seat Height - 770mm
Ground Clearance - 145mm
Fuel Capacity - 14 litres (2.5 reserve)
Wheels (Front/Rear) - 'U'-section 3-spoke cast aluminium
Tyres (Front/Rear) - 110/70-17 150/60-17
Suspension (Front/Rear) - Inverted telescopic forks / Monoshock
Brakes (Front/Rear) – Brembo Four-piston caliper on single disc / Brembo two-piston on single disc
Dry Weight - 159kg



Owning an SZR660 is akin to owning a very rare and much misunderstood animal. People have always heard of it but never seen one and aren’t exactly sure what it is anyway. Of all the bikes I’ve owned, it is the one that has caused most comment and reaction.
So what, exactly, is it? Well, take one 659cc five-valve SOHC l/cooled single from your successful XTZ trail bike (also, the one used in MuZ’s Scorpion and Mastiff), wrap a TZR two stroke frame (or one like it – I’m not sure) around it, add some inverted forks and a monoshock, dress it in an outrageously styled set of outer clothes and the largest exhaust can in the world and you’ve built yourself an SZR.
Although the engine puts out a measly 47bhp, the bike’s light weight combined with the torque of a big single means instant power on tap. Those of you who ride big trailies will know what I mean. It doesn’t matter what gear you are in, as long as you are above 2,500 rpm the motor will pull and pull all the way to the redline at 7,000. With the standard forty-one tooth rear sprocket, 100mph comes up at just under 6,000rpm and there’s still a bit more to go from there although running big singles at high revs is not recommended for long periods.
But that’s not what these engines are all about. There’s so much torque that at 50mph in top, the engine is only doing a little over 2,000rpm. The real kicking power comes in between 4-5,000 and it’s fun to wind it on in third and feel the front go light as the speedo needle climbs rapidly.
Don’t big singles suffer from a lot of vibration, though? Well, yes, it cannot be denied that this bike vibrates [see below for a different opinion on this], but this is most intrusive at very low revs and smoothes out into a more bearable buzz once things get going.
A contributing factor to the big-single “thud” must be the exhaust can. For some reason, Yamaha decided to put this monstrous can on the bike which must restrict power and doesn’t do the sound any favours. In fact, I read a review somewhere on the Net that likened the sound of the exhaust to a “fat bumble bee denied honey”. At low revs, the sound has been described as, variously, a water pump, an old diesel engine and on my way home around the North Circular the other night I was reminded of a piston-engined helicopter, so you can take your pick.
Sound aside, the bike is a pleasure to ride. The seat is low (both feet flat on the floor anyone?) settling you into the bike with the clip-ons and slightly rear-set pegs completing the racing crouch. The half-fairing is a once-piece moulding that includes the screen which is very effective at reducing wind-blast at higher speeds and the suspension…
The front forks are up-side downies and, like the monoshock under the seat, adjust for compression and rebound. Now, I’m no racer, but not long before buying this bike I took part in a Ducati 748 race school and after that I can now appreciate a bike that handles. The SZR feels so planted through corners and I now know what it means to feel the suspension working under me. I look forward to roundabouts and sweeping corners like never before and even in this foul weather we’ve been having I am still grinning like a maniac when I get home after a ride.
When it comes to stopping, the single disc is gripped by a four-piston Brembo caliper on a single disc. Eye-popping stuff with the standard rubber hose, I’ve just put on braided lines (thanks, Bandit Bikes) and it is nothing short of fantastic now. Don’t ask me about the back brake, I hardly use it. One thing, though. By Christmas, the front caliper was binding something rotten. Why is it that whatever make of caliper you fit to a Yamaha, it hates winter weather with a passion?
It’s not all a bed of roses. The steering lock is pathetic and I’ve lost count of the number of times I’ve trapped my fingers and thumbs between the bars and tank. If you take a pillion, they’d better have short legs and not be too heavy as even with the lithesome form of Kat on the back, the front goes all wobbly and you’d better be in the right gear below 3,000rpm otherwise the engine bogs down. And there’s nowhere to bungy anything on. No hooks or convenient bits of metal (apart from the pillion pegs) and no way of putting a rack on the back.
But forget all that. This bike is all about riding solo. If you can get past the looks, which do grow on you, this is a bike you’ll want to keep riding. I haven’t done any major distance on it yet but it is comfortable, has enough power to safely overtake even up to 80mph, handles like a dream and in the hands of a good rider would probably put many larger capacity bikes to shame around a track (which is where I intend to take mine at the earliest opportunity).
And the icing on the cake? Well, I bought my 1997 P reg model from a dealer. The bike had had two owners and was showing 8,500 miles on the clock. Apart from a couple of gravel scratches on the front it was in excellent condition. The price? With three months parts and labour warranty, a measly £1800. (Edit: ten years on and they're getting harder to find. There's a Yahoo SZR660 group at www.szr660.co.uk which has quite a few members and secondhand bikes pop up there now and and again, usually well under £1200. eBay has them appear occasionally but I've yet to see one break £900)
The British biking public has yet to wake up to this much misunderstood masterpiece and they’re hard to shift. God knows why. We love it.
Rog




Second Opinion
I had seen photos of the SZR before, but when Rog finally brought home our very own bike, she still looked different from what I’d expected. In the flesh? In the metal? She looked more beautiful than any photo could portray. She also felt different too. I had been warned that it was a radical riding position, but it still seemed that despite the number of bikes I had ridden before, this was the first time that my knees were truly sitting up by my ears. Within a couple of days though, I had got used to the position, and it soon felt a very natural way to sit. I also discovered something else. Forget everything you’ve ever heard about men comparing their bikes to sex, the SZR really does make you think about sex. She vibrates. And big time. Ladies…this one is for you! Put away your battery powered toys and climb aboard for a real thrill. I can’t tell you at what speeds the vibrations work best. Different things work for different people, but it’s fun trying. Let’s not have any accidents though. And even if you’re not into toys, the SZR is still a great bike to ride. She’s light and fast, with great acceleration. Definitely one of the best bikes we’ve ever owned.
Kat.

Attached Images

szr sideon.jpg (105.1 KB, 44 views)

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I've got a thing for singles - In my opinion any engine with more than two cylinders ought to be in a car

I used to have an XBR500 which taught me more about riding than any of the fourteen (and counting) bikes that I have owned so far. I'd be interested to see how the SZR compares, after all it has ten years development on the Honda.

*edit* and that can is fucking ridiculous...

Think of it as a free wheelie bin that comes with the bike

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Accelerated ageing made easy

Hmm. Seems a bit soulless compared to the only single sportster (OK cafe racer) I'd really consider - the Yam SRX400/600

We owned an XBR for a few months, a couple of years before getting the first of our 3 SZRs. I can honestly say that the only thing in common they have is the single cylinder layout. The XBR was a great "pootle around town/leisurely sunday afternoon cruise" type bike (we nicknamed ours, Chitty Chitty Bang Bang ) while the SZR is at the other end of the spectrum. The main difference is the suspension and chassis. The SZR was developed by Yamaha Italy for a one-make race series and then got put into production. While it was given that hideous exhaust for the road-going version, the rest is almost pure racer. It did well in Europe but AFAIR they only sold about 400 bikes in the UK in the whole of its 3 year run.

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Protoborg, I got your PM and I would have to say that at 6', you would probably be pushing the outer limits of comfort on the SZR. The petrol tank (130-150 mile range depending on how you ride) has a ridge longways down each side (see pic) for the knees to sit in. I imagine your knees would not fit inside this area and therefore end up being very uncomfortable after a short while. When I finish getting ours back on the road your welcome to pop up and have a test run. It might even be for sale unless I can convince the wife to keep it.

Attached Images

knee cutout.jpg (28.5 KB, 5 views)

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I knew a chap who had one of these. It had some dents in the tank, one set from where the owner had thumped it when it wouldn't start one day (armoured gloves), the other from where the chap he'd lent it to had drop-kicked it after it decided that it was only going 20 miles down the motorway, thank you very much.

I always wanted a go but never got one.

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You sure it was an SZR and not an SRX, as the SZR has a plastic tank.

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You're probably right, I was fairly tired and emotional at the time of posting.

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Worst bike I've ever ridden.

I hated it

Which was a huge disappointment cos I like singles.

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"Force has no place where there is need of skill" Herodotus 450BC

Out of interest (given that I love the bike), what didn't you like about it?

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The main thing was the inflexible motor with it's limited rev range and the off-road gear ratios which Yamaha had tried to cover up with a higher final drive which only succeeded in stretching the gap between gears.

If the revs dropped much below 3k, the drive chattered badly. Much over 5 and the vibration was appalling.

It made the gap between first and second difficult to bridge and for any particular roadspeed there was only one gear that worked - which made it awkward if you were at a speed that wanted neither of them and couldn't speed up or slow down.

...if you could get it started. It was a pig to start when cold and damp.

Aside from that, despite regular cleaning the chrome was peeling off the silencer where it hadn't rusted, various bolts dropped off (with bits attached to them!), the paint was peeling off the tank, and the paint on the sidepanels had faded in the sun. The lights were appalling, the mirrors useless and the forks twisted under hard braking with the single disc.

We had one at the bike school I worked at for two years. Aside from various CB250RS singles, I had an XBR and a Dommie. The XBR was a far better bike, with a much more flexible motor and far better put together, even tho it didn't handle as well, it was much easier to ride faster. The Dommie was a much smoother engine too, despite not having the flexibility of the smaller XBR.

The odd thing was that the engine worked much better in the XTZ.

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The dull copyright bit - feel free to nick it for personal use. If you want to reprint it for your club, I'd like a mention as author. Otherwise hands-off. Full terms
"Force has no place where there is need of skill" Herodotus 450BC

Never really felt this myself. On our first SZR I did change the ratios to give me longer legs on the M-way. Slightly less acceleration but a smoother cruise experience.

Absolutely agree with you about the gap between 1st and 2nd. In town, I was forever dropping down a gear, only to lurch as the box went into 1st.
However, about higher revs, I found that things smoothed out nicely above 5 grand. Never had any issues with excessive vibration.

Only suffered from this after I rebored and tuned the engine with higher comp. Changed from a Yuasa to Deta battery which sorted it. Pre-tune, never had a problem, with any of the three we owned.

The lights are awful aren't they.

Out of interest, are you a particularly large fellow? I'm a fairly sylph-like 62kg and barely 5' 6" and found the bike fitted me like a glove. Can't say I suffered from any twisting forks you described and the mirrors work fine for me.

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Interesting to read Spin's comments.....

It's a much nicer engine in the MZ range of bikes too. My Mastiff would chunter and drag it's feet low in the revs, but was transformed with an 'unrestricted' exhaust, much smoother, you can trickle away from tickover and roll off the throttle and let it drop back to low revs beautifully.

Anyone had an MZ Skorpion up against an SZR and SRX??

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"Unserainer Trinkt Maxlrainer"

Sorry, been a bit busy for the last 2-3 weeks and just catching up

This was a low mileage, almost new bike we had. If it had been mine, past experience with singles would have had me fitting a decent NGK V plug as opposed to the standard NGK - used to make a lot of difference to the starting on the Dommie which occasionally was reluctant to catch.


5'9" and a bit (hummpph) heavier

I liked the riding position, nothing wrong with that but the mirrors really weren't very good and the forks did twist under only moderately hard braking! It's nothing that is obvious until you LOOK round the side of the fairing and watch them!

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The dull copyright bit - feel free to nick it for personal use. If you want to reprint it for your club, I'd like a mention as author. Otherwise hands-off. Full terms
"Force has no place where there is need of skill" Herodotus 450BC