I have owned an SZR660 for 18 months now. It was my first new machine, the first disappointment was the build quality, but since you get what you pay for and they are really cheap it's almost okay. The second was the lack of power, only discovered after running in for some weeks. I should have figured forty something horsepower wouldn't crease any tarmac.

My inbuilt need to adjust / modify / spend cannot be held in check for long. My first change was to junk that huge exhaust. A 14" long carbon can was found and a piece of pipe was made up at a local exhaust fabricator. With a new bracket the can fitted nice and tight. The rear footrests were junked too. The hideous number plate arrangement was attacked with an angle grinder (cuts the plastic a treat) The plate was moved up and the light binned. Much better.

With the can I fitted a Dynojet kit. Small change, probably just the increase in noise. If you fit a kit use the small drill (not the large one as I did) I cut the top of the airbox about to leave a plastic ring to hold the K&N filter in place (about 10% more intake area to the filter). The bike looked much better and what noise, at low revs and large throttle openings (easy on a single) the bark was fearsome. It would calm down as the revs rose but it was close to 105db if not over. At least the low revs of singles and the low frequency of the noise seem to offend fewer than an open pipe on a multi.

Tyres. You can't have any fun if you are not comfortable with the tyre fitment. I don't ride like an idiot on the road but I would rather have the grippiest tyres than wish I had. I have fitted several sets of second hand race tyres following the demise of the standard set (that took some hard work). Because of the SZR rims size and the commonly available raced tyres I had to fit 120 / 160 oversizes. Availability in 600 racing of these sizes is now limited, most use 120 / 170 a few still fit Dunlop k364 160's. A Dunlop 120 D207GP and 160 D364 were squeezed on. The distorted profile means you cannot get to the edge of the tyre. The lack of power means they last okay.

I used the bike on two track days (Lydden Hill in Kent) in this form. The light bike, forgiving power, tight circuit and superb handling could take a mediocre rider like me past much more exiting kit. Track days get my maximum recommendation. You can ride fast on the road but you can ride to your limit on the track.

The seat and tail unit on the SZR is a poor job. The trainee stylist worked on this part. Now it's all in the bin too. I have a race seat from a 1998 RS250 Honda. With much jigsawing and use of DIY fibreglass kits and a paint job I have a neat well fitting but no comfort replacement. A new rear lamp was found and some foam stuck to the seat and job done.

Engine: 42 or 43 horsepower is okay for about ten minutes. After that you spent the whole time with the throttle on the stop and watching the rev counter. You cannot afford to hit the rev limiter, at 7250 the bike just stops. I spoke with Slipstream in Kent. The affordable tune consists of a 102mm piston and gas flow. I say affordable, any engine work is not affordable. Parts and labour cost real money. A tune as described will cost at least £800 and yield perhaps a 10 -12 HP increase. I don't want a bike that looks like a supermono racer and has 55 HP. I want 60!

You can have what you want you just pay for it. The 102 piston was fitted, the head gas flowed, a Carillo rod was fitted and new valve springs with titanium caps (the only bit of titanium on the bike and you cant even see it). The motor was replaced in the frame and fired up almost immediately. Hurragh.

After running in another track day came up, same circuit. The bike felt stronger all round but not strong enough for the large outlay. It was still fitted with the 7250 rev limit and the standard header pipes. Now I guess it was putting out maybe low fifties HP. Poor. I expected much better for the investment'. I lowered my expectations. Most tuning is effective in a limited way, if you are racing in a particular class the chances are that everyone will have similar power, a small difference will make a useful advantage. On the road it will not be noticed. However...

Singles need to breathe. I was put in touch with Tony Cook in Catford. Maker of race exhaust systems. Both Slipstream and Tigcraft rate his work highly. New header pipes, two reverse cone megga's in each pipe and two cans were made and fitted in the week the bike was with Tony. Because of the chain run and side stand both cans were routed on the RHS of the bike.

Wow. The first ride made the whole expense worthwhile. From 6200 ish in second, third and fourth the bike lunged to the limiter. Big grin factor. There was massive drive in the lower gears and the limiter could be hit in top gear.

One small detail to sort. That rev limiter. You may know a TDM850 CDI box will remove the limiter (but ONLY a 3VD version). If it doesn't say 3VD in the part number it won't work. You try and but one. I called all in MCN - no joy. Eventually I found one for £60 great news, almost. I was not aware of the previous warning. I found out that the unit was from a grey import jap spec model - no good. A proper race ignition is upwards of £340. A guy at Tigcraft can modify your box and move the limiter up to 9000 for a suitable sum.

This done the bike was run on a dyno to check jetting (changed to 195) and power. With all the mods the bike was making 59 at 7250, following the moving of the rev limit the power peaked at 65 at about 8000. It does not want to rev on to any great degree which is lucky. Regularly revving to up to 8500 will keep the crankcase life short and beyond to 9000 will cause tears for sure.

Sixty five. The bike is transformed. It will run to lower revs without snatching or jerking, it drives from corners and anywhere superbly. Well recommended (you could go and buy an RS250 Aprillia or RG250 and have a similarly nimble machine but you can't do it with one cylinder)

I have just fitted a pair of the correct sized Michelin Pilot soft race tyres. The next outing is 24th July at Lydden. See you there. 

Andy