It came in with the usual symptoms – snappy throttle response at low rpm, and it was very difficult to ride in traffic. The open Akro’ cans weren’t helping either. We addressed everything; close attention was paid to the ignition map, when and how much the secondary butterflies open, the emissions gubbins and also the fuelling.

At the end of the job we were very pleased, and the bike felt completely different; smooth rolling on and off the gas, and just plain rideable. And after he took it away, the customer that owns it has phoned us and is over the moon with his ‘new’ bike.

Full ECU remap using Tuneboy equals big thumbs up all round!

It uses an air-cooled XR400 engine, fortunately, which meant all the service items – an XR oil filter, Hornet air filter – fitted. But the bike also needed an MOT, and its indicators were going at 300mph, and this is where the problems of owning a grey import started to surface. We had a look, and found that the flasher relay’s wiring had been altered; when we put it back to standard, the two front lights dimly lit up as sidelights.

To sort this to UK-spec would need a wiring harness strip, another switch plus a lot of messing around. We explained this to the customer, so he just had it put back the way it was. The law states between 60-120 flashes per minute is permissible, and this thing was doing well over 240 per minute.

Some grey imports are easily swapped over, others aren’t. This one certainly isn’t.

It's got a certain classic style, has this CL400, but also indicators that flash like crazy!

It’s not bad at idle, or generally running around, it’s where you’re hanging onto the throttle but not opening it; like at fixed cruising speed with a negative throttle. 70mph is the danger zone here, on a trailing throttle, and let’s face it that’s the sort of speed (and use) that we do a lot, and this is where the engine runs dangerously short of fuel. The lambda sensor is trying to lean the mixture out all the time, and the lack of back pressure or catalyzer just makes it worse. Accelerating to this point is no problem, but once you get there, and stay there, it’s bad; sit on the motorway at 70-80mph on a steady throttle and you’re not doing the engine any favours at all.

The only solution at the moment is a Power Commander PC V and 02 Eliminator kit. We bolted both on, and focused the Dyno work around the mid-high rpm ranges and richened up the fuelling. After the work we didn’t have any major horsepower gains, but we really weren’t looking for any; instead the throttle response is much plusher and ‘fatter’ at high rpm/small throttle openings. The extra fuel really helps take the harshness out of the engine’s feel, and also ensures the life of the valve train and pistons…

Lose the standard can without sorting the fuelling and the engine in this CB1000R is headed for disaster...

Our job for him was to do a Dyno ‘shake-down’ run post engine-rebuild and give it a thorough check over. We ended up removing the PAIR emissions valve and adjusted the pilot jets, and basically gave it a gentle pre-season fettle. We also tweaked the chassis a touch, just small things we’ve learned over long experience with these bikes that really make a difference.

Have fun, mate!

Fully fettled and ready for a Summer's fun – Andrew's cool little Hornet...

When we sold both to him originally we explained that it would only switch, through the Power Commander, on the bottom injectors. To get it to cut the top injectors (for a much faster change) would need a HUB and ignition module for the PC III, making it an expensive job.

He’d lived with it a while, but really wanted a faster gear change, so we upgraded his Cordona set-up to PQ8 with full loom and ECU. This is the great thing about the Cordona system; it’s very transferable and upgradeable bike to bike.

He’s now got super-slick and sweet gearshifts.

A full Cordona loom and ECU cuts the top injectors of this PC III equipped GSX-R600, much faster shifts are the result.

We started by blanking off the secondary air ­and adjusted the airbox itself as they’re quite restrictive. We then fitted FJR inlet rubbers as they have a bigger diameter than the stock XJR items, then added a K&N filter and corrected the fuelling on the needle and pilot jets.

And Bob’s your uncle! Power rose from just shy of 100bhp to 110bhp, with much nicer throttle response all-round.

Getting this engine through emissions testing didn't help it in the long run...

We remapped the MAP (Manifold Air Pressure) map and the main fuelling table and also switched off the SAI (Secondary Air Injection) and the lambda sensors. It made good power after the work; 7bhp up on stock with 116bhp at the back wheel but, more importantly,left our workshop with an ECU brain devoid of EU interference that worked much, much better all round.

Good job!

Stealthy Triumph Tiger now has an ECU to match its open can and K&N filter...

Anyway, in the off-season he’s taken our advice and fitted an Arrow system which has transformed it – after mapping to suit the engine’s now punting out just shy of 193bhp in open exhaust form. The pipe comes with a baffle, so we did him an alternate map to use with it in place, so when he’s testing on a circuit with tough noise regs he’s ok. Admittedly, peak power is down to 180bhp, but there you are. These Kwaks really need to breathe at the top end; up until 9-10,000rpm there’s very little difference.

Good luck for 2012 Simon!

Dual maps for the Power Commander work for baffle in or out of the Arrow can.

We sucked the stock map out of the ECU and took a good look. It was carrying way too much ignition in the low throttle and rpm range; with  on/off throttle use the power came in way too hard. It was a vicious thing! First job was to take some ignition out and then sort the fuelling to match – it was running very lean (even with the stock can fitted). We looked at the throttle bodies, as it appeared that in an attempt to balance them the air bypass screws had been well and truly ‘adjusted’, causing all sorts of issues with running on and so on.

There’s more work to be done to this bike. We’ve taken a lot of the harshness out of it and calmed it down, but more needs to be done for us to be 100% happy.

This bike came in with myriad issues – we've sorted the main ones, more needs to be done.

The digital throttle is gone, and the carb-style analog feel is in its place...

He wasn’t looking for any more performance out of the engine (which, to be fair is common for most of the 990 Adventures we remap, as most owners are happy with the overall performance) but just wanted it sorted out as he wasn’t happy with it at all. He’s got other bikes, and his last words to us as he left were “If you can’t fix it I’m off down the BMW shop to get a GS…!”

We rode it, then downloaded the stock map. Fuelling adjustments were followed with work on the secondary butterfly valves, as when and how much these open is critical to how the engine feels. The ignition was next, and is an area we spend quite a lot of time because fine-tuning here nets big results for throttle control.

The bike is now rideable at slow speeds, high gear small throttle opening and has the Holy Grail (that the old carb’d 950 had) of an ‘analog’ rather than ‘digital’ feeling throttle. You can barrel up to a corner and it won’t scare you – and it did before.

That’s one less GS sale, anyway…