www.boxertrix.com

I've been asked a couple of times now if I have a website that details the changes I'm making (and have made so far) to the BCR. What little comments I've made so far are spread around in threads that went off-topic so I'll coagulate the principal here and the add to it as I go onwards.

Apologies to those who may have seen the first few posts before.

Firstly, a rapid synopsis from the beginning:

November 2009:

At my local dealership looking at the wrecked mess of what used to be the Right Hand Cylinder of my 12GS after it lunched a valve for the 2nd time. Leaving the ICU workshop, idley wondering how I was going to get to work after being told that it would be at least two weeks before the parts came in and maybe even longer, when I spotted this on the ramp:


It was a trade in that hadn't been treated very well but was mechanically sound even if some of the bodywork was less than perfect. Well, negotiations were entered and a couple of weeks later it appeared at home:


So I took it apart again to get it how I wanted it, to service it and remove some of the more useless accessories that the PO adorned it with:

June 2010: Standard Engine Baseline:
I'd decided to spend some money on the 'Cup in order to make it go more like it should. As a start, I thought it'd be best to get a baseline from the engine.



So to the results. The bike is as standard in its setup as I can get it, with valve clearances of 15/30, the standard Laser 'zorsts and Catalytic. TPS was set for 380mV and the air intake/snorkle system are the standard items.

We did lots of runs that day, the best of them was the third run with the standard BCR pinout setup (Gray CCP) pins 2+6+8 shorted:


So there is my base line, my standard 2004 gives 83hp and 64torques with a fairly linear attitude until 6K when it gets a bit cranky. Using a range of upgrades. I think I can improve it a little.. "

June 2011 - Maxxis Tyres Fitted
With the upcoming Trackday in mind I was looking for some tyres with a little less tread and a little more dry grip. Maxxis have a good reputation in Super Moto circles. Grippy and Cheap. A quick troll around on the 'web yeilded a delivery. Add about 40 minutes work with some tyre levers and I have new (hopefully sticky) rubber all ready for Snetterton.

August 2010 - Snetterton BMW Trackday:

With the BCR ready:


And everything loaded:


It was time for my first bike trackday in an awful long time. With some old (somewhat tight) leathers on a middle aged bloke on a middle-aged bike with new tyres on a circuit that I'd not been to before, it was clear that I wasn't going to be able to get right down to it even before the weather went downhill. But eventually, I started learning how to get the BCR to circulate nicely:


With the Sun reappearing as we cleared away ('Natch!). I felt pretty happy with the bike all in all. A couple of things were niggling at me, but I didn't have enough data to develop the thought beyond the intial impressions that that I needed more power in 5th and 6th and that the brakes were ok but not scintillating and that the way the bike turned in needed atttention. Nothing drastic was wrong though.
Homeward bound:

Thanks for starting the thread Damo.

Thanks Dude - onwards then so I can get to what I've been doing recently.

From April 2011 - Maxxis Tyres and MCTechnics Visit:

I have a pair of Supermaxx's on my BCR. Brilliant tyres. Warm up quickly, grip well in all temperatures. Not bad at all in the rain for a tyre with very little groove/tread, dont square off (or hasnt yet anyway) nice feeling on the power, dont skip or slide. All in all, for the £130 that paid for them a few months back, a perfect solution.
They even hit the magic 50degC on road pressures at Snetterton last year - in some pretty crappy weather.

I Loved 'Em.

Until I went to see a well known suspension guru in the Fen's [Darren @ MC Technics]. On my mind was getting my 04 BCR to feel like the '10 HP2 I rode at Snetterton (back to back with my BCR!). Yes I know it wont ever be quite as good as that but, oh never mind. The point is this:

I had some Michelin PR2's on before this set of Maxxis and both tyres give a pronouced "Gyro Effect" if you use the front brake on the lean. I mean use the front brake *at all*. If you are dragging the brake when you turn in and release it, the bike falls on it's ear sharply. The opposite is true also - If you trail the brake after turning in, it'll stand up. Both these effects are very pronouced. Not Dangerous in any way, espesh after I'd figured out what was happening, but annoying all the same. Certainly bad enough to keep me thinking about the bend entry instead of planning further up the track ahead.

I mentioned this to Darren and he suggested that the problem may be caused by the front tyre. It isn't designed for the wieght of an R1100S plus a 16stone idiot lurching it through a bend and reacts by collapsing nder the force, causing the bike to stand up. He further prescribed a set of Pirelli Supercorsa BSB's - they have a much stiffer construction and are less prone to collapse under load thus lessening the gyro-effect.

This makes much sense. So I have a set lined up for fitting tomorrow afternoon, right after my next Dyno session.

To get back on topic then, I love the Maxxis tyres. The *only* issue I have with them is this gyro problem on the way into a bend. I will be keeping the ones that come off, just in case the Pirelli's dont fix the problem.

I know you shouldn't be braking into a turn anyway, but every GS I ever had (and the RS) can take a hard stab on the brake lever with minimal standup and a gentle trail during the entry/apex transition goes completely unnoticed.

Handy, I find, cos I'm a bit greedy going in most times (I hate slowing down), and need to scrub a little to make the apex fit....

A little while later and I'm back at MCT with the BCR for some light suspension work to make the BCR better for Trackday use.

Modifications only to the standard Showa units front and rear (cant really afford to change the struts) and also on his advice I changed the tyres from the Maxxis units I had for some Pirelli SuperCorsa's.
Money well spent I think, as the bike feels much more confident now and tips into a corner with nice predictabilty and just the right amount of wieght. Prior to Darrens work it could be a bit of a struggle to get the front into a corner smoothly with too much effort required leading to over-corrections and a choppy turn. Now its butter smooth, easy and predictable leaving me able to focus less on the bike and more on the turn itself.

Money well spent and more or less standard too - only the rear spring was changed for a custom unit.

Everything esle was re-valving and adjustment.

Cant fault Darrens service or prices. I couldn't have made that much difference for less money.

Even when I do eventually get some Ohlins for it, I'll take it back to Darren for setup - he's that good...

It looks like you have the R1100S torque arm fitted to get it to turn quicker a GS torque arm can be got cheaply think i paid about £15 for mine

Hi Dai,
The shorter torque arm was fitted as standard to the RWB BCR's - partly to speed the steering up its true, but also (along with the front lower legs from the GS) to raise the bike up to give more ground clearance and so give a better lean angle before the heads go down.

The explanation I heard was that it was a deliberate move from BMW to use those parts on the Series 2 BCR's (the Red, White and Blue ones like mine) so that the teams in the Boxer Cup could use those parts for competition under the Tech and Homologation Regs for the Championship.

Changing the torque arm on a 'normal' R1100S will speed up the front for sure but for the full effect, picking the front up off the floor is required (or MotoYoyo's Pivot point mod will do similar - Tanneman has done that on his R11S and reports a good condition).

Another, purely mechanical, benefit of the shorter T.Arm is that the rear UJ runs much straighter and that can only help to generate less wear on the driveline. The down side is that the seat height is much greater.

I have been looking at yours and am thinking my driveshaft is straighter than yours could be an optical illusion though
another benifit of having the rear U,J, straight is it will sap less power from the drivechain minimal i know but on the track every little helps
[img][img]http://i902.photobucket.com/albums/ac230/daiwiskers/002.jpg[/img][/img]

From June 2011 - Phase 1 Engine Works:

"The BCR is back in one piece after spending longer than planned like this:



The Various bits I did included:
Exhaust-Box de-cat; In an attempt to prove that loosing the 'Cat would be worth it without the cost of buying a centre-pipe, I found my grinder, opened up that big, ugly, stainless box that lives under the swingarm, took out the 'Cat and had it welded back up again. The idea was only to increase the gas-flow by getting the 'Cat out of the way.

BBPower Chip:I fitted this initially to raise the rev limit for the track and give me (and my tuner: Simon @ Race Engineering of Dunmow) some easy mapping options for fuelling. The BBP uses the same connector as the BMW Cat-Code-Plug, although the pinouts are different. I already had the CCP connection extended out to my headstock from earlier CCP testing so it was easy enough to change the index so that the BBP mappings were accessable quickly just by shifting the jumper wires just behind the headstock. I later changed all that for a rotary switch on the dash:


Balance-Pipe de-restrict; The cross-pipe that joins both of the main exhaust downpipes together has a restrictor in it. It looks a bit like a washer with a 12mm(ish) hole in it. From what I can find online, the idea is to improve the scavenging effect and increase torque at lower engine speeds but as I needed power at high RPM, I got rid of it.

I also did a full lube service (with slightly reduced Gearbox and FD quantities to reduce drag), strip and lube the drive shaft joints and splines, plus resetting the valve clearances and rebalancing the TB's.

While I had the bodywork off, I took the time to replace the slightly tatty rear indicators (shown above), which are mounted on the bodywork with a smaller pair that are mounted on the 'plate hanger. This makes for a much simpler, wiring loom in the rear of the bike and makes switching into and out of Road-Legality much simpler and faster at MOT time:


So now that its had the first round of mods it was due its second Dyno day:



So thats 88hp with 65torques - moving in the right direction....

Yup, Yours is certainly straighter. If anything, it's a little 'downturned' if that makes sense.
But dont forget, that angle is also a function of the length of the rear shock too. I'm guessing that you have a Nitron replacement and that we dont have the same rear shock length's - making the FD-UJ angle different. Not too mention the ride height - mine is tall but your looks even taller but has the 'low seat' option saddle...

damoace wrote:Another, purely mechanical, benefit of the shorter T.Arm is that the rear UJ runs much straighter and that can only help to generate less wear on the driveline. The down side is that the seat height is much greater.

I would question this! That would only be true if there was only the one UJ, but there are two. The reason that there are two is that the rear one cancels out any out of alignment vibrations and pulsing caused by the front one - the same as in any drive shaft or propeller shaft on a car! If the rear joint is straight, then it just passes the vibrations and pulsing from the first joint straight through to the rear wheel!

http://en.wikipedia.org/wiki/Universal_joint

For your purposes, where handling and road holding are paramount, it is absolutely the thing to do. If tyre life and minimising vibrations are important then you need to make an effort to make the bevel drive input shaft to be parallel with the gearbox output shaft. Usually the length of the rear shock is the only way to address this.

Brilliant thread by the way!! Lots more please.

sandbar

sandbar wrote:

damoace wrote:Another, purely mechanical, benefit of the shorter T.Arm is that the rear UJ runs much straighter and that can only help to generate less wear on the driveline. The down side is that the seat height is much greater.

I would question this! That would only be true if there was only the one UJ, but there are two.

Any transmission which produces a side thrust - will lose power, when compared to one which runs in total alignment....... I'd have thought?

The side thrust of the second UJ cannot 'cancel out' the side-thrust of the first - it should double it?

Al

sandbar wrote:

damoace wrote:Another, purely mechanical, benefit of the shorter T.Arm is that the rear UJ runs much straighter and that can only help to generate less wear on the driveline. The down side is that the seat height is much greater.

I would question this! That would only be true if there was only the one UJ, but there are two. The reason that there are two is that the rear one cancels out any out of alignment vibrations and pulsing caused by the front one - the same as in any drive shaft or propeller shaft on a car! If the rear joint is straight, then it just passes the vibrations and pulsing from the first joint straight through to the rear wheel!

Correct. Back in a previous career we had to replicate the high torsional vibration on a test rig caused by the (then new) technology of dual mass flywheels being added to vehicles.

We did this with a double UJ arrangement with deliberate misalignment of UJ angles to accelerate failure of the accessories through the increased torsional vibration.

What you will have when you 'straighten' the second UJ is a torsional vibration through the wheel, in other words your wheel will be turning at varying speeds with each rotation of the drive shaft, with a corresponding increase in vibration through the final drive.

Whether this causes problems or not is another matter. Certainly it seems that the final drive on the 1100 is robust against a certain degree of misalignment.

I would not be happy doing this on my 1200 though. The final drive would seem to be fragile enough as it is.

Autumn 2011 - BOS Exhaust fitted.

I was lucky to be looking at Ebay at exactly the right time and managed to win a BOS 'Cat-Back' system for the BCR at a reasonable price. Although not common in the UK, they have a good reputation, both in Europe and with our neighbors across the pond.
After years of fitting various Remus exhaust's, I liked the build quality of it and that it's a 'twin-pipe' system all the way through (unlike the centre-section that I played with. There is a crossover in the main chamber although it's a very small apature at only 10mm wide by 20mm long. It also has neat plate hanger mounting bosses that made moving the plate hanger over very easy. There is a weight saving over the original system, mostly because it has no 'Cat, but even when factoring in that my franken-no-cat-in-the-box is lighter than the standard system, the BOS is lighter still - perhaps a kilo or so.

Side-By-Side Comparison:


It was a bit of a pfaff to fit, but looks good on the bike. Sounds great too - A nice grumble but not too loud, even with the baffles out and still passes the famously strict drive by tests at Bedford (albeit with the baffles in):



Of Course, it's useless if it doesn't flow correctly and all this is, after all, about increasing the performance, regardless of aesthetic attributes. So I need the dyno to see the real effect and that wont happen for a little while. I had a booster plug hanging around so I stuck that on until I can get the F/A ratio checked - just to make sure its protected against any unintended lean condition.