Sport 1100i More Detail And Steps Along The Way

When I wrote the Sport 1100i report I pretty much gave before and after without a lot in the middle. Plus, with the exhaust playing I’ve been doing with the 851 I figured some of the results I got may be of interest to others. So this report expands things a little (because I tend to crap on a bit more now too). Back when I was playing with this bike I didn’t have the dyno technique I have now – this was before Dave and Steve at Dynobike gave me free use of the dyno. Dyno technique is something you tend to work out for yourself, based on what you are trying to achieve. Meaning some of what was done, and the sequence, leaves a few gaps. And the descriptions of what I was actually testing are a bit vague in a couple of spots. Many of the runs end below the red line too, as they were usually reluctant to run them to the very top. I usually run things to the rev limiter when I’m testing, basically because the rev limiter is there for a reason. Finally, there seemed to be quite a bit of session to session variation, meaning I may have been playing with tune between sessions and not noting it, or the bike was more susceptible to atmospheric conditions than others I’ve experienced. In light of this, I’ve tried to compare runs from the one session where possible. This is why it may seem to make more or less overall power from one graph to the next.

So, I’ll do my best to be as clear as I can. All runs were done in 4th gear, which hit the rev limiter at a bit over 200 km/h according to the speedo. A very nice gear it was too, although running out of corners in 3rd, up to about 160 km/h was my favourite.

First I started with an all std bike, probably with 1,500 or so km on the clock. The first runs were made on the 30th of May 1998, about a month and a half after I pulled it out of the crate. A most exciting time. I ran the bike all std, then using the FIM Megazone chip I added and subtracted a little fuel. Just to see how it was std. Turns out it was pretty good for the dyno. Red is all std, green is -5.4%, blue is +10%.

The next step I’m not overly sure about (well, I was until I started typing, then I remembered it a bit more). It was about this time that I crashed my new pride and joy, falling off at very low speed at the end of my street on the way in on a Saturday morning. No reason I could see, apart from crap on the tyres from the path around from the garage. Went for the brake, found myself sliding along the road. Adding injury to insult (I was un-injured to that point) I tried to pick the bike up from its side particularly badly, burning the inside of my hand on the header pipe as I did so. Not happy. As this was the start of two weeks off to make mufflers for the Sport and the mighty KR1S, it put a damper on things.

So, I believe the next sets of runs were for my nice alloy mufflers with the otherwise std exhaust systems, being header pipes and “pong box”, as the central muffler (I’ll call it the x-over) seems to be rather unkindly referred to. The next graph shows some tuning runs with them fitted. Red is mufflers fitted with std fueling, green is +6.2% fuel over the whole map, blue is the same with zone 7 at -10% (from 5,700 ish upward), yellow is same with zone 7 -15%. As you can see, it wanted more fuel below 5,700 RPM, and less above that.

Compared to the all std runs, however, it was a bit of a mixed result. More down low where they were fairly crappy std with less at the top end. The all std exhaust made as much or more power above 7,500 RPM than any other system I had on it. Which is good for brochures, but shows the typical way production exhausts tend to limit mid range performance. Although this system from Guzzi always seemed particularly bad in the 3 – 4,000 RPM range. Red is the best from the graph above, green is all std.

The reason the previous runs were done with the std x-over was that I was waiting for a new x-over to arrive from Italy. When it did, it was a Mistral piece that looked a little odd. I couldn’t quite work out why at first, but later realized the tube used was one size smaller than std – 42mm ish compared to 45mm ish. On the dyno - this time I think we were running std mufflers again, not sure why – it was a similar result. More mid range, less top end. Bugger. Red is Mistral x-over with otherwise std exhaust, green is all std.

With this result, I decided to make my own x-over. Not too hard (he says in reflection), I made a jig using the std pong box x-over and went from there, using 1 _” mild steel exhaust tubing. Not overly pretty, but it was my first effort at custom exhaust stuff. Not to be the last on this bike. It was fitted and tested with (again, I think) std mufflers. That’s what the run notes say, but I can’t work out why. Although I did have my mufflers polished and anodised after I’d made them, so they may have been out while I was doing this. Anyway, compared to the all std and Mistral x-overs, it did fairly well. To the previous graph, with Mistral x-over in red and std x-over in green, I’ll add my x-over in blue. Best of the bunch overall on average I’d say.

Using the speed versus time scale you can see that the acceleration of the roller with my x-over was much better, especially through the mid range. This probably says more than anything else about how it worked.

At this point I was getting a bit despondent about the mufflers I’d made and why they weren’t working as I’d hoped. One of the reasons I think was that the perforated tube I was using had quite big holes, and it was also rolled to be about 50mm ID, where the muffler pipes leading into them were about 42mm ID. This would slow the exhaust gas down as soon as it hit the mufflers, and may very well have been the problem. But, I was also concerned about the length – they were very long (coz I like long mufflers) – so I cut them down, from 500mm or so to about 400mm from memory. The graph below shows some playing with this. I don’t know if I have a run for the long mufflers with my x-over – nothing is noted as such – so I’m not sure how systematic my method was at this point. Anyway, the base system at this point was std header pipes, my x-over, std muffler pipes and mufflers as specified. Green is my mufflers shortened, red is no mufflers at all, blue is with some Hindle mufflers held in place for a run and yellow is all std for reference. The blue line is what convinced me to use the Hindles.

So I bought some Hindles that Dynobike (the importer) had laying around. These turned out to be TL1000S mufflers, of which they had two pairs that no one wanted (fitted to a TL the bolt up face finish was less than desirable – as I fitted them they were great). Compared to the ones we held up for a test they were quite a bit longer, which was how I liked them, so I was happy there. When I ran them fitted they were down a bit on power, but were still the best fitted combination I’d had. To me it looked and sounded great. The next curves show how they compared to the others. Red are the Hindles we held up, blue are the TL1000S ones fitted and green is all std.

Next I started making a complete system, sort of a combination of the std and Staintune systems in style. I used the 1 3/4” mild steel tube for headers, 1 7/8” for the x-over, then 2” out of the x-over and into the mufflers. This works out to be 43.6mm, 47.6mm and 50.8mm OD. The mild steel tube is quite easy to work with and make into a system. Any size will slip nicely into the next size larger, as the size jumps are 1/8” and the wall thickness is 1/16”. This was HPC coated in satin black when I’d finished it. Very nice with the Hindle brushed finished mufflers I thought. It’s the system shown in the photo in the original report.

First up I made the headers – well, I got them mandrel bent and cut them to length – so I tested them first. Performance wise there wasn’t much difference – a little less at the bottom end. These runs don’t have the RPM trace, so are road speed based. Red is my headers, green is std headers. The rest of the system consisted of my x-over, std muffler pipes and Hindle TL1000s mufflers. For some reason peak power is up – must have been a good day.

When the rest of the system was ready, I fitted it and headed for the dyno. The result is shown in red compared to the all std run in green. Compared to how I’d been running it beforehand – std headers, my x-over, std muffler pipes and the Hindle mufflers – there was no real difference apart from the all important visual. The second graph is speed versus time – you can see by the angle of the curve how much faster the roller was accelerating with the full system. The system as it was beforehand is shown by the blue curve – pretty much the same angle as the red one.

At this point I guess I have one comment to make – next time I get one of these (hopefully some day) I’ll just buy a Staintune.

Now we come to the reason I initially thought of doing this report – a header pipe comparison. Not maybe what you’re expecting. I was curious to see what smaller headers did to the power output, so I found some Lemans 1000 headers laying around (I actually got them from Barry Jones at IME I think in the end) and fitted them up. They actually fitted straight into my x-over. The Lemans 1000 headers are smaller in OD, plus thicker wall, so are in reality maybe 35mm ID, whereas my headers were 1 5/8” ID, or 41.3mm. It was certainly quite a difference anyway. I got thinking about this due to playing with headers on the 851, and thought Lemans owners who are looking for more power may find it interesting.

By this time the bike was wearing its twin plug ported heads with the comp up to 10.5 due to thinner head gaskets (0.5mm less) and milling 1mm from the head face. Which is why it’s making 90 hp. These runs were done on the same day, and show the header size affecting the power from 5,000 RPM upward. So I’d expect this result to carry some influence for a 948 or 992cc 2V as well, as this engine is 1063cc with the same size valves as the 1000 (actually 0.5mm smaller). The cam timing is different, although from memory there’s not that much in it. Except that the Sport 1100 cam is better than the Lemans B10 in my opinion. It certainly makes good power all the way to 8,000 RPM. Red is my big headers, green the Lemans 1000 headers.

A couple of months later, after I’d done the 10,000 km service, I went back and tried running my exhaust with one muffler. To achieve this I simply removed one muffler (LH) and capped the x-over outlet. This wasn’t at the x-over itself, but about 200mm from the x-over centre section. The center section was a piece of larger pipe flattened out into an oval (same as a Staintune) about 100mm long. So there was plenty of room for the flow from the LH header to bend a little and flow out the RH outlet. I did actually make a proper 2-1 x-over (I think), but for some reason didn’t test it. When I sold the bike I gave that to the new owner as well, as it only suited this system.

The graph is shown below, green is with the LH muffler removed and the pipe capped. Red is with two mufflers as I’d designed it. No fueling was changed between these two runs. Although for best power it really needed some more fuel between 4,500 and 5,500 with the 2-1, and 4,500 to 6,500 with the 2-2. And probably less above that, as it lost a couple with the +11% that I ran for each combo. Not sure why I didn’t do it properly then, but my procedure is much better now.

It’s certainly odd that restricting muffler volume makes such a big difference at lower RPM, without a huge impact at higher RPM. On the road, it was noticeably lacking down low, but really came on higher up. It would actually lift the front wheel at around 7,000 RPM in first on WOT acceleration, something it wouldn’t do with the 2-2. Due to the steeper angle of the torque and power curves at that point, which is only a minor change in this instance. The smoother, more even shape of the 2-2 curve is why it wouldn’t wheelie with that system, even though the peak is higher.

At the time I was playing with the bike I was also doing a Fitting and Turning course at a local TAFE college, where we got to make all sorts of stuff, including lots of specific tools for the workshop. I took advantage of this to drill the cam drive sprocket to advance the cam timing. I did this on a day that was actually a public holiday, where one of the teachers let a couple of us come in for some “quiet time”. Meaning unlimited access to the equipment, unlike the usual Tuesday night - it was a popular course. As anyone who has machining experience will understand, this was one of those “3 hours to drill a hole” jobs, where setting up the sprocket to drill it was the big issue. In fact, I probably wouldn’t have got it done on a usual 3 hour night. I drilled the hole 2 degrees advanced, about 180 degrees around the locating face to the std hole, to give 4 degrees advance at the crank. At the radius the hole was at from the cam centerline (about 25mm from memory), every mm you’re off is about 2 degrees error. So you take the time to get it right (and hope like hell you haven’t stuffed it up).

When it was done and back together I ran it (as you’d expect) to see what difference the 4 degrees had made. The first graph below shows the result with no fuel changes made – something I’d be doing these days. Green is cam advanced 4 degrees, red is as was. From memory (again) the cam was set at 109 degrees inlet centerline from the factory, with spec being 108. I advanced it to 105.

As I’d expect, it picked up a little in the midrange, and lost a little at the top. I would imagine the before run was with fuel mapping that I had decided on from previous runs. At this stage the bike was running a chip Duane had made me with a modified spark map to suit the dual plugging – it was down to 25 degrees max advance at WOT. Whether the fuel map was also modified I can’t remember. I’d expect it was. A month later I went back to the dyno and ran some fuel +/- runs to see what it wanted with the cam timing changed. The fuel changes it wanted were what I normally see with cam advance – more in the midrange, less at the top end. With these changes I got the top end back. The graph below shows the chip base fuel in red, +10% in green and -5.4% in blue.

The bike did feel better down low with this cam timing, although it would get a bit more ruffled in traffic, especially hot and two up. More prone to ping a little on take off, that sort of thing. Given the software and knowledge I have now, I’m sure I could have fixed much of this with fuel and spark map changes. I don’t remember what the spark map looked like at low RPM now. I had changed it in the just off idle area for better response off closed throttle, but compared to the BMW R1100S I replaced this bike with, there was no comparison in low speed roll on – the BMW was much smoother. You could roll it almost fully open in 4th gear at 1,500 RPM and it would just pull away, something the Sport wouldn’t have been at all happy about. I did own them both for a couple of months, and just stopped riding the Sport in the end if I was heading into town. The Sport sounded so much better (and went every bit as well, especially that fat midrange), but the usability of the R1100S won me over. Which is something that really annoys me now – I’m sure I could make the Sport just as nice. And I’m far more loyal to Guzzi than BMW. In the end I went back to the original cam timing – as easy as pulling the sprocket and locating it back in the original hole (if you call that easy, not sure I call it enjoyable). Don’t really remember why now.

The final graph I’ll give you is a comparison between the R1100S and the Sport. The R1100S has a Staintune system fitted and the Ultimap chip. The Guzzi is as I finished with it. Red is the Sport, green the R1100S. The R1100S has an extra valve of each per cylinder and an extra point of compression going by its specs – the Guzzi holds its own just fine.

This brings the report to an end. I have heard of this bike a couple of times since I sold it. It is now back to running single plugs – something about the coils I was using upsetting the ECU – and runs just fine at 10.5:1 compression using the chip with modified ignition advance. Although it needed about 15% more fuel, which shows the efficiency advantage the twin plugs gave.

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