New project: XS1100 endurance racer

[Mathh]

While he was doing that I dismantled the two open shorty mufflers and started to cut them up in order to get them together at the same starting point behind the foot rest. . The inside diameter of both mufflers will be same as the diameter of the stock bikes.



As soon as Mario was ready with the collector he started welding the mufflers together and finally he welded a tiny dot on top of each downpipe to keep the clamping rings in place.





At this moment we still need another link pipe with bend(s) to the mufflers. That will be done later as the bike is coming apart any time now.
Here is the idea for the position of the mufflers. I chose double mufflers (that makes it into a 4-2-1-2) for less noise: 2 mufflers mean half the exhaust gas speed of one 4-1 muffler (with the same diameter of course) and that means less noise.

[Mathh]

And Mario could start welding everything we had put together so far..

[Mathh]

The end pipe has to come out below and behind the right footrest to avoid ground clearance trouble because of the chain on the left side. All downpipes will be held by stainless springs connecting to the 2-1 manifolds and the clamping rings holding the flanges in place. That will be done in the end.
After wasting a lot of tape, fiddling, cutting and welding pieces of straight pipe, bends and fabricating that 2-1 collector we finally found a good looking setup.

[Mathh]

The result looks great!



The idea of the following link pipes going directly to the rear and from there to the mufflers (on the right side) would mean that there would be a big difference in length in the left and right pipes. Instead we went for a couple of different bends followed by two equal lengths of pipe and into another 2-1 manifold and going to the two mufflers. Both mufflers will be on the right side. We wanted to stay as high as possible with the exhaust so we had to take away some corner bits of the oil pan to get a clean exit:



As I never throw away pieces of pipe or bends we had everything to work with using lots of tape.

[Mathh]

As expected we had to heat two downpipes (2 and 3) to get the correct angle upwards and sideways. So we inserted heat ….





Bending was done with a piece of pipe that fitted exactly over the exhaust pipe (barely visible in the picture). Very careful not to wrinkle the bend. Also both manifolds needed cutting, heating and welding in order to get it perfect.
And that is what it looked like: perfect… Time for welding the down pipes...
Mario is a perfectionist so insisted on a clean surface after the welding. Lucky for me.

[Mathh]

We now started work on getting the ends into two 2-1 manifolds. We found those on Ebay UK: they were for a stainless MINI Cooper DIY exhaust system that shared the exact inner and outer pipe dimension.



After making sure that all downpipes cleared the frame and hung symmetrically we started cutting the flanges and downpipes to the necessary angles to stay clear of the frame. After that we tack welded them in place.
With the downpipes in their correct place It was obvious why our first attempts with the down pipes failed miserably, look at the angles we needed to make to get the perfect result:

[Mathh]

Beginning at cylinder 1 we started trial fitting the downpipe with tape in order to see where we had to cut to get symmetry from all sides but ignoring the last bend at the bottom. That would be corrected by heating when all downpipes were in their final place. Then we did number 4, 2 and 3. We tried every downpipe to every cylinder in order to look for the best result...





It took a couple of days to get all four at an optimum angle and symmetrical from all sides.

[Mathh]

Well…. That new RC Engineering 4-1 that I first wanted to use gave me lots of grey hair in 2009 but the 4-1 Supertrapp collector that I cut up did the same because I could not get a decent connection with the collector afterwards and I could not swap the oil filter. So I gave it another try but as a 4-2-1. That worked better, I got them symmetrical looking from the front but it still came very close to the front frame tubes and the pipes were not symmetrical from the side up front and at the bottom due to its previous design which had pipes #1 and #4 on top of pipes #3 and #4 at collector level.





We could heat them in order to bend them a little bit but not that much. Luckily my friend Mario who is a professional TIG welder came to the rescue. First thing he told me was that we had to cut of the flanges at the cylinder AGAIN in order to gain some length and change some important angles. After that he told me to make 4 new stainless exhaust manifolds for rigidity to fit to the exhaust ports. That took some machining on the lathe, welding them to a slightly thicker piece of pipe and machining that again to get a clean look and correct thickness..





After mounting the flanges in place it was now very obvious that the necessary angle for the downpipe after the flange will be quite a compromise between clearing the frame and efficient exhaust design.

[DEEBS11]

Yup! Check, check! With actvating switch.

I love that spot you picked to mount the volt meter. Brilliant!

[oldyam80sg]

I have seen many clip ons mounted right to where the stock handlebars mount on sport bikes. I like your set up though. I like the stock XS 1100 bars as I have shoulder issues and those bars are just right.

[Mathh]

Do you have clip ons or is the handle bar clamps whcih model?

Hi! I now have FZR600 clip ons fitted to the FZR1000 forks (pre Genesis) on the racer but I am still looking for a more comfy seating position. In case of a switch to higher handle bars I would fit separate handlebar clamps. Lots of those available overhere. I normally make them myself like I did on the upper yoke on the Special in the last picture. That one has FZR750R (Japanese FZR1000 model) forks. Also overhere there are several superbike conversion kits available for forks from the racier models with fairings if you don't like the work.
The Standard on the picture above has TRX850 forks with a superbike conversion kit and XS1100 Sport handle bars, see below. . But a lot of other (and or cheaper) stuff is possible, is there anything specific that you are looking for?

[oldyam80sg]

Do you have clip ons or is the handle bar clamps whcih model?

[Mathh]

I use these on all my bikes. Really cool part.

https://www.ebay.com/itm/252918897580?hash=item3ae3241bac:g:-QkAAOSwuMZZCsDd&amdata=enc%3AAQAIAAAA0L1%2FcKWU8WVudNLIqrc9H0PtXYtaJLKN1F0Stfb%2FMXxzZL5m5BbK3vuFDL7acDotcXJLlO%2F1qvLzgrBJU4w23aYJzUbUZ%2FEreGlGCjfD7%2BEV3D1ZH6lXBMqMLcvHdexjufd%2FnejbjBPX3XeCv7iWOLX24fTmLEP3X%2BVtbBJECFIsBAXuf8fRNl%2Bhq9UrKtkqw1cLQwKm7ZbstTpXEPIqUz2Bymq9GmSMPGs4LmloOn7vz0k8fcVrn5Rk9AWPd4w7ioLovmzKb8bfIMW1Duig4ME%3D%7Ctkp%3ABk9SR9aigNqeYw

Yup! Check, check! With actvating switch.

[DEEBS11]

I use these on all my bikes. Really cool part.

https://www.ebay.com/itm/252918897580?hash=item3ae3241bac:g:-QkAAOSwuMZZCsDd&amdata=enc%3AAQAIAAAA0L1%2FcKWU8WVudNLIqrc9H0PtXYtaJLKN1F0Stfb%2FMXxzZL5m5BbK3vuFDL7acDotcXJLlO%2F1qvLzgrBJU4w23aYJzUbUZ%2FEreGlGCjfD7%2BEV3D1ZH6lXBMqMLcvHdexjufd%2FnejbjBPX3XeCv7iWOLX24fTmLEP3X%2BVtbBJECFIsBAXuf8fRNl%2Bhq9UrKtkqw1cLQwKm7ZbstTpXEPIqUz2Bymq9GmSMPGs4LmloOn7vz0k8fcVrn5Rk9AWPd4w7ioLovmzKb8bfIMW1Duig4ME%3D%7Ctkp%3ABk9SR9aigNqeYw

[Mathh]

Very cool Mathh. I worry about the regulator taking heat from the motor fins. Keep an eye on that on a 93° day. Does your display have a volt meter?

I agree but there is very little place except when I hang it outside the frame rails and that just does not look right ( I know what you want to say now hahaha). I'll have another look at it , if not ... well I still have some spares lying around Good idea that Volt meter, especially since I have one on all my other bikes... duhhh..