Topic: The Quest for Brakes and Suspension: GSX-R Treats

[bjbuchanan]

One thought about the oiling system and the coolers effectiveness. Back when porsches were aircooled, when compared to other aircooled like corvair and volkswagen other aircooler guys considered them oil cooled. Something like 6 and a half quarts

If you look at porsche oil capacity at the time it was above average, the extra oil helped to aid in cooling, the same way that coolant would (in a sense) perform in the engine. The extra oil just gives somewhere for the heat to go to. I think that that the oil coolers are most effective partly because of that, not really the little radiator on there

[sethdhawkins]

One thought about the oiling system and the coolers effectiveness. Back when porsches were aircooled, when compared to other aircooled like corvair and volkswagen other aircooler guys considered them oil cooled. Something like 6 and a half quarts

If you look at porsche oil capacity at the time it was above average, the extra oil helped to aid in cooling, the same way that coolant would (in a sense) perform in the engine. The extra oil just gives somewhere for the heat to go to. I think that that the oil coolers are most effective partly because of that, not really the little radiator on there

I agree. Any addition to oil capacity is going to be a good thing...especially with the 836. I could tell in the summer when my bike would start to get warm. Here's my buddy's oil tank that he fab'd out of 1/4" aluminum (he's making mine as well). It holds almost five quarts throughout the whole system!
Maybe we should run 3/4" oil lines, run around the bikes like spaghetti! That would certainly add to overall volume

[sethdhawkins]

Did some light reading today on motorcycle suspension (although I had done some before I started this swap). I now know more, but probably understand less. I would liken the experience to that moment, directly after your first roll in the back seat; you've learned a great deal, but the experience has just opened up a whole world of possibilities that you can't begin to fathom! If anyone is interested:

http://www.streetchopperweb.com/rake-and-trail/?image=2
http://www.sportrider.com/art-science-fun-geometry

I also ran some basic trail calculations on this site:
http://207.57.8.251/tools/rake_trail.html

I found that the stock CB750, in it's various trims, with a neck rake of 27 degrees, a 19" tire, 50-60mm offset triples, and stock forks (+\- 1" for the K and F models), has a trail somewhere in the neighborhood of 3.74-4.5".

Modern sportbikes have around 3.75" of trail.

A modern Victory cruiser has 6.7" of trail.

I calculated the new frontend of my bike to have 5.12" of trail using the numbers below (which I either measured myself, or scrounged from the intrawebs):



I realize that this is all very basic in calculation and does not take into account rear suspension height, swing arm angle, etc. Nor do I expect that I will spend my next time in the shop with a tape measure figuring out the actual trail. I just thought all this info was neat. Add anything, or correct anything that I may have missed. I'm not an engineer (even though I can copy and paste from google with the best of them), so please don't fill the thread with information that I can't digest in the length of a beer

My conclusions as the village idiot; bike should be damn stable Ina straight line, handle like a tank (not really a good thing), and may have a tendency to flop/wag in turns. Other than that, I'm not sure how I'm gonna like it.

[Retro Rocket]

Hi Seth, the 750 has around 3.7 inches of trail, most modern sports bikes are closer to 4 inches }GSXR1000 (2005-2006) - rake = 23.45 degrees trail = 96mm(2007-2008) 23.8 degrees 98mm , 100mm + 4 inches so both numbers are in the 3.9?, just a tad under 4 inches The 2012 ZX10 Kawasaki has even more trail 107mm or just over 4 inches}, trail is also relative to rake, 4 inches of trail on a 25 degree rake will feel different and react differently to 4 inches of trail on a 27 or 23 degree rake. Our bikes like a trail of closer to 4 inches giving a little more stability at the front and reducing the chance of having a tank slapper, of course bad bearings and other things can cause a tank slapper but its primarily trail related, ask member Bwaller....

[sethdhawkins]

Hi Seth, the 750 has around 3.7 inches of trail, most modern sports bikes are closer to 4 inches }GSXR1000 (2005-2006) - rake = 23.45 degrees trail = 96mm(2007-2008) 23.8 degrees 98mm , 100mm + 4 inches so both numbers are in the 3.9?, just a tad under 4 inches The 2012 ZX10 Kawasaki has even more trail 107mm or just over 4 inches}, trail is also relative to rake, 4 inches of trail on a 25 degree rake will feel different and react differently to 4 inches of trail on a 27 or 23 degree rake. Our bikes like a trail of closer to 4 inches giving a little more stability at the front and reducing the chance of having a tank slapper, of course bad bearings and other things can cause a tank slapper but its primarily trail related, ask member Bwaller....

I knew you'd jump in and give me some more precise information! Like I said, I was using that simple trail calculator, so there wasn't a ton of accuracy, just a ballpark for me. I like the part in the sportbike article above that stated that an experience road racer can detect the difference in 1mm in trail!

[Retro Rocket]

Hi Seth, the 750 has around 3.7 inches of trail, most modern sports bikes are closer to 4 inches }GSXR1000 (2005-2006) - rake = 23.45 degrees trail = 96mm(2007-2008) 23.8 degrees 98mm , 100mm + 4 inches so both numbers are in the 3.9?, just a tad under 4 inches The 2012 ZX10 Kawasaki has even more trail 107mm or just over 4 inches}, trail is also relative to rake, 4 inches of trail on a 25 degree rake will feel different and react differently to 4 inches of trail on a 27 or 23 degree rake. Our bikes like a trail of closer to 4 inches giving a little more stability at the front and reducing the chance of having a tank slapper, of course bad bearings and other things can cause a tank slapper but its primarily trail related, ask member Bwaller....

I knew you'd jump in and give me some more precise information! Like I said, I was using that simple trail calculator, so there wasn't a ton of accuracy, just a ballpark for me. I like the part in the sportbike article above that stated that an experience road racer can detect the difference in 1mm in trail!

Yeah, thats crazy accurate, i can feel reasonable changes but 1 mm, thats surgeon territory....     Thats why they ride so well i imagine, being able to set up a bike that accurately is amazing...

[sethdhawkins]

All the tins are in primer. My buddy has had some personal issues over the last month, so my paint is taking longer than anticipated.

[sethdhawkins]

I'm on a holding pattern on a few key pieces to the bike, so I've been doing a few things while waiting. Replaced the plugs...old ones looked spot on. I'll be replacing the clutch with the cyclex clutch kit. Tonight, I'm building a seat with another friend. Pics to follow!

[SOHC4 Cafe Racer Fan]

All the tins are in primer. My buddy has had some personal issues over the last month, so my paint is taking longer than anticipated.

Par for the course with most painters.

[sethdhawkins]

Seat photos. I don't think I could ever sew like this.

[calj737]

The trick to getting those results when sewing is: gotta have a pencil stashed behind your ear

[sethdhawkins]

The trick to getting those results when sewing is: gotta have a pencil stashed behind your ear

Or, a beer to aim by!

[NobleHops]

Love the custom work Seth, great job.

[snowman]

Great work, I'm in


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[sethdhawkins]

Thanks, guys! I installed a cycle x clutch kit yesterday and modified the clutch basket a la Hondaman. Hope my clutch is sleep free now. I have a '72 motor, and went with 7 friction plates and 6 ceramic plates, and left the larger friction plate out. Everything went together smoothly, and clutch action appears unchanged. The pressure plate did appear to have slight warping to it, but I ran with it. I though about chucking it in the lathe and skimming the surface, but with my luck, I'd screw it up and be left with nothing to use. I might pickup a used basket and pressure plate to test on. Still waiting on a few things....so close!

[sethdhawkins]

So, if you're tempted to buy a cheap cnc brake reservoir on ebay like this from china:
Replace the brake hose that comes with it, as it is not brake fluid compatible :-/ The brake fluid weeps through and drips down on to things you like. I ordered a clear hose from brembo, but I'm not too excited about bleeding the brakes again.

[sethdhawkins]

My oil tank is here!!!!! Mocked it up today and routed all the lines. I hope to button up some more stuff. I can't wait to get my tins and go ride.

[sethdhawkins]

Oil tank installed and plumbed.

Seat almost finished.

[SOHC4 Cafe Racer Fan]

Getting antsy for you.  Let us know how those Mikuni RS34s run.

[sethdhawkins]

I think they'd run great with a bit more displacement I think the engine is a tad over carb'd. I changed the plugs to platinums, and they looked spot on (already knew that with the afr gauge). It's really all in the off the line, and may all be in the accelerator pump. I'm mounting the exhaust as I type...and drinking some makers

[Terry in Australia]

Looking good Seth, I'm fascinated with your front end conversion, I've got some Ducati USD forks here along with some late model Yamaha 17" wheels and I'm daydreaming about a similar project. I've read your posts that the offset of the stock triples doesn't appear to be a major issue, how much left to right steering "lock" have you lost, if any? I.e., how far can you turn your handlebars before the forks hit your tank? Anyway, excellent work so far, well done. Cheers, Terry.

[sethdhawkins]

Terry,

I'd put the "lock to lock" at about the same as a modern sport bike. It's pretty appalling going from a vintage platform. I'm ok with it, but I can imagine parking lot scenarios being a bit annoying.

Seth

[Terry in Australia]

Thanks Seth, I might have to make myself some custom triples if mine ever gets past the daydream stage. Cheers, Terry.

[sethdhawkins]

Mounted the exhaust last night and fired her up. What a glorious sound There appear to be no oil leaks anywhere, which was a relief, considering the adapter plate, the oil cooler, new oil tank, and my remote oil drain.

[sethdhawkins]

I went by the shop this afternoon and set all the rebound and dampening to "stock". I'll rebuild and make the necessary adjustments to the internals next season.