More GSX11 oily questions

[rich46]

So I've think I have a handle on how to set up the oiling on the race bikes.  Next question is how large an oil cooler should I be considering ?  I've been thinking that a 13 row like all the kit use is the way to go but when I look at old photographs from the late '70's early '80's  it looks to be only an 8 or 10 row.  

[Arttu]

That's somewhat tricky questions since both generated heat and cooling efficiency are heavily depending on usage. In your case amount of heat will be relatively high since the engine will be run at high rpm and load almost constantly. But on the other hand speed of the bike will be also high which increases cooling efficiency a lot. Typically for road bikes the most challenging situation is slowly moving traffic when you don't have much cooling air flow around the engine. Once you get to higher speed the temps usually go down even if you are using much more power.

My experiences are mainly from road use so I can't provide much advice about cooler sizing for that kind race use. But to give some perspective I can tell that compared to no cooler even a stock EFE/1150 cooler made a significant difference. And that's a tiny cooler. Now I have that pretty typical 13 row Mocal cooler and it can handle my 1327cc turbo engine without any problems. I have been doing track days only few times but I think I didn't see any higher oil temps there compared to normal normal highway riding. Although my speed at the track is probably much closer to normal street riding than serious racing

[rich46]

Aryyu,

You have no idea how much value this kind of information is.  What I really was looking for how these motorbikes worked in OEM state as I know that Suzuki didn't want their bikes blowing up in traffic.

You were quite right in that most of the racing these bikes are headed for has little traffic  (maybe only when drafting on long straights) they are run at high RPM but not crazy numbers  (9500 or so) so your big engine most likely has a chance at high temps just riding around  because of the thinner cylinder walls.  Our motorbikes also have fairings  (see pictures of endurance bikes built by Yosh. ridden by  Graeme Crosby) with the early '80's look.  so I do need to consider that.   What I'm thinking is that  I do need to worry about keeping them cool but it will not be a huge issue.  The engines will have fairly mild cam grinds, not  any exceptionally high compression.  Heck if we are mostly racing in the UK I've not ever seen it far into the 70's and often external eater cooling.   

[Gixer1460]

Its always an option to include an in-line thermostat to control flow to the cooler - not often used on race bikes as coolers are usually sized as small as possible just to do the job and no more.

[rich46]

Thanks mate.  On the race bikes we usually remove those kind of bits.  I even pull out the thermostats (do install a baffle) Not having those sorts of bits  are not really needed and it's just one more thing to go amiss.  If someone wants a street version (a fellow was in a day or so ago who may want a GS750 done) I will for sure use your suggestion to help him on the warm up.  So thanks again.

Cheers 

[wraith]

I had a gs1000 over bored with bigger liners to 1148cc stage 2 cams extra, used a 8 row 330 wide cooler with an8 lines. Never had a problem with over heating but the modern trend is to go as big as you can with the biggest lines, there is a point that over cooling will loose you performance as the engine will not get upto optimum performance temp.

It will come down to how you're riding and in what out side temp and state of tune of engine you have.

Don't get sucked into the bigger the better

[rich46]

wraith,  Because these motorbikes are big and fat I, from the beginning of the build have been trying to keep everything I stick on the bikes as light as I can.  When I look at the cooler that came on the Kat's  (keeping in mind that street bikes are built to sit in traffic) and listening to folks on the forum I think I'll try going with a 6 row to at least start with.  I plan on some testing this spring and I will be running oil temp gauges so as to not over heat.  I will, of course bring along the larger cools just in case.  This is on thing that can be changed at the track.  I may even make up a set of lines for the different sized cooler just in case.  The other reason to go with a smaller cooler is on the street courses (at least at the IOM) the suspension often bottoms out on the bump stops (just the nature of the road race courses) so the small ones help with allowing more options as far as ride height, compression and the like.

Thank you for your input every bit has helped me with a bike I'm not totally familiar with  

   

[coombehouse]

I run a 1290cc katana with reasonable compression & aftermarket cams on the street only. I have a 7 row cooler fitted as the bike ran too cool with a 10 row unless the ambient temperature was approaching 30c. I have an oil temperature gauge with a memory function. The maximum oil temperature I have seen is 95c. Generally it is around 68c with ambient temperature in the low 20's when riding at speed. I'm in the UK.

If you fit a bigger cooler you can always tape it up according to conditions.