Topic: In Need Of A GT750L Water Baffalo Guru...

[RebelRouser]

I Have A Customers 1974 GT750 Lemans And It Keeps Pumping All The Trans Oil Out The Vent On The Top Of The Tranny Behind The Oil Pump, It Is Not Supposed To Do This, But It Dose. The Fluid Has Been Changed And The Oil Level Is Correct, What Could Be Causing This? Hope Someone Can Help... Thanks

KirkN On VJMOG Said Some One Here Might Know

[kirkn]

Gordon, aka, Ilbikes... 

http://forums.sohc4.net/index.php?topic=46147.0

http://forums.sohc4.net/index.php?topic=42915.0

http://forums.sohc4.net/index.php?topic=56073.0

[RebelRouser]

Thank You

[RRRToolSolutions]

Hmm, as you know this is not normal.I use BelRay Gearsaver gear oil in the 2 stroke transmissions and like it because it's red like ATF. The BelRay SI-7 synthetic I use in the oil injection tank/system is blue. This way it's easy to determine what's leaking. My first guess it that you have a leak between the primary compression area of the crankcase and the transmission - you'd know this by leaking "red" fluid. These are seperated as you know, but if you've got a small leak (bad seal, liquid gasket failure at the mating surface where the 2 halves join). A leak there would allow combustion gasses to come into the transmission cavity immdeiate behind the crank. Every stroke the engine makes transfers more pressure causing the loss of fluid.

Second possibility is that you've got leaks below the oil injection pump and it's fluid (would be blue) is getting past the seals and shaft driving the oilpump - letting injection oil mix with transmission oil (red). I am simply using this red and blue to illustrate the different systems.

If you have not had one of these engines apart to know what I'm referring to - let me know. I've got lots of detailed photos I took during my build.

Regards,
Gorodn

[RebelRouser]

The Tranny Flud Is Red, A Gear Oil, 20/40. And The 2 Stroke Oil Is Blue/Green, No Cross Contamination That I Can See. I Put A 2 Foot Long Clear Tube On The Vent And Blew Oil To The Top Of The Gas Tank, No Air Came Out Just Solid Oil In The Tube To The Top, No Other Leaks Are Visible, Except Out The Exahust. When We Got This Thing Running After Sitting For Over 10 Years, It Ran Great, No Leaks, No Problems, Barked The Rear Tire All Gears, And Now It Won't Stop Blowing Out The Oil, BTW, It Only Dose Then When Being Ridden, Not Sitting On Center Stand At High RPM's In Or Out Of Gear, Only Under A Load.

[RRRToolSolutions]

This is a photo of my 1974 GT750 during the build last year. The crankshaft area must be sealed and the pulses/pressure completely isolated from the transmission. It is not likely that you have a case sealing problem, but if you'll notice the large crank gear between #2 and #3 above that drives the clutch gear, the crank seals on each side are their to isolate the engine and transmission. If it's all red (transmission) I can only imagine pressure is building up and pushing the oil out. Here is a Suzuki board where a lot of GT guys are on-hand to help. I got a lot of advice and help with parts from several. They are a good bunch too. Regards, Gordon

http://www.motorcycleracer.net/phpBB2/index.php

[mcpuffett]

Sounds like it could be the crankshaft oil seals ?

[RRRToolSolutions]

Yes, I suspect one of the two on each side of that large drive gear between #2 and #3. Suzuki cranks are cheap to rebuild and all seals are easily available. There is only 1 bearing that is discontinued, but rarely goes bad. It's the grooved one just to the left of that drive gear - it carries the side thrust for the crank.

Gordon

[RebelRouser]

Well The Info You Gave Me Was Extreamly Helpfull, Now It's Up To The Customer

[RRRToolSolutions]

Bill Bune Enterprises up in Minneapolis is where you want to send that crank. You have to send the crank and the new seals (darn crank weighs 43 lbs!), but I got mine back completely rebuilt and balanced with the new seals for $230 including UPS freight.

Good luck on the repairs.

Gordon

[RebelRouser]

NextWeek I Pull The Motor And Tear The Bottom End Off, We'll See How Bad Then, Thanks Again For All Your Help Gordon

[bryanj]

Typical problem for a long time sat still stroker, they need regular exercise

[RebelRouser]

Yup It Is The Crank Shaft Seal, The One Between The Drive Gear And The Center Cylinder, Thank Again For The Help. As Soon As The Customer Makes A Decision, Se Will Know What We Are Doing With The Bike...

[RRRToolSolutions]

Glad I could help with the diagnosis. Bill Bune Enterprises is definitely the one I'd use for the rebuild.

Best Regards,
Gordon