tz375 wrote:Does anyone have the dimensions of T500 and GT750 rods? I was under the impression that GT750 rod was 135mm ctr to ctr and 500 is 130mm. I measured a 750 rod the other day and it's 130mm, so maybe I have it back to front.
I think I have a loose T500 rod I can check when I get home tonight.
Regarding crank rebuilds - I've found three places that do the work:
1. Bill Bune
2016 7th Ave
Anoka, MN 55303
(763) 576-9924
2. Wisconsin Recreational Crankshaft
5049 E County Road B
South Range, WI 54874-8408
(715) 399-8868
3.Paul Miller's crank guy
don't have his contact info handy but I will try to dig it up if you want it.
tz375 wrote:Does anyone have the dimensions of T500 and GT750 rods? I was under the impression that GT750 rod was 135mm ctr to ctr and 500 is 130mm. I measured a 750 rod the other day and it's 130mm, so maybe I have it back to front.
T500 rod is 136mm center to center, 22mm wide on top and bottom, 23mm head diameter, 30mm foot diameter.
Thanks you. Those dimensions are not what I expected.
The GT750 rod I have here has small end 23mm diameter, 22mm wide with 18mm piston pin. Big end is 30mm diameter and 21.03mm wide, with a 24mm pin diameter. Ctr to ctr appears to be 129.9mm or notionally 130. I have a drawing here where a crank builder measure the 750 rod at 135mm ctr to ctr .
Jim, could you please confirm those 500 dimensions. Thx.
I'm getting roughly 135mm center to center on a non-digital vernier for the T500 rod with the little end ID of 23mm and the big end ID of 30mm. Both ends are 22mm wide. To be completely accurate on this I should trace it out on graph paper and get the exact centers. I can say for certain a T500 rod is closer to 135 than 130!
I seem to recall the GT750 big end design being better and that's why racers prefer the 750 rod. Then they would trim the base of the cylinders and they could experiment further with port timing.
Zook-e, Muzza, or Pete could all probably set the record straight on this in a single email.....
My 500 race engine has 750 rods fitted. As far as I know the barrels have 3mm removed from the bottom and 2mm removed from the top. It has a pair of centre plug heads and I will have to play with the gaskets to achieve a 1mm squish clearance using Wiesco pistons.
Zunspec4 wrote:You can use the GT750 crank-pin and big end bearing with T500 rods.
oldjapanesebikes wrote:. I'm pretty sure that the GT750 con rod big end bearing is only for the GT750 con rod.
Is the Gt750 Big end bearing shorter or longer less or more needles thanT500? Another person told me they did this change too, but not many miles on it yet
diamondj wrote:I think I have a loose T500 rod I can check when I get home tonight.
.
Let me know if you do have a good one. I think i'll change just the one for now, but they may find the other big end bad. Doubt it, but never know until it is off.
Hmm, you got me thinking now. When my T500 crank was re-built it had new crank-pins and bearings fitted. I assumed that these were both GT750 type, maybe they were 750 crank-pins with T500 bearings. Darn, where are the real experts when you need them . When I speak to Pete Odell next time I'll ask him about it.
I"ll hold off buying any bearings until I hear from you. They are pricey
I did buy a new NOS rod so I think I am good to go.
I may have found one more NOS rod, the person is checking to make sure it is a T500 not GT750,
Can you ask Pete if he sells just the rods (if it works with NOS bearings) or kit only and how much.
I am curious and reluctant to get another T500 in the future otherwise.
The Crank pin # is the same for both the T500 and GT750 if you check suzuki parts online. So no worries there.
The question is the big end bearing.
I aslo recently just found someone else who is sure he purchased the GT750 bearing for his 72 T500. Just has not driven much yet nor did he compare them for had someone else do the work.
From what I understand, GT750 big end bearings are the same size as T/GT500 loose bearings. You are supposed to press apart the cranks, use GT750 bearing spacers and caged bearings in place of the 500 items. That is what I plan to do when I send the crank in for new seals and 'o' rings.
Kawasaki 650js 89-90 rod kit might work. The center to center is shorter 133mm but that could be removed of the bottom of the cylinder and the kit on ebay is only $89.98 and that includes upper and lower bearings, crank pin and thrust washers.