I went to swap my front sprocket and the JTF 565 I had on hand doesn't fit. I verified with calipers that the sprocket's spline dimensions are in fact correct, so it is in fact a JTF 565. But comparing it to the original on my GS by overlaying, the opening is noticeably smaller. I couldn't make it fit in any case.
JT says the spec for outside spline diameter is 25.0mm and I measured the part I have with my calipers, it's right. I measured the outside dims of my shaft splines and they are 24.7. Should fit, right? But I'm puzzled as to why the original part is quite obviously larger by at least 1-2mm (I didn't think to measure it while it was off) and why I couldn't make the new one fit. Is this supposed to be some kind of force fit? The original one slips on and off pretty easily.
My JT application guide says the GS500 uses "JTF516" sprocket...(not JTF 565)
Comes in 14 th....15th.....16 th.....
The rear sprocket should be JTR 823.....39 42 45 46 49 th
Quote from: mr72 on January 26, 2019, 07:42:03 AM
I went to swap my front sprocket and the JTF 565 I had on hand doesn't fit. I verified with calipers that the sprocket's spline dimensions are in fact correct, so it is in fact a JTF 565. But comparing it to the original on my GS by overlaying, the opening is noticeably smaller. I couldn't make it fit in any case.
JT says the spec for outside spline diameter is 25.0mm and I measured the part I have with my calipers, it's right. I measured the outside dims of my shaft splines and they are 24.7. Should fit, right? But I'm puzzled as to why the original part is quite obviously larger by at least 1-2mm (I didn't think to measure it while it was off) and why I couldn't make the new one fit. Is this supposed to be some kind of force fit? The original one slips on and off pretty easily.
516 is for mk2 gs500 according to jt. I have a 92. I ordered another 565. We'll see if it can be made to fit.
oh...I see the 565 for the earlier models....
Something is fishy... first sprocket mis labeled? Maybe bike is a "transition model" with later shaft installed? Maybe engine was changed at some time?
Seemingly simple job quickly becomes more complicated!
Cookie
Quote from: mr72 on January 26, 2019, 06:34:28 PM
516 is for mk2 gs500 according to jt. I have a 92. I ordered another 565. We'll see if it can be made to fit.
I think the diameter of both the 516 and 565 are the same, thickness is the only difference. Something is definitely fishy here.
Looking again a t the JT catalog...the 516, 565, and the 436, all have the same spline dimensions. The 516 used on later models has a raised flange, making it a bit wider.
The fact that your "original" fits, and fits loosely, leads me to believe a new perfect gear is going to fit hard, or not at all, and that there is considerable wear on the shaft and / or on the sprocket. If the shaft got mucked up, a new sprocket won't fit easily.
When I put on a new front sprocket, the old one was quite loose....the new one was a bit better fitting, but still a tad loose IMHO, due to wear of the splines on the shaft. I think this wear is a typical issue with GS500. I have seen some with welded on sprockets!
See if it is possible to somehow "clean up" the splines on the shaft.
Cookie
Quote from: mr72 on January 26, 2019, 07:42:03 AM
I went to swap my front sprocket and the JTF 565 I had on hand doesn't fit. I verified with calipers that the sprocket's spline dimensions are in fact correct, so it is in fact a JTF 565. But comparing it to the original on my GS by overlaying, the opening is noticeably smaller. I couldn't make it fit in any case.
JT says the spec for outside spline diameter is 25.0mm and I measured the part I have with my calipers, it's right. I measured the outside dims of my shaft splines and they are 24.7. Should fit, right? But I'm puzzled as to why the original part is quite obviously larger by at least 1-2mm (I didn't think to measure it while it was off) and why I couldn't make the new one fit. Is this supposed to be some kind of force fit? The original one slips on and off pretty easily.
FYI -- I got another JT565.14 labeled sprocket. The splines of it lined up exactly with the sprocket I took off. It fit the shaft with no issue.
So the only conclusion I can make is the sprocket I had before was mislabeled.
Or.....that sprocket....they forgot a final machining step?
Anyway...problem solved.......excelsior! (onward and upward)
Cookie
Quote from: mr72 on February 02, 2019, 12:18:04 PM
FYI -- I got another JT565.14 labeled sprocket. The splines of it lined up exactly with the sprocket I took off. It fit the shaft with no issue.
So the only conclusion I can make is the sprocket I had before was mislabeled.