Rocker arm refitting
Posted: Fri Jul 17, 2026 4:35 am
Hi guys, don't know if many will see this as I can see the forum is real quiet these days. But there might be someone out there who has the knowledge/experience I'm after.
So yes, my 750 sport is still a current project - just! I have to admit enthusiasm is not as high as it once was lol. I dont beat myself up about it, I just work on it when I have the time and feel like it rather than forcing myself.
So, over the winter I dropped the motor forward in the frame to get both heads off with a view to doing the valve clearances. Turned out most of them were pretty good, a couple of opening clearances a smidge tight, nothing a quick grind of the shim couldnt take care of but two of the closing rockers had 4 tho clearance so I re-shimmed those. I also had a broken retaining collet, and I think it was on the rear cylinder exhaust valve (I know, I should have taken more careful notes!) which is also the subject of this post as that valve guide was also clearly flogged out. I'm picking this valve runs the hottest being at the back but other than that I'm not sure why it is the only one out of the four that is rattly in the guide.
Anyhoo, I managed to punch the guide out quite easily after turning down an appropriate 8mm step punch. Thought I may have needed to heat the head in the oven a bit but no. However, I did have to remove the closing rocker arm as I didn't have enough clearance for the valve guide on its way out.
Quite easily done after screwing a long M4 bolt into the shaft the rocker turns on and then drawing it out. Only problem is there are shims and the closing spring on that shaft as well and I'm just wondering how tricky it will be to get all that back in there, esp as that spring seems to be quite strong judging by the way it flew out halfway across the workshop as I pulled the shaft out! Picture for reference below and one of the guide.
So has anyone done this particular job before and got any tips for me? Cheers.
So yes, my 750 sport is still a current project - just! I have to admit enthusiasm is not as high as it once was lol. I dont beat myself up about it, I just work on it when I have the time and feel like it rather than forcing myself.
So, over the winter I dropped the motor forward in the frame to get both heads off with a view to doing the valve clearances. Turned out most of them were pretty good, a couple of opening clearances a smidge tight, nothing a quick grind of the shim couldnt take care of but two of the closing rockers had 4 tho clearance so I re-shimmed those. I also had a broken retaining collet, and I think it was on the rear cylinder exhaust valve (I know, I should have taken more careful notes!) which is also the subject of this post as that valve guide was also clearly flogged out. I'm picking this valve runs the hottest being at the back but other than that I'm not sure why it is the only one out of the four that is rattly in the guide.
Anyhoo, I managed to punch the guide out quite easily after turning down an appropriate 8mm step punch. Thought I may have needed to heat the head in the oven a bit but no. However, I did have to remove the closing rocker arm as I didn't have enough clearance for the valve guide on its way out.
Quite easily done after screwing a long M4 bolt into the shaft the rocker turns on and then drawing it out. Only problem is there are shims and the closing spring on that shaft as well and I'm just wondering how tricky it will be to get all that back in there, esp as that spring seems to be quite strong judging by the way it flew out halfway across the workshop as I pulled the shaft out! Picture for reference below and one of the guide.
So has anyone done this particular job before and got any tips for me? Cheers.
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- IMG_0306 (1).jpeg (159.43 KiB) Viewed 38 times
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