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Old 02-10-2013, 07:46 PM   #1
munchausendrive OP
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Question Push rod contact.

I bought my first bike back in August. It's a '72 R60/5 and my life is all the better for it. I do have a question though.

I pulled one of the cylinders to replace a push-rod gasket and the push-rods showed signs of contacting the sides of the push rod tubes. Is this normal?

Also, I'm planning on rebuilding the forks. Any thoughts on replacing the stock springs with a progressive set from Hucky?

Thanks

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Old 02-10-2013, 08:28 PM   #2
supershaft
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Yes, those marks are very normal.

I recommend staying with the stock springs and adding more preload. In the end you will have better working forks for it. Plus it saves you money.
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Old 02-10-2013, 09:24 PM   #3
100RT
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Another possibilty is that the head gasket was installed upside down to cause the marks.
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Old 02-10-2013, 09:33 PM   #4
Bill Harris
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One possibility-- the head gasket fits one way. If you flip it over, it'll still seal OK but the pushrod tube holes will be offset and the pushrods will rub the head gasket. If the scoring is deep, the pushrod can be weakened. Easy to spot, just look down the pushrod tube and thegasket offset will be evident.

--Bill


Oops, didn't see 100RT's post-- yeah, what he said. :)
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Bill Harris screwed with this post 02-10-2013 at 10:20 PM
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Old 02-10-2013, 09:54 PM   #5
supershaft
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An upside downb head gasket will rub on the pushrods but they will most definitely have rub marks with a correctly installed head gasket. The pushrods flex and rub the end of the pushrod tubes in both the top of the cylinders and the ends of the tubes in the base of the heads. They seem to do it about the same whether it's a R60 cam, a 308 or a 336. Aluminum pushrods almost always have rub marks in the same spots for the same reasons in every airhead engine. Those pushrods flex a lot! I don't know for sure but I bet they do it even more with stiffer valve springs?
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Old 02-10-2013, 10:39 PM   #6
munchausendrive OP
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Thanks for the fast replies. I replaced the gasket with a new one. it definitely went on the right direction. I didn't look closely at the old one. The marking didn't seem severe so if it's not unheard on I'm no longer concerned.

Are there any good thread about increasing the pre-load on the front springs?
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Old 02-10-2013, 10:53 PM   #7
Freeagain
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I put new progressives into toan '84 G/S (replacing originals). Absolutely transformed to the bike. Horror to joy.
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Old 02-11-2013, 12:41 PM   #8
Big Bamboo
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Quote:
Originally Posted by munchausendrive View Post
Thanks for the fast replies. I replaced the gasket with a new one. it definitely went on the right direction. I didn't look closely at the old one. The marking didn't seem severe so if it's not unheard on I'm no longer concerned.

Are there any good thread about increasing the pre-load on the front springs?
One last possibility, if you didn't support the rocker blocks when torquing the heads the whole assembly can sag and the pushrods will contact the pushrod tubes at their fullest extension. If installed correctly, at top dead center (like when you are adjusting valves) the pushrods should be above center in the pushrod tube where it exits the head. This will leave room for the up and down motion of the rod, due to the rocker moving in the horizontal plane and the rod pushing up at an angle.
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