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noise in engine

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revelation1eight Member
Posts: 1
Joined: Fri Oct 19, 2007 7:26 am
Location: IN

noise in engine

Post by revelation1eight » Fri Oct 19, 2007 7:35 am

I have a 65 305 scrambler I restored last year, but ever since I got the bike running, it has a terrible rattle/knock when you hold the throttle at a steady speed around 30-40mph. Its not a rod or spark knock. It sounds like a piston rattle, but I had my machine shop bore the cyls and I put in new wiesco pistons. I checked the skirt clearance and it was perfect, so I don't think it is piston slap. It sounds like the cam is walking or rocker rattle. I rechecked my valve adj and it is perfect, but I did notice the rockers have a lot of side play. Is that normal? Any ideas would be great. I also rechecked my cam chain adj. it is fine also. I did have the cams out and replaced all the bearings, so could I have screwed up something there? I was just wanting some ideas before I go to the trouble of tearing it back down. I have rode it a couple of hundred miles and it hasn't gotten better or worse. Someone told me I may have my rocker shafts backwards because they are different sizes, but is that possible to get them installed backwards? Thanks for any help. Ryan

ggray Member
Posts: 314
Joined: Tue Jun 27, 2006 6:14 pm
Location: Joplin, Mo.

'65 CL77

Post by ggray » Sat Oct 20, 2007 5:24 am

I am redoing my 65 CL now. Would love to see some pics of yours.

Sorry I can't help you on your noise problem. Loud Mouse might be able to help.

'65 CL77 Owner

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davomoto Member
Posts: 2508
Joined: Sat Nov 18, 2006 7:36 pm
Location: Marin County CA

Post by davomoto » Sat Oct 20, 2007 12:45 pm

Pretty hard to get the rocker pins in wrong. You'd have to hammer the larger one in to the smaller hole. The rivets on the cam chain sprockets do sometimes get loose, and that will cause a rattle noise. Did you check this out while engine was apart? Did you check the rods for up and down play? These engines do tend to be a bit noisey, but without actually hearing yours, it's hard to say weather it's normal or not. And yes, the rockers do have side to side play. Hope this helps!


fastjoe Member
Posts: 38
Joined: Thu Jan 04, 2007 2:14 pm
Location: kingman az

40 mph rattle

Post by fastjoe » Mon Oct 22, 2007 11:11 pm

Hard to say for sure, being as I can't hear it from here. From the description it sounds a lot like the little rattle /tinkle noise I get with mine. I believe it is caused by loose wrist pin fit. This is common on these bikes, I don't think it is much of a risk, just annoying. Honda used to sell oversize wrist pins for this issue but I don't know if they are still around.

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