jvfd0265 1 Posted February 12 I recently had rescued this 2004 rubicon from some people that definitely abused it. After tinkering on it a bit to get it running we've noticed this chatter at idle. We adjusted the valves to spec and it's still doing it. Couple of people I've spoke to have some differing opinions on what's going on with it. It rides well just don't want to push my luck with it until we figure it out. Anyone got some suggestions on what we need to look at? 20240210_162215.mp4 Share this post Link to post Share on other sites
jeepwm69 7,611 Posted February 13 If you search my threads you'll see a lot of info I've gathered as I've delved into the Hondamatics in the last year or so. Almost all of that info came from @Brian Bertram That sounds like piston slap to me, but the Hondamatics can also make some rattling noises if they're not working properly. Brian is a member here, but doesn't get on the forum much. His email is in this thread, and he does respond to emails. He also sells an oil pressure testing set up for the Rubicons on ebay, which is usually the first thing you check on a Rubicon with any sort of issues. @toodeep is pretty good at the Rubicons as well. Were that mine I'd probably pull the rockers and head and inspect the rockers and cylinder, but I don't think you want to keep running it until you determine the cause. If it is something with the Hondamatic, it might be fixable if you catch it before it gets too bad. Once they go past a certain point, you have to replace the entire Hondamatic unit, which is about $1500-2K just for the part. 1 Share this post Link to post Share on other sites
toodeep 1,758 Posted February 14 Sounds like the cam chain to me. You can move the adjuster and see if the rattle changes to confirm. 3 Share this post Link to post Share on other sites
jeepwm69 7,611 Posted February 14 13 hours ago, toodeep said: Sounds like the cam chain to me. You can move the adjuster and see if the rattle changes to confirm. That would certainly be easier to check than pulling the top end. Share this post Link to post Share on other sites
jvfd0265 1 Posted February 17 (edited) Well we checked the valves, checked the tensioner, and everything led us to pulling the cases apart. Got into the cases and found both chains were stretched. We replaced the cam chain with a new one because I had thought ahead and ordered one but I wasn't expecting the other chain that I believe is the oil pump chain to be stretched. Luckily I had one from a parts motor we are rebuilding. Hopefully this fixes it. Waiting on the Honda bond to seal to try it. Edited February 17 by jvfd0265 Misspelling 1 Share this post Link to post Share on other sites
