Valve Train Noise '78 - w/Video

[Monowakari]

Hey Guys,

Just wondering how normal this engine noise is? I moved my phone around a bit just to pick up the variety of the sound around the cylinder head.

Increases with rpms all the way up through 5th gear at highway speeds.

My dad's a harley mechanic and I sent him the video but I thought I'd ask the expert community over here! He thinks it sounds like normal valve train noise and to just monitor it as you would most things on a bike. Obviously hard to diagnose over the phone and internet..

Oil levels are good, probably needs to be changed in a few hundred clicks (~500) so its a little "dirty" but viscosity is normal. Thought maybe I got gasoline in the crankcase but turns out it was nothing! Long story.

Just bought the bike and have only put about 150km on her. Came with 46k but lots of work into her. I will be rebuilding the carbs soon, just need to order some parts. Wondering if I need to rebuild the damn top end too.

Thoughts?
Regards.

 

[BBS360]

Doesn't sound unusual. Compare to: http://www.xs400.com/threads/valves-sound-okay.14536/#post-151710
I think a few other videos have been posted too.

Valve clearances will affect noise. Don't quote me on this but I believe properly set valve clearances will tend to be noisier. As the valves tighten up over time they will quiet down but will gradually be going out of spec.

Make sure you check out past threads on carb cleaning before you get in too deep. It's not uncommon to leave in rubber bits that can be damaged by some cleaning processes.

 

[Monowakari]

Right on man, you're wicked helpful!

Just bought some new intake boots for $50 +shipping from ebay as the existing ones are quite cracked and brittle.
http://www.ebay.ca/itm/191873847109?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

Once they arrive in <10 days I'll be doing the carb job so I have lots of time to front-load research and prep. Found a couple great youtube videos of the exact carbs I have being overhauled.

Once I've gotten a look inside them I'll know if I need to order any internal parts but I think they should be fine as long as I am careful, they got overhauled about 7 years ago the PO mentioned. He couldn't or didn't find the intake boots so here I am.

Figured I'd just use a heap of carb cleaner as I doubt they need much in the way of scrubbing or intensive cleaning. I'll probably be posting about that in the near future.

Thanks again BBS360!

 

[xschris]

Proper adjusted valves will make little noise. Using the right type/weight oil also helps. These bikes will make some noise but not loud clatter. You does sound a bit chattery and if you have never done it I would adjust them. There are threads on this in the forum and make sure to follow all the steps. A carb sync will also be needed after. Another thing that gets overlooked is tappet adjustment screw wear. If there is any chips or pits in them they should be replaced. It make a big difference on adjustments and sound with a new set.