Ticking at left top of motor when idling. What is this?

mogie

XS400 Enthusiast
Messages
36
Reaction score
0
Points
6
Location
slatington pennsylvania
So I just picked up two xs400's yesterday, a beautiful red, bone stock 81 special II with 7000 miles for 600 bucks that the guy just put two brand new tires on. Hasn't been on the road since tires went on, and a black 82 heritage special with 19000 miles for 200 bucks, a little rough but runs, drives and is inspected till may. The thing is, the black one sounds as though there is tapping up top on the left side but only at idle. Once the revs climb just a couple hundred rpms it goes away. I thought i saw something in one of the manuals about an oil inspection bolt on top of the heads. Is this where i should start? Any ideas, thanks
 

Attachments

  • xs400 046.jpg
    xs400 046.jpg
    332.5 KB · Views: 113
  • xs400 045.jpg
    xs400 045.jpg
    336.8 KB · Views: 113
Sounds like valves to me...check your clearances. Mine always has some ticking at idle even when adjusted correctly.

Oil inspection bolt? Never heard of it.
 
That's just to check to see that oil is coming to the top of the head.Your problem is probably a loose tappet.This is,to a certain point,only an annoyance,as it won't hurt anything if remedied soon enough.I always err on the loose side,as the gap causes cooling to take place and ensures full contact with the valve seat.The longer time,even infinitesimal,makes a difference in that it happens so many times per minute,releasing heat at each contact.Too tight,and heat builds up,and leaks develop,thus in high performance motors,the lift is high,and the springs are very strong.Having a clearance of .08-.12 mm intake,.16-.20 mm exhaust,I would go for .10 mm intake,with the feeler gauge sliding with some tightness.I hope that the long winded explanation has helped a little,but a lot of people nowadays have never adjusted valves,as most motors have hydraulic lifters. lha
 
Shouldn't be,just be careful when you tighten the locknut to hold the adjuster so the setting doesn't change. lha
 
When I had the same problem I also thought it's valves but actually mine had air leak on intake manifold. It did quite the same noise. Just to be sure spray some starter fluid onto carbs and see if rpm increases or not.
 
Back
Top