850 Not running as well as it should

I have a '74 Mark II Roadster I've owned for 11 years. Within the past 700 miles I've noticed excessive oil consumption with
some blue smoke until warmed up and then no noticible smoke. It has used 3 pints in the past 550 miles and doesn't leak
oil :wink: . The plugs are oily and black (NGK BPR7ES). I'm running a Mikuni 34 MM with needle clip on the top notch and a Boyer Ignition.
The compression warm is 105 lbs/105 lbs WOT. There are 21,656 miles on the original bore, 9,000 miles on a bore hone and new rings, and
9,000 miles on a valve job with new exhaust valves and seats, and new intake valve stem seals.

Bike has gotten hard to start but once warmed up goes like a scalded cat. Idle and just off idle it is rough. The compression and oil
consumption bother me and I plan to disassemble the top end for an inspection. Aside from the following items, what else should I
be looking at while it is apart?
Bore; Rings; Valves; valve guides; intake valve stem seals; seats; springs.

My kicking leg is getting palsied due to age and I'm seriously considering the new CNW electric start conversion.

Lazyeye

Just for fun you might want to do a leakdown test. I could never get decent readings from a compression tester by kicking, even when an engine was in as new condition.
The leakdown tester along with your ears (or those of a young person with good hearing) will tell you where the leakage is happening and how much it is.
The tester I like is sold by OTC tools. It is a dual gauge setup and can go to 100 PS I Max. I also have a Northern tool dual gauge leakdown tester here that i am about ready to throw away because of inconsistent readings. It was cheap but doesn't really work.

Glen

I'd pull the head and be very critical of the valve guides first. Then look at the head gasket for any internal oil leakages. Make sure it had sealed well ,no oilyness. If not either of those ,next would be the rings-piston measurings and inspections. I've never scalded a cat. Understand the desire for e-start as age sets in. Just took the plunge myself and love it. :wink:

worntorn said:

Just for fun you might want to do a leakdown test. I could never get decent readings from a compression tester by kicking, even when an engine was in as new condition.
The leakdown tester along with your ears (or those of a young person with good hearing) will tell you where the leakage is happening and how much it is.
The tester I like is sold by OTC tools. It is a dual gauge setup and can go to 100 PS I Max. I also have a Northern tool dual gauge leakdown tester here that i am about ready to throw away because of inconsistent readings. It was cheap but doesn't really work.

Glen

Click to expand...

Cheap differential or leak down testers are plagued with very cheap pressure gauges. The rest is a simple regulator and fixed orifice - not much to go wrong. You might consider putting a couple of better pressure gauges on it before tossing it.