Boxerworks.com

Hello and I'm glad to be back on the forum as I guess I'm the care giver for a 1971 R50/5 and he needs some minor work. The owner has put about 1000 miles on the bike since I got it running for him in June.

Issues now are minor but I don't want to mess anything up.

First item is the ignition switch. It's flaky but does work and I'm sure just needs the contacts cleaned. How do I open the bucket? No screws on the headlamp but I do see a slot at the very bottom. Insert a flat blade screwdriver?

Second is the valves are ticking on the right side. That is the side that was apart when I originally got the bike. I adjusted the valves when I first put the bike together, then again after about 70 miles of riding. Is it normal for them to loosen this soon after 1000 miles? New valve cover, head and base gaskets were installed at that time. I still have a new valve cover gasket so If I need to I can replace the cover gasket, or is it suggested to replace the valve cover gasket each time you adjust the valves?

oil consumption. What can I expect to be normal? It looks like it's about a quart low ( just at the add oil mark) and no real obvious leaks on preliminary inspection. I haven't put it on the lift yet to actually see the bottom.

Thanks in advance,
John

Valves are supposed to tick if adjusted correctly. You said that side was apart, what was apart? If you reinstalled the head and head gasket,the head should have been re torqued after some miles. Valve cover gaskets are reusable for years.

Cylinder and head were off the bike when I got it in May. I lapped the valves and put it all back together. At that time I used new base gasket, push rod seals, head gasket and valve cover gasket. I let the owner ride it about 100 miles and re-torqued the head bolts and readjusted the valves and gave it back to him. He has since ridden it about 1000 miles and brought it back to me to change fork oil and check condition of the fork bushings and seals. Bike only has 20k miles and not leaking from the fork seals.

I want to take the valve covers off and want to re-torque head bolts, check/adjust valves both sides.I thought I'd ask here before tearing into it tomorrow or the next day. I rode it a little yesterday and the valves weren't ticking very loud at all but I'd be remiss if I didn't check them. I also want to get a compression reading now that the rings and valves have had time to seat. The original complaint was low compression on the right side and another shop pulled it all apart then tried to buy the bike from him. When he didn't sell they quoted a ridiculous price for a complete engine rebuild. 20K miles and a rebuild? So I agreed to take a look and try to get it running. It had sat for 20 years or so and all I found was some light surface rust on the valves and seats and rings stuck.

We still have a couple of months of riding weather here but with his work schedule he only rides on weekends. I thought I'd take my time and see what else needs addressing like fluid levels, any leaks, cable adjustments etc.

While you are in there, check for a little too much rocker arm end clearance.

Headlight: yes, the slot is for removing the headlight lens assembly; I believe sticking in the slot pushes up on a spring that holds the lens in place. Be sure to be ready to catch it from popping out and falling to the ground. Sometimes these lenses were prone to releasing on their own. Best to figure out a way to secure it...a judiciously drilled hole and a small black zip tie works well.

Valve cover gaskets: no need to replace them each time the valve cover is off. They should last the lifetime of the bike, maybe changed occasionally. They should have some stickum on one side; typically, when removed, the gasket stays stuck to the head...no need to disturb that connection.

Kurt in S.A.

George Ryals wrote:While you are in there, check for a little too much rocker arm end clearance.

thank you for the reminder. I was planning on doing that before I torque the head bolts. When I first put it together I wasn't sure how much play there should be. I was guessing and probably got it on the loose side.

jdvorchak wrote:

George Ryals wrote:While you are in there, check for a little too much rocker arm end clearance.

thank you for the reminder. I was planning on doing that before I torque the head bolts. When I first put it together I wasn't sure how much play there should be. I was guessing and probably got it on the loose side.

If you've re-torqued after the rebuild...no need to continue doing it. The risk is pulling a stud from the casing.
The final torque value can be reduced a tad in an attempt to avoid that happening.

It may be a case of loud valves save lives here! Are the valves on the quiet side set too tight?

The quiet side was never disassembled. I did check torque on that side, using a couple of foot pounds under max and they were tight. As I remember the valves were loose as well and I set them. I'll of course check both sides and adjust as necessary. Don't get me wrong the valve tapping is slight so this is just to make me feel better that there is nothing loose or wrong.

Actually my biggest concern is how flaky the ignition switch is. Seems like the slightest movement in center position, kills power. With the headlight on it's much better but not perfect.

he also complained of a high rpm stutter so I'll be checking timing and plugs. Could also be fuel delivery but with new petcocks, lined tank, new fuel lines and new air filter, new plugs and new plug wires? I just have to ferret that problem out.

Don't retorque the head bolts at first and maybe not at all. Start with checking the valve clearance. Have the clearances changed? if not, then your noise may be normal, or you have other issues.

Checking the valve clearance is a test of the head torque.

I suggest that you read this article http://www.w6rec.com/duane/bmw/valve/index.htm
If it doesn't make sense, then read it again......... and again.

Keep asking questions before you make changes.

The stutter is not likely to be related to timing, but could be plugs. Measure the fuel flow first, before you do anything. I suggest that you read http://www.w6rec.com/duane/bmw/petcock/index.htm and at the bottom of the page is what you need.

thank you Duane. After reading your very well done link, I think I may have the rocker arm free play a little loose. But I'll know more when I actually open it back up and look.

As for the high speed stutter, I could not duplicate it. I'll have to ride it a little and see. I'll measure fuel flow as your article suggests. The tank is pristine and I applied the liner myself. The petcocks, fuel filters and fuel lines are all less than two months old but that really doesn't mean anything. As a wise man told me " to measure is to know".

I'm still recovering from a painful ingrown and infected toe nail and have a couple more doc appointments this week. But I should be able to start working on the bike today or tomorrow. I'm actually getting around pretty good right now for the first time in 4 days.

I just finished up a water pump in my boys Chrysler van (what an ordeal) and the Suzuki GS750E I was reviving is running so good it puts a smile on my face every time I ride it. So once I start on the BMW I hope I'll have no distractions.

I have a number of items to address on this BMW and will start a separate thread for each to keep confusion to a minimum.

Thanks again all
John