There's a /2 manual at this website:
http://w6rec.com/duane/bmw/2man/index.htm
It's for a twin motorcycle...page 166 is the start of the process.
This must be done on a cold engine. Basically, you must turn the engine so that the piston is at Top Dead Center on the compression stroke. You find that by putting your finger in the spark plug hole and turning the engine over by hand or maybe using the rear tire with the tranny in 2/3 gear. When you begin to feel pressure building against your finger, you are approaching TDC. Continue turning the engine slowly, watching the timing marks. When you see the mark indicating TDC (I don't know what it looks like on a single) in the center of the window, stop turning the engine. Adjust the intake/exhaust valves for the specified clearance. Ensure that the locknuts are tightened. Turn the engine around one more time to get to TDC on the compression stroke. Recheck the valve clearances. Put the valve cover back on, install spark plug, and you're done.
Kurt in S.A.
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bmw r26-adjusting valves
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schrader7032
- Posts: 9065
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bmw r26-adjusting valves
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
bmw r26-adjusting valves
anyone knows what is the indication of the tdc in r26?
how much is the specified clearance?
how much is the specified clearance?
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Allan.Atherton
- Posts: 503
- Joined: Fri Oct 27, 2006 3:00 am
bmw r26-adjusting valves
Added tips...
Torque first.
You can check valves with the tank on, as the rear valve cover can be maneuvered around to the front and removed. And the tank could stay on for adjusting valves. Except, before adjusting valves, you should first torque the head bolts, which requires the tank to be drained and removed. I prefer an old fashioned beam torque wrench. Back off a bolt until it barely moves = enough to eliminate any stiction but not enough to relax the bolt and maybe invite a head gasket leak . Tighten to 25 lbs max, better a few lbs less than more. Do one bolt at a time in an criss-cross pattern. After all four are tightened, do another criss-cross just tightening to 25 lbs, to see if there is any more movement in the bolts.
Then adjust.
Remove the spark plug and turn the engine over with an allen wrench in the hole in the crankshaft at the front of the generator. Or you can sit beside the bike, put your right foot against the side of the rear wheel, jiggle the shifter up into 4th gear which has the least resistance, brace yourself by holding onto a footpeg, and bump the engine over by turning the rear wheel with your foot.
Torque first.
You can check valves with the tank on, as the rear valve cover can be maneuvered around to the front and removed. And the tank could stay on for adjusting valves. Except, before adjusting valves, you should first torque the head bolts, which requires the tank to be drained and removed. I prefer an old fashioned beam torque wrench. Back off a bolt until it barely moves = enough to eliminate any stiction but not enough to relax the bolt and maybe invite a head gasket leak . Tighten to 25 lbs max, better a few lbs less than more. Do one bolt at a time in an criss-cross pattern. After all four are tightened, do another criss-cross just tightening to 25 lbs, to see if there is any more movement in the bolts.
Then adjust.
Remove the spark plug and turn the engine over with an allen wrench in the hole in the crankshaft at the front of the generator. Or you can sit beside the bike, put your right foot against the side of the rear wheel, jiggle the shifter up into 4th gear which has the least resistance, brace yourself by holding onto a footpeg, and bump the engine over by turning the rear wheel with your foot.
-
Allan.Atherton
- Posts: 503
- Joined: Fri Oct 27, 2006 3:00 am
bmw r26-adjusting valves
anyone knows what is the indication of the tdc in r26?
how much is the specified clearance?
As for all the bikes, TDC is at the OT mark, intake is .006" and exhaust is .008". Here is the page of the manual for a twin, same for a single:
http://w6rec.com/duane/bmw/2man/page166.jpg
See Para. 2 on that page.
Be aware that the valves cannot be adjusted just because the OT mark is in the window. The engine makes 4 revolutions (strokes) to fire one time, and you must adjust at that firing stroke when the valves are all tightly closed.
So as Para. 2 says, addition to watching for the OT mark and probing for the top of the piston, I also watch the rockers going up and down to follow the intake, compression, firing and exhaust strokes, to understand when both valves are closed for firing, and finally confirm that by feeling for some play in the valves. If there is no play, either this is not a power stroke (likely), or the valve adjustment has become extremely tight and removed all play (not likely).
how much is the specified clearance?
As for all the bikes, TDC is at the OT mark, intake is .006" and exhaust is .008". Here is the page of the manual for a twin, same for a single:
http://w6rec.com/duane/bmw/2man/page166.jpg
See Para. 2 on that page.
Be aware that the valves cannot be adjusted just because the OT mark is in the window. The engine makes 4 revolutions (strokes) to fire one time, and you must adjust at that firing stroke when the valves are all tightly closed.
So as Para. 2 says, addition to watching for the OT mark and probing for the top of the piston, I also watch the rockers going up and down to follow the intake, compression, firing and exhaust strokes, to understand when both valves are closed for firing, and finally confirm that by feeling for some play in the valves. If there is no play, either this is not a power stroke (likely), or the valve adjustment has become extremely tight and removed all play (not likely).
bmw r26-adjusting valves
the torque thing has to be done?
where are these head bolts located?
do i have to dismantle the engine?
i can't find anything relevant in the manual.
where are these head bolts located?
do i have to dismantle the engine?
i can't find anything relevant in the manual.
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schrader7032
- Posts: 9065
- Joined: Fri Oct 27, 2006 3:00 am
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bmw r26-adjusting valves
the torque thing has to be done?
where are these head bolts located?
do i have to dismantle the engine?
i can't find anything relevant in the manual.
Yes...it's always a good idea to torque...at least check. If you set the clearances and head bolts are loose, you won't have the proper clearance and the pieces of the top end will be "moving" around.
Remove the valve cover...you'll see the bolts. Should be four on either end of the two rocker arm blocks and two buried a bit at the 6 and 12 o'clock position.
No...just remove the valve cover. As Allan said, you'll have to remove the tank as well to retorque.
What manual do you have? The link to Duane's site was just to whet your appetite. If you're going to do this, you should have a decent manual or at least have someone watch over your shoulder.
Kurt in S.A.
where are these head bolts located?
do i have to dismantle the engine?
i can't find anything relevant in the manual.
Yes...it's always a good idea to torque...at least check. If you set the clearances and head bolts are loose, you won't have the proper clearance and the pieces of the top end will be "moving" around.
Remove the valve cover...you'll see the bolts. Should be four on either end of the two rocker arm blocks and two buried a bit at the 6 and 12 o'clock position.
No...just remove the valve cover. As Allan said, you'll have to remove the tank as well to retorque.
What manual do you have? The link to Duane's site was just to whet your appetite. If you're going to do this, you should have a decent manual or at least have someone watch over your shoulder.
Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
bmw r26-adjusting valves
and i should tighten the four bolts or all 6?
where exaclty are these bolts?
where exaclty are these bolts?
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schrader7032
- Posts: 9065
- Joined: Fri Oct 27, 2006 3:00 am
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bmw r26-adjusting valves
I see four of them in the picture. See the two wrenches on the right side, one held with a hand and the other engaging a bolt at the top. Just to the right of this upper most wrench is a hex-head bolt. That bolt is a head bolt...there are three others which serve to hold down the rocker arms and "squeeze" the head and cylinders against the block. I can't see the other two due to the picture angle.
I must say, if you're asking these kinds of questions, it would be best if you got some help. I don't know you or your mechanical abilities, but this is somewhat basic stuff for these bikes. Admittedly, we all have to start somewhere...I did. But if you're getting a handle on things, press on. Be aware, doing things wrong at this point might result in a bigger price tag later on. But hey, that's experience, right??
BTW...where are you located? Maybe there's some local knowledge you can tap into. Who did the bike restoration? Maybe they can offer some guidance.
If you do torque the heads, be sure and do the proper technique, ensure that your torque wrench is accurate, and do not over torque. I'm not sure about the singles, but the twin BMWs (at least the ones beginning in 1970) can pull out the studs from the engine case which requires a helicoil, etc....kind of ruins your day. The /2 era bikes didn't have the same kind of attachment, but again, I don't know the singles all that well. Maybe Allan can step in and provide his experience.
Good luck...Kurt in S.A.
I must say, if you're asking these kinds of questions, it would be best if you got some help. I don't know you or your mechanical abilities, but this is somewhat basic stuff for these bikes. Admittedly, we all have to start somewhere...I did. But if you're getting a handle on things, press on. Be aware, doing things wrong at this point might result in a bigger price tag later on. But hey, that's experience, right??
BTW...where are you located? Maybe there's some local knowledge you can tap into. Who did the bike restoration? Maybe they can offer some guidance.
If you do torque the heads, be sure and do the proper technique, ensure that your torque wrench is accurate, and do not over torque. I'm not sure about the singles, but the twin BMWs (at least the ones beginning in 1970) can pull out the studs from the engine case which requires a helicoil, etc....kind of ruins your day. The /2 era bikes didn't have the same kind of attachment, but again, I don't know the singles all that well. Maybe Allan can step in and provide his experience.
Good luck...Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
bmw r26-adjusting valves
thanks a lot.
i am in greece and i won't do the whole procedure.
i just want roughly to know what has to be done.
if there are some specific problems,i'll get help from the restoration crew.
thank you very much for the kind help!
i am in greece and i won't do the whole procedure.
i just want roughly to know what has to be done.
if there are some specific problems,i'll get help from the restoration crew.
thank you very much for the kind help!