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Old 06-13-2013, 08:44 PM   #31
akpasta OP
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Joined: Jun 2013
Location: San Francisco, CA
Oddometer: 161
I set the valve clearance. Really easy, way easier than on my Honda CB77. The intake clearance was spot-on both sides, but the exhaust valves were both tight, so I set the clearance to .20mm as specified. Then I re-set the point gap closest to .15mm as possible and did static timing using alligator clips and twinkle bulb so that the light went on when I rotated stator to S--- mark (it was going on at the F mark when I bought the bike). Didn't have time to sync the carbs per manual but since it was getting late but I had em pretty closely synced earlier today so I fired er up just to see. She farted and popped like shit, didn't run worth a damn at any rpm, which is odd cuz I'd expect even if the carbs weren't perfectly synced for idle it would run okay at advance especially since it ran fine earlier before I fixed the valve clearance and timing. I suspect something I did with the timing.

The bike is old, 83k miles, and some of the allen bolts heads under the points cover are starting to strip out.

1. Gotta be really careful with the stator bolt that turns the engine, it's getting there but still works. Do you have tips on what to do about this?

2. I think my farting/popping ignition may be because of one of the allen bolts that secures the points plate. The bottom one is good, but the top bolt head is starting to strip and I wasn't able to tighten it super tight with my allen wrench, although it did seem tight enough i couldn't loosen it by hand or with pliers, but you never know with vibration maybe it's coming loose and i'm losing points ground or the plate is rattling? I was thinking of cutting the that bolt head into a flat-head bolt. Is this advisable?

Do you have any other idea why it ran like shit after I performed these two maintenance items? Would have something to do with the timing stuff I'd done, I would think.

For what it's worth, at the shitty idle I was able to achieve, my strobe light showed 'S' at idle, and 'F' at advance, so the timing seems on, maybe a short, like I'm thinking?

Getting there!
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Old 06-13-2013, 09:07 PM   #32
Plaka
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Quote:
Originally Posted by akpasta View Post
I set the valve clearance. Really easy, way easier than on my Honda CB77. The intake clearance was spot-on both sides, but the exhaust valves were both tight, so I set the clearance to .20mm as specified. Then I re-set the point gap closest to .15mm as possible and did static timing using alligator clips and twinkle bulb so that the light went on when I rotated stator to S--- mark (it was going on at the F mark when I bought the bike). Didn't have time to sync the carbs per manual but since it was getting late but I had em pretty closely synced earlier today so I fired er up just to see. She farted and popped like shit, didn't run worth a damn at any rpm, which is odd cuz I'd expect even if the carbs weren't perfectly synced for idle it would run okay at advance especially since it ran fine earlier before I fixed the valve clearance and timing. I suspect something I did with the timing.

The bike is old, 83k miles, and some of the allen bolts heads under the points cover are starting to strip out.

1. Gotta be really careful with the stator bolt that turns the engine, it's getting there but still works. Do you have tips on what to do about this?

2. I think my farting/popping ignition may be because of one of the allen bolts that secures the points plate. The bottom one is good, but the top bolt head is starting to strip and I wasn't able to tighten it super tight with my allen wrench, although it did seem tight enough i couldn't loosen it by hand or with pliers, but you never know with vibration maybe it's coming loose and i'm losing points ground or the plate is rattling? I was thinking of cutting the that bolt head into a flat-head bolt. Is this advisable?

Do you have any other idea why it ran like shit after I performed these two maintenance items? Would have something to do with the timing stuff I'd done, I would think.

For what it's worth, at the shitty idle I was able to achieve, my strobe light showed 'S' at idle, and 'F' at advance, so the timing seems on, maybe a short, like I'm thinking?

Getting there!
You haven't completed your tune up. I imagine the carbs are grossly out from what you did before. Yet you are going on and on about this that and the other. You have yet to complete a basic tune up.

Slow down.

Don't use the alternator bolt to turn the engine. I know what the manuals say. Bad idea. If the plugs are in, super bad idea. Use kickstarter if you have one, or the rear wheel in high gear.

The bolt you been getting on holds the rotor in place. Stators don't turn, hence the name.

83K is not old. Not for an airhead. You keep comparing it to all sorts of other bikes. it's easier than this, etc. Cease. Llet it be what it is. Be willing to be a noob with it, learn it from the ground up. There is a whole philosophical trip here, which I will spare you. But hold focus on the machine in front of you and be as humble with it and working on it as you can manage. It's OK. All will fall into place. You don't have to be superwrench. You do have to slow down.

Just replace beat up bolts. Geeze. Hardware store, y'know? Sometimes you have to shorten them. Cutoff wheel in a dremel.

The alternator rotor bolt is special a couple ways. That one you buy new from a dealer. Get a puller bolt while you are at it, although one can be fabricated simply. Some gotchas to that. Read up..

Note the tight exhausts in your log with date and mileage. You will want to keep an eye on them. If they keep coming up tight you will need some head work.


Slow down.
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Old 06-14-2013, 09:24 AM   #33
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So Zen. Thanks for all the advice. I'll play with the carbs next per your rec.

Anyone have on hand the pitch/length of points plate screws? Would be nice to hit the hardware store on my way home so I don't have to make a couple trips.
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Old 06-14-2013, 10:12 AM   #34
SOLO LOBO
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Originally Posted by akpasta View Post
Anyone have on hand the pitch/length of points plate screws? .
If you go to any on-line BMW parts site that shows the fische (ex: Max BMW) the basic information is listed, not always pitch however.
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your bike is suitably dirty. Well done.
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Old 06-14-2013, 10:37 AM   #35
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Quote:
Originally Posted by akpasta View Post
I set the valve clearance. Really easy, way easier than on my Honda CB77. The intake clearance was spot-on both sides, but the exhaust valves were both tight, so I set the clearance to .20mm as specified. Then I re-set the point gap closest to .15mm as possible and did static timing using alligator clips and twinkle bulb so that the light went on when I rotated stator to S--- mark (it was going on at the F mark when I bought the bike).
The points gap should be 0.014-0.016 inches or 0.35-0.40 mm. Maybe the above is a typo? Of course, the bike will still run with a 0.006 in (0.15 mm) point gap but the wider gap extends points life. I expect the points plate screw threads are M4x0.7. Good luck!
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Old 06-14-2013, 11:00 AM   #36
Plaka
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Originally Posted by akpasta View Post
So Zen. Thanks for all the advice. I'll play with the carbs next per your rec.

Anyone have on hand the pitch/length of points plate screws? Would be nice to hit the hardware store on my way home so I don't have to make a couple trips.
Take one of your existing screws to the store with you. Do not buy stainless for this.

Also get a long M8xwhatever alloy steel bolt. It should have a few inches of smooth shank (2+). It must be grade 12. Will be stamped 12.9 (http://www.engineeringtoolbox.com/st...es-d_1428.html) Any head is fine, you will be cutting it off.

At some point having a metric tap and die set will be desirable. A nice big one. This takes care of most of your bolt ID needs as well as cleaning up things and fabrication. You know those weld nuts under the rear frame flanges that the muffler bolts to? The ones with the rusty bores? Didn't you wish you had the proper tap to run through there to clean them up?

I think those points plate screws go right on through the timing cover and there is nothing back there for a ways, So you can go long. But I could be wrong, My old block is in the attic and it's hot up there. Investigate with a broom straw or similar.

Plaka screwed with this post 06-14-2013 at 11:19 AM
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Old 06-14-2013, 11:23 AM   #37
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I'm sorry, it was a typo, I always forget the number. I think I meant to type .015" or whatever, but yes, I'm definitely setting the correct point gap.

What should I use instead of stainless? The bolt that's in there is a brass color. Would be faster I bet to turn the allen head into a flathead.
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Old 06-14-2013, 11:59 AM   #38
Plaka
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Originally Posted by akpasta View Post
I'm sorry, it was a typo, I always forget the number. I think I meant to type .015" or whatever, but yes, I'm definitely setting the correct point gap.

What should I use instead of stainless? The bolt that's in there is a brass color. Would be faster I bet to turn the allen head into a flathead.
Ordinary steel. That brass color is a zinc chromate coating. Scrapes off if you try. One in black oxide is fine. Stainless is too soft and you don't need corrosion protection of fancy appearance there. The big advantage of an allen head is you can get on it with a ball driver and work at angles. A button allen is fine, or the regular one. A slotted screw will be a pain. A phillips a nightmare. A hex head will work but not at angles.

You can check the point gap any time with your dwell meter. You can also point your timing light at the points and watch the advance weights operate.

if the screws are even mildly tight I doubt that plate is going anywhere. might not last but isn't going to wiggle away while you are tuning.

The points ground through the condenser as well as the plate and screws.

Stolen from Duane Ausherman:


I would go through Duanes site a lot.

http://w6rec.com/duane/bmw/points/
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Old 06-14-2013, 12:20 PM   #39
akpasta OP
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Thank you, I've read all of Duane's page that you linked, very informative, and I already bought one of those points tools just now received it in the mail. After work I'll check my work on the points. Headed to the hardware store to pick up another bolt m4x6 .7 pitch.
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Old 06-14-2013, 02:17 PM   #40
akpasta OP
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I must have done something wrong when I set the timing and/or valve clearance last night because even after playing with the carbs like you suggested I was not able to get it to idle consistently, or even run consistently at all. It pops, backfires, etc, terrible. Even if my carbs were off before, I still rode 200 miles and that was before I messed with the valve clearance and timing. I'm pretty certain i got the valve clearance right. Timing maybe not!

I'll try again I guess.

It's not possible to set the timing off 180 degrees on each side is it? I can't imagine that's possible with a twin-lobed cam and one set of points.

The only thing I can think went wrong with the timing is I set my gap too small because I didn't have Paul's tool (whcih I have today) then re-set the timing using the static method with an incorrect size gap. Going to try again after work today.

Can anyone give me a tip for getting it into fifth gear without starting the engine, I'm having a little trouble.
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Old 06-14-2013, 02:30 PM   #41
Plaka
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Originally Posted by akpasta View Post
I must have done something wrong when I set the timing and/or valve clearance last night because even after playing with the carbs like you suggested I was not able to get it to idle consistently, or even run consistently at all. It pops, backfires, etc, terrible. Even if my carbs were off before, I still rode 200 miles and that was before I messed with the valve clearance and timing. I'm pretty certain i got the valve clearance right. Timing maybe not!

I'll try again I guess.

It's not possible to set the timing off 180 degrees on each side is it? I can't imagine that's possible with a twin-lobed cam and one set of points.

The only thing I can think went wrong with the timing is I set my gap too small because I didn't have Paul's tool (whcih I have today) then re-set the timing using the static method with an incorrect size gap. Going to try again after work today.

Can anyone give me a tip for getting it into fifth gear without starting the engine, I'm having a little trouble.
Work shift lever while turning rear wheel.

I would suspect the valves are significantly off. If the timing is OK, redo the valves. Use error checking at each step. Stone cold.

It should run ok but not great on the nominal settings of the carbs. May not idle well if at all but not what you describe.
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Old 06-14-2013, 07:19 PM   #42
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Think I found my problem. In my haste, when I put the points cover back on last night I didn't route the points wire properly, kinked it in the cover. Now that I took the points off to get a look I need new points anyways. Do new points come with the wire attached or should I get soldering? Gonna pick some up tomorrow. My valve clearance work from last night was spot on, no worries there, it must have been cranking down on this wire that messed things up....

slow down!
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Old 06-14-2013, 07:31 PM   #43
Plaka
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Originally Posted by akpasta View Post
Think I found my problem. In my haste, when I put the points cover back on last night I didn't route the points wire properly, kinked it in the cover. Now that I took the points off to get a look I need new points anyways. Do new points come with the wire attached or should I get soldering? Gonna pick some up tomorrow. My valve clearance work from last night was spot on, no worries there, it must have been cranking down on this wire that messed things up....

slow down!
Points come wired.

Leave the cover off until your tuning is complete. There are things to be observed in there. You noted on Duanes page he was observing the sparks at the points? Cover gotta be off.

No fingers if running unless you want to lose them.

Pinched wires happen on the later electronic ignition bikes too. Raise havoc...

Bear in mind this is a pure build error. Is has nothing to do with a lack of knowledge or understanding. Just a boo-boo. And that crap happens insomuch as we are human and imperfect. This is why I mentioned error checking w/ respect to the valve adjustments. There some little things you do as you work, like spinning the pushrods with your fingers at certain times, that are just for error control. Should you fail to push on the rocker at the pushrod end, firmly, when using your feeler gauge you will get another error. Failure to be on the right piston stroke, another error. You observe the rockers on the side you are setting. You always turn the engine over twice by hand when done. If things are crashing inside you will feel it before it gets expensive.

Kissing a hot diode board with the top of the front cover when you remove it can be costly. This is why you always pull the ground strap. You can get the cover off fine without touching the board. One screwup and you buy a board.

Tempting perfection is tempting the Gods---they don't like that.

BTW, with respect to slowing down; as you are catching on, these things are very friendly to work on. If you want to ride fast, you ride smooth. Doing your tune ups and basic maintenance will become smooth in a couple of rounds---and very quick. Don't push it on the early laps. Learn the track. Get smooth.
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Old 06-16-2013, 01:01 PM   #44
akpasta OP
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Thanks Plaka for all your zen-like advice.

Replaced the points yesterday, left the old condenser, bought a replacement for piece of mind. Now that I have new points I realize the old ones were shot, so much arcing. Now the bike fires up on on one 'kick' from the starter.

Set the timing, synced the carbs. Runs good, idles at about 800rpms, 500 if I really want it, but I don't. Still have to set the float level on the left carb but I will get to it soon, the Clymer says to do it off the bike, but is it possible to adjust float level with the carb on the bike?

Gotta do another oil change, and this time replace the filter, Do those need replacing EVERY time?
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Old 06-16-2013, 01:20 PM   #45
Plaka
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Originally Posted by akpasta View Post
Thanks Plaka for all your zen-like advice.

Replaced the points yesterday, left the old condenser, bought a replacement for piece of mind. Now that I have new points I realize the old ones were shot, so much arcing. Now the bike fires up on on one 'kick' from the starter.

Set the timing, synced the carbs. Runs good, idles at about 800rpms, 500 if I really want it, but I don't. Still have to set the float level on the left carb but I will get to it soon, the Clymer says to do it off the bike, but is it possible to adjust float level with the carb on the bike?

Gotta do another oil change, and this time replace the filter, Do those need replacing EVERY time?
Not a bad idea @ $6 ea. and you get to tear down the filter for a look see and check the relief in the bottom of the canister bore.. Some replace every other change. Some change their oil too much.

You can set float height by measuring the amount of fuel in the bowl. I think SnowBum goes into the method. Because of the way my float needles work, this is the ONLY way I can do it. I don't bother unless something seems pretty amiss with the mixture. You can play with your float heights to tweak your mixture too. But there is so much sloshing and jumping in the bowl going down the road that you can get vaugly close and it works fine. The more important part is to have it the same on both sides. This solely serves tuning when the bike is running on the stand with minimal sloshing. I'm thinking of cooking up a little tool for this out of an old bowl or a home-made ersatz one. . See thread I mentioned.

There is a current thread on float heights....

Install the new condenser. Better piece of mind to be running it. if you think the one currently installed is worthy to stay that way, then put it on the shelf as a spare. Other wise quietly whistle taps and drop it in the trash.

Those point faces need to be utterly clean when done setting. Any oil on them and they burn faster. Some alcohol on a slip of paper. Ardbeg or Talisker is good but regular shellac thinner from the hardware store is cheaper.

Felt and advance weights get lubed when replacing points.
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