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Old 08-31-2012, 02:28 PM   #31
supershaft
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Originally Posted by hardwaregrrl View Post
It is a remote possibility you may have a 336 cam....it could possible cause your crap idle problem. It is a remote possibility, given the OP hotrodded it a bit. Any way to find out if the cam has been changed???
Except that there are quite a few on this forum that will tell you that their 336 idles real well. 336 or not, that isn't the reason for a crappy idle.
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Old 08-31-2012, 04:24 PM   #32
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I"ve been elk hunting. Sheesh!

Elk Hunting? You are going to need a g/s.
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Old 10-13-2012, 07:46 PM   #33
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Elk hunting was a success and real life took back over. We are green loctiting in the left rear wheel bearing outer race and we shall see what happens Monday night with that
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Old 10-13-2012, 11:56 PM   #34
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Make sure you follow directions when removing and installing wheel bearings. It takes heat. Most modern versions have you use hot water for the heat. They think it is safer than the old method of a heat gun. I use a propane torch. Just be careful to not over do it and keep the flame moving.

Failure to use some source of heat to expand the Aluminum hub can ruin the wheel because the bearing will spin the outer race.
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Old 10-14-2012, 12:30 PM   #35
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I have been researching that in exhausting detail. I used a propane torch to get it hot. I followed the directions here,

http://w6rec.com/duane/bmw/wheel_bearing/index.htm

and out hey popped slick as could be. Following the directions again I put the new ones in just as easy as the old ones came out. The reason I took them out in the first place was that in a post purchase inspection it was pointed out that there was a lot of play at the rear wheel. On further inspection it was revealed that the left bearing cup had spun in the hub. After much gnashing of teeth and hair pulling it was decided to use a high temp variety of green loctite to hold it in while I search for a reasonably priced rear wheel to replace this one with. There is also the option of machining out a bit more of the hub to install a sleeve to fit the bearing cup into. Monday night I'll put the wheel back on the bike to set the bearing preload and then move on to the rings to see whats up there. The compression test showed 150 and 160 put with a leak down of over 50% in each cylinder.
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Old 10-14-2012, 12:51 PM   #36
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The compression test showed 150 and 160 put with a leak down of over 50% in each cylinder.
Surely there is a problem with your procedure or instruments. You simply cannot have 150lbs compression with 50% leak down. Violation of the law of physics here.
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Old 10-14-2012, 02:27 PM   #37
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I didn't do the test but isn't the point of a leak down test to see if a piston seals well enough to show that kind of compression but be unable to hold it? I'm not sure why it's a violation of the laws of physics. I'm just a 'lectrician.
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Old 10-14-2012, 05:00 PM   #38
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High spec comp should be 145 to 150. At that level, leak down will be around 2 or 3%

Leakdown at 110lbs comp will be some 80%-90%. Any less than 90% is rebuild time.

You simply will not see 50% leakdown at 140lbs. Could be you had a good test for comp then a bit of a piece of crud ended up fouling a valve. Run the motor to full temp then test again. Ane the whole idea behind a leak down test is to determine where the loss is occuring, valves int or exh or rings or head gasket or a combination.

I doubt you would have any potential to start the motor at 50% leak down, and then if it did would run like crap and certainly would not idle.

You got some bad data due to procedure or instruments.
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Old 10-14-2012, 05:49 PM   #39
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Ok I'll do that. I am getting a lot of white smoke after it's warmed up.coming out the right side but I'm pretty sure that is because the crankcase breather hose is vented to that side. again it's supposed to have high compression pistons in rings from a 900 in it. It runs great on the highway and pulls like everything from 60 - 90. Around town as it warms up stop light to stoplight is when I see the smoke..
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Old 10-15-2012, 02:22 PM   #40
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Burning oil can come from the oil control rings or valve guides worn. That would be dark smoke. If light smoke, running too rich. You have a basic issue that correct diagnostics can find.
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Old 10-15-2012, 04:20 PM   #41
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Well first things first. I gotta get that wheel in and the bearing preload set. Then we chase the smoke.

Ok So I put the wheel all back together and greased everything like it said to. I ran the nut tight as instructed to check the preload and there was the tiniest bit of movement when I did the shake test. I took out the axle and measured the wedding ring spacer. It was .271" thick. So I lapped it on a glass plate with 220 grit sandpaper to .2695". put it back in and I had less movement during the run up but enough to pull it back out for a little more lapping finishing it with 600 grit for a finished thickness of .268". In it went preload is set to as movement free as I can stand at this point. Now to adjust that rear brake actuator arm back a spline. Then a carb look see and rebuild.
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Old 10-15-2012, 11:41 PM   #42
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Ok I'll do that. I am getting a lot of white smoke after it's warmed up.coming out the right side but I'm pretty sure that is because the crankcase breather hose is vented to that side. again it's supposed to have high compression pistons in rings from a 900 in it. It runs great on the highway and pulls like everything from 60 - 90. Around town as it warms up stop light to stoplight is when I see the smoke..
Easy test to point to valve guides...
at night when stopped at the lights just idling...with a car behind with their lights on, as you accelerate check the mirrors. If you see lots of smoke thru the back-lighting and it dissipates after a 100 metres or so will suggest valve guides as a problem.
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Old 11-15-2012, 09:39 AM   #43
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So this week end I'll rebuild the carbs so I'm at a good starting point for tuning and balancing. Does any one here have a good source for throttle cables?
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Old 11-15-2012, 10:13 AM   #44
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