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Post by rattattat on Apr 11, 2011 15:52:38 GMT -5
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Post by Chuckwagon on Apr 12, 2011 13:42:28 GMT -5
congrats on getting it running.
If it is coming out of the head flanges but not the pipe, that seems to indicate that there is oil leaking on to the flanges (valve cover or other area on external of engine) instead of burning oil. See if you can trace the source. A trick is to thoroughly clean the engine to remove as much oil as possible, dry, then spray athelete's foot aerosol powder spray on to the engine and start it up... the powder makes the oil leak more obvious. Depending upon how much you've run it, it may just need time to burn off. Now's a good time to retorque the head, which may stop the leak. If it seems like puffs of exhaust being blown at the flanges, then you need to replace your exhaust / flange gaskets.
If smoke is coming out of the end of the pipe that means you're burning oil. often means bad rings or valve guide seals.
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Post by rattattat on Apr 13, 2011 2:00:18 GMT -5
Thanks Chuckwagon, you're a great wealth of knowledge. The engine has been thoroughly cleaned and there are no oil leaks. The smoke that is coming from the head gasket/ flanges is not a lot, but it is a light steady flow. Notice in the pictures that the flanges are not completely against the engine. I believe that I tightened them very tight, but didn't want to over tighten and break something. You also mentioned that if there is smoke coming from the end of the pipes that it often means bad rings or valve guide seals. Should I see absolutely no smoke at all because there is some, but again not a lot? I will be taking your advice and re-torquing the head once I get a torque wrench. The oil has been completely changed and running 20w 50 new filters and gaskets. How do I determine if I need to replace the rings or valve guide seals or something else. I see that you didn't mention anything about the little hole that is next to the flange so I guess that is normal. I really appreciate the help. I'm on a deadline to finish this build but don't want to cut corners, but at the same time don't want to do anything that is really not necessary.
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Post by Chuckwagon on Apr 13, 2011 5:20:23 GMT -5
I don't know that I'm a wealth of knowledge, just a wealth of lots of trial and error... mainly error.
smoke coming out of the exhaust could be two things (I think) on an air cooled bike... fuel mixture is off, or oil. If you are familiar with burning oil, it has a heavy acrid smell. Most obvious is that it is blueish/whitish color and hangs in the air (doesn't dissapate quickly).
Rich fuel mixture (improper carb cleaning/jetting/adjustment) or incomplete burn of fuel (due to weak spark) will have a gasoline smell and will be black. The smell makes me feel homesick.
Burning oil is often due to worn rings or valve guide seals. Bad rings can usually be diagnosed with a compression test... and there's only one way to do that... a compression tester. Optimal to have each cylinder showing about 150-160 psi.
Valve guide seals leak oil, but probably won't affect compression. Not sure how to diagnose that besides getting into the engine...maybe someone else can chime in and correct me (on any of my "guidance").
I see a gap between the flange and head. Not sure if that is abnormal, but leaking exhaust at the flange is. Best bet is to replace the exh. gasket, as they are really cheap. With the new gaskets, use your torque wrench to make sure you have tight enough, but not so tight that you break a stud.
I don't know the reason your self-imposed deadline, but try to slow down and enjoy the process... you and the bike will be better for it. It's that whole "journey not the destination" thing.
Other philosophical words of wisdom that I heard last night: "A flute with no holes is not a flute. A donut with no holes is a danish."
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Post by rattattat on Apr 13, 2011 13:27:35 GMT -5
I'll start with the easy and cheapest fix first by checking compression, changing exhaust gaskets and checking fuel mixture. I'm not sure that you clearly answered my question on whether or not there should be any smoke at all coming from the exhaust ends even a little. Maybe I'm being too picky considering that the bike is 33 yrs old. Maybe a good ride will help since the bike has been sitting for god knows how long.
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Post by Chuckwagon on Apr 13, 2011 14:15:43 GMT -5
Under ideal conditions, there should be no smoke coming out of the exhaust. Yes, given the age and state of the bike, it is not unexpected. Rich mixture/unburned fuel is often resolved with a regular tune-up, while oil burning is not.
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Post by xsleo on Apr 13, 2011 21:14:27 GMT -5
On your head pipes, if you can get the flanges to touch the head, the gaskets are shot. With new gaskets there will be about 1/8 inch of so gap between the flange and head. The small hole by the flange is ther on all the stock head pipes. The headpipe is a double wall pipe. You might find a simular hole on the very bottom of the pipe just ahead of the rust ring where the muffler was. You can see the double walls in the ends of the pipes. If you want to be able to get the carbs tuned, you might want to put mufflers on. A free flowing muffler is easier to tune to than an open headpipe. The open head pipe is loud and looses power in the low to midrange engine speeds. It only helps at about 7000 rpms and up. I don't know about you but I don't ride my bike at those speeds much. Looking at your pics the inside of the pipe don't look bad. If you wipe your finger inthere, does it come out greasy and black or is the black dry. It looks dry to me. That says no or very little oil burning. Sooty means a rich carb adjustment. Try reading this www.amckayltd.com/carbguide.pdfBefore the carbs set the cam chain tension, adjust the valves, set the points gap and timing. At idel and 3000 rpm. Don't want over advance, burns pistons. Do them in this order. Changing the order screws up the adjustments. If all this and your spark looks weak, new plugs, then plug wires and caps. Maybe even new coils. Once you get a good strong spark at the right time, then start with the carbs. Another thing, your pod filters may have a lip on the rubber flange where they clamp to the carbs. This lip can block the air holes on the carbs. |
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Post by rattattat on Apr 15, 2011 10:25:38 GMT -5
Thanks xsleo, you provided a lot of good advice and tips, as well a great link. I plan on keeping my pipes as they are in the pic or if I change them it will only be to a custom set that are still open pipes. I was wondering if you still advise that I tune the bike with mufflers on or tune it as it will be when riding? The inside of the pipes are dry but then again I haven't ridden the bike yet only had it started and running a few times. The last time I started the bike I didn't really notice the smoke coming from the head flanges until it really started to heat up. Do you think that this is a clear sign that it is just burning up anything that might be on the pipes? I did clean the engine but not really much with the exhaust. The little bit of smoke coming out the ends of the pipe is really only noticeable when I rev the engine. Could you also tell me if it is normal for the tach needle to bounce a little bit when idling. It is idling at just over 1000 RPM.
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Post by xsleo on Apr 16, 2011 16:34:15 GMT -5
Tune your carbs the way your going to run the bike. A good muffler can make tuning easier.
Cleaning the engine can leave stuff on the pipes and head. The hottest part of the head is around the exhaust pipe. So it burns off stuff more than the rest of the head. The pipe gets hot too, so stuff on there burns off.
The smoke coming out the pipe when you rev it may be fuel. under acceleration the carbs can deliver a bit more than the engine can burn, this extra unburnt gas comes out as black smoke. Oil is comes out blue to grey.
If the bike has sat for most any length of time the lube in the tach and speedo gets stiff and the needle bobs around. After a few miles they will smooth out some. Even then they may bob around a bit.
Taking the cable off, pull out the core. Cleanout the housing with carb or brake cleaner, even WD40 works. Spray, let soak, spray, after awhile the stuff running out will come out clean. Clean off the core. A thin coat of grease on all but the last 6 inches at the top. Leave the last bit clean, don't want that migrating up into the tach or speedo. It can gum them up and they won't work well at all.
Idle speed should be at 1200-1500 rpm. Much lower and you may find it stalling unexpectedly. Like when you pull up to a stop. Keeping the idle up helps keep the battery charged. At idle it charges just about enough to stay ahead of what the bike needs to stay running. A lower idle and it won't. This may be part of the stalling.
Leo
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gordon
New Member
'80 G,
Posts: 5
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Post by gordon on Apr 16, 2011 19:02:02 GMT -5
As Leo stated, if it's been sitting around for a while, it's normal for some smoke, the insides have to get acclimated to being in use again. There is allways some rust on the cylinder wall's, and until the piston ring's wear to that, you will get some smoke. If the ring's are not stuck, it'will stop in time. The only for sure way to tell if the ring's have gone south, is a teardown. get it running, clean out the carbs, and enjoy for the summer.
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Post by rattattat on Apr 16, 2011 20:00:46 GMT -5
Good advice thanks Gordon
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