Oil change? So soon?

[darylcaribou69]

Hello all!

I've been working on my 1980 sg over the winter and finally got it on the road yesterday! It goes good! Pulls awesome through most rpm ranges. I still have a bit of tuning to do to get it just right but overall it's going good! The speedometer works very slowly, it still thinks I'm going 70 when I slow to 25 until it catches up then thinks I'm going 25 for a few seconds when I get on the highway. Probably some old gunk in there slowing down the mechanism. (I'm not really sure how these old speedos work)

It was put away by the previous owner didn't get much love for a few years. When I drained the fluids they came out dark, there was years of sludge in the bottom of the middle drive and final drive, smelled like I was at the landfill when I opened them up. I replaced all fluids with fresh. So far I've gone 50 miles on it with no issues. I was wondering if it would be a good idea or a waste of money to change the fluids again fairly soon, maybe 100 or 150 miles. My reasoning would be that the new fluid would be able to go through a few heat cycles and break up and clean out the old gunk then I could drain it and start on a regular maintenance schedule.

Any advice is greatly appreciated!

[Jerry]

I would change fluids again fairly quickly. Can't hurt anything but your pocketbook and that way you can be reasonably sure the old stuff has been flushed out.

Take it on a longer day trip (100 - 150 miles) so everything gets good and warm and then change fluids. Also change oil filter again.

[JeffH]

+1 on what Jerry said

If the old fluids were just nasty I would ride maybe 500 miles. Or a least a good 200-250 mile day ride, then change oil, filter, mid & FD. Again

Unless you had any metal fragments or extremely shiny metal sheen in the old fluids; I'd ride it to cycle up the crud so it will drain out. Different story if you had metal showing up, then I'd change it soon.

As for the speedo. I assume cable has been lubed. But i'm thinking (maybe wrong) that if the bike has been sitting for a long time that after some riding that delay might get better. Maybe one of the Speedo Guru's can help if this is a ride it or fix it situation.

btw: that nasty old 90W gear lube does smell like a sewer treatment plant so what you drained out was about the norm

Good luck with the tuning. You getting that bobble at 3,300 to 4,000 rpm? or is it at some other rpm?

Post a picture or a Ride Report for us to enjoy

Jeff

[darylcaribou69]

The old fluid didn't have any noticeable metal flakes. It was just old and nasty, like glue that smelt like "a sewer treatment facility." I did not lube the speedo cable, so it still has the old nasty lube from 40 years ago.

The bobble does happen between 3 and 4k rpm.

Thanks for the advice!

[Radioguylogs]

I think there is old (silicone?) grease in the speedometer that becomes thick with age.

I had the same problem on one of my XS750s. It went away after 1k miles and never came came back (so far).

[darylcaribou69]

Probably just have to drive it a bit to get it rolling again. I read a thread about it and the guy ended up leaving the bike outside on a hot day and it cured the sluggishness in the speedo. It makes sense that it would be slow to get moving after sitting for years.

[Tenorman]

Here's a thought...

Have fun on that bike...they do pull like a freight train... ;-)

When i did my transmission work, I had to remove the oil pan. I was amazed at the amount of sludge in a bike that had only a bit more than 30,000 on the odometer. It sat for about 15 years.

You could, if you like, remove the oil pan and give it a good cleaning...

Just a thought...

Tenorman

[donebysunday]

could be

Probably just have to drive it a bit to get it rolling again. I read a thread about it and the guy ended up leaving the bike outside on a hot day and it cured the sluggishness in the speedo. It makes sense that it would be slow to get moving after sitting for years.

About the oil, use your discretion, but do change the filter every oil change, that will keep the swarf (dirt/crap, aluminum shavings) out of the engine. Done often enough You may end up draining dark honey out on some oil change in the future.
I wrote somewhere (?) about leaving a bike with a sticky/slow speedo in the sun on a hot day, went for a ride and all was fine (not too hot or too long as I have seen warped faces). Since that fix I've gone to fixing slow speedos and cable driven tachometers by putting them in the oven (of course not too hot or too long). The heat makes the solidified/gummed up lubricant soluble, test before re-installing the gauge with a drill running it counterclockwise using one of those square bits for deck screws. Depending, my drill gets the speed up to about 65 mph. on the gauge at full drill RPM..

[DiverRay]

The safer way would be use a hair dryer to heat up the speedo. aluminum foil "box" around the speedo with a port for the hair dryer and the exit port after the speedo. Five minutes on, ten off for about three cycles should do it.

[TopCatGr58]

Hey Daryl,

I'm a bit late to this party, but to help in breaking down the sludge, before doing the oil change, put about 1/2 bottle of Marvel Mystery Oil into the oil and then gently run the engine up to engine temp. MMO is very good at breaking down varnish and gum, and will help to flush the stuff out.

T.C.

[darylcaribou69]

Thanks for the replies all!

I took it for a little ride (about 90 miles) and when I got to the turn around I was hearing a noise. It sounded like it was coming from the top end. It wasn't too loud and seemed to change with rpm. So when I got it home I immediately pulled all of the drain plugs and drained the engine oil and gear boxes. The fluids didn't look too bad but looked darker than just having 200 miles on them.

So, I wish I would have thought of the MMO before I did that to try to get out some extra sludge. Now, I'm planning on going in to adjust the valves which I never did because it always seemed to run pretty good. Also I'm going to take a look inside the carbs and set float heights again and consider enriching the jets a size or two. The plugs are white, white as can be. I'm not a carburetor master, but doesn't lean =mean =heat =expensive? They should be leaned again anyway. Also, the fork seals are shot so those will be done as well!

Like always, any advice is appreciated!

Have a good weekend,
Daryl

[darylcaribou69]

Oh yeah! One more thing, when stopped and sitting in first it'll sometimes slip out and into neutral. Trans issues seem like a common thing for these bikes, it also doesn't help that with the MAC4-2 exhaust the shift lever touches the exhaust when shifting to first, this might be one of my issues down there. I was thinking of moving the shift lever up a couple positions on the spinner with the notches (I dont know what its actual called. Gear shift spline maybe?) So it doesn't touch the exhaust. So, when I pull the oil pan to clear out sludge I'm going to take a look at what's in there! Should be quite an adventure as I've never done surgery to an engine before! Also, when going along I hear a "woo, woo, woo" noise, like a wheelbearing going but it isn't all the time, only under load(theres no dragging or play in the wheel bearings or noise when it's on the center stand) and it's not bad enough to be alarming but it is there enough for me to slightly notice when I'm being paranoid about noises. It's probably just the gears doing what they do. Also need to get into the speedo drive on the front wheel and clean and lube her up. Then up the cable and to run a heatgun on the speedo itself to loosen up the old grease in there.

This post turned into a kind of to-do list, my apologies!

[motoman]

Oh yeah! One more thing, when stopped and sitting in first it'll sometimes slip out and into neutral. Trans issues seem like a common thing for these bikes, it also doesn't help that with the MAC4-2 exhaust the shift lever touches the exhaust when shifting to first, this might be one of my issues down there. I was thinking of moving the shift lever up a couple positions on the spinner with the notches (I dont know what its actual called. Gear shift spline maybe?) So it doesn't touch the exhaust. So, when I pull the oil pan to clear out sludge I'm going to take a look at what's in there! Should be quite an adventure as I've never done surgery to an engine before! Also, when going along I hear a "woo, woo, woo" noise, like a wheelbearing going but it isn't all the time, only under load(theres no dragging or play in the wheel bearings or noise when it's on the center stand) and it's not bad enough to be alarming but it is there enough for me to slightly notice when I'm being paranoid about noises. It's probably just the gears doing what they do. Also need to get into the speedo drive on the front wheel and clean and lube her up. Then up the cable and to run a heatgun on the speedo itself to loosen up the old grease in there.

This post turned into a kind of to-do list, my apologies!

Well, your 'to do' list is just getting warmed up.

[MPittma100]

Jet change

Do yourself and the bike a favor and leave the jets stock.

[darylcaribou69]

Does the 80sg normally run a little lean? After it gets warmed up it seems to run quite well! I just dont want to cause any damage to the internals with too lean of a mixture.