'87 K100 Smoke

vttownie · 1 '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 5:29 pm

vttownie

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Number of posts : 22

From my last post, I figured out how to get my bike's fuel injection balanced and happy. Rode it around in a parking lot to work out the kinks - it ran well. Thanks for everyone for the help with the start issue.

This time, as I was riding with my brother, we noticed smoke leaking out of the engine case on the left (driver's side). Just leaking out of the bottom, top, sides. I'm sure the answer is as simple as tightening the case down better, but I fear wrecking the threads. Do I need to simply ride it out?

I have replaced all of the gaskets, including the rubber boots on the screws, on each side. I keep it on the center stand, and when I start it, smoke does come out but it stays light gray. It hasn't run at a high rev or for many miles recently - the last time it ran as a commuting vehicle was 2019. It has 73,000 miles.

Besides the common knowledge of "run it until the problem stops", is an exhaust leak a major issue? Should I check the threads on the inside of the case, make sure they're tightened down and not strippec? Should I suck it up and ride?

At the end of the day I'm grateful for this forum as a new rider and home mechanic. And at this point I am happy I made this purchase since the bike seems to not want to quit. If anyone has practical advice for this issue I'll take it.

daveyson · 2 Smoke Mon Sep 12, 2022 6:24 pm

daveyson

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Number of posts : 1339

The locations you mention are where gaskets meet, it can leak between the gaskets, a dab of silicone there will help. Don't over tighten the bolts, you'll regret it. Better too loose than too tight. Chris Harris on YouTube has a video about it.

Since the gaskets are new, they might have compressed a little, so the bolts might be loose.

Laitch · 3 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:10 pm

Laitch

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Number of posts : 3263

vttownie wrote:. . . we noticed smoke leaking out of the engine case on the left (driver's side).Just leaking out of the bottom, top, sides.

If by "engine case" you mean the joint between the camshaft cover and the cylinder head (as daveyson has alluded), smoke shouldn’t be part of the picture, especially when a cold engine has just been running for a few moments. There shouldn’t be smoke inside the camshaft area of the cylinder head. Smoke should not be rising from the upper or side joints. Faulty assembly of the gasket between the camshaft cover and the cylinder head will allow visible oil leakage. The hottest place other than the combustion chambers of the engine just after starting is the exhaust manifold. Oil dripping onto the manifold could burn and create smoke.

Clean off the surfaces and joints, dust them with bath powder and take a closer look after the engine is running to find leaks. If you find leaks you'll need to remove the cover, remove all traces of oil from the mating surfaces, apply appropriate sealant where instructions indicate and remount the cover.

Point-Seven-five · 4 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:28 pm

Point-Seven-five

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Number of posts : 4223

Is there oil visible on the outside of the engine? External oil will show you what needs to be tightened or sealed. Clean the engine well and then dust it with talcum powder. The white powder will make it very easy to see where the leak is coming from.

What does the smoke smell like? Knowing what is leaking helps narrow down the possible leak. Does it smell like fuel, burnt oil, or burnt coolant? All are possibilities and lead to different leak locations.

Does the smoke go away after a bit of run time or does it occur all the time the engine is running?

Does the smoke start as soon as a cold engine is started or does it take a few minutes to warm up the engine?

Have you serviced the header connections to the cylinder head? Are they loose? Are the copper gaskets all there?

vttownie · 5 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:35 pm

vttownie

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Number of posts : 22

daveyson wrote:The locations you mention are where gaskets meet, it can leak between the gaskets, a dab of silicone there will help. Don't over tighten the bolts, you'll regret it. Better too loose than too tight. Chris Harris on YouTube has a video about it.

Since the gaskets are new, they might have compressed a little, so the bolts might be loose.

Since starting this bike project I have learned this lesson quite well. The issue with sealing may just be this lesson again. I'll make sure to watch the video, and make sure the bolts are seated well.

vttownie · 6 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:46 pm

vttownie

active member

Number of posts : 22

Laitch wrote:

vttownie wrote:. . . we noticed smoke leaking out of the engine case on the left (driver's side).Just leaking out of the bottom, top, sides.

If by "engine case" you mean the joint between the camshaft cover and the cylinder head (as daveyson has alluded), smoke shouldn’t be part of the picture, especially when a cold engine has just been running for a few moments. There shouldn’t be smoke inside the camshaft area of the cylinder head. Smoke should not be rising from the upper or side joints. Faulty assembly of the gasket between the camshaft cover and the cylinder head will allow visible oil leakage. The hottest place other than the combustion chambers of the engine just after starting is the exhaust manifold. Oil dripping onto the manifold could burn and create smoke.

Clean off the surfaces and joints, dust them with bath powder and take a closer look after the engine is running to find leaks. If you find leaks you'll need to remove the cover, remove all traces of oil from the mating surfaces, apply appropriate sealant where instructions indicate and remount the cover.

At the moment, no liquid oil leaks from the gasket to the outside of the bike, but I will be sure to test the surfaces. I don't remember ever applying sealant to any surface, besides using grease to seat the gaskets on the camshaft cover and cylinder head.

vttownie · 7 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:55 pm

vttownie

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Number of posts : 22

Point-Seven-five wrote:Is there oil visible on the outside of the engine? External oil will show you what needs to be tightened or sealed. Clean the engine well and then dust it with talcum powder. The white powder will make it very easy to see where the leak is coming from.

What does the smoke smell like? Knowing what is leaking helps narrow down the possible leak. Does it smell like fuel, burnt oil, or burnt coolant? All are possibilities and lead to different leak locations.

Does the smoke go away after a bit of run time or does it occur all the time the engine is running?

Does the smoke start as soon as a cold engine is started or does it take a few minutes to warm up the engine?

Have you serviced the header connections to the cylinder head? Are they loose? Are the copper gaskets all there?

I can see that there is a slight leak from one of the fastening bolts from the camshaft case. The smoke is pretty acrid but a little sweet. I sure hope it isn't the oil fuel pump again, but the 2 o'clock position does still drip a little.
Smoke starts right after I start the engine.
After it runs a bit the smoke persists. We noticed that the smoke is actually worse if we take the choke off of high idle.
We recently replaced the copper gaskets to the head. Before we did, the smoke was worse on start up - I didn't notice until now. The smoke isn't as bad but it still persists.

I can check the bolt threads inside of the camcase and ensure they are all intact, just in case that is causing the exhaust smoke to leak. I may have overtightened a bolt here.

daveyson · 8 Smoke Mon Sep 12, 2022 9:20 pm

daveyson

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Number of posts : 1339

I'd remove the grease for a clean, dry contact area, and at the same time check the suspect thread.

Point-Seven-five · 9 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 9:23 pm

Point-Seven-five

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Number of posts : 4223

Do you know what burnt coolant smells like? Your acrid comment makes me think that it's possible you have a small leak that is letting coolant get on the hot engine block.

daveyson · 10 Smoke Mon Sep 12, 2022 9:38 pm

daveyson

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Number of posts : 1339

Unlikely, but here's another possibility.

I have a few bricks that sat for many years before I got them. When I finally got them going there was smoke seemingly from the engine cases, but difficult to pinpoint (old, leaked oil can smoke until it's dried out) Also the instrument clusters got foggy. After a while the clusters dried out and cleared up. After a little while longer the smoke disappeared. You might be lucky if your brick sat for years and you have just got it going.

Edit: Nup, reading your posts again, this is not your problem.

Last edited by daveyson on Mon Sep 12, 2022 10:04 pm; edited 1 time in total

Laitch · 11 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 9:50 pm

Laitch

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Number of posts : 3263

vttownie wrote: I don't remember ever applying sealant to any surface, besides using grease to seat the gaskets on the camshaft cover and cylinder head.

Start at 6:03.

Michael Sydney · 12 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 5:16 am

Michael Sydney

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Number of posts : 174

The use of grease might be the clue to the cause of smoking. I have not seen this used before, but suspect that as the engine is warmed up some of that grease might drip down onto the hot exhaust below. Smoke thus produced would then curl up around the cam cover. Maybe the greased gasket is also a cause of oil leaks.
I guess you dribbled a fair bit of engine oil onto those exhausts when doing previous work? That too will burn off on first few startups.

It is very unlikely there would be smoke forced out from within the engine covers, though please check the engine breather hose near the coils and throttle position switch is intact and not blocked.

Laitch · 13 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 8:59 am

Laitch

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Number of posts : 3263

Michael Sydney wrote:The use of grease might be the clue to the cause of smoking.

vttownie · 14 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:48 am

vttownie

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Number of posts : 22

Point-Seven-five wrote:Do you know what burnt coolant smells like? Your acrid comment makes me think that it's possible you have a small leak that is letting coolant get on the hot engine block.

There does seem to be a very minor coolant leak from the oil/water pump that could be causing some smoke. But given the response from others, the grease burning up may be the main culprit here. I will address the leak soon, it's likely from the small weep hole on the pump.

vttownie · 15 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:49 am

vttownie

active member

Number of posts : 22

Laitch wrote:

vttownie wrote: I don't remember ever applying sealant to any surface, besides using grease to seat the gaskets on the camshaft cover and cylinder head.

Start at 6:03.

Yup, that may be it! Thanks for the video, Laitch.

vttownie · 16 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:52 am

vttownie

active member

Number of posts : 22

Michael Sydney wrote:The use of grease might be the clue to the cause of smoking. I have not seen this used before, but suspect that as the engine is warmed up some of that grease might drip down onto the hot exhaust below. Smoke thus produced would then curl up around the cam cover. Maybe the greased gasket is also a cause of oil leaks.
I guess you dribbled a fair bit of engine oil onto those exhausts when doing previous work? That too will burn off on first few startups.

It is very unlikely there would be smoke forced out from within the engine covers, though please check the engine breather hose near the coils and throttle position switch is intact and not blocked.

'87 K100 Smoke - from engine cover? 112350

Very likely. A lot of old oil has burnt out of the bike since I got it up and running, but this persistent issue is likely my user error with the grease.

92KK 84WW Olaf · 17 Re: '87 K100 Smoke - from engine cover? Wed Sep 14, 2022 2:13 pm

92KK 84WW Olaf

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Number of posts : 7969

vttownie wrote:

Point-Seven-five wrote:Do you know what burnt coolant smells like? Your acrid comment makes me think that it's possible you have a small leak that is letting coolant get on the hot engine block.

There does seem to be a very minor coolant leak from the oil/water pump that could be causing some smoke. But given the response from others, the grease burning up may be the main culprit here. I will address the leak soon, it's likely from the small weep hole on the pump.

Give that time in case it needs to settle in. Not unheard of.

vttownie · 18 Re: '87 K100 Smoke - from engine cover? Fri Sep 23, 2022 10:07 am

vttownie

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Number of posts : 22

Thanks all. Cleaned up the engine cover and ran it for a bit. No more smoke, and less leak from that side of the engine. Still wonder why I was told to put grease on the gaskets in the first place, but not all advice is good advice, or at least applicable to every scenario.

Point-Seven-five · 19 Re: '87 K100 Smoke - from engine cover? Fri Sep 23, 2022 10:38 am

Point-Seven-five

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Number of posts : 4223

Grease is often used to soften and swell fiber gasket material to get a better initial seal. The crank and valve cover gaskets on the brick are a thermoplastic material that does not absorb grease so any that is applied will just be forced out onto the surrounding surfaces.

When used on fiber gaskets, the grease is applied sparingly and lightly rubbed into the surface. Sometimes it's necessary to put on a thin coat to help hold the gasket in place while covers are installed. In that case, a THIN coat is put on the gasket and once the cover is tightened down what ever excess is squeezed out is wiped off.

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1 '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 5:29 pm

vttownie

2 Smoke Mon Sep 12, 2022 6:24 pm

daveyson

3 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:10 pm

Laitch

4 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:28 pm

Point-Seven-five

5 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:35 pm

vttownie

6 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:46 pm

vttownie

7 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 8:55 pm

vttownie

8 Smoke Mon Sep 12, 2022 9:20 pm

daveyson

9 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 9:23 pm

Point-Seven-five

10 Smoke Mon Sep 12, 2022 9:38 pm

daveyson

11 Re: '87 K100 Smoke - from engine cover? Mon Sep 12, 2022 9:50 pm

Laitch

12 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 5:16 am

Michael Sydney

13 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 8:59 am

Laitch

14 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:48 am

vttownie

15 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:49 am

vttownie

16 Re: '87 K100 Smoke - from engine cover? Tue Sep 13, 2022 9:52 am

vttownie

17 Re: '87 K100 Smoke - from engine cover? Wed Sep 14, 2022 2:13 pm

92KK 84WW Olaf

18 Re: '87 K100 Smoke - from engine cover? Fri Sep 23, 2022 10:07 am

vttownie

19 Re: '87 K100 Smoke - from engine cover? Fri Sep 23, 2022 10:38 am

Point-Seven-five

20 Re: '87 K100 Smoke - from engine cover?

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