Smoke from air filters

[ashtemplar]

Hey guys!

This is my first post, but I have been on the site many times reading the forums and doing research.

I picked up a 1980 GS550E a little over a year ago. I knew NOTHING about motorcycles. Literally, nothing, and I knew even less about the bike I had purchased, other than it was red and made me smile. After about six or seven good months, I started running into issues.

Long story short (which I'm sure I'll post in the proper forum, sometime) I ended up rebuilding the top end. All new valves, pistons, rings gaskets and seals.

She's running again! I've put just over 150 miles on it since the rebuild. However, I have been noticing smoke coming from the air filters after the bike gets hot, maybe 5-10 minutes of riding it seems to be overheating. It's not a ton of smoke, but enough for me to see it clouding up in front of my headlight at night and it seems to be overheating.

I checked the valve clearance, thinking that maybe the intake valves weren't closing completely, allowing the some of the exhaust to escape into the carbs and out of the air filters. All of the valves were within the proper limits.

I also checked the cam chain, thinking that it could have jumped, causing the timing to change, and again allowing the exhaust to sneak past the intake valves. No go, again, as the proper amount of pins (20) were between the 2 and 3 cam marks.

Besides the smoking, the bike won't get past 6,000 RPM. It bogs down and lags in all gears, but up to that point, it's running great.

Since the engine is getting very hot, very quickly, one would assume that it's running lean, but the spark plugs look as if the bike is running rich.

While I've learned a hell of a lot over the last couple of months, I'm running out of ideas, and frankly, don't want to mess anything up by playing a guessing game with the engine, so I've decided to turn to the friendly and experienced experts here at GS Resources.

Info on the bike:

It didn't have the stock exhaust when I got it. Looks like a MAC 4 into 1.

Wrapped exhaust pipes.

Replaced the air box with K&N filters.

Went up three main jet sizes from 92.5 to 100

It's idling fine.


Any help would be greatly appreciated!!!

 

[Guest]

You are running lean.
Pull the plugs and report back with pics.

 

[Guest]

you're sure this smoke is fro a too hot engine? not burn off from over sprayed K&N pods. Or gas coming back thru the carbs from dirty carbs or improper set carbs or wrong jetting? just trying to throw some ideas out there

 

[JAG]

What did you do with the engine breather hose when you ditched the airbox?

 

[ashtemplar]

You are running lean.
Pull the plugs and report back with pics.

I can't get the pictures to upload. I'll keep trying.

I didn't spray the filters, so it can't be that. I have cleaned the carbs a few times. I'll clean them some more, and also adjust the needle.


I removed the breather hose. After doing some research this morning, I've decided to get a breather filter.

Thanks for the replies!!!!

 

[JAG]

I removed the breather hose. After doing some research this morning, I've decided to get a breather filter.

Seems to me at the mo, that the smoke was just oil vapor from the engine breather.

 

[ashtemplar]

Seems to me at the mo, that the smoke was just oil vapor from the engine breather.

I'm hoping you are correct! Thanks again for replying!

 

[JAG]

I'm hoping you are correct! Thanks again for replying!

That is what this site is for, although some seem to forget that at times

 

[ashtemplar]

I'm looking to raise the needles, but mine aren't adjustable. Does anyone know what shims would work for 4bel2 needles, and how much would you raise them, with the mods done on the bike?

--Or--

Does anyone know of different needles I could use that are adjustable.

Thanks!

 

[Guest]

Radio shack small assorted washer set.
Take off the spacer on the top of the jet needle. Stack washers the same height as the spacer, remove two washers and replace the spacer with the washers.

 

[ashtemplar]

Radio shack small assorted washer set.
Take off the spacer on the top of the jet needle. Stack washers the same height as the spacer, remove two washers and replace the spacer with the washers.

Thank you! I'll be heading to Radio Shack as soon as they open!

 

[ashtemplar]

Updates and such

Updates and such

Okay, it's been a while. I've had a lot going on over the past month, so I've barely been able to work on the bike.

I think I've finally gotten the picture of the spark plug to upload. This is from the #1 cylinder. The other three look about the same.
View attachment 21271

I've shimmed the needles like you said, chef1366, but it was still bogging down around 6,000 RPM, and still smoking after 10-15 minutes of riding. I've added a breather filter.

I've increased the main jets six sizes (107.5 up from 92.5). The pilot jets are the same (40) and the pilot screws are 1.5 turns out. (The PO didn't rejet, but did have the pilot screws out 3 turns).

When starting the bike, the #2 and #3 cylinders are firing, but not #1 and #4. I checked the leads, and they are getting a strong spark, so I don't believe it to be the coil. I put a squirt of starter fluid in the #1 and #4 spark plug holes, which caused them to fire momentarily.

The choke had to be completely pulled for anything to happen. I didn't have to use the choke as much before changing the main jets, which I find a little odd, considering that the mixture would be richer.

Any and all ideas or feedback would be greatly appreciated!!!! (Hell, they'll probably be the best Christmas gifts I'll receive this year!)

Happy Holidays!!!!

 

[Maddevill]

If it only runs on the choke then your pilot circuit is plugged. Fix that first. The pic looks like the plug is moderatly lean. The porcelain should be a coffee with cream color.

 

[ashtemplar]

If it only runs on the choke then your pilot circuit is plugged. Fix that first. The pic looks like the plug is moderatly lean. The porcelain should be a coffee with cream color.

Thanks! Would you recommend increasing the pilot jet size, since I increased the mains and have K&N filters and MAC 4 into 1 exhaust.

 

[Steve]

I picked up a 1980 GS550E a little over a year ago. I knew NOTHING about motorcycles.

That tells me this is going to be one exciting thread.

I checked the valve clearance, thinking that maybe the intake valves weren't closing completely, allowing the some of the exhaust to escape into the carbs and out of the air filters. All of the valves were within the proper limits.

Just for your information, if the intakes are not closing (or simply just too tight, due to neglected maintenance), the bike will be VERY hard to start, especially when cold.

I also checked the cam chain, thinking that it could have jumped, causing the timing to change, and again allowing the exhaust to sneak past the intake valves. No go, again, as the proper amount of pins (20) were between the 2 and 3 cam marks.

I know it's only word play, but it's very important, so I will mention it, just to be sure. The pin that is directly over the #2 mark on the cam sprocket is "Number 1". The pin that is directly over the #3 mark on the intake cam sprocket is "Number 20". Technically, that means there are only 18 pins BETWEEN the pins. That little detail is easy to miss, but VERY important.

Besides the smoking, the bike won't get past 6,000 RPM. It bogs down and lags in all gears, but up to that point, it's running great.

First guess would be carb jetting, cam timing or ignition timing.

Since the engine is getting very hot, very quickly, one would assume that it's running lean, but the spark plugs look as if the bike is running rich.

The picture you display shows a plug that is LEAN, not rich.

It didn't have the stock exhaust when I got it. Looks like a MAC 4 into 1.
Wrapped exhaust pipes.
Replaced the air box with K&N filters.
Went up three main jet sizes from 92.5 to 100
It's idling fine.

MAC is an "OK" pipe, do you have the stock baffle in it?
Wrapped pipes should not affect how the bike runs.
Good choice, if you absolutely have to have pods.
Three sizes is not enough for either pipe or pods. With both, you need a LOT bigger jets.
The main jets have nothing to do with idle quality.

I can't get the pictures to upload. I'll keep trying.

Have you visited BassCliff's site? He has a tutorial on how to post pictures that are easy to see.

I didn't spray the filters, so it can't be that.

Believe it or not, that could be part of your problem. K&N filters require oiling. Not oiling them will let more air through, leaning the mixture.

I have cleaned the carbs a few times.

If you have to clean them more than once, you didn't do it correctly. I would suggest doing them one more time, but correctly, by the book, TAKING NO SHORTCUTS. Every shortcut you take is just one more time you will have to remove the carbs.

I removed the breather hose. After doing some research this morning, I've decided to get a breather filter.

Ideally, you want the end of the hose placed where there is a slightly-negative pressure, to ensure air flow through the hose. Of course, you will want to make sure you have some means installed to trap the oil in the vapor.

I'm looking to raise the needles, but mine aren't adjustable. Does anyone know what shims would work for 4bel2 needles, and how much would you raise them, with the mods done on the bike? Does anyone know of different needles I could use that are adjustable.

The only needles that are available for your carbs are part of a DynoJet kit, and it costs upward of $100. You can remove the thicker nylon spacer from the top of the needle and substitute a couple small washers. Do NOT put the washers under the e-clip, thinking that will raise the needle. All that will do is increase the spring pressure holding the e-clip against the spacer(s) that is(are) above the clip.

I've increased the main jets six sizes (107.5 up from 92.5). The pilot jets are the same (40) and the pilot screws are 1.5 turns out. (The PO didn't rejet, but did have the pilot screws out 3 turns).

Six sizes on the mains might start getting you in the range, I think you might need to go a couple more sizes. Stock pilot jets should be OK. Pilot screws should be turned out about 3 turns as a starting point, then, when the bike warms up, turn each one in slowly, listening for the point where the engine starts to slow down a bit, then back up about 1/8 to 1/4 turn. It is not uncommon for them to end up in the 2 to 2.5 turn range, so you are lean at 1.5 turns.

Thanks! Would you recommend increasing the pilot jet size, since I increased the mains and have K&N filters and MAC 4 into 1 exhaust.

See comment above.

.

 

[Big T]

Echoing Steve, how many of the tip 10 newbie mistakes have you made?

You have read thru BassCliff's site?