Dealing with the consequences of neglect

[jfmerk]

Hello everyone,
It's been a long time... almost 5 years to the day to be exact since I posted. The XS11.com community helped me restore my 78 standard back in 2010-2011. The final product was something I've been very proud of. She ran beautifully. Sadly and embarrassingly, she has sat for about 3 years with lousy gas in the tank and carbs, never started in those 3 years. My passion for riding just isn't what it used to be, but that's another story. So, before I got a new battery I removed the carbs for a thorough cleaning. Lot's of corrosion on the brass components (verdigris). Got my bread tie wires, carb cleaner, a mild CLR solution and got busy. I did not separate each carb from the rail but cleaned everything, needle and seats, screens, all of it. I was confident all passages were clear, all jets and orifices open, and checked float settings. Verified the fuel petcock was working properly with a bit of vacuum on the diaphragm. Shut off and on very nicely. Re-installed the carbs, verified all vacuum lines are in the proper position. Got some fresh fuel and a battery and crossed my fingers.

Fired right up but ran very rough and I have a very obvious knock that wasn't there when it last ran. Header pipes 1,2 & 4 got hot, 3 did not.

Can carburetor issues cause a knock?

May plan is to do a full 100% rebuild of carbs including complete rebuild kits and try again and go from there.

Any suggestions? Is there something else causing the knock from 3 years of no use? The cold pipe tells me no fire in the hole due to #3 carb problem. Or maybe a plugged fuel TEE between 3 & 4, but I doubt a passage that big is plugged.

Once again, thank you for any suggestions!

Jeff

[JeffH]

Lot's of corrosion on the brass components (verdigris). Got my bread tie wires, carb cleaner, a mild CLR solution and got busy. I did not separate each carb from the rail but cleaned everything, needle and seats, screens, all of it. I was confident all passages were clear, all jets and orifices open, and checked float settings.

Shut off and on very nicely. Re-installed the carbs, verified all vacuum lines are in the proper position. Got some fresh fuel and a battery and crossed my fingers.

Fired right up but ran very rough and I have a very obvious knock that wasn't there when it last ran. Header pipes 1,2 & 4 got hot, 3 did not.

Can carburetor issues cause a knock?

May plan is to do a full 100% rebuild of carbs including complete rebuild kits and try again and go from there.


Any suggestions? Is there something else causing the knock from 3 years of no use? The cold pipe tells me no fire in the hole due to #3 carb problem. Or maybe a plugged fuel TEE between 3 & 4, but I doubt a passage that big is plugged.

Once again, thank you for any suggestions!

Jeff

Hey Jeff, Jeff here. WELCOME BACK
Just a couple comments as you wait for a Guru to give you some help.

I got my 78'E in Kentucky in 2012. It was POS neglected and obviously yours isn't and has been beautifully done. However, a couple things sound similiar.

After full cleaning of Carbs and adding some new OEM carb parts I had an engine knock as you describe. Five things. #1: I had adjusted the valves to spec, but found later that one had actually rusted open a bit due to sitting a long time in the open position. So after running the bike 100 miles found the valve clearance was WAY too tight like .002. Heck of a time getting that shim out. #2: I found after first cleaning the carb passages were clean but not clean enough #3: as you plan to do, I just got new Mukuni jets & stuff. #4: the sync was off and not all four rowing at the same pace. horrible knock since items #1, #2, #3 listed above were all contributing to the problem. #5: rpm was bit too low adding to the imbalance created by items #1,2,3, & 4 above.
Oh, and after a few initial runs i found that tank & fuel T & fine powder crud had reclogged a jet. Even with good in-line fuel filters. So even when it appears clean it "is" a dynamic system with flows & pressures so mysterious fine things can even get by in-line fuel filters. Cleaned everything a 3rd time and presto. Even new jets can get clogged till bike gets run a bit and you've gotten through a couple tanks of gas. Oh, and even after a Caswell Blue tank liner.

"Crud hides till you Ride"

Once i got that resolved all has been fine for 18,000 miles. That's my take on it. Lets see what the experts can add.

Jeff

[jfmerk]

Valve issue

Hey Jeff, Jeff here. WELCOME BACK
Just a couple comments as you wait for a Guru to give you some help.

I got my 78'E in Kentucky in 2012. It was POS neglected and obviously yours isn't and has been beautifully done. However, a couple things sound similiar.

After full cleaning of Carbs and adding some new OEM carb parts I had an engine knock as you describe. Five things. #1: I had adjusted the valves to spec, but found later that one had actually rusted open a bit due to sitting a long time in the open position. So after running the bike 100 miles found the valve clearance was WAY too tight like .002. Heck of a time getting that shim out. #2: I found after first cleaning the carb passages were clean but not clean enough #3: as you plan to do, I just got new Mukuni jets & stuff. #4: the sync was off and not all four rowing at the same pace. horrible knock since items #1, #2, #3 listed above were all contributing to the problem. #5: rpm was bit too low adding to the imbalance created by items #1,2,3, & 4 above.
Oh, and after a few initial runs i found that tank & fuel T & fine powder crud had reclogged a jet. Even with good in-line fuel filters. So even when it appears clean it "is" a dynamic system with flows & pressures so mysterious fine things can even get by in-line fuel filters. Cleaned everything a 3rd time and presto. Even new jets can get clogged till bike gets run a bit and you've gotten through a couple tanks of gas. Oh, and even after a Caswell Blue tank liner.

"Crud hides till you Ride"

Once i got that resolved all has been fine for 18,000 miles. That's my take on it. Lets see what the experts can add.

Jeff

So, after removing carbs to rebuild them I decided to run a compression check on all cylinders. My problem cylinder, #3 has zero compression. I assume a valve is stuck. Is this a automatic head removal to repair the problem? Or is there a chance to repair it from the top?

Thanks

[MPittma100]

No Compression

So, after removing carbs to rebuild them I decided to run a compression check on all cylinders. My problem cylinder, #3 has zero compression. I assume a valve is stuck. Is this a automatic head removal to repair the problem? Or is there a chance to repair it from the top?

Thanks

No compression means there is a big leak. Something wrong with either valve, head gasket, or piston rings is causing it.

A cylinder leakage tester is the right tool to determine the source. If do not have one borrow one.

If you cannot obtain the tool, and do not hear air hissing at the head gasket or around the spark plug while spinning the engine, remove the valve cover.

Check the valve lash on both valves of the affected cylinder. If there is any lash at all on both valves, that eliminates a valve being help open by the cam. At the same time look for an excessive amount of lash for each valve. If there is too much lash, you likely have a bent valve that cannot not seat.

If you have a way of putting compressed air in the low cylinder, do so with that piston at TDC. Remove the oil filler plug. Listen for air escaping at the intake, right exhaust tailpipe, oil fill hole, and head gasket.

Wherever you hear the air leaking tells you where the problem is.

Leaking at:

Intake=intake valve
Exhaust=exhaust valve
Oil fill=piston/rings
Block/head=head gasket

[MPittma100]

Additional

No compression means there is a big leak. Something wrong with either valve, head gasket, or piston rings is causing it.

A cylinder leakage tester is the right tool to determine the source. If do not have one borrow one.

If you cannot obtain the tool, and do not hear air hissing at the head gasket or around the spark plug while spinning the engine, remove the valve cover.

Check the valve lash on both valves of the affected cylinder. If there is any lash at all on both valves, that eliminates a valve being help open by the cam. At the same time look for an excessive amount of lash for each valve. If there is too much lash, you likely have a bent valve that cannot not seat.

If you have a way of putting compressed air in the low cylinder, do so with that piston at TDC. Remove the oil filler plug. Listen for air escaping at the intake, right exhaust tailpipe, oil fill hole, and head gasket.

Wherever you hear the air leaking tells you where the problem is.

Leaking at:

Intake=intake valve
Exhaust=exhaust valve
Oil fill=piston/rings
Block/head=head gasket

One thing I left out. Up to 15% leakage is allowable by the rings. So you may hear a little hissing out of the oil fill hole. Likely will have more than 15% on an engine that has not run for a while. Check compression again after you run the engine. Compare to original readings.

[jfmerk]

One thing I left out. Up to 15% leakage is allowable by the rings. So you may hear a little hissing out of the oil fill hole. Likely will have more than 15% on an engine that has not run for a while. Check compression again after you run the engine. Compare to original readings.

Thank you for the tips! I found that the compressed air test proved air coming out the muffler. Checking the exhaust valve clearance I got .045". So now that we know the reason for no compression, my question is do I need move right to pulling the head? Or is there anything I can do from the top? I doubt it but just asking to be sure.

Also, my compression readings are very high; 165, 165, 0, 170. Keep in mind this motor has only 600 miles on it since being rebuilt. Is this a problem?

Thanks

[MPittma100]

No Compression

Thank you for the tips! I found that the compressed air test proved air coming out the muffler. Checking the exhaust valve clearance I got .045". So now that we know the reason for no compression, my question is do I need move right to pulling the head? Or is there anything I can do from the top? I doubt it but just asking to be sure.

Also, my compression readings are very high; 165, 165, 0, 170. Keep in mind this motor has only 600 miles on it since being rebuilt. Is this a problem?

Thanks

Now we know why. Readings do appear a little high, but I do not see a problem except for the cylinder with the 0. Gauge could be a little off. If the numbers are real, you are going to have a very powerful engine when completed.

I would certainly like to know how that valve got bent? The typical method of bending a valve is the valve timing being incorrect. Sometimes people will adjust valves and rotate the engine forgetting that the tool is in place? The valves will interfere with each other if out of time too. This is not an easy job. Not for beginners. It is actually too easy to bend a valve if you are not focusing on the job at hand.

Either way, it appears that the valve is unable to close. Head has to come off. FYI, all valves can and should be adjusted by your machine shop if you use one. If you are doing it yourself, adjust them before you reinstall the head. Do one cam at a time with only one cam at a time on the head. Take that one back off, install the other cam and adjust the other four valves.

Remember to align the cam dots to the arrows and have the C on the engine timing wheel aligned with the tab before you reinstall the head. Be familiar with all of the procedures of reinstalling the head before you begin. If unsure, find a service manual or download one off of the site here. Good luck.





















z

[MPittma100]

PS:

When reinstalling head, only rotate the engine by hand with a wrench on the crankshaft. Do NOT use the starter. Disconnect the battery to be safe.

[DiverRay]

When you assemble the head once again, you need to do these things, in order.
1. After all the valves are back in, install ONE CAM ONLY and set the valves for that cam.
2. REMOVE first cam, and install other cam, repeat process.
3 when you are ready to put everything back together, set the timing to the TDC on the crank.
4. Install one cam, with the dots lined up for the TDC.
5. Install the other cam, putting it in with the dot lined up.
6. install timing chain (or tighten if you left it in the bike).
7. VERIFY ALL MARKS ARE STILL LINED UP BEFORE TURNING ANYTHING!!
8. With no slack on the intake side of the chain, rotate the crank S-L-O-W-L-Y until the "C" is on the mark, and install the CCT. Once released, verify marks still line up after rotating crank back to the "T" mark.(TDC)

[jfmerk]

Thanks Mike and Ray. I'll follow your advice and post my findings. Very puzzling that I have a valve hanging up, but I'll know why shortly.

Thanks again.

Jeff

[jfmerk]

So, the valve is bent. I'll be taking it to the engine shop that did the valve job for me. I know that new valve guides were installed. Could that one have been a little too tight maybe? I'd feel better knowing how it got bent... I don't see any avidence of top of piston to valve contact. I'll see what the engine shop says.

Jeff

[MPittma100]

Bent

So, the valve is bent. I'll be taking it to the engine shop that did the valve job for me. I know that new valve guides were installed. Could that one have been a little too tight maybe? I'd feel better knowing how it got bent... I don't see any avidence of top of piston to valve contact. I'll see what the engine shop says.

Jeff

I hate when that happens. Not likely that the head came from the shop with a bent valve. Most likely got that way on reinstalling it. I know that is not what you were wanting to hear - sorry. With the head off both and cams installed, you can easily see how they could contact each other.

Unfortunately, it is very easy to bend a valve if you are not very, very focused on the procedure. TDC, cam chain, cam gears, exhaust cam, intake cam. A lot more to think about with 2 cams.

Since there is no evidence of piston to valve interference, it is quite likely that it contacted the other valve in that cylinder. The other valve needs to be checked as well. I would ask your machinist to verify integrity of the other valve in same cylinder.

In other words, the valves can come in contact with a piston or each other.

Procedure wise, engine has to be turned to an exact place (TDC). Cams have to be turned to an exact place (dots/arrows). Cannot turn either cam unless they are timed together properly with the chain. Turning either cam when they are not connected to the chain can bend a valve.

Study the manual and proceed.

[jfmerk]

I hate when that happens. Not likely that the head came from the shop with a bent valve. Most likely got that way on reinstalling it. I know that is not what you were wanting to hear - sorry. With the head off both and cams installed, you can easily see how they could contact each other.

Unfortunately, it is very easy to bend a valve if you are not very, very focused on the procedure. TDC, cam chain, cam gears, exhaust cam, intake cam. A lot more to think about with 2 cams.

Since there is no evidence of piston to valve interference, it is quite likely that it contacted the other valve in that cylinder. The other valve needs to be checked as well. I would ask your machinist to verify integrity of the other valve in same cylinder.

In other words, the valves can come in contact with a piston or each other.

Procedure wise, engine has to be turned to an exact place (TDC). Cams have to be turned to an exact place (dots/arrows). Cannot turn either cam unless they are timed together properly with the chain. Turning either cam when they are not connected to the chain can bend a valve.

Study the manual and proceed.

Totally agree, I very well may have missed something, after all this bike restoration was my first engine rebuild... of any kind. Well, OK not including the 3HP Briggs I built in small engine class 37 years ago!
But, wouldn't an assembly error be noticed immediately upon running the motor for the first time after rebuild? This motor ran beautifully for 500 miles (just short little rides) and yes, had lots of power and compression on all four cylinders! She started and idled like a dream. Synced carbs and all.

Is it possible, that after I completely FUBAR'd storing it for several years that this valve stuck for an instant due to surface rust or??? and got clipped by the other intake valve? There is one shiny mark on the upper area of the valve seat. I'll look at the intake valve as you mentioned and look for evidence of a collision.

Thank you for your feedback!

Jeff

[MPittma100]

Totally agree, I very well may have missed something, after all this bike restoration was my first engine rebuild... of any kind. Well, OK not including the 3HP Briggs I built in small engine class 37 years ago!
But, wouldn't an assembly error be noticed immediately upon running the motor for the first time after rebuild? This motor ran beautifully for 500 miles (just short little rides) and yes, had lots of power and compression on all four cylinders! She started and idled like a dream. Synced carbs and all.

Is it possible, that after I completely FUBAR'd storing it for several years that this valve stuck for an instant due to surface rust or??? and got clipped by the other intake valve? There is one shiny mark on the upper area of the valve seat. I'll look at the intake valve as you mentioned and look for evidence of a collision.

Thank you for your feedback!

Jeff

Yes, totally possible that it got stuck after sitting for a while. I was under the impression that you had just put it together. Either way, its got to come back apart. Tell your machine shop what happened and let them check out the guides, etc. If you did not replace the cam chain, make sure that it is within spec.

[jfmerk]

Yes, totally possible that it got stuck after sitting for a while. I was under the impression that you had just put it together. Either way, its got to come back apart. Tell your machine shop what happened and let them check out the guides, etc. If you did not replace the cam chain, make sure that it is within spec.

Thanks Mike, will do.
Intake valve looks great, but I'll just have them look at all the valves.

Jeff