1975 GL1000 project

[RobbyMoto]

This topic continues an old topic:

viewtopic.php?f=3&t=70074&hilit=cam+out+of+sync

I decided to start a new topic because I got the timing issues under control.

The results from a compression test are:

Took off the left side head and found this:

To my eye, the cylinder heads look ok but at least 3 of the 4 valves are not seating and I assume this is the source of the zero compression.

[Rambozo]

Yup, you bent the valves. They will need to be replaced.

[RobbyMoto]

Thanks Rambozo. I’ve got the parts on order now. What about cylinders 1 and 3? Do those readings indicate problems with valves or is it more like piston rings?

Or should I let sleeping dogs lie.

I should mention, these readings were with a cold engine. So not a true compression test.

[Rambozo]

With unknown damaged heads I wouldn't venture a guess about compression readings. If you want to check the rings, you can make up a plate to cover a cylinder and do a leakdown test on it. The cylinder in your photo looks ok. If the engine hasn't run in some time, it might take some running to get back to good readings.

[Rednaxs60]

Wouldn't hurt to pull the head for cylinders 1/3, take the valves out and do a good lapping of these. Check the valves for straight when removed. Want both sides to be as close as possible.

Rings - the 1000 needs 72 mm rings. If can't find new then does the auto industry has done for years, get a slightly larger set and adjust to fit, and hone the cylinders. Caveat - taking the engine case part for this may not be the best idea - not hard just time consuming. These engines are more imposing when together than when apart, not much to the internals. Do the heads, check compression, ride for a bit and all may be well.

Good luck.

[RobbyMoto]

This might be a basic question. Is this engine at TDC for cylinder 2?

[Rednaxs60]

Crankshaft timing marks - there are two. "T1" for crank and cam alignment and is for #1 cylinder TDC, check your timing belt cam pulleys for correct orientation, the word "UP" in the 12 o'clock position:

"F1" is for ignition timing at idle.

Honda has another timing mark, "T2" and "F2". These marks are to confirm timing for cylinders 3 and 4 after #1 timing is set.

When you check the timing alignment for #1 TDC, you can use either #1 or #2 cylinder plug wire.

[RobbyMoto]

The crankshaft is at the T1 mark. Cam pulleys were in up position before I took the belt off. Cylinder 2 is pushed out. Does this mean the crankshaft was off by 360 deg?

[Rednaxs60]

Before you removed the heads, you have mentioned that the crankshaft timing mark was at the "T1" position and the camshaft pulley "UP" indicators were In the 12 o'clock position. If this was so then #1 cylinder piston should be at the top of the stroke, #2 cylinder piston would be at the bottom of the stroke.

From what you have mentioned timing could have been out 360 degrees, but that would mean work was done previously and the "mechanic" did not check for #1 TDC, and assumed that all was good with the crankshaft "T1" mark where it should be. I guess engine would start and such, timing would be 2/4/1/3 instead of the 1/3/2/4. Having mentioned this make sure that the timing alignment is correct when you reinstall the heads.

The issue with not having a timing sequence of 1/3/2/4 is when trying to setup the engine and ensure the engine operates properly IAW the OEM service manual. Everything is based on this firing sequence, and a firing sequence of 2/4/1/3 would not make sense.

This is a picture of the cam pulley timing marks and where the crank is:

You will notice that with the crankshaft "T1" mark and the cam pulleys with the "UP" in the 12 o'clock position you have to be at #1 TDC. You can verify this with the heads on by looking into cylinder #1 through the spark plug hole and you will see the piston crown. The camshaft pulleys are keyed to the camshaft and don't move.

#2 cylinder TDC is also when the crankshaft "T1" mark is visible, but the cam shaft pulleys will have the "UP" indication at the "6" o'clock position.

The cam shaft pulleys are keyed and it is virtually impossible to have the timing alignment not correct.

Rotate the crank 360 degrees and #1 cylinder piston crown will be at TDC. When you install the heads, ensure #1 piston is at TDC and the crankshaft timing mark alignment mark is at "T1". Rotate the crank 90 degrees, taking note of the direction. Install the heads, install camshaft pulleys so that left/right timing indicator "UP" is in the 12 o'clock position. When installing the camshaft pulleys, do not mix up the side each came off of. The camshaft boss is different for each side.

Rotate the crank in the reverse direction until "T1" is visible in the timing viewing port, and #1 cylinder is at TDC (visually confirm).

Install timing belts. Alignment is set.

Rotate the engine with the stator bolt and take note of camshaft pulley "UP" indicators and the timing mark showing through the timing viewing port.

Good luck.

[RobbyMoto]

Update:

I never did this sort of work before so I was taking my time.

- replaced and lapped in 4 new valves
- cleaned up the head and all surfaces real good
- did the water test- (bone dry after 1 hour)
- put the cylinder head back on with a new gasket and got some compression on cylinders 2 and 4 now.

Here are the new numbers:

Seems a little lop-sided but I think it should run. I don't know when was the last time this engine ran so that could be why the cylinders are so different.

I want to hear it run before I decide whether to crack open the right side. That 48 year old gasket was in there like cement and it was a job getting that head off and cleaned up.

-> re the TDC question from before:
On this engine it looks to me like cylinder 1 and 2 and both extended out when the timing mark is at T1 with cams at UP-12-o'clock. So when cylinder 1 is at the top of it's compression stroke, cylinder 2 is at the top of it's exhaust stroke. Is this correct?

In other words. Looking at the cam shafts, at T1 with the cam gears at UP-12 o'clock, cylinder 1 has both valves closed while cylinder 2 has just closed it's exhaust valve. I believe this should be correct but please tell me if I'm missing something. Thanks!

[Rambozo]

One will have both valves closed and the other will have both valves slightly open (split overlap).

[RobbyMoto]

I attached an aux fuel tank to the carbs and they started to leak so I have new needle valves and seats coming from Randakks. It looks like they don't include the little plastic screens. Do I reuse the old ones or buy new? Anybody know the part number? If reuse, how do I get those off there without damaging them?

[Rambozo]

According to Randakks those are only available from Honda as part of the OEM needle valves.
Randakks has a bunch of great info on these carbs, but you really have to dig around on his site to find it all. I have yet to checkout his carb DVD but I bet it is a fantastic resource, too. He says you can remove those screens and reuse them if you are careful and they are good. Info on the site.

Excerpted from Randakk's page on carb rebuilding misstates not to make.

"b. Fuel inlet screen. These are located under each float valve seat. Usually can be removed with a small pick, cleaned and reused If they need replacement, they are only available from Honda as part of the float valve needle and seat assembly."

[RobbyMoto]

Just got the needle valves and seats from Randakks. They came with new filter screens. Glue was not necessary. They snap on and seem to be on there pretty well. Also they are held in place in the little opening they live in.

These are SKU: 16011-371-305. Here is a new one next to an old one.

I replaced all 4, hooked it up to the aux fuel tank and no leaks.

[Rambozo]

Thanks for the update. Nice to see they now come with screens like the OEM.

[RobbyMoto]

I put the bike back together and tried to start it. Seems like it wants to start but never quite takes off. Even using starter fluid it revs with the starter but then nothing when you let go of the button. I verified there is spark on all 4 cylinders. The float bowls all have gas in them. I'm not sure if the gas is actually getting into the cylinders but all 4 cylinders are warm like they are firing while the starter is engaged.

I removed the plugs to see if the engine is flooded, the plugs are dry, not covered in fuel.

I have an aux fuel tank hooked up and its hanging a couple feet above the bike.

Does the fuel pump need to be in the circuit for the carbs to draw fuel into the cylinder?

The bike has one of those windjammer cowls. Does that need to be plugged in for the electricals to work right?

Anyone have any thoughts on this? Thanks!

[RobbyMoto]

Well, I found something...

Tough to see but that's the ballast resistor and that's a broken wire.

Researching more on here seems that the ignition runs through this resistor when the start button is released. From the behavior of the bike this could definitely be the issue.

The resistor is at 2.4 Ohms btw.

Going to repair this wire tomorrow and hopefully get this girl running.

[RobbyMoto]

UPDATE:

I repaired the ballast resistor wire and the bike is running but won't idle. It idles for about 5 - 10 seconds then dies off. It responds to throttle and choke but won't stay running.

It seems that cylinder 2 is not firing. I'm not sure if this is the problem with the idle but it's not helping. I removed the spark plugs and cylinders 1, 3, and 4 look ok but cylinder 2 is like brand new and no gas in there.

Does anyone know if this motor needs the pressure from the fuel pump to get gas into all 4 cylinders? Cylinder 2 is farthest from the fuel inlet on the carb body so it would suffer the most from low fuel pressure. In my test setup I'm just using a motion-pro aux tank with a couple inches of gas in it, but holding it up higher had no effect on the idle.

The other issue is the spark plug caps. I removed the caps and measured them with a multimeter. They all read 10.4 kOhms (should be 5 kOhms?) The exception is the cap on cylinder 4 which is reading open (> 20 kOhms). This is mysterious because #4 was firing. Does 10.4 kOhms seem too high?

Any help or insight on these two problems would be appreciated. Thanks!

[RobbyMoto]

UPDATE:

I replaced the spark plug caps. Checking resistance between wires to cyl 1&2 and cly 3&4, I measured just over 24 kOhms on both circuits. The bike ran much better but still stalling out without constant tending to. Making small adjustments to throttle or choke.

I thought this could be low fuel pressure due to being on the auxilary fuel tank and not using the fuel pump. I reconnected the fuel line from the tank through the pump. Added some fresh gas but the bike is still idling weak and I noticed a dribble of gas from the weep hole on the pump. I ordered a new pump and put that on. Leak is gone but then the bike started stalling out and then wouldnt start.

I noticed the fuel was starting to look cloudy and dark, maybe rusty. (I have a clear fuel filter in the line after the pump.) Looking in the tank I found this:

I thought it could be remnants of evaporust I used before or it could be the rust or an old tank liner coming off the sides of the tank. Draining out the gas, there is a lot of moisture and sediment. I also made sure to drain the carb float bowls. I hope I got it all out in time but if I have to take the carbs out again and clean them then so be it.

I removed the tank to clean it the right way. I have it sitting, filled with vinegar and will let that sit for 1-2 days. I'm also planning on applying the POR 15 fuel tank liner once the bad gas/ rust are cleaned out.


Anyway, when I removed the tank I found this:

The dust boot on the swingarm universal joint is torn

These dust boots seem to be super rare and hard to find. I am wondering about:

• Has anyone tried using a rubber patch kit on this dust boot?

• What about this universal joint? How can I know if it's ok? It seems to be relatively rust-free inside. When I was pushing the bike around there was no clicking noises so maybe it's ok...

[cfairweather]

I have browsed your post and there is a lot in this thread, so please forgive me if I missed something and suggest something you have already solved. First, I have an extra boot and will send it to you if you pay the shipping which will probably cost about $10.00. Send me a PM if you want it. My first suggestion is to buy a Dyna electronic ignition clone on Ebay. It will cost about $45.00 and this is the best thing you can do for this bike. Also, get the Dyna Clone coils for about $25.00 each, which will allow you to safely remove the ballast resistor. I wrote instructions on how to do this and they are on this web site. If you are using new spark plug caps, buy new 7mm wires that have copper wire inside from a local auto parts store and use non-resistor plugs. You could also use a Dyna wire kit and use resistor plugs.

Also, you had questions about the timing belt pulley. Honda designed one pully and it can be used on either camshaft. Just depends on which direction it is installed. They also designed one head and it can be used on either side. I would not worry too much about the low compression until the engine runs an hour or two at operating temp to allow the rings to free up from sitting.

You bought a Randakk master carb kit, correct? Did you thoroughly clean the carbs, plenum and each jet? Getting the jets perfectly clean is very important on these bikes. The tiny slow jet #35 is probably plugged which might be part of the idle issue. Even after you rebuild and run gas through the carbs, this jet will often get plugged again from a tiny foreign object. Did you run an guitar E string or a #80 drill bit through the jet to make sure it is clear? The fuel system must be perfectly clean or you will have issues. The float levels are also very critical on the GL1000. I highly recommend using the clear tube method of setting the float level. I can provide details if needed.

[RobbyMoto]

Thanks cfairweather. I'm hoping the ignition system is ok but I had to fix a lot of other things before I could get back to troubleshooting the poor idle. I tried to patch the boot with a piece of inner tube but I doubt it will hold, so I will take you up on the offer to send that boot. I sent you a PM.

Here is an update on what has been done since the last post.

gas tank

• removed

• soaked in vinegar for about 3 days

• used por 15 kit to seal it up.

• Cleaned and painted outside of tank

• reinstalled

here is a pic of the finished, sealed tank:

note: I think the vinegar was a waste of time. The por 15 metal prep stuff is awesome and did more in 30 minutes than 3 days of vinegar soak. Also, 5 gallons of vinegar is just a mess waiting to happen.

replaced all control cables

• throttle x2

• choke

• clutch

brakes (in progress)

• removed and rebuilt front and rear master cylinders.

• Cleaned, painted and rebuilt all 3 calipers (in progress, waiting on more parts).

• Replaced all brake lines

exhaust

• I cut my losses on the OEM exhaust. I took it off to clean and inspect and I found some large holes that are beyond my skills to repair. I plan to keep it with the bike in case I want to repair it in the future.

Here I was trying to patch with JB Weld but it is beyond that.

• I have an HM 431 exhaust I am planning on using. Google search didnt turn up much info on these but i gather these are OEM on '78 wings. If anyone knows more about these I would appreciate the info. Specifically whether they will fit on the '75. Looks like it should.

[RobbyMoto]

In case anyone is interested, HM 431 fits perfect on the '75 GL1000 and it looks good imho.

[Joneszy]

Good info on the fitment of the 78 exhaust system on prior models. Nice to know the crossover info.

[RobbyMoto]

UPDATE:

I put the bike back together and the right side of the engine is not firing. The bike will run for a short time and then stall out without constant attention. Cylinders 1 and 3 stay cold. They have spark and there is air pushing out of the exhaust but its cold air. When I pull the plugs, they are flooded. If I dry out the plugs and cylinders and try again, still no fire on the right side. I'm trying to think what those two cylinders have in common and I have a sneaking suspicion the right belt might have skipped a tooth again. I've had issues with this before on this bike. Would this cause the issue?

The only other thing could be a vacuum leak on those two intakes or issues with the carb on that side. Is there any other common factor for those two cylinders?

One side note: I tried to set the static timing. Cyl 1&2 is perfect but cyl 3&4 point opens early and I cannot get it within spec. Ordered new points to install but there is a polar vortex going on right now.

Here is a review of what has been done to the bike for reference:
- new timing belts
- left side valves replaced (right side had compression so I left those alone for now)
- cleaned/ sealed gas tank
- new air filter
- new OEM fuel pump
- new spark plugs (gapped correctly)
- new plug caps (ohmed out correctly)
- new fuel line and filter

It goes without saying but also fresh gas. It's non-ethanol. Octane is 89 which I though the GL1000 would appreciate due to the high compression ratio of the engine.

Thanks!

[cfairweather]

I don't believe the belts have skipped a tooth. I have worked on too many GL1000 engines and I have never seen that happen. If you install the belts correctly, they will not skip. Are you sure you have all three woodruff keys installed on the pully shafts? When you install the timing belts, you must follow the instructions. Please refer to the manual, but you can basically verify they are installed correctly by aligning the T1 mark with the index while the camshaft pulleys have the "UP", in the up position. If the UP is upside down, rotate the flywheel 360 degrees. With your eyes at the same plane as the index marks, verify the pulley marks are perfectly aligned with the index marks. I have a feeling you have damaged the valves on the right side.