1993 Goldwing problem

[Brent1204]

1993 Goldwing 1500.
Once bike warms up when riding down highway and I go to pass someone and give it throttle the RPMS rev way up then it will start going faster. Also when I take off from a stop I have to give it a little throttle or the RPMS will rev way up. Someone told me maybe a vacuum leak? I am at my Witts end.

[winguyjo]

i will be curious to read what others think, but to me that sounds like a slipping clutch. is this bike new to you ? if not, has it been slowly getting worse ? have you recently done an oil change using non-motorcycle oil ?

[Brent1204]

The bike is new to me. I changed engine oil with what the manual recommend.
It seems like the hotter the bike gets the worse it gets.

[DenverWinger]

+1 on slipping clutch.

Vacuum leak won't affect the clutch. Worth asking, since it is a '93 how many miles are on the clock? The clutch is pretty robust in these bikes, not unusual to see one with 300,000 miles on original clutch, but with high miles and abuse they can be worn out.

Oil may or may not be the cause, other possibility is plugged return port in clutch master cylinder keeping pressure on clutch slave cyl.

How far out do you have to release the clutch lever to get moving from a stop? That is to ask, where's the friction point on the clutch lever? Half-way (normal) or most of the way out?

And exactly what brand/weight oil did you use for your oil change?

[Brent1204]

25000 miles on bike. Mobil 1 10W 40 have to let clutch lever out close to 3/4 of the way out

[Andy Cote]

The manual does not recommend Mobil 1 10w40. Unless this was Mobil 1 High Mileage or Motorcycle specific, it contains additives that are detrimental to oil bathed clutches. If you still have the bottles, see if the bullseye on the back includes the words "ENERGY CONSERVING."

You might save this clutch. I would change oil to Honda brand non-synthetic along with half a can of Seafoam and ride carefully for a couple thousand miles to see if if improves, then change again.

[DenverWinger]

+1 on checking for "ENERGY CONSERVING" in the API donut on the oil bottle.

3/4 clutch release to get friction seems a little far.

Pop the cover off the clutch master cylinder to see what the fluid looks like inside. If not nice and clear recommend a fluid flush. If there's a lot of gunk in the bottom of the reservoir you still may have a plugged return port. While you are at it, would be a good time to flush the fluid in the brakes, too.

Get a My-T-Vac. Makes flushing the brake and clutch fluid a breeze, that's what I used on my '93. Should be done every couple years anyway.

[WingAdmin]

Sure sounds like a slipping clutch. Look at the oil you put in it. Does it say Energy Conserving in the circle on the back? Like this:

If it does, that's your problem.

[blupupher]

The manual does not recommend Mobil 1 10w40. Unless this was Mobil 1 High Mileage or Motorcycle specific, it contains additives that are detrimental to oil bathed clutches. If you still have the bottles, see if the bullseye on the back includes the words "ENERGY CONSERVING."

You might save this clutch. I would change oil to Honda brand non-synthetic along with half a can of Seafoam and ride carefully for a couple thousand miles to see if if improves, then change again.

Mobil does not currently make any 10w-40 oil that is energy conserving.
They currently have Mobil 1 10w-40 High Mileage, Mobil Super/ Super High Mileage 10w-40, and Mobil 1 Racing 4T, none of which are "bad" oils for wet clutches.

Not saying it is not an oil issue, but most likely the OP used Mobil 1 10w-40 HM which many here and elsewhere use in wet clutch systems without any issue. Unless it is an old bottle of regular Mobil 1 10w-40 (which I don't believe was energy conserving anyway), the energy conserving angle is not really there.
Sounding more like a clutch master cylinder, slave cylinder, clutch line or fluid issue.
That said, switching to Honda oil to rule out a clutch slip issue due to oil could be an option to rule it out.

[Brent1204]

This is the oil I used

[offcenter]

Sounds like a slipping clutch to me too.

[WingAdmin]

20201223_205822.jpg

This is the oil I used

That's the correct stuff. Do you know what your previous owner used? Did this problem start after you got the bike?

[Brent1204]

Don't know what they used.

[Brent1204]

Thanks for all the information. I am new to the Goldwing world. I am gonna try a fluid flush and more than likely take the slave cylinder off and see if it needs a rebuild. I will post what I find out. Hopefully I don't have to remove the clutch because it looks like that ain't no fun. Again thanks for all the information.

[cwinn]

You can usually confirm clutch slippage with the engine oil smell test. The slipping clutch very quickly turns the oil dark, & makes it stink with a rank corky burning smell. Smell the end of the engine oil dipstick, or the inside of the engine oil filler cap.

Clutch slave cylinder malfunction normally causes failure to disengage clutch, not slipping, so don't take that apart yet. But the advice to change clutch fluid & verify clutch master cylinder correct function is very good. When you look down in the master after removing the cap & diaphragm plate & diaphragm & white foam float, you'll see a 3/16" hole offset towards the lever, & a tiny hole, hidden under a steel deflector right next to it offset towards the hose end. When you squeeze the clutch lever, fluid should jet up out of the tiny hole (that's why the deflector is there) for the first little bit of clutch lever movement, & then stop as you squeeze further. If this jet doesn't happen, heat will cause the fluid in the clutch hose to expand & partly disengage the clutch.

Since engine heat cooks the brake fluid in the clutch system constantly, this fluid deteriorates much quicker than the brake fluid in the brake system. Change out all the fluid, clutch & brake, at least every 2 years to prevent deterioration & malfunctions.

[Brent1204]

Thank you I will definitely do this first

[Brent1204]

You can usually confirm clutch slippage with the engine oil smell test. The slipping clutch very quickly turns the oil dark, & makes it stink with a rank corky burning smell. Smell the end of the engine oil dipstick, or the inside of the engine oil filler cap.

Clutch slave cylinder malfunction normally causes failure to disengage clutch, not slipping, so don't take that apart yet. But the advice to change clutch fluid & verify clutch master cylinder correct function is very good. When you look down in the master after removing the cap & diaphragm plate & diaphragm & white foam float, you'll see a 3/16" hole offset towards the lever, & a tiny hole, hidden under a steel deflector right next to it offset towards the hose end. When you squeeze the clutch lever, fluid should jet up out of the tiny hole (that's why the deflector is there) for the first little bit of clutch lever movement, & then stop as you squeeze further. If this jet doesn't happen, heat will cause the fluid in the clutch hose to expand & partly disengage the clutch.

Since engine heat cooks the brake fluid in the clutch system constantly, this fluid deteriorates much quicker than the brake fluid in the brake system. Change out all the fluid, clutch & brake, at least every 2 years to prevent deterioration & malfunctions.

I flushed clutch line probably got some air in line but now I have filled master cylinder back up and I am starting the bleeding process clutch is loose and barely any fluid comes out of bleeder

[cwinn]

Did you smell your oil for a burned clutch smell? Even if it doesn't smell, changing your clutch & brake fluid is time well-spent.

Easy master cylinder & hose bleeding:
Turn your handlebars to the left to make the clutch master cylinder the highest part of the system, orient the hose & master so all the air in the system can bubble uphill into the master cylinder. If the master cylinder is working correctly, & the tiny hole in the master cylinder reservoir is not plugged, you should be able to stroke the clutch lever 1/4-1/2" & see bubbles squeeze up through the tiny hole. This can take 5-10 minutes of tapping the lever. When you get no more bubbles, tap the brake hose with a screwdriver handle to dislodge any remaining bubbles in the hose, let it sit an hour, & then stroke the clutch lever 1/4-1/2" & look for bubbles again. Repeat if needed til bubbles stop. This can generally do a good air bleed of the system so the lever feels firm when you do a full lever squeeze. Then just a few cycles of "pump the lever", squeeze & hold, while opening & closing the bleed fitting (with a clear hose leading into a jar of brake fluid) will squirt out healthy slugs of fluid, & any residual air in the slave cylinder. If you end up with no more bubbles, & a good solid clutch lever pull & release, the clutch master cylinder is OK. Clean & grease your clutch lever pivot bolt & the brass plunger pivot with silicone grease, & you're done.
If you don't have bubbles coming back through the tiny hole in the master cylinder reservoir, or you don't get a healthy slug of fluid out the bleed fitting while holding the lever pulled in, it's time to disassemble the master, inspect the bore for excess corrosion, unblock the tiny hole (with a tiny wire), replace the plunger assembly, & bleed it again.

[Brent1204]

Well this is what slave cylinder looked like. Got it rebuilt and changed the engine oil. She runs like a top now. Thanks for all the information

[WingAdmin]

Wow, that's definitely seen better days! Lots of dried up hydraulic fluid there. Good job!