1978 Gl1000 Severe Loss of Power and Throttle Response in Gear


Information and questions on GL1000 Goldwings (1975-1979)
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coleman
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Joined: Fri Sep 22, 2017 1:40 am
Location: Los Angeles, California
Motorcycle: 1978 GL1000

1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Sun Oct 22, 2017 11:39 pm



Hi All,

First post relating to my first GL1000 (and motorcycle for that matter). Bought it off a college kid who rode it infrequently, left it outside, and did no maintenance besides getting the oil changed. No maintenance besides oil change from previous owner as well so I'd estimate at least 3 years with no love. It wasn't running when I bought it due to electrical issues. New battery, solenoid (which wasn't the problem), cleaning the starter switch, and rebuilding the kill switch got it running.

Starts immediately by giving it a little throttle. Needs choke to keep the rpms high as it can die when they get lower and makes a sort of banging noise that I believe to be the chain slapping (per what I read on other forum posts). It ran quite well for about a week and 3 rides, but last week it began dying on my way down the hill. What I mean by this is:
1. Firstly, the throttle stops responding smoothly and it kind of cuts in and out between giving it power and having no effect. At this point I couldn't get it to accelerate at all but managed to maintain speed in 3rd mostly. At the stoplight it dies and took a while to get back on.
2. Throttle responds in neutral, but it's very hard to get it moving in gear. As I release the clutch, rpms drop and I have to keep the rpms high and sort of go back and forth on the clutch until its moving fast enough to fully release the clutch.
3. When its finally moving and in 1st gear, I have to fully open the throttle which gets up to about 5k rpms (speedometer also gave out recently so I'm not sure what speed that equals but feels like 20-30ish) and that's as fast as I can get it going. When switching into second it kind of luggs like it doesn't have sufficient power to get that gear spinning so I keep it in 1st.

I managed to get it home and tried to figure out the problem. I opened the airbox and there was what looked like oil in it. I took it apart and it turns out some previous owner (I've noticed some shotty maintenance that looks like a few owners ago) had put a screw into the top of the plastic piece in the airbox that recirculates engine air into the airbox (this is part of system for reducing air emissions by reusing air I believe) and had also basically blocked off the tube that brings in the engine air and the drain tube for the engine air condensation. I cleaned it all out and reconnected the drain etc. replaced the air filter.

Last night, it started up with a lot of backfiring and smoke. I ran it on the center stand for a minute or two, turned it off, and then started it up again a little while later. It was running well, the backfiring stopped and I thought I'd solved it (for the most part, I'm sure some carb cleaning and syncing is required at minimum).

So today I take it out and all is going well, put in a fresh tank of gas, drove it for about 20 minutes and then parked it to get lunch. When I started riding it again, the same loss of power thing started happening. It was also hard to keep the engine running and I basically had to give keep the throttle open whenever it was in neutral to keep it running. It was a struggle to get it moving in 1st gear without the engine giving out. Using choke made it worse and resulted in jolting and inconsistent power. With choke pushed in, it was at least consistent in the 4-5k range, but couldn't get above 5k and had to have the throttle fully open to keep it at that speed. I turned it on and put it in gear on the center stand and the wheel spun and seemed to respond to the throttle just fine.

It's back in the garage on the center stand and I don't know where to start. Randakk's blog says I need to do the valve adjustments and compression tests first and foremost before getting into carbs so is that where I should start? By valve adjustments does he mean changing the timing belt (which I know I need to do anyway) and making sure the marks and stuff are aligned properly? It also says to check for ignition issues first but I'm not sure how to do that. I was thinking of doing the lazy carb cleaning method Randakk talks about here http://www.randakksblog.com/carb-cleani ... zy-method/ but wasn't sure if Seafoam could be used instead of the yamaha stuff.

Overall, I need guidance on where to start diagnosing this issue, and then on a bigger level (which I can split into a different post) what all I should do and in what order to get this bike back into great shape.



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Maz
Posts: 442
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Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by Maz » Mon Oct 23, 2017 4:17 am

Firstly, the timing belt change is a MUST! It won't solve your issue but it will prevent destruction of your engine.
Your carbs should also be cleaned thoroughly, as per Randakks video. However, your issue sounds remarkably similar to a problem that I had on mine a while back. I think you may have an ignition fault, whereby you are losing power to one of your coils and, when you are having the issue, the bike is only running on two cylinders. Remember, the front two cylinders fire from one coil and the rear two from the other. When you are having the issue, pull a plug cap off and see if it has an effect. If it does (ie the engine stops or runs significantly worse), put it back and try all of the others, one at a time. If you pull one and it makes no difference, that plug is not firing. Maybe carry a spare plug and try that in the plug cap and rest it against the engine to check if the coil is firing.
Maz
Nostalgia is not what it used to be!

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Fred Camper
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Motorcycle: 1977 GL1000, 1976 LTD GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by Fred Camper » Mon Oct 23, 2017 8:26 am

Electric sounds most probable based on the event appearance. A short stop will heat the Coils. Sure seems likely. The other is fuel flow past the filter. Could be the tank was not kept full and flakes of rust dropped in. If the filter gets intermediate then fuel may flow and be insufficient to keep all 4 bowls filled. But sure sounds like a coil issue to me. Had that same symptom and a cracked could was discovered. Mostly a running in the rain issue for me.

coleman
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Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Thu Oct 26, 2017 1:24 am

Thanks guys, I think the coil issue sounds like what’s happening. I’m going to check the primary and secondary coils this week or weekend and will report back. Do we think temperature is the reason what’s bringing out the fault? Just wondering why it it rides normal for a while before he problem starts.

Also, the gas tank is for sure rusted. I’m not really sure how to check the fuel filter. It looks clean when I shine a flashlight on it but I’ll take it off and give er a look this weekend.

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Maz
Posts: 442
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by Maz » Thu Oct 26, 2017 2:02 am

coleman wrote:
Thu Oct 26, 2017 1:24 am
Thanks guys, I think the coil issue sounds like what’s happening. I’m going to check the primary and secondary coils this week or weekend and will report back. Do we think temperature is the reason what’s bringing out the fault? Just wondering why it it rides normal for a while before he problem starts.

Also, the gas tank is for sure rusted. I’m not really sure how to check the fuel filter. It looks clean when I shine a flashlight on it but I’ll take it off and give er a look this weekend.
Temperature is a likely suspect, as Fred Camper suggests. If a coil is failing, it tends to show when it warms up, which they do in normal operation. They also tend to get hotter when you stop, as the heat from the engine isn't being blown away by the breeze and warms them up more.
Fuel flow is another distinct possibility. If your tank is rusty inside, it's very likely that the filter will be full of fine rust particles and not allowing full flow. They are only a few pounds / dollars to replace . You can get a replacement one from Randakk or Wingovations which is made of alloy and can be taken apart for cleaning and then re-used. There's no point in replacing the filter before de-rusting the tank, though.

Maz
Nostalgia is not what it used to be!

coleman
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Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Mon Oct 30, 2017 10:50 pm

Hi guys,

So there were particles in the fuel filter, pretty sure it's a cleanable fuel filter (looks just like this but it's 5/16" and the filter material is more like mesh) <https://www.glencoeltd.co.uk/fuel-filte ... -8mm-tails>. Going to clean it out and see if it helps.

Rode it for a bit on Friday night, same loss of power happened. I tried pulling the plug caps off but from what I could tell they all made it die. I was having a really difficult time keeping it running for the tests so I couldn't really say they were conclusive. I tried the test on the center stand before riding it and it seemed to make a bigger difference when I pulled plugs 1 and 4 (1 being top right and 4 being bottom left as they are labelled on the spark plug cables) than 2 and 3 but since those are on different coils I think it was more indicative of poor carburetor synchronization than coil health. Is there any way to tweak the fuel mixture without removing the carb? I played with the synchronization screws by ear (since my carb sync gauges didn't fit in the holes) which in retrospect probably wasn't very smart but I think it's sounding better (before the power loss thing of course).

How can I test the coils and find out which one if any is failing? Should I put them in the oven at 200 degrees Fahrenheit and then test with my multi-meter like Randakk describes in a blog post? I was kind of being lazy this weekend about doing it since it requires taking off the false tank again but I'll get to it this week. Sorry for the lengthy posts.

coleman
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Location: Los Angeles, California
Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Mon Oct 30, 2017 10:55 pm

Oh also, while I have the fuel line disconnected, should I run some seafoam gasoline mixture into the carbs through the other fuel line as described in this post? Is seafoam mixed with gas an adequate substitute? I can't run seafoam through the tank until I take derust it so I'm wondering if this is worth doing in the meantime.

http://www.randakksblog.com/carb-cleani ... zy-method/

coleman
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Location: Los Angeles, California
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Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Mon Nov 06, 2017 4:55 pm

Seems like I'm talking to myself but it appears to be the coil. When I pull the plug on the rear cylindars, 3 and 4, there is only a slight affect on idle. When I pull 1 or two, the engine dies. The resistance of the system is like 25-26k which is a little high so I guess that backs the test result.

If anyone who's done this sees this, what coils should I replace it with. Could you please link me to one. Do these options below seem like they'd work?

https://www.ebay.com/itm/1976-1979-Hond ... SwpONZXxEf

https://www.ebay.com/itm/Honda-CB650-CB ... SwQiBZ078j

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Fred Camper
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Motorcycle: 1977 GL1000, 1976 LTD GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by Fred Camper » Tue Nov 07, 2017 9:26 am

Dyna Tec makes excellent Coils. Here is a link
http://www.dynaonline.com/products/acce ... coils.aspx

Way better to have new than 40 year old Coils.

coleman
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Joined: Fri Sep 22, 2017 1:40 am
Location: Los Angeles, California
Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Tue Nov 14, 2017 2:00 pm

I ended up going for this Caltric coil. Super easy install and it looks nearly identical to the stock coil. Turns out the coil wasn't the culprit. I believe it's the points because the left side opens and is gapped correctly but doesn't spark or barely sparks. Ordered new CB450 points and will report back on the result.

https://www.amazon.com/gp/product/B014W ... UTF8&psc=1

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badandy
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Location: Weirton, West Virginia
Motorcycle: 1977 GL1000 Goldwing
1982 GL500I
1983 VT500 Shadow

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by badandy » Tue Nov 14, 2017 4:57 pm

You should have very little sparking at the points if they are adjusted correctly and only at idle. Heavy sparking at the points is usually and indication of failing condensers and your points will look like terrible from all the arcing and not last long at all.

Correct point gap and timing is critical to these engines. Look up the "split timing" method and learn how to set these up the proper way. After that a good carb cleaning and sync is in order with fresh fuel and filter. You must have the proper sync tool (vacuum or manometer) to dial them in. You can't do it by ear.

I still have the original ignition system in my 77 GL1000, but one of my winter projects is converting to electronic ignition and upgraded coils eliminating points and condensers.

coleman
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Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Tue Nov 14, 2017 8:29 pm

So the right points throws big sparks while the left side doesn't spark most of the time. Both looked terrible from the arching. Note: I was watching them in a dark garage at night which made them look more pronounced I imagine.

Just ordered a new condenser and will probably perform Randakk's condenser ground update at some point soon probably.

I did sync the carbs with a proper sync tool, but I'll have to redo it of course once I get it firing on all cylinders.

The spark plugs are firing, but when I pull plugs 3 or 4 there's no change in idle. Hoping that the new points and/or condenser will fix.

I also need to adjust the valve timing. Do we think I can get away without replacing the valve cover gaskets? I'm having a hard time bringing myself to spend $20ish per side on a gasket.

coleman
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Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Tue Nov 14, 2017 9:48 pm

Got the static ignition timing and valve timing mixed up. Will do the ignition timing when replacing the points. Still wondering about the valve timing though.

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badandy
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1982 GL500I
1983 VT500 Shadow

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by badandy » Wed Nov 15, 2017 6:01 am

Make sure you get two condensers. One for each point set.

Get your ignition problems sorted before moving on. If the bike was running before I doubt the valves are an issue, however adjusting them before a carb sync is recommended.

coleman
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Motorcycle: 1978 GL1000

Re: 1978 Gl1000 Severe Loss of Power and Throttle Response in Gear

Post by coleman » Fri Dec 08, 2017 1:18 am

SOLVED

Just wanted to give everyone an update. Bought two new points and two new condensers (all from 4into1). The 4into1 stuff was great because it looked identical to stock and was super easy to install. Not sure if it was the points or the condensers that did it, but the bike is running on all cylinders.

Still have some hesitation between 4k and 5kish rpms kinda like a stuttering, but now that it's running on all 4 its not very noticeable. Not sure if the bike used to feel faster though or if I was just less prepared for the power. Any ideas what could cause the stuttering?



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