Struggling with carb3/plug3


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UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Wed May 01, 2019 3:06 pm



Hi Gord, on both my bikes I've plugged that vacuum advance spigot off on the carb as-per Randakks comment about it being barely noticeable so........ah (brain thinking that through as I type) right, the seized mechanical advance meaning the spark was unable to advance at all with increasing demand. Got it. That must've meant you weren't even able to rev it though, no?

I've got to be careful not to conflate two problems here. The standard bike with the carb No.3 problem that I still haven't solved. And the modified bike that refuses to pull the skin off a cup of cold coffee, even when the carbs that are basically fine on the standard bike are fitted to it.

In the intervening days I've put the standard motad exhausts on the modified bike (along with the carbs from the standard bike) to no avail, it still won't pull away. I figured I was wasting time but did it anyway to rule out exhausts and leaning-out because of them as the culprit.

I've now got both bikes cam covers off, more to double check I've done the cam belts/timing correctly on the modified bike - comparing one against the other. Once I've satisfied myself that it's not a 'tooth out' problem, I'll get the advance mechanism off the modified bike to see what's going on there. With any luck by the end of the weekend I'll have the standard bike back to normal and ready for the road again, with it's problem No.3 carb. Square one.

Thanks.
Nathan.



Gord
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Re: Struggling with carb3/plug3

Post by Gord » Wed May 01, 2019 6:51 pm

My advance stuck in the advanced position. Hard to turn over. It sounded like a dead battery. Started the bike by using kill
switch till the motor was turning over then flipped the kill switch on. In your case I was thinking more of a vacuum leak.
L8R
Gord

msgoodwrench
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Re: Struggling with carb3/plug3

Post by msgoodwrench » Wed May 01, 2019 7:51 pm

Hi! I have an 83 Aspencade, and I had this exact problem, on that exact plug! The answer to my problem was a poor connection in the plug wire/plug cap. The cap screws onto the wire, and when I took it apart, there was apparent green corrosion it was so bad. Cleaned that all up and that cured my problem. Just something else for you to check out; it is simple enough. Good luck!

pixel288
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Re: Struggling with carb3/plug3

Post by pixel288 » Wed May 01, 2019 8:17 pm

Is the plug wire/cap good? and how are you sure? I'd ohm it out and see if it meets the specs of the other ones. You may have spark, but it can be so weak that it just isn't enough to fire the charge rapidly and on time. If you wanted a quick and dirty way, I'd stick a screwdriver up one of the good caps and roll it over, grounding it with your hand. Then do the bad cylinder. You'll be able to feel the difference if it is very weak. Yeah, I know. Safety first. But I'm a pragmatist, so if it does the job, that's what I do. So for me, it's Safety Third. :shock: Doing the job is first.

Phil

Pedro70
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Re: Struggling with carb3/plug3

Post by Pedro70 » Fri May 03, 2019 2:26 am

I had a similar problem with my gl1000, please pull off the exhaust header pipes and check internally, in mine, the inner wall of no 2 cyl header pipe had bubbled up and virtually blocked off the exhaust.
good luck
Pedro

pixel288
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Re: Struggling with carb3/plug3

Post by pixel288 » Fri May 03, 2019 8:40 am

‘Pedro 70’, that is brilliant! Had a weedeater that plugged the exhaust screen and it acted much like he is describing.

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Re: Struggling with carb3/plug3

Post by WingAdmin » Fri May 03, 2019 8:42 am

pixel288 wrote:
Fri May 03, 2019 8:40 am
‘Pedro 70’, that is brilliant! Had a weedeater that plugged the exhaust screen and it acted much like he is describing.
I had a Buick that clogged its catalytic converter and bogged down when you tried to produce any kind of power. By the time I got it replaced, the car would barely maintain 30 mph. But it got fantastic gas mileage!! :)

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Tue May 07, 2019 3:35 am

Hello folks, thanks for the recent replies.
I'm losing time to spend spannering presently, but did what I said and got the standard bike back together with its own carbs (the reason for this thread being that No.3 is seemingly causing plug 3 to get fouled) and tested some suggestions along the way.

msgoodwrench - I checked all the wire to plug cap connections, all clean, all good. I'm pretty sure the wires are new(ish) - they're not the same as what look like original wires on the modified bike. Clean and good at the coil end too. I tested each wire for continuity and each read 0.00 including when I was flexing the wires.
pixel288 - Hi Phil, I've tested the plug caps for resistance now (forgot to bring the readings to the office) and each measured between 4.88K to 5.48K (more specifically, two caps seem newer and had the lower readings, and the older caps had the higher readings.) I've now put a newer cap onto plug 3 and will see how I get on. I tried grounding through myself (!) but every time I hit the starter button my left hand let go. PML, I needed a glamorous assistant to catch me out with it. It's a bit odd that two caps are new, and two not. For the cost of caps, if you're thinking one is down, you'd surely just do all four, after all they're all the same age and going the same way. Anyhow...

pedro70 - This is a different problem and exists on the other bike, and I checked out the headers. One exhaust is a 3-4 year old Motad stainless replacement, very similar to original, and there's nothing wrong with it. The other is a custom made pair of headers, no blockage their either. Neither of these exhausts results in the project bike being rideable. Totally gutless. I've now got the custom pipes on the standard bike with new exhaust gaskets, sounding sweet, and just awaiting a ride out. In the mean time I check the timing on both bikes, with photos to be sure of comparison. Timing looks good; both cams pulleys in the right place going off the raided mark, with 'Up' up, and the lines either side of T on the flywheel lined-up right. I haven't made an inspection window for the timing mark on the flywheel yet, so still don't know if the project bike is actually advancing as it should if that is something different to advancing on a stationary bike with an open throttle.

As ever with modified things I need to make an adjustment to the gear selector lever now in order for it to be able to select 1st with the custom header pipes on (I also had to swap out the engine bar for one that I've cut the side stand lug off as it was in the way). I'll get the hot spanner on that tonight, bend it, ride the standard bike with these exhausts on, and find out what problems or noticeable changes these freer flowing exhausts and silencers (with no balance pipe) introduce to the bike, if any. I'll pull plug three and see what it looks like.

With respect to the carb3/plug3 problem, the only things I've not replaced or checked now are the coils and carb 3.

Thanks for reading
Nathan.

pixel288
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Re: Struggling with carb3/plug3

Post by pixel288 » Tue May 07, 2019 5:00 pm

Nathan: it sounds like you are doing a good job diagnosing the issue.... keep testing theories until you can move the problem to a different cylinder. That will tell you what the problem is.
Question: are you sure the #3 carb is correct for the bike? I mean that it’s for a gl1100, not a 1000 or a 1200? I seem to remember reading somewhere here on Goldwing Docs that different carbs were not interchangeable. Just a long shot thought, but you never know what can put you on the right trail.
Phil

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Wed May 08, 2019 2:58 pm

Evening, been out ridden it. Plug has the cap and wire from plug 4 on it now, and vice versa. Plug 3 is still fouled, plug 4 is still fine. SO I'm happy that that rules out the wires and caps.
Phil, it's def a full GL1100 rack of carbs. 1000s and 1200s carbs look quite different - vacuum caps are different and the difference continue from there from what I can make out.

I've bought a Gunson Colourtune at Maz' suggestion, and should have it on Friday. Might help shed some light on what's going on.

BTW, I've also proved that the custom pipes aren't a problem for the running and riding where my modified bike is concerned. I had to modify the gear selector so I could get 1st with the new headers on the standard bike, and riding tonight for the first time with the flat 4 exhaling through Remus carbon silencers is wonderful; deep, sonorous, whopping sound, not dissimilar to those flat 4 Subarus, understandably. Wanted to keep it at 30mph so I could hear it.

I'll post some Colourtune photos at the weekend.
Nathan.

pixel288
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Re: Struggling with carb3/plug3

Post by pixel288 » Wed May 08, 2019 9:49 pm

Just had a thought.... is there a possibility that the main jet is either wrong by being the wrong size (I don’t know if there are #’s on them) or that it could have been drilled out larger by a previous owner?
That would definitely make one carb richer than all the others.
Jest thinkin’

Phil

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Sat May 11, 2019 1:51 pm

Hi folks, the introduction of a Colortune (thanks Maz) to the troubleshooting arsenal has revealed the problem.
Check the 5 sec video for cylinder 1 - bunsen blue ring, fuel screw wound out some from the spot where the engine slows. I happy with cylinder 1.
https://1drv.ms/v/s!AnQfkYySuMRHo3tQb5yV3NY-Hgas

But the video for cylinder 3 is quite different, there's no blue ring, not even yellow. All there is is spark, a good spark, but no bang. I'm definitely not happy with cylinder 3.
https://1drv.ms/v/s!AnQfkYySuMRHo3pWHcv6WJIpxCNh

So I've got a good spark. I've got compression the same as the other cylinders (all exactly the same). There's fuel leaving the plug wet, but there's no proper bang. How is that? This certainly explains the heat images from the start of the thread. No bang, no heat. Yet the bike appears to run smoothly in this state, until the cap of plug 3 is removed, at which point you know a cylinder just went down. It's just weird.

What are people's thought's now?
Dinner time for me.
Cheers
Nathan.

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Sat May 11, 2019 2:33 pm

It's the carb. Carb 3 is not healthy. I just thought I'd see what happens when a flick the throttle half open. Not just a little tickle for small accelerator pump squirt, but a good big squirt. The cylinder lights up. A steady opening of the throttle even up to 4000rpm doesn't yield this result. It needs a blast.
https://1drv.ms/v/s!AnQfkYySuMRHo30-Ob11BXVBdz4B

2 and 4 are just nice, like number 1.

Now I really do need to get some food.
N

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Re: Struggling with carb3/plug3

Post by Maz » Sat May 11, 2019 5:01 pm

If the plug is wet with fuel but the fuel isn't igniting, I would guess there is insufficient air or too much fuel. Possibly the idle air circuit is totally plugged up. Are the jets in that carb the same as the other 3 ?
Maz
Ironically, Common Sense is the LEAST common of all senses!

pixel288
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Re: Struggling with carb3/plug3

Post by pixel288 » Sat May 11, 2019 9:08 pm

That colortune is a fantastic little device for diagnosing. Never saw one in use before! That being said....
In your last video, when you were revving it up, right near the last, I noticed as the throttle snapped shut completely, the blue ring came back. I'd be interested in a second test. This time putting it in gear on the center stand and running it in gear. Maybe in as high as 3rd, revved to about 4k rpm. Then snap the throttle shut. It looked to me that as the throttle shut down, it may have gone rich enough to ignite again. But with the motor returning to idle so fast, it's hard to tell. By adding the momentum of the rear wheel it may show proper combustion at throttle close long enough to be certain. That would mean the vacuum is going up high enough to pull the fuel in to the cylinder. If it does indeed do that, it would point to an excessively lean condition. In which case, I would start by spraying some carb cleaner around all the connections looking for vacuum leaks.
Again, just my tuppence... :lol:

Hoping this helps
Phil

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Thu May 23, 2019 7:08 am

Hello,
Phil I've done the 3rd gear, shut off test, from roughly 3500rpm: I don't think it's lighting up at the shut-off. I think the slightly brighter blue flash is just the spark getting bigger as the revs get slower.
https://1drv.ms/u/s!AnQfkYySuMRHo3_51AAy4ZGbET1W

I missed a fortnight of great weather with all the messing around and changing this-and-that, so last weekend I took the custom headers and carbon pipes off and went back to standard Motad stainless, and have been riding to work on it this week.
I had a day of **** performance on Monday because I had the fuel screws too far open having been messing around in the garage. That didn't take long to sort out once I got home, and now the bike is flying down the road again. I still have the carb3 problem, but I'm going to ride with it for the rest of the summer because taking it off the road will drive me nuts, and I've not got the time until the weather turns the corner of winter.
What I do note now, having ridden it more is, that it's returning roughly 45mpg (UK) while getting on down the motorway at 80mph. But while it's doing that it's not only burning fuel, but also burning 80cc engine oil per 100 miles traveled (I've been syringing oil in for an accurate measurement). So I think I know that I've got stuffed rings - which could very well be evidenced by the earlier compression test returning 105psi on all 4 cylinders. Perhaps my compression tester is good, and that info plus the burned oil points to rings being the culprit of the low psi. But I'm going to carry on riding it while the oil's being burned like that too, because it's getting down the road nicely enough.

In the last fortnight I've ordered 2 Randakk's rebuild kits from the States, and someone who's on holiday over there presently will be bringing them home, with some other Randakk's shop bits, in their suitcase. So this winter's job will be rebuilding the carbs again (I got one kit with Howard's booklet too) of both these bikes. Doing the piston rings in the standard bike, and also changing the oil filter over to the spin-on kind with the Randakk's adaptor plate.

If this thread hasn't been archived in the next 6 months I'll add info back into it once I've done the work, and hopefully bring some closure to the original problem and also to the compression.
Many thanks for your suggestions in the meantime, and I hope you enjoy the summer.
Best
Nathan.

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Wed May 29, 2019 7:51 am

Minor Update:

I tried a separate piston, needle and vacuum cap on carb3 - no different, still no detonation in the cylinder. I did this because of the sticking problem I captured on video earlier on in this thread. I thought that maybe I'd not sorted out the sticking problem, but it seems I have.
And in pondering whether there might not be enough air in the cylinder (I know I've got no air leaks from the air box down to the cylinder head) I openend up the vacuum take-off screw on the inlet to deliberately allow more air in - no change. What this leads me to believe is that....Christ knows!

Back to just riding it again in the meantime.
Nathan.

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Re: Struggling with carb3/plug3

Post by Gord » Thu May 30, 2019 11:23 am

Back to basics. You need spark, fuel, and air. These have to occur at the proper time. You have checked all these.
Time for oddball checks. If number 3 is not firing proper, there must be a problem with that hole. Compression test is done at crank speed.
It may not be compressing properly at running speed. It may not be getting the air it needs. Blocked or restricted flow. There may be enough air at low or idle rpm but not as the rpm goes up. Check cam lobes for wear. Make sure they move as much as number one. Be sure that there is no restriction in the entire intake tract. Number 1 and 3 are on the same camshaft. Number 1 works. Valves should have the same amount of lift. If I can think of any thing else I will let you know.

UrbanPeasant
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Re: Struggling with carb3/plug3

Post by UrbanPeasant » Fri Sep 20, 2019 2:47 am

Bringing this thread to some sort of close:

The last update was that I'd tried a different piston and cap on carb3 to no avail; still had a fouled plug. I've now had the time to completely clean and rebuild (Randakk) my GL1100 project bike rack of carbs and install them on the standard bike (with fouled plug3). The result of this is that exhaust 3 now runs hot, like it should, and the plug is no longer black. What I experience riding the bike is, as you might expect, quite a lot more 'go' from the throttle, which is really nice. The apparent lean-out condition on pulling away is gone too, because all four carbs are working to get the bike underway. Annoyingly this rack of carbs has a hanging idle - the revs drop off normally down to about 3250 rpm, but then fall really slowly. That's a pain in town. But the carb3/plug3 problem was gone. I've been through Randakk's list of things that can cause a hanging idle, and drawn a blank, which is frustrating. Then I found out that my Dad took these carbs to a shop to be looked at because of this same hanging problem. That was in 1999. These carbs and the bike they came off (now my project bike) haven't been on the road since. I'll not go into it here, but that shop turned out to be brutal butchers, but at least I'm back a square one with this particular rack; they work almost right.

I've also had the chance to dismantle, soda, ultrasonic, and rebuild (Randakk) a separate carb3 body off a spare rack I bought, and install it into the original rack that was the cause of this thread. This also got rid of the carb3/plug3 problem. So even though the original carb3 had been fully gone through and dealt with, and I can use a syringe to put air through all the passageways I can find, something inside it is preventing its proper function. Its piston and cap work fine on the separate carb3 that I've put them on. So out of the three racks of GL1100 carbs I've got, one carb3 body has turned out to be a dud at present. That, the process, and other problems I found along the way, have sucked up a ridiculous amount of time, but so far as this thread, and this particular fouled plug problem are concerned, I think we've got to the bottom of it.

Annoyingly, with the project bike, which is now basically complete and on the road for the first time since September 1999, MOT'd, taxed and insured, a new problem has sprung up with cylinder 4 hurling copious amounts of oil out into the exhaust and making a real mess along the way. That can only be one of two things so far as my understanding goes, and the valve stem oils seals are new, so that leaves me with a top end tear-down on the cards. May well be a new thread for that. But it looks like the bike won't be going on the Distinguished Gentleman's Ride in Manchester next weekend, and that was the point of getting it together this year. Bugger!

Thanks for the input along the way. I've taken many notes from the comments and put them to one side for future reference.
Over-and-out for now.
Nathan.



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