1974 Norton Commando 850 - Part 5 - Carburetors or Electrical problems?
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- čas přidán 29. 01. 2022
- 1974 Norton Commando 850 - Part 5 - Carburetors or Electrical problems?
I hope that you will enjoy this little mini series of the new motorcycle in the mighty garage! Hopefully you got the chance to watch the Christmas special during which I revealed this new bike. In this episode, I will check out the carbs and fix the idle, only to discover another problem with the auto-advance unit.
Tap thread for the new pilot jet screw plugs:
I believe the Amal screws are probably 2BA. I don't have a 2BA tap so I use a 10-32 tap. It is close enough in this situation. M5 is also very close and might work. Also, it is not essential to use an Amal screw to plug the hole and any suitable screw that matches the thread cut could be used instead.
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Thoroughly enjoyable, thanks for posting. I have a similar IV setup that I use, if I'm working on carbs the tank usually comes off first thing. I use clear fuel line on mine. The acupuncture needles are interesting, what I have used idle jet cleaning for decades now is the small "E" string from a guitar. They are quite rigid and come in diameters from 0.009 to 0.013 (maybe 0.014) inches and are readily available, especially if you play guitar or know someone who does. When inspecting a jet I have just cleared, I use a magnifying glass to make sure the "daylight" I see through the jet is perfectly-perfectly round, otherwise it still won't idle right. Your idle circuit modification may save an old set of Amals I have, thanks for sharing that!! Thanks for posting.
I remember my 69 triumph tiger came with a email 9:30 I acquired several sets over the years now it had a single carburetor but anytime something triumph was available I would buy it . When my son moved away I gave him all the parts and the bike I still miss my triumph
Thank you Moe. Cheers, Mike
Yes, that's definitely an acupuncture needle Mike (and looks like a really good alternative use !)..👍
Well it is alternative medicine, why not have it for bikes as well as humans!!, Good fix though. Although I did end up taking the electronic off my BSA B40 and refitting points to it, starts a lot better now.
Oh the joys of old bike/cars. Still if they worked all the time we would have nothing to do, fiddling, fettling, fixing is great keeps us out of the house. Good luck with it all Mike.
I always take out the choke slides. The tickler is a perfect enricher and it makes the handlebars much neater.
Thanks Dean. I may do that. I'm going to see how everything goes for a few rides and will then decide to keep em or take them off altogether. Cheers, Mike
Amals on my trident same, piss off choke slides cables and plug cable holes, good mod.
Always learn something watching, Mike. Thanks for posting.
Another trick is to use a No. 78 drill bit, pushed into the end of a piece of plastic tube of the sort you get with some aerosol cans. The drill is rotated by hand and pulls any debris out of the pilot circuit from the air screw side. Although I haven't done this as I junked my worn Concentrics and fitted new Premiers. Problem solved.
Excellent video. Been there many times……
Thanks a lot Ian. The carburetors have calmed down now and I haven’t had to touch them for a little while… Cheers, Mike.
@@TheMightyGarage Result!!
You did an incredible job with the camera, the hole is easily seen as you show it. It was real clear as you drilled out the plug. That looks like a good fix for getting that jet cleaned out. Thanks for showing this so clearly.
Every time I see that paint. Love it!
I learn so much from you Mike. Great mug too 🙂
I do admire you patience Mike but you are getting there with the wonderful bike. Looking forward to the next episode 👍😃 as always thank you for the video
Hello mike.
I found that when your Norton has a hanging idle, it’s because your idle mixture is a touch lean. Try closing your idle screws a quarter turn and see if that helps.
It’s been interesting watching you get this bike back to perfect running condition.
Looking forward to the next episode.
That's a fantastic tip I have a g 12 Matchless with this carb I will definitely do this mod many thanks. Videos are great and informative.
As you have drilled out the blanking plug, why not carry on and press out the pilot jet and replace it with an Amal Premier removable pilot jet? If you look up in your bike manual what original pilot jet size is, you should find a suitable removable one.
With regard to the sticking throttle, I suggest the carb slides are worn. The problem is that the carb body will also be worn. What is happening is that when you open the throttle, the slides are being pulled forward by engine suction. They won’t easily come back down to idle.
There are 2 solutions. One is to buy new carbs (if you can get them). Alternatively get the carbs bored and the slides sleeved with brass sleeves. This solution actually does work extremely well. The carbs won’t wear out any more.
Thanks Rob that's a very good idea about replacing the jet. The Amal premiers look to be in very good condition so I'm going to see how they run for a while. Cheers, Mike
Thank you, I will check out those websites. Love your channel and bikes
the fuel/air screw when in front of the carb slide (engine side) it is metering fuel not air hence the idle jet being located where it is. from the video with the idle being held up/not coming down after revving thats typically a possible lean condition. Im assuming by the comment 'most carb issues are electrical' we may learn the real issue when you install electronic ignition :) good luck Mike, enjoying the new bike commissioning.
Thanks very much Malcolm. I appreciate your advice. Yes, good news coming on Sunday morning with the installation of the Electronic Ignition! Best wishes, Mike
As someone who owns a classic bike but wouldn’t know one end of a screw to another ( when God gave out brains 🧠 I thought he said train’s 🚂 so I asked for a small slow one lol 😂 ) your content makes me believe I could do that ! Thanks Mike Ray 🇬🇧
Thanks Mike! Didn’t know about drilling and tapping other side of pilot jet to clean. Good to know. I put new Amals on mine a few years ago because the slides and bores were bad shape. The electronic ignition I’m sure will help the idle. It did for me. Thanks again for your instructions. Stay warm up there.
Thank you Philip! Hope all is well. Yes it's still cold and damp up here, but looking a little dryer may even get to ride the black Norton to the club meeting on Saturday, depending upon the weather. The electronic ignition made a significant difference. I'm glad that we did it. It wasn't super hard but I'm not good with electrics and so my friend Geoff was an enormous help. Best wishes,
The drilling of the blanking hole, tapping the hole and putting in a cut off air screw is a great idea.
I'm still rebuilding my Bonneville with twin Amal 930's, I've had the blanking discs out of the underside of the main body which gives access to some of this troublesome area, had it in the ultrasonic cleaner and blown out the airways, put new discs in but haven't had it running yet...time will tell. If it doesn't work I'll definitely consider the drilling, thanks
I like to use a #78 drill bit to clean the pilot jet. As you twist the bit in the debris collects in the flutes and you can pull it out instead of showing it to the other side. You can superglue the bit into a red plastic tube off a WD 40 can or similar to make a handle.
Mike "Sorry the bike is shaking the garage floor."
Me "Yeah baby!"
👍
😄😄 Thank you! 😄
I have a '66 T100 Triumph project that uses a single Amal Monobloc carburetor. Try as I might, I could not get a consistent idle. (Or any idle at all) Unlike the Amal Concentrics, hese carbs have a removable pilot jet and an accessible idle circuit passage. It still took me three tries, cleaning the carb, to get the idle circuit working properly. All I could determine was that it was because of some lingering dirt getting stuck. Also on this carb I had to make sure that the pilot jet was seated. I used a smear of red marker on the jet to act as machinist bluing so I could see if the taper was making a full connection..
Accupuncture needles ? love it the Chinese are clever buggers for sure ...
ps. I also ride and love a Chinese bike , CFMoto 650NK , great bike .
😀 Very cool Brian! Cheers, Mike
Great title Mike.
You can see the Manxman, thinking, when is it my turn 👍
Can’t wait for the next, thrilling instalment, you’ll get there I’m sure ☕️
Take care Mike, where’s the Swiss Army knife 🤔😀
Compared with previous videos there is a notable improvement, but not perfect. I'd also look at the mixture screw settings once more as it's possible the idle mix a a tad rich. I guess the original instruments may have been a little worn causing the erratic running. Electronic ignition a good upgrade, irrespective, IMHO. Thanks for the vid Mike - I always enjoy your careful style and problem solving.
Mike, if I may Sir, I have felt it was the mechanical or centrifugal spark advance unit from day 1. Now as the engine temperature increases, and the idle down speed starts lagging, I truly believe that this is the cause. I have nothing against breaker points, don't misunderstand, in this case it should be a win-win providing the advance is now controlled electronically.
And 1 other thing you might try is always keeping the handlebars pointed straight ahead while diagnosing. It only takes a slight kink or a slight misrouting of the cables to affect the idle speed.
Thanks for listening and the wonderful videos.
T.S. RACING
Many thanks for your tips and advice. I really appreciate it and you are absolutely right about the root cause. All will be revealed next week! Thanks again, Mike
Ah yes the old drilling out of the pilot jet blanking plug. This is described fully in the Bushman's guide for tuning Amal carbs guide....can be found easily over on the Access Norton forum Technical Information thread. One other point that might be helpful to others, the fuel pickup passages from bottom of float bowls, then into the carb body, all the way to the pilot jet, need to be checked for good clear flow and blown out/reverse flushed etc. I find a bit of kitchen twist tie wire can get in this passage and bent around the internal corners etc. Even a spray straw of a WD40 can seems to work as a good poking tool here.
My '74 850 was also showing a bit of that failure to drop back down to idle while out riding. Even happened with my EI (Wassel) and no amount of carb clean up seemed to resolve it. Even switched to Premiers. What ultimately got the bike running best was using a good carb balancing tool to get the slide cables properly sync'd. Even though I had them very good beforehand by the drill-bits technique, the carb balancer showed the actual air pressures were still quite far off in the manifolds...needed quite a bit of cable adjusting to make it right. I bought a Morgan Carb Tune (www carbtune com) for this, which uses solid rods moving up.down in clear tubes, much nicer than the low quality dial gauges many try to use. Bike has never run better.
It can be frustrating diagnosing an issue on old bikes. I have had my old Honda for a year, she wouldn't run when I bought her. Now, shes rideable but still not perfect...I call it character lol.
A different bike (Harley so single carb) and a Mikuni and the same problem with the idle..... I had a spare set of throttle cables (push/pull) that were new so I tried fitting them and things changed. I can only assume that the inner cable had worn grooves in the outer cable and was 'stepping out' of the grooves thereby keeping the slide raised..... something to think about maybe ? I had taken thel tank off so I could make sure the cables weren't pinching or had too tight a turn in them and things were OK but as soon as I put the tank back on the problem recurred, but new cables and the problem was solved !
I know that clutch cables have the same problem especially when heavier springs are used.
I second that idea.
It's not hard to pinch a cable,removing or replacing the tank,to get to the carbs.
Been there,done that.
@@billysolhurok5542 Yes, I have done that as well, but the situation was - I am 100% sure - in this case due to worn cables as I routed the new throttle cables in the exact same place. When I had both sets off the bike the older cablles were not as smooth and 'free-flowing' sort of thing. When I now let go of the throttle the carb almost snaps shut. On an aolder Harley (1990) I could run just a single cable to open the throttle but the newer bikes run a cable to close the throttle as well which is just gonna make things worse.
Good evening,
If you are running points then you have a rough spot in the movement. Once the idle falls it stays there but if you blip the throttle then the advance hangs up a bit and the engine tends to run faster. It is the difference between a 850rpm idle and a 1000 rpm idle. Unfortunately the advances wear relatively quickly. I leave it to you to find a solution to rebuilding the advance. I like the points especially as you can get home without a battery. The practical solution is a Boyer or your own favourite electronic ignition. For the original carbs no ultrasonic cleaner will do the job ever. You need to get physical. Lots of pro info using number drills, guitar strings or a strand of old throttle cable to open pilot jet. It may block a few times before it is solved. You can run a drill or wire into the jet when on the bike too. If you have a parts washer check to see that fluid comes out of every orifice. Check that 2 strong streams come from the bottom of the bore downwind of the needle. Sorry but blowing with air is not positive enough.
Gerardus
Many thanks for your advice here and in earlier comments. Sorry for the delay in replying. I appreciate it. I've now fitted the Tri-Spark and it seems to have done the trick, but I haven't had the chance to ride the bike much since. It's a step by step process, isn't it! Best wishes, Mike
Hello my friend when adjusting the idle circuit lubricate the o ring and make sure you have a positive closed position sometimes you can get a false reading and not truly bottomed as we have to be very careful not to use too much torque make sure that you have seated the idle screw and back it out 1.1/2 turns out from fully seated should be a good start then tune when running it looks like a fuel mixture screw as its on the engine side air screws are usually on the air side of the carburetor I will have a better chance to look at your video later. I used to have a Norton atlas the predecessor to yours witch I built up from box's and it fired 2nd kick and started 3rd time regards Alan let me have a closer look at your video I take it you can alter the idle circuit and its not the closed form. Ps it's the oring that does the same job as a spring and holds the settings.
How frustrating Mike, with that amount of checking modifying & testing I sincerely hope the electronic ignition solves the issue .. 😢
atvb t .. 😉 .. 👍 .. .. 🏍
As others have said.Throttle cables may be the problem.Turn the bars lock to lock.See if that changes the idle.
The other reason your old carbs probably wouldn't idle properly, is because the slides are probably and bores are probably worn. To much unregulated air will enter the engine by going around the slide and into the combustion chamber and will cause irratic idleing. You will never over come that. Best bet is just replace the carb with new premier carbs.
Berryman's B-12 LIQUID carb cleaner is the only chemical that will clean that tiny pilot passage, circuit, jet ! A one gallon can comes with a perforated basket, put the carbs in to soak for three hours minimum. Let 'em drip dry in the basket hanging over the can, rinse with tap water, blow dry !! Ya always have to check that the pilot circuit is clear on ANY carb- compressed air works the best A gallon WAS $30, you can get a 5 gallon but it's a bunch of money.
Can't get that stuff anymore here in Canada :-(
The initial boiling point of petrol is about 30 C. Thats why you will never get a Norton to idle perfect when hot. The inlet studs transfer heat to the carb body, and make the petrol unstable. Together whith the very simple construction of the carburator it is impossible to get it wright. Rubber mounted carbs solve problem.
Many thanks for your great comments. Really appreciate it. Cheers, Mike.
Weak advance unit springs in conjunction with sticky / worn advance unit.
Thanks very much Hillary for the advice. You're completely right! 👍👍
@@TheMightyGarage We called that," Nortonitis." Worn out advance.
I have a 750 commando ,rode it all last season and the idle was acting up at end of season, will be disassembling carbs shortly and also look at electronic ignition. Hopefully is solves the problem
Thank you Ron. The upcoming video on Sunday morning is going to cover the electronic ignition installation. Hope it is helpful. Cheers, Mike
Also, typically a hanging idle can be caused by air leak. Also, I didn't see where you set the float levels. The Amal premiers do not come with float levels set correctly (at least not for Triumph), amal even has a bulletin about it on their website. I think you have some more things to check out with your carbs. You can't just bolt them on and go.
Hi Mike. Sometimes I feel like Sherlock Holmes when trying to diagnose strange things like your experiencing. Probably on the right track with the ignition advance but……. I noticed the handle bars cocked all the way one way. Did you try turning the handlebars lock to lock while playing with the throttle. I’ve had bikes where the cable routing was just so, that depending on where the bars were positioned it would interfere with the idle/throttle position like your experiencing. Just a thought. Cheers my friend. You’ll solve it. Sometimes that’s half the fun.
Mick
I've noticed the same with handle bars turned in the past too. Just since not mentioned, normally I'd adjust the idle air mixture just a bit richer under the conditions you describe. 1/8 turn should suffice.
What I noticed is that Mike cleaned the carburetors in the ultra-sound machine then he put all the cleaned parts onto that filthy work bench where they could be contaminated very easily.
@@autodidact537 if it’s like my bench, it’s is stained from use and looks dirty but I wipe mine all down and it looks terrible but is spotless. 🤩
I ran into this on my 71 Mike. Turning the bars did have an affect. After some reading/research one should have 18+ of play in your throttle cable so the position of the bars do not come into play. Your idle should be down at the carb, not by cables. I also noticed around 11+ minutes into the video you could see the engine mover around some, you know what that indicates. Looks good Mike thanks for sharing. Oh by the way leave them points in!!
Thank you Mick. I appreciate it and I'm quite proud of all those stains! I also wipe it down before these kinds of jobs. Cheers, Mike
I hope you figure this out without going the electronic ignition path. I'm having the exact same issue with my 1970 Triumph. This has happened to me in the past and changing out the springs on the Automatic Advance unit fixed the issue. This time that same fix hasn't worked, but I'm not convinced the "new Lucas" springs I bought on EBay were not really new. Seems like everything you've done kind of rules out the carbs from being an issue.
Hi Myron, thanks for your note. The electronic ignition has fixed the issue as far as I can tell. I was always planning on getting one and it the improvement was immediate. There's still some fine tuning with the carbs and timing light, but it seems to be much better now. Cheers, Mike
Who'd have thought acupuncture could have been a cure for carbs on an old Norton 🤣🤣 My friend had an 850 Commando back in the early 80s , we had it apart so many times it became a weekly ritual , we could never get it to run right , he sent it to a specialist in the end, an ex police mechanic who had set up on his own ( the police in the UK ran commandos for a while ) it was in his shop for ages , eventually he sorted it , I can't remember what the problem was now , but my friend got it sold while it was running well . No such thing as CZcams back then of course, I hope this video helped some poor soul with commando running issues . Getting them to run perfectly is a challenge , lets see if new ignition solves yours , fingers crossed eh 🤞
I thought you may have a problem with idle when I wached the first vidio, (when you cleaned the carbs) I have had that problem over the years) it is possible to clear the gantry's, in the Amals body, I have never Found a thin enough locking wire, I think those gantrys are 0.4 mm. Best thing I found was the stainles steel middle of a tie wrap, that used to come with food bags. It is a fiddle, but there's two holes at the outlet side in the bottom of inlet (difficult to explain) I did get a good tickover.
Great video but aren't these little buggers fiddly to remove and replace, Norton didn't leave any knuckle room!
😥
Hehe, so true Paul!! Best wishes
I was able to clean out my plugged pilot jet using a cut off "B" guitar string. The string must be 0.015 inches or less because the pilot jet orifice is 0.016 inches. (on mine) P.S. At 8:40 you really don't need to true up those surfaces because there is an "O" ring on one and a gasket on the other. At 10:45 I can hear that you have the bike running better now, it is running on two cylinders. You can walk away and it might not stall. At 11:40 you can hear by the 3 second, slow delayed return to idle that one idle screw is up farther than the other. That is why it delays a few seconds before returning to a rough idle. You can listen/feel the exhaust to see which side cylinder is doing most of the work, then adjust accordingly until the idle sounds even. The idle adjustment screws (head of the screw) should be roughly 0.020 inches (0.060mm) above flush with the carb casting that they screw into. Best way to coordinate the slides is to look/feel the slides when you twist the throttle open from idle. Also try to keep the throttle cable adjustment height the same at the top of the carburetors about a quarter inch of threads above the small lock nut.
With that idle holding up could you check if the slides "actually seat back down at the same time" i:e with two finger dial gauges , probably not practical, easier with two drills under slides sticking out , your balanced because the slides are sitting on the idle screws , but different when pulled by cable , or is your advance mechanism slow to come back ? Love the heavy metallic paint . Cheers .
I've had an identical slow running/ idling issue with my 74 commando 850, watching and listening to your bike its a carbon copy ... went though the same pilot circuit woes..everything cleaned out a million times , on and off ..on and off , new slides,needles,needle jets etc. So in an attempt to eliminate a few
Possibilities I fitted a mates Mikuni single carb conversion to my bike, started first kick , idled beautiful, responsive with no
Lag and 'hanging on' , we set the timing with the strobelight 28° full advance @3000 rpm . This now pointed squarely at the carburettors. Anyway the answer was , after some logical thinking and doodling with a pencil and paper , found, the theory tested and proved, an unbelievably basic schoolboy error ????......air screw 1 1/2 turns .. set throttle stop to idle at 1500 rpm with 1 plug cap off then repeat for opposite cylinder and obviously adjusted air screw for best running as per normal then 1/8 th turn at a time , or less bring the idle back down to 1000 rpm and now this is the final and MOST IMPORTANT part , which had me pulling my hair out.....Now 'synchronise the the slides. That my friend had her running absolutely perfectly, yes a simple simple
SIMPLE mistake caused me so much grief and head scratching. 😂
Always so interesting, another school day. What was the cause of the rising idle speed? Greetings from England 🇬🇧
Thanks Mike, very useful. Why does your garage floor cause camera shake? Is it wood on battens or tiled concrete? Just interested that’s all!
Thanks Neil. The garage floor is a concrete slab but it must be pretty thin! I also think that it doesn't take much for the vibration to resonate through the tripod into the camera. Cheers, Mike
Mike, great video. One question, what size and thread type tap do I need to order to tap out the other side to perform your modification?
Hi Charles, I asked Geoff and here's his response below. Best wishes, Mike
I believe the Amal screws are probably 2BA. I don't have a 2BA tap so I use a 10-32 tap. It is close enough in this situation. M5 is also very close and might work. Also, it is not essential to use an Amal screw to plug the hole and any suitable screw that matches the thread cut could be used instead.
Ditch them for a Mikuni! They’ll do your head in trying to get them to idle
Where did you get the handy gravity gas(petrol) fuel tank ?
Hi, I can't remember where I got mine but found it on a few sites. It looks to be sold out on some but hope you can find one.
Cheers, Mike
venue.com/product/alpha-moto-motorcycle-shop-auxiliary-gas-fuel-tank-professional-tool-compatible-with-honda-yamaha-kawasaki-suzuki-kz-xs-cb-ks-450-550-650-750-850/?attribute_default=Default&Google+Shopping&WP-cpc&GMC+-+WP+(Google+Shopping)
www.walmart.com/ip/Alpha-Moto-Motorcycle-Shop-Auxiliary-Gas-Fuel-Tank-Tool/143329127
thealphamoto.com/products/motorcycle-auxiliary-gas-tank
Hi Mike what size tires did you put on Norton commando 850
Hi Christine, they are Avon Roadrider MK11 100/90-19 tires on front and rear. A lot of the guys in the club are also using these tires and very happy with their performance. Cheers, Mike
I've owned Nortons (P11, Hyrider, Commando 750) for almost fifty years....to find your problem, I would have removed one side's sparkplug and ran the motor on one cylinder, setting the idle to 500 rpm and then do the other bank...if you think it's electrical, just swap coil leads to keep the same timing on both. this will ensure each bank is in balance...or point to another issue such as valve clearance...BTW...I changed over to Boyer almost 30 years ago so I didn't have to modify the 6 volt coils to get 12 volts when starting....my P11 didn't use a battery, so it took a few kicks...the Commando will sit all winter with a full tank of non-ethanol, and start the first or second kick in the spring, without tickling, but on choke.
Thank you very much Kenneth for the advice. I really appreciate it. Wow, that’s amazing. 50 years of Norton ownership! Best wishes, Mike
I've not worked on "parallel twins" in twenty years, Yamaha XS 650's last, and Triumphs, in the seventies, that reminds me of something I'd forgotten all about, thanks, good idea.
Zenner Diaode no more ?
☕☕☕☕☕👍🏆
Perhaps ignition is not retarding ??
In the final decade or two of the British motorcycle industry, the makers were leaning very heavily on suppliers, like Amal, to decrease prices. Hence Amal, not only did not have development funds to keep up with other carb manufacturers, but made their existing carbs cheaper by using pressed in jets etc.
Many thanks, absolutely agree and the EI has fixed the problem! I really appreciate your advice. Best wishes, Mike
i rememver the electrics. Lucas, prince of darkness
Mike, know you probably will answer this question on next episode. But I've just began having the same issue with the idle not coming down or it will either idle up on its own. It's fuel injected, have any idea what's going on?
If your bike is fuel injected won't it be a modern Norton . Not sure if what Mike is doing would have any relevance to a F I bike . Any way , hope you get the issue resolved and safe riding .
@@anthonycarty9433the 2 bikes act the same. A vacuum leak could be a common cause. I'm just asking.
Got to check for air leaks. One method is to spray heavily with WD40, carb cleaner etc on all the rubber and manifold joint while idling. Any variance means its drawing in the fluid and affecting idle. Unsure what bike this is but on my modern bonneville with FI, the carbs are mounted on rubber sleeves to the manifolds and these can crack or not clamp properly. There is also a pair of 3mm vacuum lines from manifold tops to the MAP sensors, notorious for leaking which then means computer gets false readings. Also on the bonne, the two throttles are operated in unison by an adjustable rod...these can come out of balance and need tweaking.
a sticking cable would be to easy .
Resisted plugs resited caps still get neighbours whinging its messing up their tv
Super tight? …probably a misguided choice of words. I think you mean tight seal thanks to super flat mating surfaces. OverTIGHTening fasteners can cause distortion of mating surfaces.