Joined: 03 Sep 2007 Posts: 131 Location: Tulsa, Oklahoma, USA
Posted: Thu Oct 16, 2008 8:28 am Post subject:
kommando wrote:
Sounds like the pilot jets are clogging up, the latest fuel makes them very prone to clogging.
That is a possibility I'd considered, Kommando, but had discounted it after I found the system so clean. Still, it is a good idea to go ahead and clean the carbs while I have the fuel system apart.
Will I need to remove the carbs to clean the pilot jets? Do you have any specific tips on how to go about the project? (I'll read the manual, of course.)
Should I be prepared with a gasket kit before beginning the project? I had the carbs cleaned when we originally started the project. It cost over $400 but included other work as well. I considered taking the float bowls off and looking for grime. Will I need new gaskets for that?
Thanks for the tip, Kommando! It's hard to find pure gasoline here in Tulsa but there are several stations which sell it. Most offer 10% ethanol. We used "gasohol" when we first returned the bike to the road, but have used pure petrol for the past couple of tanks. It ran much better until this most recent challenge.
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Thu Oct 16, 2008 11:27 am Post subject: Re: Rough Running
Tulsaalva wrote:
The left petcock will flow air only when set to "On," not to "Res."
The right petcock will flow air only when set to "Res." not to "On."
I'm not sure if the petcock/tap in the photo of the bike (on page 2 of this topic) is the standard Triumph item? And presumably the L/H one is the same type as the R/H one, so I can't give you any answers as to why they are only drilled to flow at one position? Originally one petcock would have been for "(main supply) on & off" and the other would have been "reserve & off".
Edit: After closer examination of the petcock in the photo, there is a chance it is the correct item. Are there any markings on the back of the bodies (BAP?)?
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Thu Oct 16, 2008 11:48 am Post subject:
After digging out one of those BAP taps, do those petcocks/taps actually have RES (or RESERVE) marked on them, as well as ON & OFF?
As the one I've got is a single supply tap, - even though the lever has three positions = "ON -OFF" and a third position with no marking that is also ON with the lever 180 deg. away from the other ON position.
Joined: 03 Sep 2007 Posts: 131 Location: Tulsa, Oklahoma, USA
Posted: Fri Oct 17, 2008 2:13 am Post subject:
I need to work on my powers of observation, Les.
Both taps have a BAP logo in raised letters surrounded by an oval on the back.
On the left tap, "ON" and "OFF" are stamped.
On the right tap, "OFF" and "RES" are stamped.
Both have three positions.
Only the left petcock has a tube extending upward inside the wire screen filter.
I believe I understand how this is intended to work but perhaps there is a crossover fuel line missing? My BMW has a fuel line connecting the left fuel line to the right one, but it has all three positions on both taps. The Commando also has a crossover fuel line.
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Fri Oct 17, 2008 4:10 am Post subject:
Tulsaalva wrote:
perhaps there is a crossover fuel line missing? My BMW has a fuel line connecting the left fuel line to the right one, but it has all three positions on both taps. The Commando also has a crossover fuel line.
Yes, there should be a crossover pipe between the fuel line banjo fittings on each carb, as the banjos would normally have double spigots, so that either the "main" or "reserve" tap/petcock feeds both carbs.
Joined: 03 Sep 2007 Posts: 131 Location: Tulsa, Oklahoma, USA
Posted: Fri Oct 17, 2008 8:39 am Post subject:
L.A.B. wrote:
Tulsaalva wrote:
perhaps there is a crossover fuel line missing? My BMW has a fuel line connecting the left fuel line to the right one, but it has all three positions on both taps. The Commando also has a crossover fuel line.
Yes, there should be a crossover pipe between the fuel line banjo fittings on each carb, as the banjos would normally have double spigots, so that either the "main" or "reserve" tap/petcock feeds both carbs.
Yes, Les! Hidden down there behind the carbs is the crossover line. So... since the fuel tank was full at the time the bike was running poorly, it wouldn't have mattered where the taps/petcocks were set, both carbs would have been getting enough fuel.
Therefore, there must be another problem. I guess it's time to remove the float bowls and look for squirrels' nests... or something similar. Have you any suggestions on what I should look for?
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Fri Oct 17, 2008 11:44 am Post subject:
Tulsaalva wrote:
Therefore, there must be another problem. I guess it's time to remove the float bowls and look for squirrels' nests... or something similar. Have you any suggestions on what I should look for?
It's difficult to say what it might be from your description of the symptoms, but start with the easy stuff first, and, as kommando has suggested, check the pilot system, and I would also suggest checking the inlet rubbers and inlet balance pipe for splits? Also check the carb choke linkage is shutting both plungers completely, also check the condition of rubber gaskets on the ends of the choke plungers, as they are known to disintegrate when they get old.
Another thing, check the floats as they can split and let in fuel.
I'm not sure how much room you have to work but I can pull my float bowls on the bike. I'm sure you can remove the air cleaner unless this quite unlike my old Commandos. If you can do that you can remove the pilot air screw and crank throttle and choke wide open. Then you ciould apply air to the pilot jet circuit and see if it comes out all the proper holes.
If you have to clean the jets they are so miserable unless you got lucky the crabs have to come out.
I soaked mine in carb cleaner, blew them out, used spray cleaner, blew them out again, and finally used the old sixties trick of applying a guitar string to clear one. We all played guitar back then and I still have several.
If you just cleaned them a bit ago it seems they would not be too bad.
I'm pretty sure my Norton had sat with fuel in it for ten years or so, no real surprise one was good and plugged.
I only know a couple more tricks for those, boil in water to get the fuel to loosen, and finally the last ditch stand of driiling from the back side and plugging the hole up after.
I like to put a new kit in but you may not need to if it has just been done.
I guess I'm jammed on Concentrics. I can remember very little of working on my earlier Amals.
I'm already thinking of picking up another older bike to restore so the more i can pick up the better.
I'm learning a lot here,
Joined: 03 Sep 2007 Posts: 131 Location: Tulsa, Oklahoma, USA
Posted: Fri Nov 07, 2008 10:43 am Post subject:
Sixteen took the Special to his motorcycle mechanics class at Tulsa Tech. They cleaned the carbs and removed a "blob" from the left one. They are cleaning the tank (again) and have filters installed in the fuel lines.
Sixteen thinks he may have gotten dirty gas at our favorite "Pure Gas" (no alcohol) station because the bike started running poorly shortly after leaving there.
Although the Triumph will start when kicked, Sixteen has not been able to get it to run smoothly or idle once it's started. Of course, the carb adjustment was lost in the cleaning.
Has anyone determined what is a good "initial setting" for the mixture control? Often manuals suggest opening the adjustment "one and a half turns" or some other setting to arrive at a starting point.
I use a system on the '85 R80RT which works like a charm. I screw the adjustment screws in until they just seat lightly. Then I open them one and a half turns. I disconnect one spark plug wire, leaving the dead plug in place. I insert a modified plug into the plug wire connection and using an alligator clip, secure the electrode to a cylinder fin. (Suggested by a member of this board.)
I increase the idle adjustment on the live plug side until the bike will idle at about one thousand on one cylinder. I turn the mixture adjustment screw back and forth until I achieve the highest RPM. I then very slowly lower the idle adjustment until the engine stalls.
Then I reverse this procedure for the other side. When the dead plug is reconnected, the bike idles smoothly at about 900 RPM. If the idle seems too high I lower it by turning the idle adjustment screw one width of the slot at a time, making sure the screws have been turned equally.
If the smoothness doesn't seem optimal, I ride the bike until it is well warmed and do the procedure over again, using the first adjustment as a starting place.
The problem is that I've never used this method on a vertical twin and have no idea where to start with an initial adjustment. Does anyone have any tips on adjusting the Bonneville's Amal Mk II Carbs?
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Fri Nov 07, 2008 11:05 am Post subject:
Tulsaalva wrote:
Has anyone determined what is a good "initial setting" for the mixture control? Often manuals suggest opening the adjustment "one and a half turns" or some other setting to arrive at a starting point.
The problem is that I've never used this method on a vertical twin and have no idea where to start with an initial adjustment. Does anyone have any tips on adjusting the Bonneville's Amal Mk II Carbs?
One and a half turns does appear to be a good starting point, and I can't see why your tuning procedure wouldn't work just as well with a vertical twin as it would do with a flat twin.
"2nd: Pilot jet
The pilot system governs engine tickover and can affect pickup and transmission to the main system. Choose a jet that when the engine is set for steady idling, the pilot screw is one and a half turns from its seat. If the adjuster is further on its seat, a larger jet is needed, conversely if the adjuster is screwed out a long way a smaller jet is needed. There are two alternative pilot jet locations; the one in the float bowl is generally considered best for four stroke engines, that located in the body beneath the air tube usually best for two stroke engines. This is not a hard and fast rule and the reverse may sometimes be the case. Irrespective of engine type, when the carburetter is mounted in a down draught attitude, the pilot jet should be placed in the mixing chamber body."
Joined: 03 Sep 2007 Posts: 131 Location: Tulsa, Oklahoma, USA
Posted: Sun Nov 23, 2008 10:22 am Post subject:
Sixteen cleaned and rebuilt the carbs at the Tech school and brought the bike home. Yesterday we used the old BMW method to balance the carbs and the Bonny is running smoother than it has since we've had it running.
Next week Sixteen is out of school for Thanksgiving (celebrated on the 4th of July by Brits, I've been told...). We're going to use the time to pull the drive train on his 924 and replace the rear engine seal, the clutch, the shift linkage, and the half-shafts. Since the Triumph is running beautifully again, he'll have transportation. The weather looks good so far.
Joined: 20 Nov 2004 Posts: 1946 Location: Norfolk, UK
Posted: Sun Nov 23, 2008 12:18 pm Post subject:
Tulsaalva wrote:
Sixteen cleaned and rebuilt the carbs at the Tech school and brought the bike home. Yesterday we used the old BMW method to balance the carbs and the Bonny is running smoother than it has since we've had it running.
That's good.
Tulsaalva wrote:
Next week Sixteen is out of school for Thanksgiving (celebrated on the 4th of July by Brits, I've been told...).
4th of July?
It's just the day between the 3rd and 5th of July to us Brits, Al, as there's no "Thanksgiving day" in the UK, but I hope you all have a good one!
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At the end of 1967 the Norton Commando was announced.
The Norton Commando was greeted with a certain amount of scepticism because on first sight the commando appeared to comprise of the old Norton Dominator twin cylinder engine mounted at an inclined angle in a set of new cylinder parts.
It was not realized that the new Norton Commando Isolastic method of engine suspension damped out all engine vibration and produced a machine which had uncanny smoothness for a vertical twin. In due course the critics were silenced and the Norton Commando had the distinction of being regarded as the first of todays so called superbikes. There can be little doubt that the original design concept of the Norton Commando has proved correct, since comparatively few modifications of any real consequence have been made since production commenced during 1968.
Now nearly 40 years later Norton Commando riders like us are a breed of our own, and as far as we are concerned its still more fun to go for a blat on the old Norton Commando, and fast. As a Norton Commando owner and enthusiast, my goal here is to promote and give credit to those who keep the Norton name going.
It is more deserving to give credit to the Commando itself, for after all these years it continues to be respected. The original Commando designers like John Favill are those who deserve the credit for developing this incredible motorcycle.
The Norton Commando Roadster and Interstate of the late seventies, never died. Although the Norton Villiers factory dispersed the tradition lived on. Today Kenny Dreer in the USA is developing the new 952 CC Norton. What a great looking bike this is, and its engineering is still based on the original layout. It will be interesting to see how the new 952CC Norton does in todays tough motorcycle market. One thing is for sure, I would own one if I could afford it.
We're going to use the time to pull the drive train on his 924 and replace the rear engine seal, the clutch, the shift linkage, and the half-shafts. Since the Triumph is running beautifully again, he'll have transportation. The weather looks good so far.