RH cylinder running cool

texasSlick said:

@Bodger reply #18

One would intuitively think an over rich condition would go away at high revs, but mine did not when my jet block gasket (call out 27, 376/074 on a monobloc parts diagram) was leaking.

Prompted by my last post, I went to the Atlas and pulled the main jet holder, then the needle jet. Lo and behold, the new [HASHTAG]#106[/HASHTAG] needle jet does NOT have the bleed holes as in my originals. John Healy states that ".... removing, or making it (the bleed hole) smaller, increases the fuel flow" Seems like that will solve my rich issue, i.e. my old needle jets go back in. The main point is .... new jets, even if the numbers are the same, may have differences that upset the original carb setup. As I stated in my post #17 above, "one more thing to keep in mind".

Agreed! We should not make too many changes at once. AgentX may have some magneto timing issues, but we need to resolve why he is "single cylindering" before addressing any timing mismatch.

Slick

Click to expand...

All the variation in Amal jets is weird. I just got a 106 needle jet from Hitchcock in the UK (they seem to be a large distributor with an extensive inventory). The jet came in a sealed plastic bag with Amal markings and it had the standard bleed holes.

Bodger said:

All the variation in Amal jets is weird. I just got a 106 needle jet from Hitchcock in the UK (they seem to be a large distributor with an extensive inventory). The jet came in a sealed plastic bag with Amal markings and it had the standard bleed holes.

Click to expand...

I got mine from Burlen. Just went to Amal site. There are two [HASHTAG]#106[/HASHTAG], one with bleed holes, one without. My bad, I did not pick up on that.

Learn sumptin new every day.

Slick

@AgentX

Your carbs should have a model/suffix number on the mounting flanges (The thin edge).

If you take those numbers (R and L carbs are different) and go to the site below, you will find a table of Amal model/suffix numbers. The table will give you the factory configuration. Then check against what you have.

I am a strong believer in returning to original config. when struggling with a problem such as yours.

http://porklips.org/~mason/moto/amal_specs.html

Slick

Ok--checked my Haynes and my Norton manual and it was me misreading on the exhaust valve clearance... .008 it is.

No change with leaning the air screw on RH carb.

Swapped LH carb to the RH side, leaving the carb off and plug out on the LH cyl. Got an occasional pop but it never caught. I think the pop was the sporadic sound I heard when the bike was running.

Swapped plugs and leads, confirmed spark all ways.

Also re checked the pilot circuit and jet on the RH carb; seemed fine.

Confirmed the carbs are the correct stock models (and originals...now resleeved...)

Guessing re-timing is my best option now, just to be sure.

AgentX said:

Ok--checked my Haynes and my Norton manual and it was me misreading on the exhaust valve clearance... .008 it is.

No change with leaning the air screw on RH carb.

Swapped LH carb to the RH side, leaving the carb off and plug out on the LH cyl. Got an occasional pop but it never caught. I think the pop was the sporadic sound I heard when the bike was running.

Swapped plugs and leads, confirmed spark all ways.

Also re checked the pilot circuit and jet on the RH carb; seemed fine.

Confirmed the carbs are the correct stock models (and originals...now resleeved...)


Guessing re-timing is my best option now, just to be sure.

Click to expand...

It would seem that you have ruled out the carbs!!

O.K., let's go from here.

What is the point gap on each ramp of the magneto cam ring? For your engine to run on the left cylinder, and not on the right, and if carbs are not the cause, then there must be a severe timing mismatch. I am ruling out magneto slip ring or high tension pickup, because you state "confirmed spark all ways".

Checking the point gap is a easy way to get an estimate of timing mismatch, without going to the trouble of a degree wheel.

Report back with gap on lower ramp (left cyl), and upper ramp (right cyl). I am assuming the lower high tension lead is going to the left cylinder .... verify that.

Slick

I think I have deduced the probable issue. Valve timing. I will pull the timing cover, check, and re-phase as required.

I think it could explain symptoms, yeah?

If not I still need to look at the ignition timing, so opening up the side cover is going to happen one way or another.

Valve timing would affect both cylinders equally.

However, some condition, for example, that was preventing a valve from opening would explain your symptoms. Such a condition might be a broken rocker arm or spindle, or worn lobe on the cam. Such a condition would be easily verified by looking in the rocker box.

Slick

AgentX said:

I think I have deduced the probable issue. Valve timing. I will pull the timing cover, check, and re-phase as required.

I think it explains symptoms, yeah?

Click to expand...

texasSlick said:

Valve timing would affect both cylinders equally.

However, some condition, for example, that was preventing a valve from opening would explain your symptoms. Such a condition might be a broken rocker arm or spindle, or worn lobe on the cam. Such a condition would be easily verified by looking in the rocker box.

Slick

Click to expand...

Yeah, I was initially looking for a condition like that but did not see anything. Then it occurred to me maybe I had the timing marks wrong.

I am used to my Enfield which has independent cam wheels for exhaust and intake and can be phased individually. I realized the single camshaft doesn't offer that point of failure, but it still seemed likely to me that this could be a cause, since everything else is coming up negative.

Regardless, timing cover is coming off and I will check both valves and ignition.

Oh, and I checked the points gaps; forgot to report back. .011 and a hard-fit .012.

Didn't work to even that out anymore at this point.

AgentX said:

Oh, and I checked the points gaps; forgot to report back. .011 and a hard-fit .012.

Didn't work to even that out anymore at this point.

Click to expand...

At most, I would open up the gap to 0.012 - 0.013 with the adjusting screw. A 0.001 difference in gap will amount to 2 degrees difference in timing at the crank. If your cam ring is spot on, this slight difference is not preventing the right cylinder from firing. If you are a perfectionist, you can work to reduce the gap difference to zero.

You should put a degree wheel on the engine and check timing on each cylinder to determine if the cam ring is good (2 degrees max. timing difference) and also to see what the timing set point is.

Slick

Had been hoping to get to that today, but family plans took over...next weekend at earliest.

And my Enfield has a loose valve guide, after I finally found and fixed the charging issue it was having. Repairs on that now delayed, too. No riding for me nearly at all this summer. Ugh.

texasSlick said:

At most, I would open up the gap to 0.012 - 0.013 with the adjusting screw. A 0.001 difference in gap will amount to 2 degrees difference in timing at the crank. If your cam ring is spot on, this slight difference is not preventing the right cylinder from firing. If you are a perfectionist, you can work to reduce the gap difference to zero.

You should put a degree wheel on the engine and check timing on each cylinder to determine if the cam ring is good (2 degrees max. timing difference) and also to see what the timing set point is.

Slick

Click to expand...

Had a cam ring out lately. I found that a paint can lid removal tool makes a very useful lever for removing the ring. You can fit titthe bent edge that is supposed to go under the paint can lid behind the ring and rock it sideways to put some pressure on the bottom of the ring. To keep the ring from jamming you have to work around the ring evenly. I've got to say that "adjusting" the ring to lift the points evenly has got to be a bear of a job if done with the magneto on the bike.

Ok, this is tremendously embarrassing now.

Got some time today. Pulled timing cover and primary cover. Checked valve timing, it was fine. Had degree wheel and cutaway timing cover installed when I realized I hadn't checked the points gap immediately prior to starting, per TexasSlick's instructions and general good practice.

Now, realize this bike is pretty new to me, but my Enfield ran on points and coil before I put the EI in. And I *have* adjusted the points on the Matchless, at least once prior to pulling the mag off for service, which included installation of the Brightspark EasyCap since it came recommended, and I didn't want to have to dig into the mag again if the cap ever went bad.

But try as I did today, I literally could not figure out how to adjust the points gap. Neither the seemingly-obvious fixing screw (now holding the easycap in place) nor the hex in the center let me move the stationary points arm to set the gap, no matter how loose it was or how I pushed on anything that seemed like it might move the points.

Instructions I could find all just said to adjust the gap without detailing how, which seems like it should be glaringly obvious, but I'm at a loss now.

Points look like this set now:



What the hell am I doing wrong??

And what size is that hex in the middle, anyhow? Smallest Brit sized wrench I have is 1/8W, and a 7mm was not an exact fit.

-Mike

AgentX said:

Ok, this is tremendously embarrassing now.

Got some time today. Pulled timing cover and primary cover. Checked valve timing, it was fine. Had degree wheel and cutaway timing cover installed when I realized I hadn't checked the points gap immediately prior to starting, per TexasSlick's instructions and general good practice.

Now, realize this bike is pretty new to me, but my Enfield ran on points and coil before I put the EI in. And I *have* adjusted the points on the Matchless, at least once prior to pulling the mag off for service, which included installation of the Brightspark EasyCap since it came recommended, and I didn't want to have to dig into the mag again if the cap ever went bad.

But try as I did today, I literally could not figure out how to adjust the points gap. Neither the seemingly-obvious fixing screw (now holding the easycap in place) nor the hex in the center let me move the stationary points arm to set the gap, no matter how loose it was or how I pushed on anything that seemed like it might move the points.

Instructions I could find all just said to adjust the gap without detailing how, which seems like it should be glaringly obvious, but I'm at a loss now.

Points look like this set now:

What the hell am I doing wrong??

And what size is that hex in the middle, anyhow? Smallest Brit sized wrench I have is 1/8W, and a 7mm was not an exact fit.

-Mike

Click to expand...

By memory you adjust the gap by moving the fixed side of the points set. If I remember correctly you just loosen the slotted screw, which in your picture is located above the green Brightspark "piggyback" condenser, and perhaps also loosen the pillar bolt. The pillar bolt is BA which is a UK metric standard used often on electrical components. A small metric should fit it, particularly since it should have very little torque. The bolt holds the point plate against a slot on the magneto armature axle and does not need to be very tight - don't strip it. I would put a clean rag under the points plate end of the magneto because there are a number of small plastic and fiber insulators that are programmed to get lost whenever you do anything to the points.

Well I reckon you got a duff coil!

Bodger, thanks--will try when I'm back home in a few weeks.

Steves--What am I missing? Is there a "coil" inside the magneto? Both leads give a fat spark.

AgentX said:

Bodger, thanks--will try when I'm back home in a few weeks.

Steves--What am I missing? Is there a "coil" inside the magneto? Both leads give a fat spark.

Click to expand...

I think Steve assumes you are running a points/coil ignition. As I stated in a reply above, if a K2F sparks on one cylinder, it will spark on both, barring a very unlikely fault in the slip ring, high tension pick ups, or the plug itself.

I am awaiting the result of your timing check, BOTH CYLINDERS!. Since your point gaps were, for practical purposes, equal, the only way timing is the cause of your problem, is there is a severe fault in your cam ring. The two cyl. timing check should verify or rule out that possibility.

Keep us posted.

Slick

I bought a dear friend's 74 mk2 after he lost his battle with cancer last year. It had not been touched since 1983. It was in rough shape but i figured it would be a nice project for my 18 year old son and i over the winter. We did not take the engine apart but we did disassemble and clean the carbs (along with many other fixes etc to the bike). To our great joy it fired up and we put it on the road in late april. We put approx 300 miles on it staying close to home and it ran fine until i went for a ride last night. Rough running and low power. RH muffler was cooler than LH. RH spark plug was black, LH was tan. I cleaned the RH plug but no improvement. I ran it up to 3000+ rpm while riding in 1st and no improvement. I parked it and started surfing here for info. I found this thread with the same problem but it ends without a result. We'll start checking into it but if anyone has found a solution please pass it on.

I replaced the spark plug - all ok now. The previous plug only had 300 miles on it.

Posted this earlier for the young chap who inherited a 650ss. Had mine for over 40 years and was a pig to get tick over for 20. Had a lucas refurb on the mag, no change. Eventually by luck more than knowledge I fitted copper leads and unsuppressed caps. A completely different bike for the better, then she blew the head gasket. Not used to running properly i reckon. No issues since then, my right monoblock always ran a bit lean but I fitted concentrics over 30 years ago.