Timing Gear

[redbloke1956]

Hi to all,
I have now arrived at the timing chest of my '51 Comet, I have found some small damage/wear to the large alloy idler and will be replacing it with a steel one.
You can see from the attached photo that the steady plate is quite distorted, it seems as though the Breather Valve Spindle has not been inserted far enough (the steady plate returns to pretty close to flat when removed)
I am wondering wether I should strip the timing gear and try to insert the Breather Spindle further or simply shim the other spindles to match its height, having never removed and retimed/replaced timing gear before?
Any and all suggestions appreciated.
Thanks
kevin

 

[bmetcalf]

If the cam and follower spindle nuts are farther out because of the extra shims, they will press harder into the recesses in the timing cover and maybe keep the cover from sealing without distortion of the cover. This might also affect the big end quill oiling. Better to nsert the Breather Spindle further. That will take some care, even with the engine dismantled.

 

[nkt267]

Is there a thick washer between the breather pinion and the steady plate, or is it an optical illusion?.There should be a 1/2 inch thrust washer on the inside and a 5/16" one on the outside..John

 

[davidd]

Kevin,

It is a fairly complicated exercise to to set up a timing chest so that it runs correctly because if you want the steady plate to be flat you really cannot follow the instructions in the literature, you have to start setting the chest up and then set all the spindles to the same height of the only spindle that does not move, which is the big idler spindle. Additionally, if you have to line up the cams and followers to run properly, you will need lots of shims that are not called for in the literature and you may then find that you need to shim the big idler to mesh properly with the cam wheel after you have shimmed the cam.

My understanding of the literature is that you set the spindles to the height of the ET162, which is the spacer for the steady plate. The spindle shoulders shoud be 0.025" below the height of ET162 when it is in place as most of the spindles have an ET98/1 sitting on the shoulder of the spindle and the thickness of this is 0.025". Theoretically, this means that the shoulder height of the spindles is 0.42" above the joint face.

Having said all that, it seems to me you should pull of the steady plate and set everything down on a piece of cardboard where everthing is marked for its position. I would be curious about the thickness of the two ET173's, one on the big idler and one on the small idler. These are rather thick and measure 0.070" as I remember. Check all the shim and washer thicknesses and make certain that they make sense to you (run a straight edge to various spindles and measure to the joint face). If what you see looks good except for the breather spindle (you should wiggle the spindles to check for looseness) then I would consider moving in the breather spindle to the correct height.

I think most of us have changed spindles in running bikes before, but I am hoping someone else chimes in before I explain the procedure. It involves several evacuation drills for the family, an increase in your insurance coverage and you must sign a waiver! Please also chime in if you see errors in my logic or numbers as I am doing it from memory.

David

 

[bmetcalf]

I think most of us have changed spindles in running bikes before,

When you do that with a Twin, you really learn what a big heat sink those crankcases are! But, my oversize cam spindles are still in after 25+ years.

 

[redbloke1956]

Is there a thick washer between the breather pinion and the steady plate, or is it an optical illusion?.There should be a 1/2 inch thrust washer on the inside and a 5/16" one on the outside..John

Hi John,There is a small washer inside the steady plate and the rest you can see is spindle, when you say "inside" are you talking about inside the steady plate? and do you know what thickness the thrust washer should be?
Thanks John
Kevin

 

[redbloke1956]

When you do that with a Twin, you really learn what a big heat sink those crankcases are! But, my oversize cam spindles are still in after 25+ years.

Hi Bruce, in "know thy beast it says that the spindle can be replaced with localised heat with a butane torch after preheating cases with a fan heater? does this sound feasible to you? Is that how you changed yours?
Thanks in advance
Kevin

 

[redbloke1956]

Kevin,

It is a fairly complicated exercise to to set up a timing chest so that it runs correctly because if you want the steady plate to be flat you really cannot follow the instructions in the literature, you have to start setting the chest up and then set all the spindles to the same height of the only spindle that does not move, which is the big idler spindle. Additionally, if you have to line up the cams and followers to run properly, you will need lots of shims that are not called for in the literature and you may then find that you need to shim the big idler to mesh properly with the cam wheel after you have shimmed the cam.

My understanding of the literature is that you set the spindles to the height of the ET162, which is the spacer for the steady plate. The spindle shoulders shoud be 0.025" below the height of ET162 when it is in place as most of the spindles have an ET98/1 sitting on the shoulder of the spindle and the thickness of this is 0.025". Theoretically, this means that the shoulder height of the spindles is 0.42" above the joint face.

Having said all that, it seems to me you should pull of the steady plate and set everything down on a piece of cardboard where everthing is marked for its position. I would be curious about the thickness of the two ET173's, one on the big idler and one on the small idler. These are rather thick and measure 0.070" as I remember. Check all the shim and washer thicknesses and make certain that they make sense to you (run a straight edge to various spindles and measure to the joint face). If what you see looks good except for the breather spindle (you should wiggle the spindles to check for looseness) then I would consider moving in the breather spindle to the correct height.

I think most of us have changed spindles in running bikes before, but I am hoping someone else chimes in before I explain the procedure. It involves several evacuation drills for the family, an increase in your insurance coverage and you must sign a waiver! Please also chime in if you see errors in my logic or numbers as I am doing it from memory.

David

Thanks David for taking the time and effort to explain that,
I have contacted my insurance broker, signed a waiver, read several copies of Zen and the art of motorcycle maintenance, given up my first born child, sacrificed a goat and kicked the neighbours dog....all I need to do now is climb the highest mountain (in my underpants), clean the toilets for a week, mow the lawns and hope the domestic Goddess grants me the boon of use of her hairdryer to preheat the cases before using a gas torch to localise heat and reseat spindle....am I getting close or am I missing something....I mentioned the goat didn't I ?

Kevin

 

[bmetcalf]

Yes, but we used an acetylene torch. Use this http://www.tempil.com/closeup.asp?cid=39&pid=173&theme=2 would help keep you from overheating. See what others have to say, though, before you go ahead with this.

 

[davidd]

Yes, a goat...you are on your way. For a twin we removed all fuel from the carbs and removed the gas tank. A kerosene construction heater was used to get the engine warm, which is about operating temperature then used a torch to do the local heat. On a Comet you have a lot less mass so you can adjust accordingly. I think having a hot torch is ideal because you may need the heat, but I have done this with a propane torch on the racer. The cases were about 200 F. The spindle was in the freezer so it went right in. To move in a spindle I make a sleeve using a piece of scrap tubing with a length of exactly what I am looking for. I use a slide puller with an end I made to screw one end on to the spindle and the other end on the end of the slide hammer. I slip the sleeve on and screw the slide hammer on the spindle and give it a wack and its home. I can supply photos of the tool I use if it is not familiar to you, but except for the adaptor it should be easily available. The quick and dirty way is to put the sleeve on, a washer and nut an wack it with an alloy hammer. The slide hammer is nice if you have to pull a spindle out a little or remove spindles.

David