Stripping a Dominator

Previously paul_standeven wrote:

What tool to use to remove wire type circlips on pistons?

Paul

I rotate them til the end is in the milled gap then I use a watchmaker's screwdriver to pry it up and I can grab it with needlenose. Alternatively, pry it up then keep rotating it over the screwdriver tip (by pushing on the other end of the clip) til it is all the way out. You are going to throw them away anyway.

Your pinion extractor is essential. I know no substitute for that.

I am probably telling your granny how to suck eggs, but I cannot stress wearing safety glasses when removing the wire clip or any circlip come to that as the consequences of them flying off does not bear thinking about! Safety First.

Previously paul_standeven wrote:

What's the best way of separating the crank cases?

You must make sure ALL the screws are out.

If you don't have a helper you can support the cases as in photo (pretend there is a crankshaft in there). and rap the corner of the case on the wood block to make full use of gravity. Also you can hit the cases with a wood block at the drain plug boss and the big opening at the top.If you have a roller bearing timing side (like all my motors) this won't work and my next post tells you what to do.

Previously paul_standeven wrote:

What's the best way of separating the crank cases?

Paul

Ball bearing timimg side will be tight and requires the tool in photo. Details of how to make it are in the manual. Support the cases as above and put the tool over the crankshaft end then hammer with a heavy hammer. It is probably better to try and get the drive side off first (by wood block hammering in the big opening and the drain plug boss) since there is no resistance from the bearing. Keep things vertical so there is no jamming. In the manual the cases are already apart when using this tool.

Previously paul_webb wrote:

I am probably telling your granny how to suck eggs, but I cannot stress wearing safety glasses when removing the wire clip or any circlip come to that as the consequences of them flying off does not bear thinking about! Safety First.

Absolutely right! A trip to the emergency room will ruin your day. Also you won't want to do engine work when you have an eye-patch or stitches and bandages.

Today I offered up the half-time pinion extrator, and pulled the pinion out without using the centre bolt, just pulled it out easily by hand. I hope that doesn't mean it's too loose....

To me, too loose means slopping back and forth on the shaft. If the Woodruff key and the keyways look like they are not wearing at all and they are tight then I would just reuse the pinion and key. You can try different pinions and a new key and see if they feel tighter. I have heard of plating the inside of the pinion to take up slack (also Locktite, of course). If it is not moving in service (there would be evidence of that) then I think it is safe. I seem to recall that in the Mick Hemmings video he rebuilds a motor that has that same problem but he does not say it is serious. Let's see what the experts say.

Previously paul_standeven wrote:

How do I tell which way up to fit piston rings?

Paul

Install top ring last. If there is a dot on the top ring, install with the dot to the top of the piston. If there is no dot, but there is a chamfer on the inside diameter, install the chamfer to the top of the piston. If there is no dot or chamfer on the ring, it is symmetrical and can be installed in the groove either way.

Of course, if you see the word "TOP" you know what to do.

Who made the CNC rods? Can we see a photo?

You will need to weigh your new conrods and the old ones. If the weight is different, which it probably will be, you will need to get the crank/rod/piston assembly re-balanced. Ignore this step at your peril; you could end up with a very unpleasant, vibey motor.

'How to seal the primary chaincase?'

You need to make sure that inner and outer are straight and true. Clean and degrease the mating surfaces thoroughly, and fit the rubber band as per the manual. Apply an even bead of good quality silicone gasket all around, inside the outer case, where it steps at the point where the rubber band will meet the outer case. Assemble the outer to the inner, tighten up, but not fully. (thanks to Phil Hannam for this!) Leave overnight, for the silicone to cure, then give it a final tighten, before assembling footrest etc.

A search on this site will reveal past threads on this subject.

Previously paul_standeven wrote:

Must borrow the pick to remove the other so I can get the crank out of the left case, and remove the rod.

The left case should just fall off. Do you have a ball bearing there or roller?

How long is it since we were able to buy new std rods for an 88/99 ? . Must be at least 40 years. Surely the club should have done something about this. Another option which I am exploring is the manufacture of a 650 crank which will fit into std 99 /88 cases which will allow the use of modified availiable rods ,99 barrels (slotted!) etc.

The 650 crankshaft will fit straight into 500 cases. The problem is the 650 rods which have high and wide shoulders. It is this that causes them to foul the cases. You can get round this issue by using Carillo rods. You could try making a 650 crankshaft with 1.50" journals but would it hold together?

The Norton factory experimented with 1.60" journals in an attempt to improve the reliability of their tuned 88 & 99 motors. Eventually they chose 1.75" for the Domiracer.

Model 7 conrods were a little weak but I have not ever had any 88 rods die in my 500 engines. It is usually the failure of the rod bolts or lack of sufficient oil presure that causes problems in this area on the 500cc engines.

Rods do not seem to be a problem in 88s, it's 99s which seem prone to breaking them. Certainly the case in my experience. Late 99 crankcases are bulged and will take a 650 bottom end. I have a set under the bench. If you are contemplating a 650 bottom end, you would be better going the whole hog and having a 650 engine. The 88 barrel is too short for the 89mm crank throw - a visual clue is 88 barrels 8 fins, 99/650 barrels 9 fins.

I would suggest just sticking to your 88 motor without going wild with modifications- they arepretty good as standard.

I am not looking to " hop up" old motors , my interest is to extend the life (and use) of the 88/99 motors.I have a perfectly usable 99 which gets lots of use. However many are languishing possibly because their owners are concerned about the loss of rare parts if a rod goes.I would much rather just fit a set of new rods but it appears that only expensive and overweight aftermarket rods are out there,so looking at other possibilties as I have a friend in crankshaft manufacturing.

Hi Paul, The crank will need to be re-balanced and if it were mine I would pay to have heavy metal added to the crank if necessary. I would not be Interested in lightening the crank, Before going further check the fit of the piston pins in the small ends. Seems to be some issue with sizing on some new components.Are the rods drilled for cylinder lubrication?.Not sure its a good thing but if not drilled it may mean a change in pump capacity depending on your set up.

Hello Crankcase after March 1961 from number 96496 on , where in fact Norton Manxman 650 cases but stamped up has ether 88SS or (99SS) models yours anna J

If you have drilled rods you need an uprated oil supply,equally if you have undrilled rods then an excess of oil supply brings other problems.I don't think you have any thing to worry about re the small ends.

Con rods were never (to the best of my knowledge) drilled on 88 and 99 engines. Others will no doubt say precisely when it was first introduced on the 650/750engines which have the larger 1 3/4"approx big-ends

Hi Gordon, we are talking about thunder rods. After siezing the drive side piston at 90 + and finding several Motors with partialy siezed D/S pistons I certainly would consider drilling the rod on a Dommy and would not be surprised to find that others had done so.At one time I thought that the drive side siezure (fairly common I hear) was due to timing irregularities ,but as i always time the DS any difference would affect the TS. I now think the siezures are down to poor oil supply to the DS .I also note that the DS big end has the most wear.

Pardon me for poking my nose into Dominator territory but on a Commando there is a good chance that Thunder rods foul the crankcases. When I spoke to Thunder engineering the guy said "yes sometimes they do somtimes they don't" I'm not sure if it's an issue with Dommies but might be worth a practice fit/rotate before you get all the glue in place for assembly.

When i get my crank ground I expect to find that my rods are oval after 55 years of use. Has anyone any experience of getting them re-sized?.

To fit some new CNC milled con-rods, I am pulling down my 1955 Model 88 Dominator, and want a few tips:

What's the best way of separating the crank cases?

What tool to use to remove wire type circlips on pistons?

How do I tell which way up to fit piston rings?

How to seal the primary chaincase?

Carburetor settings and Ignition timing to suit modern ethanol mixed petrol?

I bought an expensive half-time pinion extractor, and it pulled off easily by hand.... My crank sprocket and cam sprocket extractors I made myself.

Paul

I'm with Anna on this. I can't see that milled/machined billet rods are going to be as good as the originals, unless those are broken or damaged and you don't have a choice. I would recommend putting the old ones on your buffing wheels and polishing them until they look like chrome - then check with your jeweller's loups (I have magnifications up to 10x which only cost a few quid from China!) to look for any sign of cracking. I can't remember what the "stain" is that you can use to trace cracks - Anna will know though! Anything dark and water-based would probably do so that you can wipe it off to leave residue in any cracks. This is why you need to polish them well to start with - or get them X-rayed at quite a cost.

Previously anna jeannette Dixon wrote:

Previously paul_standeven wrote:

To fit some new CNC milled con-rods, I am pulling down my 1955 Model 88 Dominator, and want a few tips:

What's the best way of separating the crank cases?

What tool to use to remove wire type circlips on pistons?

How do I tell which way up to fit piston rings?

How to seal the primary chaincase?

Carburetor settings and Ignition timing to suit modern ethanol mixed petrol?

I bought an expensive half-time pinion extractor, and it pulled off easily by hand.... My crank sprocket and cam sprocket extractors I made myself.

Paul

Well I would not even think of using Billet milled Con rods Has they will not be very strong Like forged con rods with forging your squeezing the metal so its hard like in the rolling process of steel to get it hard , then they mix other metals with it to get the strength into the alloy . with billet they don't do this, if you need some racing con-rods you need Carrillo Rods and pistons too match them , or if its a road bike a good set of original will be far better the any thing else , We do have a lot of experience in this I have been Motorcycle engineering for well over 40 years and raced solo and sidecar and built my own bikes from scratch and made my own frames too and parts too go with the bikes yours anna j ,

Previously Jonathan Soons wrote:

Previously paul_standeven wrote:

What's the best way of separating the crank cases?

Paul

Ball bearing timimg side will be tight and requires the tool in photo. Details of how to make it are in the manual. Support the cases as above and put the tool over the crankshaft end then hammer with a heavy hammer. It is probably better to try and get the drive side off first (by wood block hammering in the big opening and the drain plug boss) since there is no resistance from the bearing. Keep things vertical so there is no jamming. In the manual the cases are already apart when using this tool.

Jonathon,

This is an ideal way to turn your crankshaft into a door stop, far better to use a sensible ammount of heat on the crankcase. Large hammers and crankshafts just don't go well together.

If you intend to use a later pump or 6 start pump gears then you should consider drilling the rods ,together with decent oil rings,pressure fed rockers ,non scrolled rocker spindles enlarged oilways etc. I don't think its all worthwhile though. The standard system works ok with perhaps a little tweaking of the oil banjo's to send a bit more oil to the head if it looks dry (like mine). I don't suppose anyone is listening but its been 50+ years since anyone made 88/99 rods,surely all that spare cash swilling around in the club funds could be put to use!!.