16H Norton

Thanks I got new carb as suggested. but have hit other problems, i.e hard to start when warm. Any ideas

Hi Robert, I have a 1950 Big 4, same as your 16H except more cc's and I have a WD16H. Love those sidevalvers!!!

I've bought a brand new carb from amal for the WD16H but have not fitted it yet. I've got the thing running ok at the moment and so it ain't broke so I ain't gunna fix it with the new carb, just yet. Both bikes start ok hot or cold. Do you have an air filter on your carb? Both mine don't. Cold starting sequence for both bikes is always give it a good tickle, flooding of the carb, then I cover the inlet of the carb with my fingers to act as a choke and give it a kick. Bike will pretty well always start first or second kick. I've fitted a choke , but for one reason or another I removed it and use the manual 'fingers' method. Works for me. After the bike has warmed it will nearly always start straight up, however it doesn't take much for it to cool enough that i at least have to use the fingers over the belmouth trick again in which case it will start. If you have confidence in your magneto, then most starting difficulties I experience revolve around getting fuel into the combustion chamber. It's a long way on these sidevalve engines and fuel mixture has to go up hill as well. It's easy to flood the carby, but often hard to flood the engine, so severe choking of the carb has a slightly different effect on the SV engines than doing the same on the OHV single.

Removing the timing chest cover can be a bit tricky depending on how it has been sealed in the past and with what sealant. Use a sprocket puller to remove the magneto sprockets. Don't know if you have one of these, but a simple two legged puller will do the trick and is well worthwhile having in the tool kit. Remove all the screws, remember the one or two inside the magneto chain cover.

Here's where you need to apply plenty of patience. If the cover has been glued on, then you will have a real test on your hands. Most people start by pulling on the magneto chain inner housing as that looks like a good long lever. I have a couple of timing covers with the magneto chain casting broken off the cover from various forms of impatience & gorilla handedness. Look along the joint seam on the front lower side of the cover, on some motors there was a slight gap / recess allowed in the casting, so you could get a screwdriver blade into the joint. Being careful & gentle you can prize the front apart and using a convenient spot between cylinder and the maggy chain housing extension with a piece of wood like a hammer handle you can lever the rear off. Working screw driver at the front and wooden lever at the back you can work the cover apart. You'll then be able to get a flat blade in various spots and work the cover away from the cases. being careful not to damage the sealing faces of the joint. Any bruising of these faces will need to be dressed with a file later, before you refit the cover.

Once again, BE CAREFUL because as you pull the cover off you may be bringing the camshafts with you. As you get the cover a little bit away from the cases look down the gap and see if the cams are coming with the cover. You don't want this to happen!!!! As you will then have to redo the cam timing. NOTE: Some camshafts had timing marks on them, some didn't. Pretty well all of the early cams did not have marks so cam timing had to redone from first principles. You don't want to go there!!! So, slip a thin blade inside the timing chest and push the cams back into the timing chest as you remove the cover. Be careful (again) there might be shims on the camshafts to take up end float. If there are, note which came from where and put them back as they were. Clean the whole lot up and have a good look inside. There is not much in here to go wrong. Unless you've had a disaster then all this can go back together without worry.

I have not seen a gasket for this cover. I've made a gasket and fitted it, then next time I had the cover off I discarded it, you need to take the gasket thickness into account with camshaft endfloat. The earlier WD16H timing cover is harder to seal than the later 1950 type cover. I just use a gasket sealant and thats it. I have also gone to the trouble of fitting fibre washers behind all the cover screws. I bought 1/4" fibre washers, threaded a heap of them onto a long 1/4" bolt, put a nut on the bolt to crush all the washers together, stuck it in my lathe and turned the OD of the fibre washers down so they would go neatly in the cover behind the screw heads. Either that or stick a dab of sealant behind the screw heads as you replace the screws on tightening up the cover.

What sort of sealant do you use??? Just use whats locally the flavour of the month at the time, I find all good quality sealants are about the same. You probably have your own personal favourite. Remember oil leaks today were not what they were in 1950. Oil to lubricate the magneto chain seeps down the inlet camshaft outer bush, lubricates it and then sprays around inside the maggy chaincase, lubing sprockets & chain then simply dribbles out the hole in the bottom of the cover, down the tube and onto the ground!!! or into your catch bottle if you go that far. I usually try to park my bike somewhere more politically correct so my Norton can leave it's mark without attracting the attention of the oil leak thought police.

Next job will be to re-time the magneto......

Let us all know how you get on.

Have fun.......

Bob

Thanks Bob. I use Truloc 742 gasket eliminator. it is quite expensive but worth it. It can be got online.

The restarting of my 16H, I kick and kick, I flood but no use. I have noticed that after all this the plud is as dry as snuff.

The mag I am going to see to, but it will start after 3or 4 kicks when cold.

I will try the chocking by hand and see how it goes.

I am wanting to remove the valve chest, (part C18 in spare parts list). There are 4 rubber washers two top and two bottom . There is an oil leak here. This is where you set the tappets at.

Do I still have to follow your instructions for the removal as you have stated.

I am still unsure as to the petseal problem but may chance putting the new seal on top of the old stuff.

Will keep you informed. Thanks and good luck.

Robert

Hi Robert,

The valve chest............I was totally barking up the wrong tree, so to speak. These are the 'chimneypots'. So named because thats what they look like....

My big 4 had a leak from one of the rubber rings on top of the chimney pot. I'd been running the bike for a while and it was going quite well. The head gasket on the Big 4 was quite good and sealing well and I didn't really want to disturb it and wasn't looking forward to pulling the head off to do the job, but the oil leak was a real bother. I suddenly realised I probably didn't have to remove the head from the cylinder at all!! . In the end I just undid the four cylinder base nuts and lifted the cylinder off the cases without disturbing the head. At first I thought I'd just lift the cylinder enough to replace the rubber ring, but the old rubbers broke apart and the sealing seating surfaces really needed a good cleanup. It wasn't a major job.

From memory there was a little trick to get the cylinder & head off the piston, but I'm sure you'll figure it out. Something about holding your tongue in the right position, and I think you need to keep your left foot off the ground at the same time. It's good to have an extra pair of hands to help. With the cylinder off, you can clean up the surfaces where the rubber rings go and dab a bit of that sealant around and put it all back together again no worries. No, you won't need to touch the timing chest at all, nor disturb your magneto timing. Phew,....thats a whole lot of messing about you don't have to do. I made my own base gasket. Wiped out the cylinder and put it all back together as it was. I don't think there was any real difficulty apart from the awkwardness of getting the cylinder off and back on the piston.

Look here for some pics of the Big 4 and WD16H

http://wristpin.multiply.com/

How does your 16H go, the Big 4 gets along quite well and is a bag of fun to ride.

Previously wrote:

Hi Robert,

The valve chest............I was totally barking up the wrong tree, so to speak. These are the 'chimneypots'. So named because thats what they look like....

My big 4 had a leak from one of the rubber rings on top of the chimney pot. I'd been running the bike for a while and it was going quite well. The head gasket on the Big 4 was quite good and sealing well and I didn't really want to disturb it and wasn't looking forward to pulling the head off to do the job, but the oil leak was a real bother. I suddenly realised I probably didn't have to remove the head from the cylinder at all!! . In the end I just undid the four cylinder base nuts and lifted the cylinder off the cases without disturbing the head. At first I thought I'd just lift the cylinder enough to replace the rubber ring, but the old rubbers broke apart and the sealing seating surfaces really needed a good cleanup. It wasn't a major job.

From memory there was a little trick to get the cylinder & head off the piston, but I'm sure you'll figure it out. Something about holding your tongue in the right position, and I think you need to keep your left foot off the ground at the same time. It's good to have an extra pair of hands to help. With the cylinder off, you can clean up the surfaces where the rubber rings go and dab a bit of that sealant around and put it all back together again no worries. No, you won't need to touch the timing chest at all, nor disturb your magneto timing. Phew,....thats a whole lot of messing about you don't have to do. I made my own base gasket. Wiped out the cylinder and put it all back together as it was. I don't think there was any real difficulty apart from the awkwardness of getting the cylinder off and back on the piston.

Look here for some pics of the Big 4 and WD16H

http://wristpin.multiply.com/

How does your 16H go, the Big 4 gets along quite well and is a bag of fun to ride.

Thank god I was dreading going through all that. The bike runs well, I tooter about the coast at around 40ish mph. The bike was just restored after 30 odd years off the road. I submitted a few pics ets to Roadholder and the printed a bit about its restoration It was earlier this year but not June issue. You prob have a copy. I also run a 1961 Dommi and a Pan. Would love a flat tanker. Thanks for help. Robert

Previously wrote:

Robert,

If your bike has a magneto ignition system and is hard to start when warm it is an indication of the breakdown of the "shellac" insulation on the magneto rotor windings. There is no cure other than to have the rotor rewound and insulated with a modern material. Fortunately there are a few competent specialists that can undertake this for you - it will then last another 40 years.

Regards,

Peter Bolton

just in case youhave a new plug lead , make sure it is made of copper, not a modern carbon trace tyre...... cheers