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I'm at my wits end with my Captain that I've been working on and off for some time now. It is incredibly difficult to start. I have good spark, fuel is definitely being supplied (villiers 4/5 carb), compression is good, not great. The only thing I'm not sure about is the timing. I've done my best to measure the appropriate distance before TDC using a dial indicator, however due to the angle of the spark plug hole it is difficult to get the indicator square on the piston head.

Maybe someone out there with a 6E could measure the CCW circumferential distance from the TDC notch on the case to the point where the points open, that would be a great point of reference for me to work from.

Any advice on mixture lever position and throttle opening for starting would be great. I've tried most combinations to no avail.

Also, what ratio are people running? I’ve seen anything from 20:1 to 35:1 being recommended. I’m using modern 2 stroke oil with 87-91 octane gasoline.


Timing doesn't usually have to be exact, and it rarely is.

I'll take a stab at the problem being the crankcase seals.
That’s a possibility.

Villiers part numbers are E9718 and E9720. Anyone know the dimensions of these seals?


James, Is this it's first start for a long time? Have you had it running for long periods previously or is this you trying to bring it back to life after a long hibernation? If so you will find that firstly most Villiers are an exceedingly grumpy starter for the first time after a long lay off and secondly, if it's been a long time since it ran properly you need to replace the crankcase seals. If the engine hasn't been mauled about it's more than possible it is still fitted with the original factory seals which will have long gone to God.
Personally, after a full engine overhaul on a Villiers I find for first start I can rarely do it on the kickstart. I have a socket arrangement that fits the crankshaft nut on the flywheel magneto so I can spin the engine over with a large electric drill. That does me. I'd like starter rollers but haven't managed that yet.
You're overthinking the timing thing. Getting it minutely right doesn't help unless you have already got everything else minutely right. Accurate timing depends on good main bearings and a good points box, particularly the hole the rocking point lever sits in. If this is excessively worn the timing can be quite sloppy. I have set up a timing strobe light on a Villiers engine with a worn points box and it's surprising how much the timing wanders around. It was still an easy starter and ran well low down but had no guts.
Perol/oil mix. For the 6E the factory recommended 18:1 for running in reducing to 20:1 thereafter. Why would you use less oil? Oil is the engines life blood and much cheaper than a new engine.

What is the story?

Further to the above James, I dragged out my 6E notes. When I replaced the seals in the 6E of my own 1951 James Captain de luxe I recorded the seal details.

They are as follows;
Oil seal, crankshaft drive end; Dimensions 1&1/4" OD, 3/4" ID and 1/4" wide. This seal was marked MI. 1000162.
Oil seal Magneto end; Dimensions as oil seal above. This seal was marked MIS. 012.

I could see no difference between the two. No makers name on either seal.
Looking forward to the ongoing story.
On the oil situation, use the factory recommended as mentioned. It’s a petroil mix and using less oil will be less oil to the bearings. Might be a different story with systems which feed the main bearings directly.
Thanks all for the responses. I am in the process of replacing the crank seals as suggested. It looks like they have been replaced a some point relatively recently, and to be honest they appeared to be in good condition. The old seals are National 470954 and that is the same as I am using as a replacement.

I have had the bike for a couple of years and worked on it sporadically. I have never been able to start it reliably. From what I know the previous owner had not had it running for some time either. He was well on his way to restoring it and and done most of the cosmetic work but lost interest in the project when it came to resurrecting the electrical. I have completed the rewire and fixed some other electrical issues, also done some minor work on the gearbox and kick-start mechanism, and rebuilt the carb (still using the Villiers 4/5. Side note: are there other carb options that have an idle circuit?). So, to answer the question, I have not had it running for long periods and I am bringing it out of hibernation.

Regarding the ratio, my intention was to stick with 20:1. I was surprised to see such a wide range of ratios being used and how oil-lean some people run.

What cylinder compression do you have on your 6E? I think it is specified at 8:1? I will recheck this today. I am considering pulling the head anyway to check the condition of the bore and check the clearance.

Thanks again.
I don’t have a James myself although my first bike was very nearly the same as what you have, but I cut my teeth on Bantam’s, there’s a lot of similarities even though the engines are different. Cylinder head compression is everything, if you start lowering it then you loose the torque when in higher gears.

Other thing is in case your not versed is fit the crank seals so that the side showing the spring is facing inside the engine, they often get fitted the wrong way around causing good seals to blow past on crank case compression.
Hi James,
I haven't any idea of the 6E compression ratio. Villiers just don't mention it in any of their handbooks and manuals. As the cylinder head on the 6E was ground in to seal it with no head gasket fitted mine tend to have a slightly higher compression ratio from standard. This arises purely from me lightly skimming the head in my lathe to clean up all the years of previous owners grinding the head in to fit but never effectively cleaning up after themselves. I like to start with a nice new flat surface so I skim it just enough to clean up the bearing surface. I believe head gaskets are now available for those who can't get an effective seal. To be honest I've never found it to be that much an issue.

I find the 4/5 carb works well. However it gets very grumpy if you try to run it with the twist grip set to automatically shut off when you take your hand away. If you look at the spare parts book you will see the 4/5 was designed for a lever throttle which is not self closing but stays where it is set. It doesn't shut itself off. The original Amal twistgrip fitted by James to replace the outdated throttle lever had a friction adjuster underneath which you tightened up so neither did it shut down of it's own accord. Set like this it replicated the Villiers factory lever action .You have to close it yourself. Back in it's day there were good reasons for this style of throttle set up. The bike has neither turn signals nor an ignition key. Also it was built for a country where they drive on the left hand side of the road and most hand signals are given with the right hand, the throttle hand. A bike that lost all power immediately you tried to give a hand signal obviously has a bit of a problem. You stood a good chance of being hit hit up the proverbial every time you signalled..

It was also expected that the engine would stop when you completely closed the throttle. This got around the lack of an ignition key. End of journey? You want to stop the engine? Simple, just close the throttle. Some two strokes of the day were also subject to spluttering, banging and four-stroking on the over run or down long hills. Some did it, some didn't. Some did it sometimes. A throttle set up to completely shut the engine down at those times cured all that.

So, the 4/5 carb works well but needs to be set up 1951 style not 2019. That will nicely solve your idling issue.

It's all great fun isn't it. Who knew that riding a 1951 bike would be so different from riding a current one.

Well, I took the cylinder head off to measure the piston/bore gap. With the piston in the cylinder I was able to fit a 0.010" feeler gauge between the piston and the wall which to me is too much clearance. Continuing on, I pulled the cylinder. The bore looks to be in good condition, but the piston has certainly seen better days, has some scoring on the walls. I'll get some measurements tonight of the cylinder and piston at different locations, but I think it will need boring. I removed the piston from the con rod and discovered that the small end bushing has worn as the gudgeon pin can 'rock' in the bushing. At the big end, there is a small amount of side-to-side play (axial) between the con-rod and crank; how much is deemed acceptable? That may be a moot point however because I was also able to detect a very small amount of up-and-down (radial) play, which I assume should be non-existent.

So, it seems like a full rebuild is in order. Wondering how difficult it is to rebuild the crank and con-rod for one of these engine? I know Villiers Service in England offer a full rebuild service, including engine, primary and clutch, and gearbox. Thinking this might be the way to go at this point.

Hi James,
Essentially you describe a pretty normal wear pattern. Nothing obvious stands out that would cause hard starting. You do not mention anything like stuck or broken rings or any major issue, only a degree of every day service wear found in any used engine. There has to be clearance between the small end and gudgeon pin so of course there will be a small amount of rock. The same applies to side to side play between con rod and crank. There will always be at least a minute amount of up and down play as well even on a new big end. All bearing surfaces require a clearance between them for normal operation. It all sounds as one would expect of an engine with a few years of normal use.
Nevertheless you are seeking peace of mind and I agree with you that a full rebuild by Villiers Services will give you that. If you send them the complete power unit including carb and magneto they will send you back a unit with your every concern dealt with. I think it a good idea.
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