SQ4 mainshaft issues

[Akumar]

Dear fellow Ariel owners,

This is my first post on the board and in fact it is regarding my first Ariel purchase. I will appreciate any help you can provide. I recently bought an Ariel square four. After buying it I found that it is a non-matching number bike. Here is a picture:



Bike origin: The Classic Motorcycle Warehouse (also called Classic Style) in Seaford, Victoria, Australia. Sold by them to a buyer in Hawaii. Then bought by me.

Frame: is 1948 (XP series)
Engine: is 1937 (DC series)
Gearbox: has a stamp: XLBAPDH 62179

Current condition: not in running condition

First obvious problem faced by us: the kick starter was not able to turn the engine over

My first question was that is this the correct gearbox?

Paul Jameson commented: “I suspect that the gearbox fitted is from an Ariel single. It is certainly pre war from the number you give. The Square four gearboxes have a mainshaft which is longer than the singles one. The gearbox casing is also different as the mounting lugs are offset to line up the chains”. Paul sent us a diagram showing how the mounting lugs are different between singles and SQ gearbox. It appears that we indeed have a singles gearbox fitted to our SQ4.

Then our team went ahead and took the gearbox, clutch, and primary drive apart. We found out that the mainshaft in this bike was built of two pieces (the long rod and a sleeve like ending). Please check the pictures below. The first picture shows the mainshaft with the sleeve fitted to it. The second picture shows the sleeve removed. The mainshaft rod was freely rotating inside the sleeve. That is the reason the kick was not engaging the engine.



Our second question was: is the SQ4 mainshfat built of two pieces?

Paul Jameson answered that question: “Somebody has modified the singles mainshaft for use in the Square Four. The mainshaft should be one piece, without the larger diameter section that the "sleeve" fits over. You need a replacement Square four mainshaft but you can modify the mountings of the gearbox case rather than getting a Square Four case if you want to”.

We then sourced a correct SQ4 mainshaft. Please check the picture below. This mainshaft is exactly 12 inches long.



We put the mainshaft in position. Check the picture below. Now we are facing the problem that the new mainshaft is not long enough on the clutch side for the cluth assembly to fit over it. Interestingly the mainshaft which was origanlly fitted in this bike fits beautifully but then it has the aforementioned problem of being split in two pieces.



Here are our questions:

1) What is the correct length of a mainshaft for this model of SQ4? Is our new mainshaft (12 inches) correct?

2) Picture above has the new correct mainshaft in place. But it is not projecting far enough to fit the clutch assembly over it. How far the mainshaft is supposed to project into the primary side?

3) The old mainshaft with its sleeve fitted is about half inch longer than the new mainshaft. As I mentioned, it fits beautifully in terms of length. Our team is thinking if we can just weld or pin that shaft and sleeve together and reuse it. Any thoughts here?

4) Paul commented that “you can modify the mountings of the gearbox case”. Please see picture below. I am guessing we can shave off the part of the mounting lug which stick out. But I see two problems. First, we will gain only half centimeter maximum which is probably less than the gain we are looking for. And secondly, it will throw the secondary chain out of alignment. Right now the secondary chain is perfectly aligned.



Any thoughts and comments are appreciated.

Many thanks,

Kumar

PS: does anyone have any idea of bike's history? How is ended up in Australia? I emailed classic style and they never cared to reply back.

[john.whiting]

That is a nice bike,I think I remember it for sale for around $13 K (A).This is cheap in this country for a 4.I would suspect it was imported from England by the dealer.,but a lot of these bikes come from the US.Of course in the US they sell for half this much.Having mismatched motor and frame numbers is no big deal ,IMHO.However young people have become obsessed by this,not only in bikes,but in other collectables too.Anyhow,the mainshaft you show in the picture appears to me to be 11 1/2 inches long,which is the same as a single mainshaft I have in front of me now.You should alse be aware that the clutch centre spline was increased in length around 1947,and clutch centres are different to match.It appears the two piece mainshaft would be OK with a couple of shallow keyways,assuming it hasn't come too loose.It appears the perpertrator of this deed has relied on locktite alone,and maybe a press fit.Regards John.

[brenton.roy]

Hello Kumar,
Welcome to our forum.
Following John's comments, the bike could also be local. There were plenty used by police here.
You've been in touch with Paul, the club archivist. He has access to the factory records and would be able to say where the bike(s) were delivered.
The club also has an excellent library, which is accessible online.
Brenton

[Akumar]

Thanks John and Brenton,

There is something I do not understand and do not see a way around it. Let’s look again at the “two-piece” mainshaft. Since I can adjust the length I can move the chainwheel assembly in and out to clear the chaincase outer piece. However to have the chainwheel clear the outer chaincase I have to move it so far in (towards the gearbox) that the engine sprocket will rub on the crankcase. What could be the reason and is there any other way around it? One way out would be to engineer a spacer between chiancase inner and outer pieces but that seems a lot of machine work. Any insight will be appreciated.

And what is the correct length of the mainshaft for this model? Does anyone have an answer to that?

Thanks,

Kumar

[nevhunter]

At risk of stating the obvious, why not just get the correct parts. (The longer mainshaft and the proper offset gearbox lugs. It's only the main case involved, in respect of the gearbox proper. There is not much room there to play with. I adapted a SQ4 box the other way to fit a single years ago. I still have the bike and could remove the box (at some stage) and replace it with a (1950 dated one, if available) The shaved off sides I could easily build up with weld and remachine as per the SQ4. and it wouldn't be detectable. I have fitted a drain plug to it. That is the only alteration Nev

[john.whiting]

I think something else will have to be considered,that is that the Sq4 wheel was different to the single wheel.It was offset to the left side by 1/4in to allow for the gearbox (and rear frame LHS) offset,with the rim offset to the right a similar amount to keep the track correct.Hence if your chainline is good with the single gearbox casing,the wheel must have some non standard dimension.It may be a standard single wheel,on which the rim was spoked centrally,or it maybe a special to achieve chain alignment.If so special spacers will have been made ,and this will have to be returned to standard.The wheel is the old non detachable type,with taper roller bearings.If it was mine,I would make a special mainshaft to suit,and leave the gearbox as is.I think I would also make the shaft to suit the later detachable clutch adapter(from the GB box).I still think its a nice bike,and this is a minor problem compared to the knackered motors that I see people trying restore in basket cases.Regards John.

[Akumar]

Dear fellow enthusiasts,

With combined efforts of many local experts, this 4G has come to life. Many thank also to all of you for great help.

I rode it four times so far (6 miles per run) on four different days. This has a resleeved engine(standard bore), new valve guides, new IMD pistons (bought off Ebay), new gaskets, old con-rods, rebuilt bottom end, reconditioned Solex carb, Morgo pump, and an oil filter. Here are few observations and questions:

1) Any special tips for break in? Someone who has rebuilt a 4G can provide any special insights?

2) I am using 20W/50W oil. Any problems there? Weather here in Minnesota is not too warm (30 to 35 Celsius).

3) At what mileage oil change is suggested?

4) It is starting to leak oil from both right-sided head bolts. I am assuming they can be tightened a bit? The left side head of the engine is completely dry. No leakage there.

5) At low engine rev, it (sometimes) sounds one piston is dead. But at higher speed, it seems okay. Maybe it is just an illusion in my head?

6) There is difference in amount of smoke coming out from left versus right side. The left side is more smokey compared to the right side? Anything to worry there?

Thank you.

Kumar

[nevhunter]

There's usually more oil to the RH side of the motor. Give it quite a few miles to settle down and bed in as regards a bit of smoke. Wouldn't hurt to recheck tappet clearances early in the piece with head retension. Nev

[roger.fellows]

Have you read the relevant notes about head nut torques by Bruce Longman?

[stuart.wilby]

Here's my two penorth,
1, run in the engine without rapid blips on the throttle, not too high on the revs between gear changes and no labouring at low revs on the hills (as if that would be possible) check the oil flow habitually, you have to be aware that the rings and bores will be bedding in, the rings touch the bores where they touch and will rapidly wear at these high spots until bedded in, it is at this point the compression will rise to given data If all is well, the main bushes and big end shells, similar.
This is where the metal in the oil comes from.
2, I use mono grade 40 and it seems ok, oil is a choice, we all have our own ideas, I discuss with the vintage club and look at the lubrication charts for oil.
3, oil changes, first one before 500 miles, that metal is in there and the new filter will catch it, hopefully not too much metal in the oil but change the filter canister, and clean all the others while your at it, then every whenever you feel like it, oil is the cheapest thing you'll buy for any motor, ( that's my personal rule).
4, could be an oily plug, valve guide worn more than the other, or a tight tappet, valve guide is fed with oil from the rocker shaft, wear can occur if the oil is not getting to the furthest rocker on the left side looking down, check with the cover off, and engine running, if this is evident, investigate, make sure the feed line is not blocked, ( mine was blocked) blow it out with the airline. Make sure the unions top and bottom are clear, (I'm sure you've checked them on the rebuild).you will need to re apply the torque on the head bolts after an hour or so after starting up after a rebuild, these engines are not known as the cooker for nothing.
5, check the slow running jet is clear, and working, the bi-starter off when ticking over, but some petrol gets through in the off position, the air screw accommodates this and it will run erratically if it is not getting the perfume of Arabia, you may have main jets for economy, go up a size.
6, smoke, you're still running this engine in, there will be some smoke until all the high spots are gone in the cylinders, if there is a lot after say 500miles, it could be that valve guide, worst case, a broken ring, put the compression tester on the cylinders, I will not state the obvious.
Nice bike, looks like mine.
Regards
Stuart