primary Chain

[Slymo]

Yes been wondering about the advisability of ATF. Might go back to motor oil and whilst waiting for the chain might look at the input and output seals.

[BSA_54A10]

Yes been wondering about the advisability of ATF. Might go back to motor oil and whilst waiting for the chain might look at the input and output seals.

ATF ( Dextron not Ford type F ) will work fine in the primary
I use it in engines with alloy primaries .
Being thinner it gets down into the rollers easier and because it is meant to be used in boxes tha have brake bands it does not cause as much clutch slip as std oil when it gets all over your fiber plates.
But the biggie for me, it is pink so that alows me to work out which oil resevior is leaking as I use different coloured oils in the engine gearbox & primary .

[Slymo]

I do like the fact that ATF is a different colour. It has allowed me to work out that the vast amount of fluid loss on my SR is related to the primary case. I wonder though if it is less affected by the oil thread on the clutch centre as it goes through the sliding baffle plate.

[BagONails]

Yes been wondering about the advisability of ATF. Might go back to motor oil and whilst waiting for the chain might look at the input and output seals.

ATF ( Dextron not Ford type F ) will work fine in the primary
I use it in engines with alloy primaries .
Being thinner it gets down into the rollers easier and because it is meant to be used in boxes tha have brake bands it does not cause as much clutch slip as std oil when it gets all over your fiber plates.
But the biggie for me, it is pink so that alows me to work out which oil resevior is leaking as I use different coloured oils in the engine gearbox & primary .

I do hope this isn’t turning into one of THOSE threads and I have no wish to go there but I think we need to be a bit careful here. There are many and varied ATF’s, they have been developed hand in hand with the big three OEM’s in the USA for as long as there’s been automatic transmissions I.e from the late thirties on.  Dexron is a GM spec and Ford has Mercon. There are others but within those two marketing brands there are umpteen different specs that have evolved as trans have obviously developed over the years. Pretty much any early spec fluid from 60,s through to the early eighties is going to adequately lubricate your chain being around 20 weight viscosity. In fact they are highly over specified for such a basic simple job. The conditions they are formulated to survive are way harsher than ever seen in our primary drives. Extreme heat and pressure and shearing forces for example combined with much lower service intervals. I would not however, advise using a Mercon V, LV or ULV or their Dexron equivalents as these are tending toward much lower viscosities used in modern trans that no longer have brake bands. (5,6,8,10 speed planetary gear types with electromechanical servo valve operated shifting)

Ford Type F  (1967)and type G (1972) out of interest are actually specified to not contain friction modifiers and to have higher static coefficients of friction which resulted in a harsher power take up and firmer shift characteristics as demanded in the day for certain applications. If anything you’d think this might make them eminently suited to our application.

For some reason I am not aware of, SRM who have done considerable work to develop improved clutches and have some engineering credentials in this area actually don’t advise ATF in any form be used now and suggest straight twenty grade or a 10W40 multi suitable for oil bath clutches I.e. any modern bike pretty much.

So yep it’s a total minefield and a question of paying your money and taking your choice.
One thing is for sure tho. Any 20 grade gear oil, hydraulic oil, engine oil, snake oil, hair oil or cooking oil will lubricate your chain no problem. Your clutch may take exception however….

[berger]

clutches on our bikes, don't we love em. i had a 6 spring on mine for years and used 20-50 in the primary. i set the 6 spring up not to slip and get it out of gear at traffic lights, this resulted in me cracking brazil nuts in my left hand at christmas   the 4 spring now fitted is second hand and gives the same result on the road but is far easier on the left hand, very light, the days of cracking the nuts now fails     i still run the chain in 20-50 no problem. in fact the four spring is easier than urma the yonda. maybe i should go out more on urma and start squeezing the necks of a certain political party in england

[Slymo]

Ok some development in the primary chain story. Grabbing the clutch I discovered that the input bush was totally flogged out. It is one I replaced about six months ago with an off the shelf bronze bush from the bearing wholesalers. I reamed it to fit and machined the gap in the middle. Seems though that the material is far too soft as it has trumpeted itself out. Remarkably little bronze in the oil so it hasn’t worn away, more hammered out. Anyone got an idea of what alloy I should be using as the bush inside the sleeve gear?

[KiwiGF]

Ok some development in the primary chain story. Grabbing the clutch I discovered that the input bush was totally flogged out. It is one I replaced about six months ago with an off the shelf bronze bush from the bearing wholesalers. I reamed it to fit and machined the gap in the middle. Seems though that the material is far too soft as it has trumpeted itself out. Remarkably little bronze in the oil so it hasn’t worn away, more hammered out. Anyone got an idea of what alloy I should be using as the bush inside the sleeve gear?

I bought some bronze bushes from draganfly, they only lasted a few hundred miles, the replacements were fine. I put it down to the first set being made in the wrong material, but I also used a hone on the second set to get 0015 ish clearance, to make certain the oil got into the bearing.

Long discussion here https://www.a7a10.net/forum/index.php?topic=5202.0

[Slymo]

Ok so it's definitely my fault not Renolds. The chain shows distinct signs of overheating and everything was looking a bit stressed. Seems I just let the levels get too low. Examining the options to stop the oil pissing out again I've checked the reversed threat collar on the back of the clutch centre and discovered that it was basically worn away. Made up a new one on the Myford but rather than 4tpi it is now 8 as the Super7 gearbox doesn't deliver anything coarser.

I checked the alignment again carefully and found that the engine sprocket was a little proud and this combined with lack of lube obviously caused the problems. VERY GLAD it didn't crap itself at 70mph on the motorway where I was the day before the graunch noise.

New chain apparently arrives today. I have machined about 40 thou off the back of the engine sprocket and replaced the sleeve gear with a good secondhand spare I had in the collection. It has clearly done some miles but is still a good fit and the bush hasn't oozed out either end of the sleeve gear like the other one did. The clutch posts that I made up the last time are still tight and fine so it should all go back together this evening with plenty of lubrication.

There doesn't seem to be an embarrassed face emoji but you can take it as given.  you mean this one? musky.