Atlas Primary Chain

hillbone

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Hi.
Rather than add a belt drive, can a modern O Ring chain be fitted and just sprayed every now and then. I'm over the mess of the oil bath.
Cheers Hillbone.
 
According to Andy the Chainman, lots of people do this ..... I do not see why spraying with oil will be of any benefit whatsoever. You might consider a light grease such as Lubriplate, or other lithium base grease to lube the clutch rollers.

I take it you cannot get your Atlas primary oil tight.

Slick

PS: Another thing that comes to mind is whether you are running Barnet clutch plates. Barnet plates will stick unless run in oil. Even with oil, I am having trouble freeing up the clutch.
 
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I considered this as well and talked to Andy who said it would work well and had no issues even on race bikes. I ordered a couple of the chains and found to have clearance issues with the inner primary and stator bracket. The o-ring chains are slightly wider and the rivets protrude a bit more as well. Too bad because they are excellent quality solid chains. If running an open Manx style primary it would have worked well. Seems every bike is different in how the stamped metal primary fits together so you might get lucky? I ended up going with a belt drive in my Atlas and Domi build.

Scott
 
kernel65 said:
I considered this as well and talked to Andy who said it would work well and had no issues even on race bikes. I ordered a couple of the chains and found to have clearance issues with the inner primary and stator bracket. The o-ring chains are slightly wider and the rivets protrude a bit more as well. Too bad because they are excellent quality solid chains. If running an open Manx style primary it would have worked well. Seems every bike is different in how the stamped metal primary fits together so you might get lucky? I ended up going with a belt drive in my Atlas and Domi build.

Scott
Click to expand...
 
Fortuitous time for your question, as I installed a 428DID X ring chain today on my Atlas primary..

I was having issues that I couldn't fix keeping oil in my primary, and as I use the bike fairly regularly got sick of the mess and top up.

My last chain was an RK non oring, it only lasted about 10k miles (ran dry, not a chain quality issue I don't believe).

One small issue you will come up against is the outer link plate on xring chians is effectively a press fit, but you won't fit your chain breaker/press in the primary. I just put the split link up against a ridge near the alternator and taped it down with a punch bit by bit until the clip would fit.

The other option would be to contect it all up (76 links) with the clip or rivit it, and then take the drive socket and the clutch basket off, put the chain on and slip it all back on, time consuming.....

I had no clearance issues.

My only concern is it will run to hot inside the primary case with the cover on, I figure I'll see how it goes and if it doesn't last I'll get a nice open primary and let that air in for cooling.
 
I ran a Regina O ring chain for a while with no clearance problems. I switched back to a wet primary out of [non empirical] concern about the speed the relatively short chain was running and the consequent potential for excess wear on the rollers and failure. My concern may have been misplaced but I figured that since the wet primary was a proven system, running a conventional chain in oil (ATF), would be one less failure point to worry about. I would really be curious to know what some forum members with engineering and/or race experience think.
 
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1down5up said:
Fortuitous time for your question, as I installed a 428DID X ring chain today on my Atlas primary..

I was having issues that I couldn't fix keeping oil in my primary, and as I use the bike fairly regularly got sick of the mess and top up.

My last chain was an RK non oring, it only lasted about 10k miles (ran dry, not a chain quality issue I don't believe).

One small issue you will come up against is the outer link plate on xring chians is effectively a press fit, but you won't fit your chain breaker/press in the primary. I just put the split link up against a ridge near the alternator and taped it down with a punch bit by bit until the clip would fit.

The other option would be to contect it all up (76 links) with the clip or rivit it, and then take the drive socket and the clutch basket off, put the chain on and slip it all back on, time consuming.....

I had no clearance issues.

My only concern is it will run to hot inside the primary case with the cover on, I figure I'll see how it goes and if it doesn't last I'll get a nice open primary and let that air in for cooling.
Click to expand...
I also now remember that I was concerned about the lack of lubrication to the clutch bearing. I know it only functions briefly when the clutch is disengaged, but in the (sad) real world it's more often than not that you get stuck in a situation in traffic or at a light where have to hold the lever in longer than you really want to
 
O ring chains do waste a little horsepower ..... this power loss is dissipated as heat, thus they run hotter. I do not know if this will be problematic in a closed chaincase.
As 1down5up says, you will have to wait and see, and use a ventilated cover if it runs too hot. My guess is, if you get a short life (<5K
miles?), it is too hot.

Slick
 
I was concerned that the velocity would be to high as well but then considered the following

From my understanding one of the factors (apart from pure hp/torque and abuse) that effects chain life is the radius and speed the chain needs to go around on the smallest sprocket.

Modern sports bike drive chains are designed to run at well over 200km/hr, with often a much smaller sprocket than my primary (17t v 21t), from my (very quick) calcs this results in a similar speed at higher rpm for a standard atlas (need to verify this).

I was going to run it for a week or so without the primary cover, and then see what the temp of the chain was and compare it to the drive chain. It will obviously run hotter once the cover is back on but will give an indication anyhow.
 
Thanks to everybody.
Great advise again from all.
Thinking now just go with a belt drive.
Makes sense based on the advise.
Cheers Hillbone
 
1down5up said:
I was concerned that the velocity would be to high as well but then considered the following

From my understanding one of the factors (apart from pure hp/torque and abuse) that effects chain life is the radius and speed the chain needs to go around on the smallest sprocket.

Modern sports bike drive chains are designed to run at well over 200km/hr, with often a much smaller sprocket than my primary (17t v 21t), from my (very quick) calcs this results in a similar speed at higher rpm for a standard atlas (need to verify this).

I was going to run it for a week or so without the primary cover, and then see what the temp of the chain was and compare it to the drive chain. It will obviously run hotter once the cover is back on but will give an indication anyhow.
Click to expand...

O ring chains are "stiffer" and resist flexing. It is in the turns about the sprockets that such resistance comes to require extra power. You are correct that tighter radii will exacerbate the problem.

Keep us informed how your test turns out.

Slick
 
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