Follower scar oil tests

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I too have four bikes on the road and they do 1500 miles each. This year they are all using XL 20-5o. Pulling the oil
last week I noticed that the oil does seem to be fairly dark . Id say there was one day that was a bit warmish and the OP was lower than I would see when cooler.
So maybe that RP might be a better plan for next season.
 

comnoz

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Can you recall what its called Jim?

It’s important to be precise about these things because, as your testing showed, sometimes oils that appeared very similar initially, and were even from the same maker, tested VERY differently!
Yes, It is Royal Purple Max Cycle. It is available in 10-40 and 20-50. Both grades tested about the same.

I run the 10-40 in my FJ .

I run HPS 10-40 in my 68 Mercedes 2.8 liter.
 

robs ss

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Still, if you're running a belt & dry clutch, the choice for a Norton twin (961's aside) is Royal Purple HPS 20-50?
 

elefantrider

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HPS 20w50 is $7 a quart at my local speed shop. They have plenty stock with 2 different types of RP bottles and labels but can't tell me which is the latest one. I gather they don't sell much.

BelRay V-Twin costs almost twice as much online. I don't use it since.
 
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Okay okay… I've been following this oil research and use pretty closely since coming here last year, and have finally become convinced to make the change to the synthetic. I've read it all, but there being so much info to glean couldn't make a decision until now. So RP 20-50 HPS is going in my old motor when next I change oil..... This last few pages of discussion is what threw the switch because I'm hesitant to tamper with such a sweet running relatively higher mileage motor. Any deviation from what has been working is difficult. My 850 is transitioning into the new millennium.... Hopefully without a bang.
 

gortnipper

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Yes, It is Royal Purple Max Cycle. It is available in 10-40 and 20-50. Both grades tested about the same.

I run the 10-40 in my FJ .

I run HPS 10-40 in my 68 Mercedes 2.8 liter.
Does the XPR work with a wet clutch? I have seen generic commentary that intuits it should, but nothing specific.

HPS 20-50 is cheaper per liter here in NZ than Mobil 1.
 

comnoz

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Does the XPR work with a wet clutch? I have seen generic commentary that intuits it should, but nothing specific.

HPS 20-50 is cheaper per liter here in NZ than Mobil 1.
The XPR is not designed for a wet clutch but it may work fine in some applications.

However the XPR is definitely not suitable for an air cooled pushrod motor. It is formulated for modern engines.
 

Fast Eddie

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Well, if it’s good for maintaining the performance and reliability of politicians, we should try using some over here !!
 

Fast Eddie

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Jim,

Just getting back to the ‘best oil for a wet clutch’ question...

The Royal Purple Max Cycle is in your table titled “Oil Protection For Stock, Low Compression Norton Commandos”.

The data recorded was: Royal Purple Max Cycle 20W50 syn: Load: 170. Temp: 1.10

There appear to be many oils above this. I chose the Bel Ray 20w50 V Twin synthetic which is in the table titled “Extreme Oil Protection For Norton Commandos”.

The data recorded was: Bel-Ray 10W50 V-twin synthetic: Load: 500. Temp: 3.58.

I’m struggling to see why you recommend the RP Max Cycle over the BR v Twin syn ??
 
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There's been a lot of disussions about "scar tests" on auto racing forums...Many well experienced builders dismiss it as have no relevence to operating conditions inside the engine...And many lower rated "scar test" oils perform very well in actual running engines...
To each his own beliefs...
 

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