McDouglator/Kubota Torque Setting? Gasket for McDouglator?

CarlHungness

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Hi:
I believe John McDougal himself, inventor of the McDouglator told me, "No, not foot pounds, inch pounds," when referring to the 40 lb. torque setting of the main drive nut on the unit. I told him I knackered a drive sprocket and how much I had tightened the nut. His instructions definitely state 40 ft. lbs.
Thus I'd like to ask the group two questions. How much torque did you use on the nut and secondly, have you made a gasket where the unit meets the crankcase and is your alternator snug up against the case. Thus, you would have a sealed primary, correct?
I seem to recall John made an upgrade to the installation with the inclusion of a seal where the snout of the alternator passes through the case and he eliminated the oil flinger and replaced it with a hardened washer if I am correct.
I never have had the hole in the engine case completely sealed and have had, I'm sure a leak there for years.
 

Bill Thomas

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That's funny Carl, I fitted mine many years ago, I have been a Car and motorcycle mechanic for most of my life, And when I did that nut up, I said to myself, If I keep doing this up to what he said, I would be in Deep Stuff !!, So I did it by Feel !. I have often worried that I did not do it up enough, But it has been fine.
I think mine was an early one, I did not seal it, Wish I had !!, It is not right up to the case because the Sprocket would not be in the right position, It has always leaked a bit, But I don't want to touch that nut again !!. I know it's a Bodge!, But a bit of sponge jammed between the Gearbox and the rear frame makes it look better when parked up after a ride. My engine is an old race unit , Now used on the road, But with old type pistons with big clearance, No crank seal etc, So I thought that did not help.
Have Fun, Bill.
 

Nigel Spaxman

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When I fitted mine I tightened the nut to what felt right. Probably around 25 ft lbs. Anyway I knew that the whole idea was that the drive was supposed to provide some slip. So what I did was I tightened it up and then tested the function by making sure the alternator rotor could slip. The instructions say the slip should happen at 5 inch pounds. It is working well so far (1300 miles) Mine came with the seal and it doesn't leak a drop. It is just a shaft seal that fits perfectly in the hole in the case. The spacer behind the sprocket must have been made the right diameter for the inside diameter of the seal. The instructions say the seal is a 1 1/2 x 1" x 1/4". That must be an easy seal to get anywhere in North America.
 

Bazlerker

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Carl, I remember your primary chain bereft of the centre row of rollers due to the sprocket and the drive not being allowed to slip at the Cannon Falls Rally with Messrs. Watson, Smith et al in attendance in the parking lot of the hotel performing major surgery on the transmission of your primary drive and the transmission due to a failed bearing...Was this not sufficient proof that the nut was over-tightened?
 

CarlHungness

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Carl, I remember your primary chain bereft of the centre row of rollers due to the sprocket and the drive not being allowed to slip at the Cannon Falls Rally with Messrs. Watson, Smith et al in attendance in the parking lot of the hotel performing major surgery on the transmission of your primary drive and the transmission due to a failed bearing...Was this not sufficient proof that the nut was over-tightened?
Hi: No, the center row of rollers in the drive has never been knackered on my bike. My bearing problem was my own however as I had shifted the bike quite rapidly for a day as I recall, and missed a couple of gears. I'm sure it was my own hand that ruined the bearing. But you're right, my Kubota nut was too tight, so now trying to get it right. By the bye, thanks for your help (you drove to town and got me an impact screwdriver set). It was a fun time doing the tranny in the parking lot. Dan Smith, Robert Watson, Mike White showed me way. Glen Bewley just happened to have an extra bearing. Dan poked a couple holes precisely and we were able to remove the old one.
DSCN0640.jpg
 

Michael Vane-Hunt

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According to John's notes, the nut on the rotating end of his setup is set to 60 ft pounds and locktited. The nut at the sprocket end is tightened to 35 ft pounds. The amount of crush on the Bellville washer is adjusted by changing the length of the shouldered spacer where it abuts with the sprocket adapter. On the later McDougalators, John did away with the oil flinger and used a seal, and the Bellville washer had a notch on it's outer edge that fit over a pin that is riveted to the sprocket.
 

CarlHungness

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According to John's notes, the nut on the rotating end of his setup is set to 60 ft pounds and locktited. The nut at the sprocket end is tightened to 35 ft pounds. The amount of crush on the Bellville washer is adjusted by changing the length of the shouldered spacer where it abuts with the sprocket adapter. On the later McDougalators, John did away with the oil flinger and used a seal, and the Bellville washer had a notch on it's outer edge that fit over a pin that is riveted to the sprocket.
Correct, I do have the later model and wanted to check on the nut torque. Thanks.
 

bmetcalf

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In #5 above, "Dan poked a couple holes precisely and we were able to remove the old one" The rallyists determined that getting the bearing out of the blind hole the usual way was not realistic there in the parking lot and drilled from the right side to use punches on the outer race to remove the bearing. With Dan Smith and Mike White concurring on that, it worked well.
 
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