Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Rectifier and Compensator Failure

Here's a great picture of JV's rotor with permanent magnets and the stationary stator inside the crankcase. There is no way to get compensator debris from inside the grease filled housing into the stator. Maybe the possible stripped splines yes, but nothing else.



[img]http://www.picturetrail.com/sfx/album/main/24797881/413981221[/img]

The new Centa cush drive uses a lot better means of attaching the rotor than the early compensator model using the Harley compensator. This new rotor should never strip and come loose.



Sorry about the cush drive and compensator references, but they truly are just that. The new Centa is a cush drive as we know it from motorcycles with the rubber rear wheel hubs being called cush drive from decades. And usually they are relegated to the rear drive, not between the motor and transmission.

The Harley on the other hand, has always been called a compensator as it is used on the motor to help reduce crank torque pulses. And MMC uses a true Harley compensator as directly used on the Harley bikes, no modifications at all. Just dowel pins that align with the sprocket teeth to secure the sprocket hub side to the M3W housing that is than filled with grease. Can't believe that was ever going to work as grease does not really flood the wear ramps and stay put well. Whereas the Harley oil bath primary cover slinging oil around constantly does, for the most part, keep the wear ramps lubed.

Here's the M3W as removed and full of grease. I bet there was a pocket void inside from the spinning.



Here's the actual Harley compensator with worn out ramps. Granted some did last for quite some time, but I'm also sure that they were being packed frequently with grease.



The Bellville spring pack from the Harley compensator setup.



Richard I understand from where you're coming from on your terminology, but they are what they are, an original compensator style drive coupling and a cush drive style coupling. This is of course my opinion only...

Regardless of what it's called, it's a piss poor setup and MMC should have been forced to replace under recall regardless of warranty time lines. Even under warranty after the Centa was implemented, they still only replaced them with the original Harley type unless you paid extra for the upgraded Centa unit. I may be wrong on the timeline, but that's what I remember.

Philip I hope the dealership takes good care of you and get's you all good as new again. Well actually better than new as it will be the Centa now!

Have a Happy Holidays everyone!

Hi Phil, just a few observations:-

If your engine ran "sweetly" then the Cush drive is fine - don't be duped - you would know if the splines were shot!

The Centa hub is of soft steel and often a poor fit on the crankshaft - they do fail.

The nut holding the Centa hub on to the splined crankshaft has nothing to do with these failures. Sliding splines in your gearbox are not held fast by any nuts. If the splines are loose then the nut will come undone in the first seconds of running the engine regardless of how tight it is.

My advice is replace the rectifier, mount it directly to the bodywork behind the near side suspension unit. Then drive the vehicle listening carefully for the rumbling noise which accompanies spline failure. If the Centa rollers fail it is a recovery job but will not cause any further damage to the cush drive.

Good luck - hope its not too expensive.
Phil

Thanks for comments Dan and I take your point that early HD style cush drive couldn't affect stator - just armchair postulating on my part .

As I've said before my personal view is that a cush drive be it between engine and transmision or within the rear wheel of shaft drive bikes cannot correctly be called a compensator as by (engineering) definition a counter-procedure is needed to compensate. A balance shaft for example could therefore correctly be called a compensator as it fulfills that definition. It's just a case of semantics though and I'm feeling outnumbered so will put up and shut up

Philip - as previously mentioned firstly try the Harley regulator - someone’s bound to have one on here they carry as a spare - The Harley ones are a straight replacement but get the right one see the MTWC spare parts list planenut has put together for the club.

It's the HD p/n 74540-01 rectifier/regulator that you want Philip. Plenty on Ebay for less than £100. As others have said, it is less fragile than the CE 601 that is fitted as standard. Check the earth cable is good.

It is actually a self aligning marine prop shaft coupling but cush drive is just such a lovely name.

this is a Harley compensator. In the Harley engine this is in the oil bath of the primary chain housing... so always bathed in oil. Grease would not work well in this setting.

If my comp. nut hadn't come loose there would have been zero wear on mine after 19k miles, apart from the tips of the ramps being excessively worn due to it ramping over every component was in perfect condition which is why I have rebuilt it with new Harley components. Using new Nordlock washers under the bolt head and plenty of Loctite on the threads.

I spoke with someone in aftersales at MMC regarding the cost of a complete Centa coupling and it was eye watering, which also swayed my decision especially when he told me they have had to replace some Centa rubber bobbins after only 500 miles on their demo cars!!!

Just need to finish putting it all back together now.

Define “eye watering” please. Just curious.

When my rectifier failed the dealer thought initially that it might be an alternator fault & quoted me 10 hours to to remove the engine to get to it. A new HD rectifier sorted the fault. When my chassis needed changing when cracked I had to pay £695 + VAT for the Centa compensator parts June 2017 & MMC covered the labour. As the engine had to come out anyway its likely the extra work to fit the centa was not that great.