New Combat owner

Good afternoon. I am a new Commando owner and am hoping to get some technical input. I am the fourth owner and unfortunately have no early history on the bike. The person I purchased it from bought it in March 2016 from the estate of the third owner, he died in 1978. The bike was parked after he moved onto the afterlife. My question relates to the main bearings. Everything I have read indicates that the odds of them not having been replaced are slim. The bike was built in April of 1972 and only has about 4500 miles on it. Is there a way, short of disassemblng the entire engine to verify the it has the "Superblend" bearings installed?

Thanks for your input.

Tim

There is a REMOTE change you MIGHT be able to confirm, by removing the primary drive and the crank seal on that side, and see if you can see any I.D. makings on the inner race shoulder.

Same goes for removing the timing side cover and pulling the crank pinion and it's plate/seal to see if THAT side might offer a clue.

I kinda doubt it, though. I don't seem to recall mfr info on the inner race shoulder, only the outer race.

grandpaul said:

I kinda doubt it, though. I don't seem to recall mfr info on the inner race shoulder, only the outer race.

Click to expand...

It should at least be possible to identify the bearing type from the inner race. If the bearing is the FAG 'Superblend' it will have an 'NJ' single-lipped inner race.

If it is the standard R&M/RHP 'MRJA30' bearing it will have an 'NF' double-lipped inner race.

L.A.B. said:

grandpaul said:

I kinda doubt it, though. I don't seem to recall mfr info on the inner race shoulder, only the outer race.

Click to expand...

It should at least be possible to identify the bearing type from the inner race. If the bearing is the FAG 'Superblend' it will have an 'NJ' single-lipped inner race.


If it is the standard R&M/RHP 'MRJA30' bearing it will have an 'NF' double-lipped inner race.

Click to expand...

ADDED:
In timing side... the FAG NJ603E will be right in your face on the inner race. stamped brass sheet metal roller cage held by "peened" cross pieces... 12 rollers

R&M/RHP Fully machined brass roller cage... 13 rollers, Dave :mrgreen:

I've got similar Combat put together in April 1972 .... top end has been refreshed in the mid 80's .... bottom end is as it came from factory .... fitted single Mikunni , 21 tooth counter shaft sprocket , boyer mk IV , oil filter kit , and I keep rpm away from red area .... no troubles or warning rumbles yet .... relax and ride your bike it's a really cool machine ....
Craig

Thank all of you for the help. That's what I was going to do for the rest of the summer. Maybe this winter I will take a peek inside and see what I have.

Tim

The factory issued a recall I believe so dealers had to replace the main bearings.

Torontonian said:

The factory issued a recall I believe so dealers had to replace the main bearings.

Click to expand...

I'm not sure that's true.

Personally, i would not worry if the bearing were replaced or not

bike has very low mileage, and the stock fitted bearings were just fine UNLESS the previous owner revved the hell out of it, redlining it which causes the crankshaft ends to whip and dig into the bearings, fixed by fitting Superblends which had barrel type ends to allow for this over enthusiasm

Congratulations on your acquisition
My Combat was the best 'grin factor' bike I've ever had.

Well worth reading this before deciding on your winter activities...

https://www.oldbritts.com/n_c_case.html

I did the mods to mine and it was fairly straightforward. I also fitted a PCV to the relocated breather - helps keep things oiltight.
Also replaced the mains with Superblends.

I'm fairly confident the biggest issue was oil starvation under sustained acceleration. It seems they're fine under 'normal' use.

I was only a nipper at the time so can't claim to know, but from what I can gather there were more thrown rods than snapped cranks - as usual I'll stand to be corrected :wink:

Andy,
Great article! I am still trying to get use to the opposite shifter and brake LOL, so I don't think I will be getting even close to over revving the motor.

Thanks to all.

Tim