John Player Special restoration project

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

ZERO evidence of burned oil on the small ends of the con rods; I haven't seen that EVER on an old Britbike teardown.

Front iso is fatigued opposite of what I would have thought; the off-center is UP rather than DOWN. Maybe I just hadn't noticed another one like this before, I sure don't remember. It's pretty dry and cracked. I'm going back together with new stainless vernier adjustables.

Crank pinion came off without using a wrench to turn the nut on the puller, just slipped right off; same with the cam sprocket!

Easiest case-splitting exercise ever. It went so quickly, I didn't even get a photo.

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

Cam lobes are in good shape, no gauges, flat spots or excessive wear (they're almost always uneven in appearance, but that's due to the casting, not actual uneven wear)

There are no markings of any sort on the cam; no stampings, no castings.

Same with these lobes...

The far right cam follower has the slightest shadow of a flat-spot line, second one from the left appears to have a couple of little flaws. I may have them re-ground or replace them with a spare set I have on the shelf.

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

THERE'S all the grunt! Actually, it's really not that much, I expected more. Again, other than the dregs at the bottom, the inside of the cases are nice and shiny.

there is a little bit of metallic particles, I'm guessing that represents the entire life of the bike to-date. The drain plug was undisturbed and brand new under the layer of caked oil & dirt under the engine.

"Free at last, free at last"

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

Big end journals are like new, ZERO wear. I always have to mark the flywheel rotation direction, the factory stampings are typically so uneven as to be useless.

As expected, near ZERO wear on the big end shells right across the batch

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

HERE is where it gets ugly. Instead of the usual creamy sludge in the tranny, I found what appears to be grease. I really hate to see rusty parts inside trannys, it can mean the gears will also have some rust...

Photo was actually taken with the tranny standing up on the mainshaft, You can see all the studs are rusty, as is some of the clutch lifter assy.

grandpaul · Dec 2, 2015

Re: Eliminate doubt on this JPN

This time for sure. Added the sidestand to the powdercoat pile after welding a new end extension on it, matched to the one on the Green 880. Also added the front iso mount. Off to powdercoat tomorrow!

This is the entire chrome batch. Not much to it...

Here's all the stuff to be polished, just need to disassemble the forks to remove the lower legs. A typical Commando would have had the meter cups, but the JPN meters are mounted in the fairing.

jimbo · Dec 3, 2015

lookin good IMHO, I would not have polishers polish the rods.

jimbo · Dec 3, 2015

http://www.airtech-streamlining.com/vin ... tonJPS.htm

Fast Eddie · Dec 3, 2015

jimbo said:
lookin good IMHO, I would not have polishers polish the rods.

I thought exactly the same!

Paddy_SP · Dec 3, 2015

Good luck with it - I spent the morning polishing the primary cover as well as one of the rods from the 850 I'm doing. The other one will have to wait for another day!

Northton · Dec 3, 2015

Great thread. Thanks for taking the time to post. Great tip on freeing the cylinder!

grandpaul · Dec 3, 2015

jimbo said:
lookin good IMHO, I would not have polishers polish the rods.

They have some odd scratches here and there that SEEM to indicate they've been touched since the factory installed them, but it doesn't make sense since it is almost certain the engine was never opened. The only other explanation I could come up with, is debris drifting around the crankcase, but there was none in the sump big enough to scratch them like that. Also, the small ends look very unfinished as though they were last hit with a belt grinder to final shaping before finish polishing; maybe they skipped that last step? I'll post close-ups tomorrow.

grandpaul · Dec 12, 2015

1 of 8 batches of bits for cad plating - larger and odd-shaped bits.

2 of 8 for cad plating - misc bits

3 of 8 for cad plating - washers

grandpaul · Dec 12, 2015

4 of 8 for cad plating - nuts

5 of 8 for cad plating - medium-sized bolts & studs

6 of 8 for cad plating - screws

grandpaul · Dec 12, 2015

7 of 8 for cad plating - small bolts & studs

Batch 8 of 8 for cad plating - front end bits

That should be everything for cad plating, nearly 15 pounds.

Fast Eddie · Dec 12, 2015

grandpaul said:
jimbo said:

lookin good IMHO, I would not have polishers polish the rods.

Click to expand...

They have some odd scratches here and there that SEEM to indicate they've been touched since the factory installed them, but it doesn't make sense since it is almost certain the engine was never opened. The only other explanation I could come up with, is debris drifting around the crankcase, but there was none in the sump big enough to scratch them like that. Also, the small ends look very unfinished as though they were last hit with a belt grinder to final shaping before finish polishing; maybe they skipped that last step? I'll post close-ups tomorrow.

The reason for saying 'I would not have polishers polish the rods' isn't about whether or not to polish them, we're suggesting that DIY would be better.

Polishers are polishers, not mechanics or tuners, they are unlikely to treat a conrod any different to anything else and stick on on their course mops taking who knows how much metal off of who knows where!

grandpaul · Dec 12, 2015

Maybe this is why the front brake wouldn't pump up with fresh brake fluid...

Evidence that the brake hose is shedding pieces of lining. Add that to the replacement parts list...

Inner caliper doesn't have as much debris, because the primary chamber served as a "trap"

grandpaul · Dec 12, 2015

Fast Eddie said:
The reason for saying 'I would not have polishers polish the rods' isn't about whether or not to polish them, we're suggesting that DIY would be better. Polishers are polishers, not mechanics or tuners, they are unlikely to treat a conrod any different to anything else and stick on on their course mops taking who knows how much metal off of who knows where!

The people I use are extremely professional; they do polishing for many NASCAR teams. They DO know what a rod is, and handle them accordingly.

grandpaul · Dec 12, 2015

Pucks have some surface pitting

Inside the rubber boot on the master cylinder is grunty, corroded contacts. I'm going to use some soft foam seal strip going back together, to keep it clean in there.

Notice the difference? Standard master cylinder on the left, JPS cylinder on the right. (they are exactly the same casting, photo makes them look different size)

grandpaul · Dec 12, 2015

Also grunty inside the fork gaiter caps, once they dry out they don't do their job

Fork bushings and stanchion tubes are in excellent shape, thankfully (brake side). Froks were about half-full of gray milk...

Off-side leg; they'll get new seals