1973 Mk1 Rebuild, back from the grave!

Tony Pierce · Jan 1, 2021

The old filter housing was as crusty as they come I think. It cleaned up ok. I bought some stainless metal springs also to put back over the hoses.

I purchased a solid one piece axel from Don Pender to replace my old one. The old one was so rusted I had to cut it out with a saw. It went together pretty smoothly overall.

I found a front wheel off ebay, since my old unit was pretty rusted as well. I mounted a new TT100 tire, but I haven't balanced it yet.

bill · Jan 1, 2021

On of the most over looked items on a fork rebuild it new damper caps and rods. The caps at minimum should be replaced.

Tony Pierce · Jan 1, 2021

I put a set of "Dunstall" rearsets, also from Don Pender on. I really like the feel, and as I am going for the "cafe" period correct look I think they will be spot on.

Right now I am working on the wiring and assembling the primary.
I am upgrading the wiring to EI and Tri-spark rectifier. I think I am going to keep positive ground, just because I think it will be simpler as I am using a modified lucas wiring loom (new).

I picked up a set of side panels from Ebay, and they look remarkably nice for the price. The old ones that came with the bike are in really rough shape, so I thought I would gamble on a set from India. I can't say I am disappointed.

I also picked up a set of new Amal Primer carbs from Greg Marsh. He has been super to deal with and highly recommend him.

My goal for this bike is to try and get it finished before my new baby arrives in May. I think as long as Mr. Comstock gets me the heads before too long I can get it knocked out even if I am working full time and going to college!

Tony Pierce · Jan 1, 2021

bill said:
On of the most over looked items on a fork rebuild it new damper caps and rods. The caps at minimum should be replaced.

I didn't realize that. I did not replace them. What happens to them if they are reused?

jbruney · Jan 1, 2021

I reused mine and have yet to be taken out by an oncoming speeding bus careening out of control.... Just a good idea, which I didn't follow.

grandpaul · Jan 1, 2021

Tony Pierce said:
I didn't realize that. I did not replace them. What happens to them if they are reused?

The threads on the caps and/or body can crack and/or strip, resulting in pogo stick action.

Tony Pierce · Jan 1, 2021

grandpaul said:
The threads on the caps and/or body can crack and/or strip, resulting in pogo stick action.

Do you think it’s worth tearing it back apart or just keep an eye out?

bill · Jan 1, 2021

The main problem i have seen is the cap wears where the rod goes through the cap and the rebound damping becomes non existent. The big issue with the rods is rust or they get rough. This will cause rapid wear on the caps. IMHO i would look at this again

Tony Pierce · Jan 1, 2021

Just to make sure I understand, number 19 on the diagram here?

Tony Pierce · Jan 1, 2021

Tony Pierce said:
Just to make sure I understand, number 19 on the diagram here?

Also, there was absolutely no rust inside. I replaced bushings, tubes, fiber ring, gaters, cleaned everything up well. It seemed ok from what I could see and feel anyhow.

Fast Eddie · Jan 2, 2021

From the pictures you’ve posted so far I was under the impression that your bike hasn’t done an awful lot of mileage.

So, unless you’re bored, or plan on going racing, I would think there is nothing to be gained by stripping the forks again.

Tony Pierce · Jan 2, 2021

Fast Eddie said:
From the pictures you’ve posts so far I was under the impression that your bike hasn’t done an awful lot of mileage.

So, unless you’re bored, or plan on going racing, I would think there is nothing to be gained by stripping the forks again.

Thanks. Bike only has about 6000 original miles.

Tony Pierce · Jan 3, 2021

I finished putting most of the primary together but I will pop the clutch apart once the pushrod seal kit gets here.

I started cleaning up the primary cover and saw rubbing. Does this indicate the rotor has spun loose at some point?

The cover was pretty weathered but seems to be polishing up nice. I’ll post before and after pics when I am done.

I am running oil lines now. I plan on running pod filters or velocity stacks instead of the air box for looks. Any opinions on how I should vent the oil tank? I think it was vented to the ham can before.

gortnipper · Jan 3, 2021

I have had that on the bike of my degree indicator too. Looks like it has been pushed into the rotor? Mine was.

grandpaul · Jan 4, 2021

Indicator scales that have been damaged like that, need to be clearanced, then calibrated with a degree wheel or else...

Tony Pierce · Jan 4, 2021

grandpaul said:
Indicator scales that have been damaged like that, need to be clearanced, then calibrated with a degree wheel or else...

Before I put the stator on I did use a degree wheel for static timing and it looked really close. What’s the best way to calibrate?

grandpaul · Jan 4, 2021

Once you have absolutely determined TDC and set your degree wheel at "0", rotate the crank counter-rotation several degrees PAST the appropriate ADVANCED position depending on your configuration. (it is advised to OVER-rotate, then approach and arrive at the advanced position from the running rotation direction).

Fix the crankshaft from turning, and/or mark the camchain position relative to the idler or cam pinions.

Tap the scraped side of the scale away from the inside as evenly as you can (to insure a gap to the running rotor), then fit up the primary cover.

Check your scale against the alternator rotor mark and "persuade" the scale as required to align with the ADVANCED timing mark as appropriate.

Tony Pierce · Jan 4, 2021

grandpaul said:
Once you have it timed with the degree wheel, rotate the crank to the appropriate ADVANCED position depending on your configuration. (it is advised to OVER-rotate, then approach and arrive at the advanced position from the running rotation direction).

Fix the crankshaft from turning, and/or mark the camchain position relative to the idler or cam pinions.

Tap the scraped side of the scale away from the inside as evenly as you can (to insure a gap to the running rotor), then fit up the primary cover.

Check your scale against the alternator rotor mark and "persuade" the scale as required to align with the ADVANCED timing mark as appropriate.

I’m sorry if this question is a bit dense. It is my first complete rebuild and I might not understand everything properly yet. I don’t think I am following the advanced timing mark. Wouldn’t I just set it at 31 degrees BDC and then it should line up or am I thinking incorrectly?

grandpaul · Jan 4, 2021

NO, you are not thinking incorrectly. I more or less repeated myself, come to think of it. The first part should have addressed FINDING TDC, the second part is rotating back 40 or 50 degrees, then advancing up to 31 degrees BTDC. I corrected my first post.

Tony Pierce · Jan 4, 2021

grandpaul said:
NO, you are not thinking incorrectly. I more or less repeated myself, come to think of it. The first part should have addressed FINDING TDC, the second part is rotating back 40 or 50 degrees, then advancing up to 31 degrees BTDC. I corrected my first post.

Thank you! You have been incredibly helpful.

1973 Mk1 Rebuild, back from the grave!

Similar threads