General Category > Bike Builds, Rebuilds And Restorations Only
My "Project 2025" - 1980 Moto Guzzi V50 II
Antietam Classic Cycle:
--- Quote from: vxn750 on December 11, 2025, 11:54:35 AM ---Now that I have confirmation that she runs, I can move on to the brakes. I've got all the parts lined up: Brembo brake rebuild kits, new brake lines, etc. The first challenge is removing the frozen pistons. I've stalled on the pistons since I don't have an air compressor to pop them out. I've unsuccessfully tried a couple different techniques gleaned from online videos. I'll check with a neighbor to see if he's got a compressor and go from there.
Definitely a fine balance between elbow grease, brute strength, the right tools, know-how and stick-to-itiveness that I will be straddling throughout this process. So far, so good.
Question regarding the electrical system:
I'm considering going with Greg Bender's wiring harness/loom setup. Aside from the basics, he does offer a lot of options, upgrades such as the Domino handlebar switches. Has anyone upgraded their fuse box for a modern one that would allow for a 32Ah battery instead of the standard 20Ah? I'm leaning towards upgrading all of the electrical but I'm curious to know what most folks do.
--- End quote ---
If the caliper pistons are steel, heat the caliper body and apply your favorite penetrating fluid. Before using iar to pop the pistons out, wrap the caliper in a sturdy rag to keep the piston from flying off and causing havoc.
I've never upgraded the fuseblock - just cleaned the fuseholders and made sure they gripped the fuses tightly and used new fuses. I would recommend wiring in a relay to power the coils, and rewiring the starter relay so that it receives power directly from the battery. I'd also recommend LED bulbs in the dash warning lights so that you can see them in direct sunlight, LED headlight and taillight as well (saves power and brighter). If you install an LED in the "battery" warning light, then you'll need one of Greg's "bootstrap harnesses" in order for the charging system to function. I also recommend removing the four wires to the ignition switch from the 12(?) connector on the main harness and putting them in their own 4 (spade) terminal connector. The dinky Molex pins of the 12(?) pin connector aren't up to handling the amps involved and can heat up, melting the plastic connector shell.
Domino switches would likely be better than the stock switches, but if the throttle is part of the right switch, then you'll need a different throttle also and possibly custom length cables.
I'd stick with the 20 ah battery and change the starter to a Valeo type (plenty of copies for less than $100 on ebay).
vxn750:
--- Quote from: Antietam Classic Cycle on December 11, 2025, 04:52:28 PM ---If the caliper pistons are steel, heat the caliper body and apply your favorite penetrating fluid. Before using iar to pop the pistons out, wrap the caliper in a sturdy rag to keep the piston from flying off and causing havoc.
I've never upgraded the fuseblock - just cleaned the fuseholders and made sure they gripped the fuses tightly and used new fuses. I would recommend wiring in a relay to power the coils, and rewiring the starter relay so that it receives power directly from the battery. I'd also recommend LED bulbs in the dash warning lights so that you can see them in direct sunlight, LED headlight and taillight as well (saves power and brighter). If you install an LED in the "battery" warning light, then you'll need one of Greg's "bootstrap harnesses" in order for the charging system to function. I also recommend removing the four wires to the ignition switch from the 12(?) connector on the main harness and putting them in their own 4 (spade) terminal connector. The dinky Molex pins of the 12(?) pin connector aren't up to handling the amps involved and can heat up, melting the plastic connector shell.
Domino switches would likely be better than the stock switches, but if the throttle is part of the right switch, then you'll need a different throttle also and possibly custom length cables.
I'd stick with the 20 ah battery and change the starter to a Valeo type (plenty of copies for less than $100 on ebay).
--- End quote ---
Thanks Charlie,
Success with removing the stuck piston out of the first brake caliper!! One down, five to go :grin:
I didn't have access to an air compressor, but the heat along with the freeze-off and lots of prying and finagling did the trick. Although getting an air compressor is on my list, it's not on the top unless I find a great deal on a used one. If the other pistons are as stuck as this one was, I'll be much more liberal with the penetrating fluid. Heating up the caliper really did help a lot.
I've made note of your recommendations regarding the electrical:
-I'll stick with the original fuse block and the 20Ah battery :thumb:
-I've been thinking about switching all the lights to LEDs. Any recommendations of where I can source the bulbs? I just checked SuperBrightLEDs, looks like they have them.
-I'll look into the Valeo starter and get more info on the Domino switches.
Antietam Classic Cycle:
--- Quote from: vxn750 on December 13, 2025, 01:02:59 AM ---Thanks Charlie,
Success with removing the stuck piston out of the first brake caliper!! One down, five to go :grin:
I didn't have access to an air compressor, but the heat along with the freeze-off and lots of prying and finagling did the trick. Although getting an air compressor is on my list, it's not on the top unless I find a great deal on a used one. If the other pistons are as stuck as this one was, I'll be much more liberal with the penetrating fluid. Heating up the caliper really did help a lot.
I've made note of your recommendations regarding the electrical:
-I'll stick with the original fuse block and the 20Ah battery :thumb:
-I've been thinking about switching all the lights to LEDs. Any recommendations of where I can source the bulbs? I just checked SuperBrightLEDs, looks like they have them.
-I'll look into the Valeo starter and get more info on the Domino switches.
--- End quote ---
These are the bulb I use in the warning lights:
https://www.superbrightleds.com/74-led-bulb-3-smd-led-miniature-wedge-base
Match the LED color with the lens color. Polarity matters, so they only work when inserted the correct way. I use a jewelers file to slightly round off the sharp corners to make then easier to insert.
Headlight and taillight bulbs I buy on Amazon.
I've bought several of the Chinese-made Valeo copies, they work just as well as genuine Valeos.
https://www.ebay.com/itm/157367854914
vxn750:
Frozen piston #2:
Since I’m back in So Cal, I went to pay Moe Cycle Garden a visit and got a tour of his shop. I had one of my brake calipers with me and asked Moe if he could give me a hand with it. He fired up his torch and heated up the caliper while Stevie yanked out the piston with the removal tool that I had wedge in it. They were of the opinion that an air compressor would not have been sufficient.
Next question:
Is it better to replace the rusted bleeder nipples or just clean them up? I’ve gotten most of the exterior rust off but I can’t tell if it’s rusted on the interior.
faffi:
If you remove it, you can check it for pitting on the sealing face an also that all orifices are clean. You can clean the visible part if it with a brass brush on a dremel or similar to get rid of the remaining rust. If you then polish it, it will be reasonably resistant against new rust. Then again, a new one probably does not cost the world.
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