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#41
Haus of Projects / Yamaha YA-1 Resurrection
Last post by Yamanatic - May 10, 2024, 11:52:49 AMThe 1955 YA1 Yamaha 125 (2T) restoration has finally started after lurking in the corner for many years. These bikes were also known as the Akatombo, or Red Dragonfly. Some say blasphemy against the Yamagods: "Leave it original." I think not:
Let the project begin! First order of business is get the motor out and apart - it took a week to nurse the cases apart since a couple pullers had to be engineered, and surprisingly most of the internals are serviceable; a good thing since NO parts are available, not even from Japan. Here are the cases after being stripped and the first pass through the parts cleaner:
This is going to take some time. The bike spent 40 years in Hawaii at the first Yamaha Dealership in the United States, so the original finish has much surface-rust; the metal beneath is 100% sound and solid and amazingly straight.
The chrome will be a challenge as it didn't fare as well as the painted parts - the handlebars, rims, and exhaust system will take some heroic (read 'expensive') plating work.
Interesting history: the YA-1 was not only the first Yamaha, but it was also the first Yamaha race bike, having won the first race they ever entered, the 1955 Mount Fuji Ascent in Japan ... they finished minutes ahead of the pack. The YA-1 was produced from 1955 to 1957, and one had to be quite wealthy to buy one ... "the average starting salary of a college graduate (in Japan) was around 10,000 Yen, the YA-1's 138,000 Yen price put it well beyond the reach of most users."
There are less than 10 YA-1's in the U.S., and this is one of two 1955's - the actual count is unknown, but the other dated bikes are 1957's. The Yamaha Corporation was formed in July of 1955, and the date tag on this frame shows Aug-1955, so this is likely one of the oldest in existence.
Updates will be slow in coming - I estimate at least 1-year to finish (it is a very simple and basic bike), which probably means it will take at least 2!
Warren
Let the project begin! First order of business is get the motor out and apart - it took a week to nurse the cases apart since a couple pullers had to be engineered, and surprisingly most of the internals are serviceable; a good thing since NO parts are available, not even from Japan. Here are the cases after being stripped and the first pass through the parts cleaner:
This is going to take some time. The bike spent 40 years in Hawaii at the first Yamaha Dealership in the United States, so the original finish has much surface-rust; the metal beneath is 100% sound and solid and amazingly straight.
The chrome will be a challenge as it didn't fare as well as the painted parts - the handlebars, rims, and exhaust system will take some heroic (read 'expensive') plating work.
Interesting history: the YA-1 was not only the first Yamaha, but it was also the first Yamaha race bike, having won the first race they ever entered, the 1955 Mount Fuji Ascent in Japan ... they finished minutes ahead of the pack. The YA-1 was produced from 1955 to 1957, and one had to be quite wealthy to buy one ... "the average starting salary of a college graduate (in Japan) was around 10,000 Yen, the YA-1's 138,000 Yen price put it well beyond the reach of most users."
There are less than 10 YA-1's in the U.S., and this is one of two 1955's - the actual count is unknown, but the other dated bikes are 1957's. The Yamaha Corporation was formed in July of 1955, and the date tag on this frame shows Aug-1955, so this is likely one of the oldest in existence.
Updates will be slow in coming - I estimate at least 1-year to finish (it is a very simple and basic bike), which probably means it will take at least 2!
Warren
#42
Haus of Projects / Re: RD350 forever project
Last post by skyline - May 10, 2024, 12:40:58 AMNice work! 
#43
Turning Wrenches / Re: idle screw does not raise ...
Last post by m in sc - May 09, 2024, 11:06:11 PMsounds like the pilot isnt the right size or the fuel level is incorrect. sounds like the pilot is too small IMHO
#44
Micro Muscle: Under 100cc's / Re: YL1.. Project thread
Last post by Perattzi - May 09, 2024, 05:03:00 PMCool ride! 😎 My DT100 cylinder sat at the local machine shop for like 4 months before I got a call back. I had sort of given up hope lol. $300 is crazy just for the bore job?!
#45
Micro Muscle: Under 100cc's / Re: Dt100a restoration!
Last post by Perattzi - May 09, 2024, 03:28:48 PMAnd here's where I'm at with it. Now that the weather has improved I can work on the body work. The fuel and oil tanks and pipe all need some sort stripping. I'm torn between trying to do it myself or have them all dipped. The quotes Ive gotten are pretty high.
#46
Micro Muscle: Under 100cc's / Re: Dt100a restoration!
Last post by Perattzi - May 09, 2024, 01:54:40 PMFork tube was trashed, found replacement on eBay. New bushings, seals, and oil. Doubt these things do much of anything anyway lol. There was still a tiny bit of pitting so I decided to fill with epoxy and sand smooth and run for boots. Not original but I prefer the look.
Polished the hubs and fitted new bearings, shoes, NOS spokes. Original rims cleaned up well!
I spent a TON of time restoring as much of the original hardware as possible. By using a tiny hammer and files I was able to repair slightly stripped bolt heads etc. Bolts that needed replaced I filed off any markings and 'sculpted' them to look like the vintage ones. After all that I sanded and polished all the bolt heads. Then everything was dropped off to be zinc plated.
If I did it over I would do a better job of cataloging the hardware and comparing to parts diagrams BEFORE to ensure everything is there.
Polished the hubs and fitted new bearings, shoes, NOS spokes. Original rims cleaned up well!
I spent a TON of time restoring as much of the original hardware as possible. By using a tiny hammer and files I was able to repair slightly stripped bolt heads etc. Bolts that needed replaced I filed off any markings and 'sculpted' them to look like the vintage ones. After all that I sanded and polished all the bolt heads. Then everything was dropped off to be zinc plated.
If I did it over I would do a better job of cataloging the hardware and comparing to parts diagrams BEFORE to ensure everything is there.
#47
Turning Wrenches / Re: 28mm Mikuni - What are the...
Last post by racerclam - May 09, 2024, 01:35:49 PMK&N filters are junk , they pass as much dirt as the do air. Use Uni filters
#48
Micro Muscle: Under 100cc's / Re: Dt100a restoration!
Last post by Perattzi - May 09, 2024, 01:18:37 PMNot the most ideal paint setup, but it works.
#49
Micro Muscle: Under 100cc's / Re: Dt100a restoration!
Last post by Perattzi - May 09, 2024, 01:15:19 PMThanks guys! Sharing it here helps keep me motivated. Most people don't appreciate just how much work even a tiny bike like this is to redo.
So I stripped it all the way down and had all the painted parts media blasted. Some light hammer and dolly to the rear fender, most everything else was surprisingly straight. Followed that with some body filler and epoxy primer and sealer. The black parts were sprayed with single stage, more glossy than it would had been originally but I like the gloss. Not sure I'll paint a frame again. I keep having the issue if trying to get the paint on wet to flow and look nice, but overspray would land on the other tubes. Powdercoat is the way perhaps.
Fenders, headlight, and headlight ears still need to be painted silver.
So I stripped it all the way down and had all the painted parts media blasted. Some light hammer and dolly to the rear fender, most everything else was surprisingly straight. Followed that with some body filler and epoxy primer and sealer. The black parts were sprayed with single stage, more glossy than it would had been originally but I like the gloss. Not sure I'll paint a frame again. I keep having the issue if trying to get the paint on wet to flow and look nice, but overspray would land on the other tubes. Powdercoat is the way perhaps.
Fenders, headlight, and headlight ears still need to be painted silver.
#50
Turning Wrenches / Re: 28mm Mikuni - What are the...
Last post by SoCal250 - May 09, 2024, 12:38:01 PMThe flat hard back of the filters can cause reversion waves and interrupt the intake signal. This can lead to flat spots and tuning/performance issues.