Some riders like a challenge and one that doesn't involve a triple.
Trying out different machines comes with the territory for those who have spent time on a dirt bike. Subtle nuances here, pretty big distinctions there all help define specific makes, models and years. But for anyone wishing a taste of past glory the only way to ride a dirt bike that blazed the track or trails from their youth or even before their birth, is to find someone who owns one or built one themselves.
Yet, even if you found someone with a vintage dirt bike, good luck convincing the owner to let you throw a leg over and rip a lap.
So, you really only have one option: Rebuild your own.
Rebuilding an old dirt bike comes with several challenges. First you need to find the bike in good enough condition to rebuild. A rusted, clapped out dirt bike offers little foundation to work from. Once unearthed (sometimes literally) you need to find parts. A true vintage enthusiast only accepts original parts but sometimes getting to the finish line means using universal parts that fit a cross section of dirt bikes, or as we will find out, ATVs.
Well, how do you find old and even discontinued parts to rebuild an old dirt bike? Let us help.
A rebuilt 1979 Yamaha MX175
MotoSport has its own vintage bike rebuilder on staff. If you have ever ordered custom graphics from us, you have at least some association with Eric Doubet, MotoSport's Custom Graphics Designer. Doubet has had his hands dirty over the years in a number of rebuild projects including motorcycles, ATVs and dirt bikes. Doubet usually gets into rebuilds during the winter months when he doesn't ride as much.
"I've failed a couple of times here and there but it's just my version of a puzzle," he said. "I get to learn a lot in the process as well."
His latest beauty goes back 40 years in a 1979 Yamaha MX175 - a 175cc air-cooled 2-stroke - found on Craig's List for $300 and though not a junker, it was far from whole. Doubet is a Yamaha loyalist and chose this particular bike out of familiarity because the engine had only minor modifications throughout the years and was practically identical across different models even as late as a 2004 RT180 dirt bike and the 2006 Yamaha Blaster ATV.
So, it sounds like he just dropped hint #1 when looking for parts on an old dirt bike. Find one with little variations in the meat of the bike, i.e. the engine, so you don't have to go looking for 40 year old parts that may or may not exist anymore.
The entire bike fit in the trunk of a car
"It was literally a bunch of boxes, but complete, and I was able to pick it up in my car," he said of the bike's condition. "The bottom end had been rebuilt already which is what really sold me. Having that be in spec and not having to search for a crankshaft or rod made it worth that price alone."
He needed a top end and gaskets to commence with the project so Doubet went with the usual companies that offer vintage parts first:
- Vesrah Racing - complete gasket kits
- Wiseco - forged pistons in stock and overbore sizes
- Motion Pro - cables
- EBC - brake shoes and clutch kits
Yamaha stayed consistent through the years reusing part numbers so Doubet found many parts cross-listed by OEM part number but not by the aftermarket manufacturers. It turned out the MX175 uses the same clutch fiber plates as a current year Yamaha TT-R230.
"If you dig deep enough into the OEM parts diagrams you can find a lot of pieces that have superseded part numbers and are still in production by the OEMs," he said.
Banshee carb on the left
Next, he turned to a Taiwanese shop on eBay for replacement spoke kits that only work on the 1978-81 rear wheel. A spare stock carburetor (left-side) for a Yamaha Banshee (ATV) worked as a direct replacement for the original carb that Doubet admits he was too lazy to clean but did have trouble finding a cable throttle that fit.
A kill switch off a 1984 YZ125, also found on eBay, suited the original style better and ended up helping to simplify the wiring process. The stock thumb-sized footpegs were "upgraded" to aftermarket pegs from the era found online at an Australian vintage shop.
Vintage aftermarket footpegs
Finally, he went with a modern 1 1/8-inch oversized bar, Pro Taper Profile clutch perch, ODI Emig v2 grips, Artrax tires and tubes, and of course the graphics. You can probably guess where he got these parts!
"This was a cheap build," said Doubet who spent roughly $250 to $300 to rebuild the bike. "I was more interested in getting parts any way I could rather than focus on OEM replacements or era-specific parts."
Doubet said if you strike out with manufacturers, try Craig's List and eBay, then check out local, national and international vintage dirt bike groups on Facebook which have incredible resources and you can probably find someone who knows someone or who at least has additional ideas. Salvage yards and swap meets also work, if available in your area. Overall, Doubet spent about two months rebuilding the MX175 and says he's happy with the final build.
"I would have liked to start with a bigger bore or more race-oriented bike for vintage racing, but those just weren't in the cards," he said. "This is a great little play bike to have around."