So I found my YZ100!! Anybody have any good info about them?

LuckyStar64

LuckyStar64

PR Addict
Well-- In true Wizard of Oz admonishment, I found the elusive '83 YZ100 I was looking for, right in my own backyard. Z-Man mentioned this piece a few years ago, but I wasn't super interested in vintage racing, other than to show up and look at all the super cool old bikes. It really didn't occur to me that the guy never sold it back then, and he still had it after three years. I should have it here by Monday or Tuesday.

I picked the YZ100 because I'm a mini-bike F-R-E-A-K, and this is the closest thing to a vintage pit bike they'll let me race for now. I loved Z-Mans' '83 YZ125, but it cost twice what I wanted to spend. Not only that, but this 100 has similar suspension to the 125, but IMO-- the air cooled motor might save me some frustration with old and cracked radiator hoses and an old radiator. I believe the bike shares quite a few parts with the old IT175 and 200, and I THINK an '80 YZ125 motor, so I was thinking parts availability would be decent. Realistically-- I doubt that I'll race the bike more than a couple times per year anyway, but I wanted to have a choice vintage ride for Mid-O at least, along with some mature garage porn. Someday I might do a full resto-- but I want to ride the bike, and if I do the resto-- I'll just want to look at it.

Anybody have any sources for more info on this piece? I wasn't riding yet back in 1983, so I don't have old mags or any other info about them. I DID check out the DMC bike that Dave Miller put together, and that was part of the catalyst for me wanting one myself. Any info would be strokeworthy! I kinda feel like I'm getting the bike I shoulda had when I was 14 back in 1983! --L*64
 
Congrats ! Is the bike already a runner ? If not , my buddies and I have found ( after many bike resurrections ) that it pays off in the long run to do a total engine tear down . Check all the gears , shift forks , etc. and replace all seals and bearings that are even questionable ( all is best ) . This way you start with a solid , fresh motor . I know a bunch of guys who have resto'd a " runner " to a shiny classic ride only to have the engine lock up in the first couple of rides . At least pull the top end and check the piston and rod .

Another tendency for newbies to the vintage scene is to try and trick out the motor right off the bat . Many of the old bikes actually had decent motors . I know a 100 can usually use all the help it can get though . A set of Boyesen reeds and meticulous jetting is about all I'd do to start with . Pay attention to fuel too . My bikes seem to LOVE some leaded race gas mixed with pump fuel and a good oil (Maxima Super M is my preference but there are many good ones ) but the old Huskys have a higher compression ratio than some other bikes and may get more benefit .

The best advice I can give is to concentrate on suspension/handling . This can be some of the most expensive mods you can make but will most likely give you the best returns for your money . You might find fork " kits " for your bike from back in the day but we have had excellent results with the fork emulators available today . Better forks from a newer or larger model YZ may be a possibility and still be " legal " . The rear suspension is where the $$$$ get serious . Riders being equal , I believe the guy on the better suspended bike will win out over the horsepower bike especially on most of the tighter , twisty vintage tracks I have ridden .

Drum brakes are an issue on all the old bikes . A couple of tricks are to have the actuating arm on the backing plate lengthened a bit to increase leverage and to " arc " in the shoes to match the drum for fuller contact ( doing a search should provide how to info ) . Being able to dive a little deeper into corners and outbrake the competition can be a big advantage .

Sorry I don't have any specific info about your new old ride but I will look through my stash of old magazines for any articles . There used to be some YZ specific websites too but I don't know if they still are up and running .

Best of luck and enjoy !
 
Breyley Yamaha might be able to dig up the old Yamaha Wrench Reports from that model. I know Zman followed that for his '83 YZ125.
 
Speed and Sport out of PA is a good source for vintage Yamaha stuff. http://store.speedandsportinc.com/index.tpl You might think some of their prices are high but they have a pretty good knowledge of what is rare and what isn't. Their wicked tough decals are fantastic as well and it looks like thy have them for an 83 YZ100. Also - if you go to www.partzilla.com and go to OEM parts for that bike when you click on any part# it will tell you which bikes share that specific part - I have found that to be a huge help when I am hunting... Good Luck.
 
I'll definitely follow up on the leads. She IS a runner, but I could see taking the motor apart to freshen it up. Problem is that everything is discontinued that would be needed for the freshening up! haha! Wiseco may do a piston and rings. I'll look into that too.

I wasn't planning to get silly with the bike as in a Racetech shock or anything. I always wanted one of these YZ's, AND she's my cheap date for the Mid-O race. I really don't care that much how I finish-- I really just want to come check out the scene, and see how they did it back in the day. I'll make the event and go back to my play bike assault, and road racing after the vintage days races. I would like to change the fork/shock oils, reeds, freshen the motor up if I can, and basically take it apart and grease it all up. That's about it. Like I said before-- I love to ride bikes, but I don't wanna spend alotta chips. ---L*64
 
Pressure test the motor of air leaks ASAP, old seals get dried out, and lean the engine significanlty, I learned the hard way with an old RM125 bike, 1 hour = 1 piston with a hole in the top, read the plug constantly until you get the jetting right. I would also change the brake shoes they can delaminate over time and a trip over the bars may be in your future.
 
I raced these bikes in the 1980's until the class was gone, and I had to compete in 125 Schoolboy on these little air-cooled machines. I owned 3 of the '82-'83's. Only major issues I remember was the frame was weak and fractured just above the footpeg mounts on the middle tubes in front of the airbox. I believe you are right about some of the 1980 YZ 125 and IT175 motor parts being interchangeable. I remember sitting on the gate at Malvern in 1982 with more than 30 other YZ100's.
 
Damn! Really? I wasn't riding yet back then. That's awesome! Any pics? How was the motor? I rode this one a little bit, and it's a bit quicker than what I was thinking. About the frame cracking-- I was only planning to race it a couple times a year on the vintage tracks. I wasn't gonna launch the thing or anything. It's one of the bikes I always thought was cool as hell, but never owned. --L*64
 
I weighed between 150-160 lbs when I raced these, so I was (and still am) a little on the heavy side. I don't think you need to mess with the frame, but I would look closely for cracks above the footpegs and on the main backbone under the tank. Overall a great bike with a sweet powerband. The YZ100 was one of my all time favorite machines. There were some super-fast local guys who raced the 100 class. I remember seeing Fred Andrews and Jeff Stanton ride YZ100's at Malvern(lapping me). I'll look for some photos. I ran number 44, 94 and 104 between 1982-1983 and raced mainly CRA tracks like OIR, Gran Prix, Malvern, Valley View, Western Reserve, etc.
 
So far, I haven't been able to find any photos of any of my 100's. M I'm checking with another PR member and good friend (who got me into racing). He's got some great old photos from Malvern, Yankee Lake, Smith Road, etc.
 
Sounds great! Keep looking! I was up at the Apple Cabin last night, and I ran into this fellow that had a mega sweet '74 YZ250 with the strap tank and a pair of Ohlins shocks out back! It was a gorgeous resto. Hope I'm not going to catch the illness myself. One vintage bike is fine, more than that.... well.... hahahaha! --L*64
 
LuckyStar64, I wanted to reply back to you on the YZ100 photos. Unfortunately, I have not been able to locate any photos of my old YZ100s. I will look through my brother's photos when I visit him next. I did find an old DVD where someone in my family captured some racing footage (converted from Super 8 film)of the 100 class from OIR around 1982. There isn't much detail, but it was neat. We will keep looking.
 
LuckyStar64, I rode Bobd168 YZ-100 back in the day. They were awesome bikes. One of the best handling bikes I ever rode. I could corner that thing like it was on rails. You are going to have fun with that bike.

By the way, that 74 YZ 250 at Apple cabin used to be mine. Talk about a fun bike.
 
Oh really? That guy had it set up really nice with Ohlins shocks. It was so nice, I'm not even sure I'd have ridden it. The vintage guys I've met so far seem like quite an affable bunch. I was just thinking about my YZ today, and what I wanted to do to it. I keep wanting to do a full resto, but then it'll sit and look pretty! I really wanna get dirty with her, then restore her later! --L*64
 
LuckyStar64 said:
Oh really? That guy had it set up really nice with Ohlins shocks. It was so nice, I'm not even sure I'd have ridden it. The vintage guys I've met so far seem like quite an affable bunch. I was just thinking about my YZ today, and what I wanted to do to it. I keep wanting to do a full resto, but then it'll sit and look pretty! I really wanna get dirty with her, then restore her later! --L*64
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That's the same problem I have. I restore them and then they looks so nice I don't want to ride them.
 
Whaddya got in the shed? Any cool old bikes? What's funny, is that I thought bikes were technological wonders in the mid '80's. Now that I have this old one hunnert, I keep looking at it thinking...."Who in the F designed this??". --L*64
 
Original44 is responsible for mentoring me as a young rider and for taking me to watch my first MX race. The jury is still out on whether this was a good idea! We had a lot of good times riding back in the '80's and we are now trying to pass on the love of riding to our kids. Cool stuff.
 
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