Added reply in a thread YZ125 1979 Race build 5/11/2016 8:22 AM

I had a little more time to play in the shop. Turned a spigot for the carb boot and installed that. Also noticed that the boost bottle spigot at 90* doesn't really want to fit on the bike, so I cut and laser welded it back on at an angle. I wasn't going

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Added reply in a thread YZ125 1979 Race build 4/4/2016 7:24 AM

LOL!!! Yes, rumor is that even though All-Balls makes great seals, they have a lot more drag than the RateTech seals. Either way, just replace the seal and be done.

Added reply in a thread YZ125 1979 Race build 4/3/2016 7:56 AM

That sounds familiar. It's been a while, but I think I might have had to leave one retaining ring out as well.

Added reply in a thread YZ125 1979 Race build 3/31/2016 12:00 PM

Well, I like playing with ports and engine building, so my time may be different than yours, in terms of "worth it". But yeah, I did the same on a YZ80 cylinder and it made a difference even with small Boyesen ports. The size of the port is limited by ... more »

Added reply in a thread YZ125 1979 Race build 3/31/2016 6:38 AM

New top end has been on the back burner for a while now. I ditched the modified YZ250 re-cast head idea. Might play around with this Sachs / Penton head if it runs hot. All I've done so-far is to have the cylinder welded so I could create boyesen ports,

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Added reply in a thread 89 YZ490 Rebuild 3/30/2016 11:09 AM

I just sold my '87 after a few years of non serious racing and riding. I'm faster on my 125, but I'm starting to miss that beast. FWIW: I ran 92 pump gas and Spectro at 40:1. Never pinged after performing the "Yahoo YZ490 Group" carb mods.

Added reply in a thread YZ125 1979 Race build 3/30/2016 11:05 AM

That drain goes into a waste oil bucket, right? wink wink. I've seen worse oil, but that's pretty ugly. Are you revalving the shock?

Added reply in a thread YZ125 1979 Race build 3/29/2016 1:59 PM

175 - 200 psi should be good. As was mentioned, make sure the separator piston has about 2" of space above it for the nitrogen to compress. If you purge all the air out of it / fill it up completely, it won't move.

Added reply in a thread 1980 Yamaha YZ175... 9/15/2015 6:20 AM

Max, I've thought of that too, but I get a little nervous putting so much heat into a precisely machined cylinder like a fork lower. With my luck it would end up binding at the end of the stroke or something! Both components changed in about 81 or 82. ... more »

Added reply in a thread 1980 Yamaha YZ175... 9/14/2015 12:48 PM

Hey Mike P. Sweet bike! I've got a '79 YZ125 that I race and I've got a DLS front brake for it. I'm intrigued by your setup. I was waiting to machine a plate to relocate the 3:00 slot to the 1:00 position, but I see you went ahead and installed it with ... more »

Added reply in a thread 1980 Yamaha YZ175... 6/10/2015 8:14 PM

Looking at my 125J, I would have to make a governor cover plate and eliminate the water pump. This is easy stuff and can be done with regular people's tools (I'm a machinist but sometimes I revert to the die grinder and hack saw when I don't have access ... more »

Added reply in a thread 1980 Yamaha YZ175... 6/10/2015 9:21 AM

It's right side ignition, right? Spins clockwise? If they're on the same side, then yes. Yamaha has used the same backing plate mounts and shaft taper forever.

Added reply in a thread 1980 Yamaha YZ175... 6/10/2015 8:23 AM

I'm not sure, but being a yamaha, it's a good chance. Take a look into partzilla and compare shaft end bearings and such...

Added reply in a thread 1980 Yamaha YZ175... 6/10/2015 6:29 AM

If it were me, I would look into using the IT motor, cases etc, and drop the YZ125 close ratio trans into it if possible. If you want the 175 motor to wring out like the 125, then you will need to raise the exhaust port a little and rework the head for ... more »

Added reply in a thread 1980 Yamaha YZ175... 6/9/2015 5:36 AM

Which rod is longer? If the YZ rod is longer, you could keep it and make a spacer to lift the cylinder so the piston meets the deck of the 175 cylinder. Or mill some off the top and bottom of the cylinder to get correct deck height. You'd have to adjust ... more »

Added reply in a thread Project Impossible? - updated 5/12/2015 12:01 PM

Amazing work Heck! That pipe looks absolutely gorgeous!

Added reply in a thread Bike recovery at Diamond Don's? 4/22/2015 10:16 AM

I think his bike came out a little cleaner than you're KDX, Sir Roostalot! That's a great war story.

Added reply in a thread 82 or 83 Rm 125 silencer ? 4/22/2015 10:11 AM

Looks great! I just picked up an '82 myself. I think the silencers were different between those years... Different placement of the pipe-to-silencer joint. So I think you lucked out with that purchase!

Added reply in a thread 90's bikes? 4/15/2015 9:42 AM

This may be the sad truth. I didn't think about that when I started my ornary rant.

Added reply in a thread 90's bikes? 4/13/2015 4:44 AM

That's a great point. The reason I started this post wasn't to stir the pot or be a troll. I guess I was just looking for some convincing, since a lot of bikes I see on here just seem "new" to me.

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