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Messages - bitzz

#1
There's issues....
A "G" had a aluminum swingarm and shock... and a "low boy" frame
Here's a  "G"

$12k for "G" is about what I'd expect (If you're gonna race a TZ, you want a "G"... or a CMR)
I think this is an "E" (try not to notice the engine mount on the top of the case... that was dis-continued on the "C")
#2
Turning Wrenches / Re: Most used gear oil and 2stroke oil
February 14, 2026, 10:20:48 AM
Quote from: JKV45 on February 13, 2026, 04:09:12 PMAs I understand it, you want the higher levels of ZDDP on any non-roller cam valvetrain.

You WANT about 1100-1200 PPM ZDDP. Too much ZDDP is a BAD thing.
Most motorcycle oils have about that level of ZDDP, any car oil advertising elevated ZDDP levels should have that much ZDDP. "Normal" car oil has about 800-900 PPM. ZDDP clogs car cat converters.
ZDDP is a lubricant of "last resort", if all else fails, there's still ZDDP... or boron or .... The idea is if you wipe all the oil off a metal surface (run out of oil), there is still a coat of ZDDP. You don't WANT to use the ZDDP... but it coats all metal surfaces, not just cam followers, mains and big ends too.
ZDDP is not the be all and end all of oil choices.

And the two things that have changed the most since these bikes were built is oil and tires. When these bikes were built; there was no "gear lube" and they were designed to use Reg 30 oil in the trans, not because it was GOOD, but because it was available everywhere. Gear lube is BETTER... you can build a gear lube with more sheer and less lubricity than a motor oil, that works better in a transmission.
IF you are going to run gear lube: you MUST use GL4, nothing else (use GL3 if you can find it, but GL3 was superseded by GL4). GL4 has lower levels of sulfur, the bright metal in the trans doesn't like sulfur. So no GL4/GL5... must be GL4.
Viscosity is rated differently in gear lube than motor oil... so a 75-80 gear lube is about the same viscosity as a reg 30 motor oil... about.
#3
All the good stuff?
Where's the pipes? carbs? brakes?  That's all good stuff.

If this thing was complete... and a little less crusty, it would be worth the ask.

If anyone is looking for a TZ with all the good stuff: get in touch
#4
General Chatter / Re: Yamaha production
December 30, 2025, 11:09:38 AM
We can't log in to your gmail

maybe post your password
#5
... been down this road before. Too bad i don't remember where the road went.

The RD was built through the introduction of tubeless motorcycle tires. The 1A1 bikes are not, the Daytonas might be.

The first tubeless rims were denoted as tubeless, they had either "tubeless type" or "TT" cast into the rim. You can also tell if they are tubeless type by the hole for the air valve: tubeless have bigger holes.

... and in case you didn't know: RD rims are a knock off of Andrews rims... 'cept Andrews rim don't weigh as much. RD rims are boat anchors
#6
The final RD400, the 3J7, the F and G models in Canada (and there was an Australian model 3M4?)had the same taper as the later RD-LC or RZ.
That final crank looked more like a TZ crank than a RD crank... it had holes in the cheeks and no heavy metal for balance... and the key was 90 degrees off... and I think the pins were serrated (I don't remember)


Before the F and G models, the Canadian RDs and the US RDs were the same
#7
The problem with racing that is it isn't going to be competitive against a more modern TZ750, with a modern frame... and tires... and wheels... and brakes... and cartridge forks....

Looks cool though
#8
$35,000
Who says prices are depressed?
#9
Turning Wrenches / Re: Crank work?
September 20, 2025, 11:10:16 AM
If it's already been welded, you need someone that actually knows what their doing to try to rebuild it.
It MAY have been welded because "Racebro thought he was dealing with a 100hp bike or something,..." OR it was welded because it was loose when it was last taken apart.
We were talking about what press to use... when I take them apart, I find they take (IIRC) 5-7 tons to press them apart, and they POP when they come apart... That's a good one that can be pressed together. Then OTHER ones take a couple of tons and just kinda smooosh apart... THAT one gets welded.
If done right, just grind out the weld, and start again. There shouldn't be GOBS of weld, you only need a tack or two.
I have often said that anyone with a brain and a press can rebuild cranks... then I saw some of the abortions done... so I have to retract that statement. I have seen new, aftermarket cranks that had to be trued. Rebuilding cranks is simple, but kinda finicky... I guess it takes practice.
Use stock RD400 pins, they're serrated, so they hold better. Wiseco makes hollow pins if you're doing a performance motor. Wiseco and Suzuki offer silvered big end bearings. ProX rod have a split big end, like the TZ rod, that oils better... again IIRC (I don't do a lot of RD350s, I'm a TZ or RD400 guy)
#10
General Chatter / That Tony Foale TZ
July 02, 2025, 10:04:11 AM
The first time I saw that frame I had to have one.
Got in touch with my good friend Denis Curtis, of CMR fame, to build me one.

So as it turns out: they couldn't keep rings in the thing. The frame set up a sympathetic vibration in the motor that made the rings flutter. If the rings lasted the whole race, the bike probably won, but the bike dropped out of a lot of races with ring/piston failure.
... and that's why they only made a couple of them. Coolest LOOKING TZ frame out there
#11
1975 King Kenny won the Indy mile (dirt) on a TZ750.
At the end of the race Chris Economaki rushed through the crowd for his comments, Chris pushed the mic into Kenny's face and King Kenny said to the world "They don't pay me enough to ride that thing".
... and the bike was banned.
#12
What I have a problem with, being Canadian, is the later, '85 and newer, Canadian model RZ is a better bike but nobody wants them. A mint, mint '89 sells for $10,000 CDN, to a Canadian, Americans don't want them.

$27 grand for a '84 RZ is stupid. I have a TZ350B in better shape than that RZ and there isn't a hope in hell I could get $27 grand for it. They made 4200 TX250/350Bs and they made a bazillion '84 RZs. I think the seller did better than the buyer. That bike was "well sold".
#13
They're as reliable as any true racer can be... they're 2T so there isn't a lot to go wrong.
There are pattern parts available for MOST stuff. Cases are unobtainium. They don't really share any parts with street bikes. Cylinders can be nikosil'ed (they're chrome stock). The cranks are rebuildable. The bearings are "off the shelf". I think Nova does a transmission.

I have a fleet of TZ250/350s and have no problem keeping them going... I have also been collecting TZ parts forever.
Obtaining a TZ750 isn't easy or cheap. A TZ250/350 is easier to ride, easier to keep going and in comparison CHEAP ... AND it still is competitive (because of the TZ750's relative rarity at vintage race meets, they get lumped into classes where they don't stand a chance.
If you go to vintage meets in western US try to find Dave Crussel... nice guy, knows more about TZ750s than most.
CMR racing did a TZ750 frame... if you want one it could probably be arranged (I know a guy).
The TZ750 was a seminal bike... they kinda suck now... history marching on and all. I've not owned one, but have worked on lots of them. They are not a "fun" bike to ride. I might know of one for sale in Canada.

Internet gossip says there is someone working on a custom cased TZ750 with 4 Whampus jugs, that is rumoured to put out 250HP all day long, that Dave Crussel is supposed to ride.
#14
General Chatter / Re: 75' RD350 chain swap to 520..
April 26, 2025, 09:36:35 AM
A decent 520 chain will have no problem with the "higher power" of your RD.
A modern 520 has more tensile strength than the stock POS 530 chain.
I run a 520 on a GS1000 racer with twice the HP and almost twice the weight of your RD
The TZ250/350's of the day ran a 520 chain and the sprockets are drop in to a RD... the RZ front sprockets fit too. IIRC the Daytona rears are different, I think you use XT/TT rear sprockets
#15
Turning Wrenches / Re: 1977 rd400 dg heads
October 15, 2024, 10:07:30 AM
We will NOT speak of the mess the swingarms are