YZ465 question

[mainline]

excuse my ignorance but did these usually have a frame loop behind the seat or is this thing a bitsa?

http://cgi.ebay.com.au/1980-YAMAHA-YZ465G-YZ-465-VMX-Vintage-Motorcross_W0QQitemZ330207949816QQihZ014QQcategoryZ102690QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Maico31]

It's a definite Bitsa.. must be an IT frame. Looks like it has 38mm forks too, the 465 had 43mm forks.

[Nathan S]

The YZs didn't come with a frame loop.
Not sure what's going on there: An IT's frame loop sits a lot further back behind the seat than that. Maybe an add-on during the bike's previous life as an enduro bike or something?
Looking at the full-size pic of the LHS, is it a bolt-on? Again, and IT frame has an extra piece of tube to triangulate the rear section.

Everything else looks YZ, FWIW. Should have a TLS front brake, which appears to be replaced by a SLS one. Not sure about the forks either - look to be 38mm but should be 43s.

I guess the seller quoting the correct serial number suggests that it's a real YZ465G, but then again, it might just be the engine number... (sorry for the cynicism, but we are talking about Ebay after all).

Edit: Duh... no engine number means that the quoted serial number 'has to be' the frame number. I'd be interested to know what the prefix cast into the barrel is (should be 3R5). The missing engine number might be nothing or might be a sign of a bike with a questionable history - easy to tell though, because Yamahas have the engine number stamped over a textured finish, so if the number has simply been ground off to hide it, then the texture will be gone too.

Edit2: Something else about the forks looks wrong... Maybe too short overall? The YZ-G forks were super-long (for some weird reason that I've never understood) so they should have about 60mm sticking out of the top triple clamp, or the bike should sit too high in the front.

[wesley]

OK guys i have a yz 465G and a yz465H,,,the changes...
yz465G had 38mm forks
yz465H had 43mm forks,,this is the changes over the G model,revised port dimensions slightly higher and wider intake ports and wider exhaust port,completely new exhaust system ,the G had the lumpy headpipe and the H and the more conventional straight design,the H model got stronger engagement dogs on first gear and the gearbox breather got moved to the clutch arm,the cdi got a hotter low speed spark in the cdi to improve starting a roomier airbox,the H model had a thinner walled frame to reduce weight,the H model footpegs are 10mm higher,the H model steering stem is hollow,the 465G had a steering geometry its stem was set at 30 degrees and trail 5.12 inches,the H now has the rake tucked in 1.5 degress and the trail 4.72 inches,the rear shock on the H  was revised, the H model rear drum was reduced in size by 10mm the same as the 250 to reduce locking,a bigger rear axel,the H model fuel tank in a little storter and wider,,,,,thats about it and apart from the grafix changes,,,the G model had more bottom end power but the H had more top end power..hope this helps!!!!

[Viper666]

I tooo looked at this and had the same assumption till I looked closer.
I think it is a YZ.
Looks to be an add on handle, maybe to help lift onto a stand.
Swingarm deffinitely YZ, IT's had the quick release.
No bash plate but may have been taken off.
Very tempted to buy but didn't