1981 YZ 250

1/28/2014 11:07am
There's only one way to find that out.

I'd imagine the gain is negligible. Probably only worth it if you need to replace the parts anyway.
Probably easier to lose some mass in the driveline somewhere for a similar gain.
Ardfarkl
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1/28/2014 11:47am
Gotcha. That actually makes sense. The only issue is my clutch basket is pretty nothched. We will see. Thanks!
1/28/2014 2:23pm
The 80-81 helical geared baskets have a different number of teeth , than the 82 up baskets and primary gears
You could always rivet a newer basket
on your 81 gearset
Barnnet or Hinson might have a basket
that matches or would also work with your
gear set
I.D , O.D , Depth match

I lucked out a found a NOS basket at a toyota dealership in alabama.
DirtDgr
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2/17/2014 8:24am
The 80-81 helical geared baskets have a different number of teeth , than the 82 up baskets and primary gears You could always rivet a newer...
The 80-81 helical geared baskets have a different number of teeth , than the 82 up baskets and primary gears
You could always rivet a newer basket
on your 81 gearset
Barnnet or Hinson might have a basket
that matches or would also work with your
gear set
I.D , O.D , Depth match

I lucked out a found a NOS basket at a toyota dealership in alabama.
I have thought long and hard on that one!

Just have never followed through.

My clutch fades to the point of non existence on my 250 and my 465 in big bottlenecks in cross country racing.

The Shop

MaxPower
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2/17/2014 4:27pm
I very very much doubt it could work, but I have some kind of billet basket from a 400/426 Yamaha with no gear on the back. Its beyond a long shot , but if you give me your info I'll get you dimensions . If it could work, you can have it.
Yamaha kickers still fit newer bikes so there is a snow balls chance this could too
Ardfarkl
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2/18/2014 8:52am
What info would you like?
MaxPower
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2/19/2014 6:03pm
Your email .
You can try sending a pm. For some reason I have had a issue with them on this site.
That would be great if it worked . Id love for someone to get use from this thing
Ardfarkl
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2/20/2014 4:45am
Sent. let me know if you got it.
5/17/2015 11:13am Edited Date/Time 5/17/2015 4:56pm
Bump for a cool thread. Hey there is an '82 IT250 local to me at a great price complete and running.
I may be able to purchase a G or H YZ250 frame and swingarm from a friend.
I am thinking of building up a race bike with this package. I know gearing would be
off a little for MX but that could be addressed. Read the '82 IT250 test on the Yamaha It Aussi forum and
they mentioned it's basically an '81 YZ250 with a rear frame loop and some case guards as well
as the lighting, final drive and other stuff. It remains a 6 speed like
the '81. Just thinking out loud.
5/17/2015 11:39am
Shawbridge, the 81 YZ250 is a 5 speed.
Ardfarkl
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5/17/2015 2:55pm


Thinking about putting this on the '81, but also freaking out about opening it too. What do you guys think?
5/17/2015 3:03pm Edited Date/Time 5/17/2015 3:04pm
I rode an 82 IT 250 Eric Gorr did - that was a good motor.

I'd have him do my 81 YZ250 if I still had it
MaxPower
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5/17/2015 3:59pm
Bump for a cool thread. Hey there is an '82 IT250 local to me at a great price complete and running. I may be able to...
Bump for a cool thread. Hey there is an '82 IT250 local to me at a great price complete and running.
I may be able to purchase a G or H YZ250 frame and swingarm from a friend.
I am thinking of building up a race bike with this package. I know gearing would be
off a little for MX but that could be addressed. Read the '82 IT250 test on the Yamaha It Aussi forum and
they mentioned it's basically an '81 YZ250 with a rear frame loop and some case guards as well
as the lighting, final drive and other stuff. It remains a 6 speed like
the '81. Just thinking out loud.
That is a cool bike. Why change the swingarm and frame? Tweak the engine and suspension and race it as it. Those are cool bikes. If you did anything find a euro white YZ tank to replace the bigger IT tank to make it slimmer for moto. You will always have a slight psychological advantage beating someone on a full blown mx bike with a woods bike and a lit head light.
5/17/2015 4:59pm
Cool, yeah the '80 was 6 sp and '81 5 sp correct. The '82 IT250 is for sure a 6 sp. I'll see what transpires this week and will pull the trigger if all is good to go. Good idea on using same frame maybe just cut off the rear frame loop and use a YZ tank/seat as you say, thanks Max !

Ard, that number plate is dope for a nineties bike, I had a vented Acerbis on my '99 YZ400 for awhile. I got tired of the look though.
MaxPower
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5/17/2015 7:25pm


These are cool looking bikes
Maybe because I've seen so many more YZs I think I like the look of the IT better
5/17/2015 7:48pm
Cool nice pic !
Want a good laugh here goes :


MaxPower
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5/18/2015 5:35pm
oh my
5/21/2015 6:48am Edited Date/Time 5/21/2015 7:02am
Well turns out it's an IT465, so off I go tonight to put a deposit on it until I can get back to pick it up later ! Going to be a motocrosser once done, but will leave the lighting coil on it for shits and giggles as MaxPower sais.

Sorry for the highjack ARD, have more photos of your ride for our motivation ?

On edit : maybe a 250 after all, I'll update you guys tomorrow. The seller is clueless me thinks.
MaxPower
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5/21/2015 9:31am
If its that bike in the pic its a 490
5/21/2015 3:44pm
It's an '81 IT250, frame no 4V5, I'll pass on it. 465 would of been worth snapping up for sure. I already have a '79 250 that I need to get working on.
MaxPower
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5/21/2015 4:13pm
Sorry. I didn't see the triangle swingarm on my phone screen
5/23/2015 8:22pm
MaxPower,

What would it take to make this into an YZ bike like ARD's ?
Could the porting and pipe be changed to give it a motocrosser like powerband ?
The frames are same, would just cut off the rear fender stay and remove the skid
bars under the engine.

The gearing is taller but after having looked over some YZ G and H tests it's fairly close.
1 st is lower, but 2nd through5thg is near same, 6 the being an overdrive.
I could overcome this with final drive tweaks.

I'd do a 43mm front end though, I think it's 38 as it is.
Serial No. starts with 4V5 ( '81 IT250 )

The bike starts and runs, shifts fine. I may be able to get it for 400

5/23/2015 9:51pm
I thought the YZ's were center exhaust port with a split downtube while the IT's were side port with a single downtube(?). Maybe that's just the 465's?
barkhard696
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5/24/2015 4:54pm
The '83 IT250 used the '80 YZ250 motor with different porting and gear ratios, a heavier flywheel and a lighting coil. Unfortunately this motor was put into a 490 frame, so the bike was a big, heavy beast.

Typically Yamaha kept the IT one-two years behind the YZ but given Yamaha's love of parts recycling, I'd say virtually all the IT250 motor parts are sourced from the YZ of 1-2 MY previous. The '81 and '82 IT250 are the same bike, the only diff was the entire 81 IT line was white.
barkhard696
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5/24/2015 5:10pm Edited Date/Time 5/24/2015 9:46pm
Shawbridge, it's going to take a lot of work to get the IT close to the YZ.

Beyond obviously removing all the off-road foof, you're going to have to do some engine work (lighter flywheel, porting, probably a bigger carb, ditch the spark arrestor for an MX silencer), and source replacement plastics (I doubt YZ plastics will fit). For any year, IT plastic is almost impossible to find. Yamaha was awesome at recycling mechanical parts, not so much with plastic. Then you've got the expense of upgrading to 43mm forks.

Because these were built as road-going bikes for Asian markets, the IT was considered a separate line in more respects than you might think at first blush. The IT465 did have a lot in common with the '81 YZ465, and the '83 IT250/490 were based on the '82 YZ490. But I think the '81-2 IT250 was an orphan.

Look at the '82-3 IT175 -- mechanically similar to a hybrid of the YZ100/125. But really neither. I think its like this with the '81-82 IT250.
5/24/2015 7:40pm
Thanks BarkHard, I did some research read up on the test and the '81 IT250 is basically an '80 YZ250G, same frame and running gear they added on the rear frame loop. But yeah on the flywheel, silencer etc. I offered 350 we'll see where that goes. At least it runs. My '80CR125 is for sale to fund this !
450exc115
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5/26/2015 8:05pm
Thanks BarkHard, I did some research read up on the test and the '81 IT250 is basically an '80 YZ250G, same frame and running gear they...
Thanks BarkHard, I did some research read up on the test and the '81 IT250 is basically an '80 YZ250G, same frame and running gear they added on the rear frame loop. But yeah on the flywheel, silencer etc. I offered 350 we'll see where that goes. At least it runs. My '80CR125 is for sale to fund this !
80 YZ250 = very cool and is worth getting at that price. The ITs were in a class of there own back then and unless you are an A card holder in motocross you might be able to go faster on the IT motor with the flywheel added. I put a 450R flywheel on my CR250R and the increase in traction and added over rev made it more fun and easier to ride.
colinac34
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1/12/2016 9:18am Edited Date/Time 1/12/2016 9:19am
Hi i have a project yz250 1981 model and i was wander were everyone has been getting parts for 1980/1981 yz250 models. Just wander if i can get some help.

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