YZ 250B restore

[SteveYA6]

Hi, I am new to the forum. I have a YZ 250B that I am looking at restoring. I hope that I can help and get help from you guys.

Here is the bike as we loaded it on Saturday evening.






I have done a bit, but will post more pictures as I progress along.

[OverTheHill]

Oh Mate, i was lucky to have ridden one of those for a season [after it had already done a season]. Best bike i ever rode--well it was at that stage & probably remained my favorite right up to my 465G in in 1980, maybe that's stretching it a bit but anyway. Lucky you & great to see another one found to be bought back to its former glory. Cheers.

[Rossvickicampbell]

ooooh - bit of work there.  I have a 360B that I agree with OTH - best bike I have ridden.

I have an MX B airbox (body only) that will fit and maybe some other spares also when you work out what you need.  Lots of contacts for spare parts as well.

All the best

Rossco

[SteveYA6]

Thanks guys, I managed the teardown quite successfully, only three issues, one sheared bolt, the front engine mount bolt frozen and the swingarm bolt frozen. I have taken the frame in to see if we can get the swingarm bolt pressed out gently, before I start cutting anything, although I think cutting may be inevitable.

Here are a few more pics of the bike stripped.

bucket of bits, I am quite happy that the old fibreglass is still good, if a bit dry.



front forks - definitely a spot of new chrome needed here.



Bare frame with it's swingarm bolt.




And of course the rear shock - my suspension guy is going to get excited when he sees this - he got really excited when he saw the 79 IT175 back shock.

[Rossvickicampbell]

swingarm with the vertical stay shows an early model B.  I have a complete spare shock if needed.  The fibreglass parts you show are available aftermarket - would just have to clear some Alzheimer's and remember where

[SteveYA6]

Just been to the engineering shop and the swingarm is now not part of the frame. All removed and no damage done. He also kindly removed the sheared bolt. Looks like this bike wants to be restored, it is fighting much.

[Rossvickicampbell]

good to hear - have heard some horror stories about getting swingarm bolts out.

[80-85 husky]

it will be a pretty sweet bike when your finished....polishing and cleaning with Mr Sheen

[SteveYA6]

Isn't it awesome restoring Yamaha's. Our local agent had all the swing arm parts in stock.

[BSA-B5]

where did you find that beauty.

[OverTheHill]

The 360 my boss had for a while & was probably second hand [although we may have sold it new] leaked behind the air filters because the base was only pop riveted to the fibreglass airbox & the dust got through behind, Sealed it off properly & was ok but damage had been done previously. Also i suppose seal off the flange where the inlet hose goes to the carb. This is all from memory [how many years ago lol]. 250 i had a loan of for a season was just awsome even though it had done a season previously. Think i mentioned all that bit going back some.

[SteveYA6]

We found it in an old guys garage. I went with a mate to look at two IT 490's, there were no IT's just this. The guy was just grateful for the garage space.

[SteveYA6]

Just fetched some of the electroplating. Not too bad for parts that are 41 years old.

[BSA-B5]

Well, That was a great fined.

[Rossvickicampbell]

Steve - is it going to be a rider/racer?  If so get rid of the standard kick start knuckle now before you break something - if I remember rightly the earlier DT1 is MUCH better (but can dig up the info to confirm if you like)