YZ250-A ignition cover

[firko]

It's probably so obvious that I can't see it but what's the difference between a DT1, DT2 and YZ-A/B ignition covers other than the raised lettering on the very first DT1 version?
                                                                       
                                                                       
                                                                       

[Tahitian_Red]

One word: Magnesium.

At least that's what I read somewhere.  I already picked up an aluminum ignition cover, but I'm still on the hunt for a Clutch cover. 

[firko]

I wonder how many YZ-A's still have the original mag cover? I'll have to go through my ignition cover stash because I've got one that seemed noticeably lighter but didn't think much of it at the time. Out come the scales....again

[Davey Crocket]

Only the B has magnesium clutch and ign covers.....the A's are alloy. Another point is the B ign actually sits about 10 mm higher because it has the later type coils....the inside of all those covers are totally different. You know you should ask the cripple Firko.

[firko]

Only the B has magnesium clutch and ign covers.....the A's are alloy. Another point is the B ign actually sits about 10 mm higher because it has the later type coils....the inside of all those covers are totally different. You know you should ask the cripple Firko.

So, you decrepit old goober ....Are you telling me that the DT2 and YZ-A covers are externally the same, overlooking different casting marks inside? Another question.....is the YZ250-A barrel stud spacing the same as a DT1? I know the 360's have different rear spacing but wasn't sure of the 250's. I just bought a YZ250-A barrel so I can now use my YZA transmission and clutch and clutch cover in a set of DT1 cases and build a poor boy YZ motor for my little spare Hindall. Ah sweet joy.

[Davey Crocket]

The barrel will fit old timer.

[Slakewell]

With the knowledge I have now I would love to know how hard a YZ A 250 would run with the right reeds and cage and a well tuned 38mm Bing PVL ignition,more compression,  except I probably know its about 3 moto's before the dogs wear off 5th gear running that setup.

[Iain Cameron]

Some of the early covers DT1 have only two mounting holes . Iain

[KB171]

This'd be a YZ 250 B cover.

[firko]

With the knowledge I have now I would love to know how hard a YZ A 250 would run with the right reeds and cage and a well tuned 38mm Bing PVL ignition,more compression,  except I probably know its about 3 moto's before the dogs wear off 5th gear running that setup

I've got a YZ250-A transmission in my methanol DT1 piston port engine that I got off a bloke who'd replaced them because the dogs were rooted. I undercut them myself with a die grinder, didn't bother re hardening them and the gearbox survived three solid years of thrashing in the DT1 from Hell...and you know the flogging that old beater copped Slakey. I had a look at the gears a couple of weeks ago and they're still in good usable condition, ready for new adventures .

Thanks KB you saved me a lot of weighing......I haven't got one with Magnesium cast into it. I guess I've just got plain old DT1 stuff. Oh well, at least I've got the right YZ-A clutch cover and a sprocket cover from Joan Engineering.

[Davey Crocket]

The one good thing about evilbay is that those impossible to find parts are now accessable....there are plenty of YZA gears available an evilpay most of the time.The 250/360 A/B Y zed engines are works of art when you look inside one....no wonder Yamaha lost a fortune on them, but it sewed the seed for later models and perspective buyers.

[firko]

Well, the deal's done and the YZ-A barrel's on its way. What reed valves fit? Is there a V-Force kit to suit or do we adapt one from something else?

[Davey Crocket]

V force fits, I'll get the p/n for you.

[firko]

This supposed YZ-B magnesium ignition cover is for sale on Marks Swapmeet this morning for a cheap $75 BUT it doesn't have "MAGNESIUM" cast into it like the one KB posted above. I'd like to buy this but don't want to get stuck with another DT1 cover so what's the story YZ-B Brains Trust?
                                                                                           

[Davey Crocket]

That's just a std alloy one Firko.