250 Auto 80 - 82

Not all 250 swedes are the same grasshopper....

FAKE NEWS !!!
The 250 -87 & 88 has 70.8 mm stroke. The 390-420 has a 71 mm stroke.
Anyway the 250 vs 430 has a 3.2 mm difference stroke, so it must be 1.6 mm up and
1.6 mm down.

I use cylinder 16 11 790-01 (250 CR -81) instead of 16 11 772-01 (258)
The crankcase 16 11 828-01 (420 AE -81) instead of 16 19 820-01 and 16 19 819-01 (MC 258 left and right crankcase) for better gas flow..
Crankshaft 16 11 792-01 (MC 258) for correct stroke
The gearbox are 258 except for 1'st gear second axle 16 12 747-01 and first gear first axle 16 12 746-01 instead of the 258 1'st gear, second axle 16 12 723-01 and first gear first axle 16 12 704-01. With this I have another ratio as I believe is better when I have 250 CR spec.

I am very interested in this, I have a bottom end which I hope to graft a 250 top end too so will look forward to your progress Fabrice.

i like the plug cap!

Note, I believe there is a difference in porting between the auto and standard trannys. Could the auto tranny hold up to the cr porting that has more power?

Isn't the length of the connecting rods all the same in the 70's early case between the 250, 360, 390, 420. Then the connecting rods changed in the newer case from '82 on in the 250, 430, till 88 I believe, the 500 is a different rod. The position of the crank pin hole changed to adjust the stroke.

Sorry for my other posts we went from 80/82 auto to 87/88 LC auto. Different beasts.

The flywheel weights are to calm down the hit.

I was told years ago when the auto tranny was raced by a pro rider here I believe it was Kevin Hines he had no problems, but he was on the gas all the time. It was the up and down constant shifting were it hammered itself apart. This kind of tells me the auto must be modified. There's a older racer in Stratford,ct who raced a 390 auto dirt track.

you are confused Bill. he is talking about FLYWIEGHTS in the auto transmission. NOT flywheel weights.

I saw that trike earlier in one of claudes posts. very cool. and my apologies to BIG BILL.

No problem. I'm learning. Flywheel weights in the drive train is different. do they allow it to shift gears?

In Belgium there's 2 days but sold (250AE 81)

Left and right brake pedals..

wow, nice work

Replacing a small part from the frame

The replaced and new framepart

The bracket for doublebrake is soon on place

Kemppi is my friend...

Nice job Micke.

Now I have got back the frames from the powder coating, I have both my 250 and 420 as new and it's just the assembling left

Wow, great job on the pics! Looks like a really fun project