Can I swap this part? Please help

[Lquad71]

I have a 250R 86 motor that has a seized piston.

I also have rod fowlers old 88 or 89(cant remember) 250r motor with a bad transmission.

Can I take the head from the 88/89 motor and put that onto the 86 bottom end so I have one good working motor? If not what can I do to make it work?

[DezSled]

http://assets.hookit.com/rfs/82/70f42696-fe6d-4f80-b8ad-e4f7da962dc1.jpg?size=520

Dean Sundahl & Rod Fowler Yamaha Banshee introduction '86 Baja 1000 starting line

[sameltoe]

I like the handicapped sticker on the hood of that r!

[DezSled]

IIRC I think he had a prosthetic leg!

[Lquad71]

does anyone know if I can do this? and I like the pic:D

[C-LEIGH RACING]

Yes, you can mount the 88/89 cylinder on the 86 bottom end, but you will need to use the 85/86 model piston because of the 86 short rod crank.

You need to check to make sure that is a short rod crank in the 86 engine.
Did the 86 engine have a spacer plate under the cylinder ??.
Neil

[Lquad71]

if it has a shorter rod, then why would I need to replace the piston and not the rod? I am not saying you dont know what you're talking about but it would just make more sense and would clear things up for me. Thanks.

[beastlywarrior]

Originally posted by Lquad71
if it has a shorter rod, then why would I need to replace the piston and not the rod? I am not saying you dont know what you're talking about but it would just make more sense and would clear things up for me. Thanks.
Because the piston pin is in different spots on the long rod and short rod motors so you need to match the piston with the rod but the heads never changed right?

[C-LEIGH RACING]

Originally posted by Lquad71
if it has a shorter rod, then why would I need to replace the piston and not the rod? I am not saying you dont know what you're talking about but it would just make more sense and would clear things up for me. Thanks.

One reason, is because you said the 86 seized up, so that piston is no good. Another reason is, you cant use the 87/88/89 model 250R piston on the short rod crankshaft, because the piston skirt will hit the crank at BDC.

The Sundahl engine, does it have a spacer plate under the cylinder ??.
If it does, it probably has the 85/86 model 250R piston, so you could just switch it over.
Neil