As I recall from posts on here years ago, The head has to be removed first and then the engine finagled into position in the frame. I also want to think that you have to reinstall the head and reassemble everything before bolting the engine to the engine mounts.

I do know that member Fatcaaat modified an SL70 frame and fabricated a removable frame strut to make engine swaps much easier for him.

 

Thanks for the reply

 

Just out of curiosity, what is that rear wheel to the far left in the top pic attached to?

 

1981 xr500 with a yamaha tt 500 engine

 

You can put the chinese midblocks in these by taking the head off first and then putting the motor in and then putting the head back on once it's in the frame. I have not tried to put a 190 in it, but I've seen someone with a 190 daytona in one of them.

 

The last time I raced that bike was in 1977 and got smoked by all the YZ80s then blew 3rd gear at another race and its sitting since 1982 . There is no substitution for horsepower . I hope any 190cc will fill the space if I can get it to fix . I never even knew there were crate motors for these things. If anybody has a picture of any 190cc motor in a sl70 I would appreciate it.