1100 to 1200 conversion

[oldktmdude]

  G'day everyone, back in April I started a post looking for a set of 1200 pistons to go into my '85 1100. Just a bit of an update as to how I got on.
After posting a wanted add on this site, looking for a set of good used 1200 pistons (money is a bit tight at the moment) Harvy, from just up the road (1,500 klms north) came to the rescue with a set of low milage pistons and the 1200 cylinder block they came from. A big thank you to Harvy.
Four sets of standard size rings were purchased from    http://www.boats.net    Great prices compared to genuine part prices over here! New non-genuine 1200 gaskets were sourced from a local bike shop. After a bit of honing the bores came up looking like new and still well within  tolerances.  New wrist pin circlips were installed as the bottom end was assembled. After inspecting the valves, some pitting was evident, so  I lapped them and reassembled the head. After fitting the head and setting up the timing, some valve shim adjustments were necessary, (due to lapping the valves) as valve clearances were checked and found to be good before pulling down. Carbies and exhaust system went back on without any problems and fuel tank and battery were connected. Started within 3 seconds of hitting the start button. Sounded great except for a slight miss
at idle. Turned out to be a low float level in #3 carbie. After an adjustment the miss disappeared. Due to some very wet and windy weather I didn't get to ride it for a few days but in the meantime I came across a web page http://www.mototuneusa.com/break_in_secrets.htm describing a running in method that made a lot of sense to me.             
It was a procedure I have used to run in two stroke moto-x and enduro bikes before but was never brave enough to apply to EXPENSIVE road bike rebuilds. So to cut a long story short I followed this method and the rebuild was run in after 20 miles.
   Just as a side note to those of you who may be interested, the piston ring end gaps in the 1100 bores were around 45 thou, 3 times the specified 15 thou service limit. The old motor still started well, performance was still very acceptable and used very little oil.  Testament to the great motor these FJ's have.        Peter.

[andyb]

The breakin that is described on that site is specific to the new engines that use a coated cylinder bore for the most part.  Do a leakdown/comp check to be sure of where you're at.  Entirely possible that it'll work on a rebuild with modern materials though, even in an uncoated cylinder.

[oldktmdude]

  G'day andyb, a leakdown/comp test is a good idea, just to check on the breakin progress. The article does state that this process is applicable to both coated and non-coated bores. He does mention that modern machining processes and better materials allow for this method of running in and I assume  that FJ's fall into this category.
  I'm going on a 200km (120 mile) ride in the morning so I'll do a comp test when I get back. I'll let you know how it goes. Thanks for your feedback.

[ccsct203]

I did a 1200cc swap on my 1100.
Cylinders and wiseco 10.5 to 1 pistons
bolt-on simple swap