I may have found an "old superbike" engine for this type of yamaha. I was thinking of putting it into my current track bike, basically a stock 1994 YZF750. I've been doing some research before commiting to buy this engine and I have a question that I can't find the answer to. Hopefully there's an yamaha engine GURU here on the board. The engine has various goodies, crank, rods, pistons, cams and head work. The problem I'm having is with ignition timing. From the SP materials I can find the ignition timing was 5 degrees, while for the regular R version the timing is 10 degrees. I would be removing my stock R engine, replacing it with this "superbike" engine and pluging it into the stock ignition box. I'm assuming the "superbike" engine was built for the YEC kit ingition unit, 5 degrees. If the engine is set up for ignition timing of 5 degrees but the firing is 10 degrees what will happen? Will the engine be damged? If not damaged, I understand the power will be different. The only solution I can think of is to find the corresponding ingition box. Any other ideas about fixing this ignition timing problem for this era yamaha engine? Thanks!
I think you could just just replace the ign advance on the race motor with that of the stock motor or I am way off base
Call Doug @ JJP - Ive seen them building several OW01's here recently - (828) 683-2538, if Doug doesnt know , Im sure Bill Brown can help - Dont know his contact info off the top of my head though - Think its pretty cool, even as old as those monsters are, Yamaha still provides kit parts for them -
Thanks for the contact info. I'll call him about it. I'm thinking that some sort of change to the ignition advance would need to be made. I was thinking to myself, that changing the reference point by 5 degrees to get it to fire at the correct time, i.e. trick the ignition box that 5 degrees is really 10 degrees. I don't know if this is physically possible. Thanks again!
Let me know what Doug at JJP says, he has my kit manuals and my OW01 they are building, I'm now curious as it has a YEC ECU and I don't remember if the timing is stock or if it was adjusted when the engine was built to the kit specs. In the past I've done kit ECU's with both OW01 and YZF750 stock engines and never had an issue. Never tried a kit engine with stock ECU though. People have been stuffing 1000 engines in the SP's and R's and I've never heard of this being and issue.
My concern came about by either reading the Hayes Manual specs or one of the Yamaha technical bulletins from back in the day. I believe the SP stock ignition timing is 5 degree and the stock R is 10 degrees. If the spark is sent 5 degrees earlier, for an engine with higher compression and different cam timing, I don't know what will happen?
