Cdi for big bore 750

[ziggy]

Does a big bore engine require different cdi? Can't recall people changing their cdi's when going 1216 but how about 884, 907, 955? Would these run ok on standard 750 cdi? And if not, what sort of cdi would they require?

Will be building a 907 soon and will have to make a loom for it from scratch and, as much as I should be ok with everything else, I'm not sure about cdi.

Cheers

[dupersunc]

ignitech. Set your own advance curve and rev limit to suit the engine.

[canamant]

Doesn't make much difference really.  Look at most engines and full advance is similar irrespective of cylinder size.  As for rev limits, weigh the pistons/rings/pins and compare with standard. then do the load calcs to see what revs will give the same load as the standard piston.  My 860s use standard ignition systems  but I limit the revs to 10k with the odd squirt to 10.5 if absolutely essential.  No biggie really as peak power is at 10k. The piston assembly is slightly heavier than the 750.

[ziggy]

Cheers for that chaps.

Is it possible to adjust rev limit on oem cdi @canamantor are there stand alone limiters?

Edited April 8, 2018 by ziggy

[canamant]

The slabby ones are sealed units so no adjustment.  Even if you did get it apart, and the components were get-attable I would not bother trying to tweak a 30 year old electrical component.  Just keep an eye on the tach and make sure the gear link is positive with no slop.  If you really want an adjustable unit - the ignitech is supposed to be a good reliable unit but I haven't tried one myself.