[86gixxxer]

my engine builder is telling me that the alternator that was installed on my first gen 750 engine no longer fits. it was my engine that developed a rod knock, so i know that it ran well, and had the alternator installed without issue. supposedly, the engine builder is telling me that i need a "later style" alternator, which probably means from an oil-cooled second gen engine.

this sounds odd to me, so i figured i'd ask; is there a difference between a first gen alternator and the second gen altenator? is it possible that if the crank was replaced, to cause the alternator to NOT fit/engage?

i'm confused, and don't want to disagree with the engine builder, since i am not sure if what he is telling me is true.

thanks

 

[Beairsto Racing]

The 1st gen 750's and 1100 used different sized alternator drive gears...you can swap them around...the mount itself is the same.
I'm more familiar with the Slabby's, but I would hazard to guess, you're having a similar issue with your bike...try another alternator gear.

 

[86gixxxer]

The 1st gen 750's and 1100 used different sized alternator drive gears...you can swap them around...the mount itself is the same.
I'm more familiar with the Slabby's, but I would hazard to guess, you're having a similar issue with your bike...try another alternator gear.

thanks for replying. i did not know about the 750 and 1100 alternator gear size difference.

BUT, isn't the alternator driven off of the clutch side? meaning, even if my engine had the crank, bearings and connecting rods replaced, but NOT the clutch assembly, that should NOT affect the alternator no longer fitting/engaging? the alternator was installed and working properly before i dropped off the engine to be serviced.

the good news is that i have an extra alternator, and so does a friend, so between them the two alternators, i'm hoping that one of them will fit/engage...otherwise, i do not know what to do. it just doesn't make sense to me...

 

[Lachie]

Your right, if the clutch hasn't changed then the alternator should still fit. I'd be asking for an explanation TBH.
Did he put the same model crank in? The clutch must match the crank, gear type and count.

 

[86gixxxer]

thanks for the reply.

i finally have the track engine in my possession, and i never really got a definitive answer on why the alternator did not engage/fit.

what i do know is that the engine had a "19C" crank, which means it's from the 90-92 750, and it was replaced with a "27A", which means it's from the 85-87 750. not sure if the 85-87 750 and 90-92 750 cranks caused the alternator gear to not fit, but i'm thinking it shouldn't, because from what i understand, the alternator connects to the clutch basket/gear, but i don't know.

oh well, i will have to find out how this engine performs soon. i'm hoping that the engine rebuild/cost is worth the money i spent.