Stroker crank in B12

[opalmanta]

New here to the site. I am collecting parts and info in hopes of building my B12 into a big inch street bruiser that I can also start making passes down the strip again on.  I am just a few years from retirement as a machinist for the City storm and sewer dept. Stinky job but pay is good. Any way I want to start on this bandit 1200 01' model. Already have extra head as a core for the followers and cams to be sent to Megacycle to be welded up and redone. I plan on getting oversize valves and doing a bit of port work. Bought two Big blocks for the project. One is a virgin, never had sleeves installed and seems to have a bit more material to work with. The second one is lighter in aluminum content and appears to have sleeves in it that can be cleaned a bit and pistons installed (86mm for a 1371) . This block is o'ringed and has more and thinner fins than the virgin unit. I have some Gen I busa rods to use.  I plan on sending the crank(B12) out for welding and stroking (4mm-5mm) . Wondering how well does the Hyvo style timing chain hold up in a performance application when RPM is held down to no more than 9000? Or do I need to score an earlier GSXR 1100 crank that used standard style chain.  Already spent some time reading many posts on this site but did not see info about this. I look forward to this build and posting the results here on the site. 

[Gixer1460]

Without seeing the two different cranks side by side, I would guess that the hyvo type would be slightly stronger around the sprocket due to shallower teeth compared to the deeper tooth profile of a roller chain tooth profile? I don't recall any reports of the hyvo chain being weaker through normal use - obviously heavier poundage valve springs and increased lift cams may add more stress on the chain / sprockets which could require just more maintenance observation? A 9k red line should be well within the chain's capability for 'normal' life. Certainly a stroked crank will help in that respect - mine is a +5mm stroke but done from billet and not a forging that has been welded and i've set my max @ 10.5k.

Sounds like an interesting project so i'll watch for developments.

[opalmanta]

At one time Falicon offered billet cranks up to 8mm additional stroke but that company has left sunny Florida and gone to Ohio I think. Stated they no longer do crank work.  There are rumors of one of the 8mm falicon billet cranks floating around here. I am trying to chase it down. Not sure of how much clearance grinding needs to be done in the cases to swing all that. Currently trying to wrap my brain around the oiling system changes (re routing) needed when using these big blocks. Both of them have a blockoff pin in the oil transfer goove leading from the rear stud hole.  That tells me I have to route oil from that stud to the front some how but not alter the use of factory restriction inserts. Like I said studying this oil system , I have factory manual showing oil routes.

[Jaydee]

3 hours ago, opalmanta said:

At one time Falicon offered billet cranks up to 8mm additional stroke but that company has left sunny Florida and gone to Ohio I think. Stated they no longer do crank work.  There are rumors of one of the 8mm falicon billet cranks floating around here. I am trying to chase it down. Not sure of how much clearance grinding needs to be done in the cases to swing all that. Currently trying to wrap my brain around the oiling system changes (re routing) needed when using these big blocks. Both of them have a blockoff pin in the oil transfer goove leading from the rear stud hole.  That tells me I have to route oil from that stud to the front some how but not alter the use of factory restriction inserts. Like I said studying this oil system , I have factory manual showing oil routes.

I have all Falicons old PDF's from years back saved somewhere

A lot of their cranks were 7mm extra stoke, such as for the Hayabusa.. They would normally offer (for example) a +7mm crank with matching set of -3.5mm shorter rods. This would make move the extra stoke down to the bottom of the pot meaning that normal thickness gaskets could be used as pistons were below the deck height. Compression and squish were pretty much as stock as a result. 

You probably wouldn't get away with some machining of the crankcases for clearance though.