696 Engine modifications

[Raux]

Got an email from Dynojet. the PC V should be out last this spring for the Siemens controlled bikes !!!

[dbran1949]

Sorry if that seems an obscure question....

The 696 belts will be *way* too short if you raise the head 4.4mm.

This just came   arrived  in my email from CA-Cycleworks

Exact fit timing belts
http://www.ca-cycleworks.com/exactfit/?utm_source=California+Cycleworks+E-Newsletter&utm_campaign=40417a1e0d-Newsletter_1_18_2010&utm_medium=email

[Raux]

This just came   arrived  in my email from CA-Cycleworks

Exact fit timing belts
http://www.ca-cycleworks.com/exactfit/?utm_source=California+Cycleworks+E-Newsletter&utm_campaign=40417a1e0d-Newsletter_1_18_2010&utm_medium=email

thanks for the link.

[Raux]

alright... since i actually haven't even started tearing apart the motor... have one more direction i have looked at...

boring. no not as in i'm bored.

how big can the cylinders on the small bikes be bored out to?
the current bore is 88mm. i 'think' Brad has a 90 on his chart.

Bore/Stroke	88mm	89mm	90mm	91mm	92mm
57.2mm	695cc	711cc	727cc	744cc	760cc
66mm	802cc	821cc	839cc	858cc	877cc

[Link]

alright... since i actually haven't even started tearing apart the motor... have one more direction i have looked at...

boring. no not as in i'm bored.

how big can the cylinders on the small bikes be bored out to?
the current bore is 88mm. i 'think' Brad has a 90 on his chart.

Bore/Stroke	88mm	89mm	90mm	91mm	92mm
57.2mm	695cc	711cc	727cc	744cc	760cc
66mm	802cc	821cc	839cc	858cc	877cc

Not sure exactly what power characteristics your looking for but the new Hypermotard is using an 88mm bore stroked from 57.2 to 66mm to get 803cc outta the 696 motor so with that stroke your gonna have a shit load of torque can you 3rd gear power wheelies 

[Raux]

Not sure exactly what power characteristics your looking for but the new Hypermotard is using an 88mm bore stroked from 57.2 to 66mm to get 803cc outta the 696 motor so with that stroke your gonna have a shit load of torque can you 3rd gear power wheelies 

yeah i have the 66 crank waiting to be put in, just wondering if an overbore is possible with the smaller motors.

[brad black]

ca cycleworks have 91mm pistons for the small 2v motors.  but you'd need a custom piston to suit the late head piston shape i'd think.  all the old 750 to 788 kits were 90mm.

[Raux]

OK to revive an old thread with a new idea.

So i'm working on an idea to increase the volume of the airbox for the motor. And in doing so, i've been playing with some ideas about fueling and intakes.

I came into the possession of some intake cones with the shower injectors from a 999 (although haven't arrived so don't know if the ejectors are included or just the mounts... i do hope they are or i paid too much-- last second ebay grab, no time to ask questions)

so i'm thinking about building the airbox around the new injector/cones and pluggin up the old injector holes.

any thoughts on the idea?

[Duck-Stew]

Injection timing could be *slightly* off due to the increased distance between the injector and valve.

If you're going *that* far...why not have the throttle bodies over-bored? 

[Raux]

Injection timing could be *slightly* off due to the increased distance between the injector and valve.

If you're going *that* far...why not have the throttle bodies over-bored?  

ok, need to think about the injection timing issue. going to try and get the injectors as close to the butterflies as possible i think.
for the TBs...already planned

we measured everything out. we're going slightly larger on the ends and smoothing everything from there to get more flow to the reworked heads.

the stock butterflies are pretty big already, so not going to increase those, so there will be more of a venturi effect going on, maybe speeding up the intake charge enough to compensate for the increased distance from teh injectors

that with the larger volume airbox, the better flowing heads and reworked exhaust... DP ECU and the new PC V...  

[Duck-Stew]

Part of the reason the injectors on an SBK are placed above the bell mouth is to help keep the fuel atomized in the center of the air stream as it goes into the intake throat.  If you move the injector too far down the bell mouth (closer to the butterfly), would you lose some of that effect?  Maybe?  Would it be noticeable?

[Raux]

ok will look at that.

as soon as i get the injector setup in the mail. i'll start measuring things out.

[Raux]

ok another question...

sprockets. i'm going back to the 15t front sprocket due to changing the ride height and want to give the chain more lift off the swingarm in the front. but what about rear sprockets>

the stock 45 is going away for sure, but to what?

any ideas? lightweight? up how many teeth? 46 or 48 is that all available?

[dbran1949]

Not sure if this will help. I made this table a while ago while trying to decide what to do with my S4RS. It is simply a selection of 14 and 15 fronts with rear sprockets from 38 through 50, then sorted by ratio
This way if you are running a 14-45 @ 3.214 you can go to a 15 front then choose either 48 or 49 to maintain similar characteristics. (very simple excel spreadsheet as you can imagine)

Front   Rear   Ratio
15   38   2.533
15   39   2.600
15   40   2.667
14   38   2.714
15   41   2.733
14   39   2.786
15   42   2.800
14   40   2.857
15   43   2.867
14   41   2.929
15   44   2.933
15   45   3.000
14   42   3.000
15   46   3.067
14   43   3.071
15   47   3.133
14   44   3.143
15   48   3.200
14   45   3.214
15   49   3.267
14   46   3.286
15   50   3.333
14   47   3.357
14   48   3.429
14   49   3.500
14   50   3.571

[Raux]

perfect thanks. going to get the lightweight 48 then.