Game time

[Krandall]

Actually it's neither really of what you're thinking

All 9.2:1 (stock) vs 11:1 vs 14:1 means is

That the higher the number the more its compressing the air inside the cylinder. so. the higher the point, the bulkier the top of the piston will be.


I'm not saying run a 14:1  just weigh your options. Preddy runs XC and has a stock bore w/ 14:1 piston running mid 70's hp.

I'ts just a matter of where do you draw the line.

[Peelz]

higher compression needs a higher octane motor to prevent detonation.

[Alkire193]

higher compression needs a higher octane motor to prevent detonation.

I figured sooner or later id end up running 114. I know, its 110. But my place got theirs tested at 114. Thats why my bike wouldnt run right on VP for the first 6 months.

Ok so that idea helps. Larger the number the bulkier the top of the piston. Im getting it a bit more now. Kind of a crash course, I have to make this call by Monday. How bad can mid 70 horse be right? GO big or go home. Im gonna build a YFZ over the winter as I rebuild this one, so if I overdo it ill make it a sand runner or hill shooter.

[Alkire193]

We are getting there, need the cylinder back from US Chrome, +3 TB from Kenny and a few more of my head parts back from Kenny ( I screwed up and said I didnt need them ) But here they are, 13:1 CP piston and my beautifully done KDS head with RJ cam. And Kennys' son even signed the bottom so its official!

[preddy08]

Im a 727 14.1 compuression XC rider and I'm always looking for more. This winter I'm doing a stroker, bigger cam, and FCI intake. We'll see how it truns out!

[Alkire193]

Thats going to be a great build Preddy. I cant wait to put up some decent numbers ina  few weeks when I get it all together. Im still worried about the tranny though. On the table it doesnt seem to shift through all the gears. Not sure if it should or not

[Kamakazi]

do you have ur quad running yet alkrie?  if so, what did you do for a map? im trying to compile some maps so that i can see if my autotune is working properly.

[Alkire193]

Yea um, a map....about that. I uh, im doing this 770 build thing with a 105 bore and +5 stroker and I have no idea what to do for a baseline test map just to start her out and try her before she gets dynoed. Last time I dynoed her the front end started to come apart on the dyno, I dont want the motor to do that when shes in 3rd at 6,000rpms. Anyone have any thoughts!? 

[Krandall]

There are a few 770's floating around here. let me see if I can get my hands on a base map for ya. I wouldn't start it up w/ out something semi-close

[Kamakazi]

i do have a map for a 727, it may be close enough if ya bump a few things up

[Alkire193]

Cylinder should be here tomarrow or Wednesday from US Chrome. Turnaround time is excellent and they were able to bore it to 105mm and replate.

Kran, if you could that would be a huge help.  started thinking about the program a few days ago and didnt know what to do. If you could get me something close that can do a few thousand RPMS just to make sure the motor and tranny functions well enough for dyno that would be music to my ears!

I think the A/F for a 727 might be a little off Kami. I think it all works well at Idle but when I start revving it up it might cause problems on my engine. I thank you for all your help though. And ill post the map on our database after I dyno it so the next (Preddy) 770 builder can have it as a baseline.

[preddy08]

TroyWcc should have a bunch of 770 maps floating around. I'd hit him up.

[Alkire193]

Ok I hit up TroyWCC and im hoping for a baseline this weekend. Got the wrong piston rings with my 105 piston (got 102's instead of 105's) so thats a small set back so I snapped some shots for  a video im slapping together and thought id share them, Enjoy!












The mix up, the silver ring to the left is my original 102 ring, the rest is a 102 kit when I have a 105 piston. More delays......

[Alkire193]

so the +3 tb came in and I swapped over the TPS and fuel rail. I shaved the new TB adapter to fit the porting on the head, matches perfectly. Still waiting for those piston rings. Cmon Kenny!

[Alkire193]

Well guys I screwed up. Despite this awesome video. (Well, awesome to me) The tranny doesnt shift right. According to a reliable source, I didnt install a washer on a shifting component which is somewhat hidden in the crap -  manual. So the bike is not fully engaging its gears, however neutral and second work so I was able to create this lil clip, I was jumping all over the yard when she fired, but not on camera, have to keep my composure. 
http://www.youtube.com/watch?v=dcUVyJfmim8