If you look at my sig you can see my set up. I was wanting to change my s&s cams for woods cams! My bike was set up with 10.9 to 1 COMP and I was wondering if changing to those 777s would cause spark knock on pump gas because it would raise my corrected compression..... right?

 

Well, playing with the bigboyz calculator, you would be going from 9.3 corrected to 10:1 corrected. I don't think the bike is going to make it very far at that compression ratio.

 

If compression is a true 10.9, changing cams with a 55* intake close to cams with a 42* intake close will boost corrected and cranking compression higher and detonation will very likely be an issue.

First thing to do is to check your cranking compression and see what you have. Should be about 190psi if static is a true 10.9. If you are running domed pistons, you could replace them with flat tops. If you are running domed pistons that would indicate that the heads have been decked to 76cc (or thereabouts) and another set of heads with larger chambers would be required.

Why change cams anyway? Get a larger TB and intake and get everything you can out of the 625s.

 

To make a long story short my bike from a 30mph roll to 110mph is very fast but people pull me out of the Hole and I play catch up. Another engine builder rode my bike after fixing my broke belt and told me it had way to big of cams in it. Saying it would be much faster with se259s or something comparable.

 

Sounds to me like you should contact a competent tuning shop and talk through what you want of your bike. I can't help thinking that the S&S or Woods cams you mention will need a lot of help to get the most out of them and that is best done using advice from someone with a lot of experience.

 

You may be right I just think those s&s 625s makinh 105tq at 5400 rpms is hurting me instead of making peak tq at 3500ish. Plus those woods cams are making 125tq with the same mods.

I just hate to spend $1000 on a throttle body to make 5 more HP and tq and loose more bottom end? Any ideas or suggestions?

Thanks guys I know it's hard to trouble shoot a motor build over the net.

 

New update talked to S&S and they said the 625s are much too big. They recommended 585s but I called Andrews and they said after looking at the Specs of my 625s that its a perfect cam....LOL. what to do to not get out ran

 

You need a low/mid performing cam, like the 40ish degree family of cams out there. However, to switch from a 55 deg cam you need to address your resulting corrected compression issue. So, listen to what DJL has to say - find out what piston you are running and you may have to switch from a dome to a flattop. While you have the heads off to deal with the pistons you can 'cc' them to determine the combustion chamber volume. Working with a tool like the bigboyz calculator you can set up your engine as a system, considering head gasket thickness, displacement, chamber volume, piston dome, etc.

 

I know there flat tops and that's. About the extent of my knowledge

 

Well, you came to right place to learn. Talk to guys like Scott and DJL. If you really want to get in depth knowledge, there are several good books out there (and articles, too).