Topic: first time builder here with a few questions

[Ayrity]

Hey, so later this summer I am going to be tearing into my cb550k engine to replace the cam chain and do an all-around check on things, so I figured this would be a good time to pump up the power a bit. I have a 650 cam shaft, so I was planning on dropping that in since it is a direct drop in (changing out the cam gear of course). So my question is, how much can I do to the engine without going crazy on spending? I have read that it's a good idea to clean up the valve head for a port job, I was planning on doing that myself with a dremel, heard it was pretty obvious where and what to smooth out since the casting was kinda rough on these bikes. Should I hone or bore out the cylinders? run 650 or 750 pistons? can I hone the cylinders out a bit to get smoother fresh metal and run bigger rings? etc. thanks so much for putting up with my newb questions guys.

[turboguzzi]

ayrty

a 650 cam will certainly not be a hi perfomance mod, more an enhancement mod, there are quite a few posts in the general forum about this mod, search for them.

going bigger bore is more like it, will require boring and then machining the stock 750 pistons to fit, cheap if you have access to a lathe, if not you might be better off going for the ready to fit 605 kits. maybe define what means not going crazy on spending?

You need to do quite a bit of reading if you are asking about fitting "bigger rings" , so you have some homework to do

Dont be discouraged by this, sounds like you are the beggining fo your tuning learning curve, so grabbing any general tuning book to learn about the subject will help lots. we've all been there at one point or another!

TG
 

[Ayrity]

ha ya well I am def at the beginning of the engine mod curve thats for sure! I might be able to find a friend with a lathe to machine the pistons for me. I have been searching, but I usually run into the same 3 or 4 good long posts, then they turn into people talking about off topic stuff, and the project thread is never ended. But I am reading as much as I can. When you say "enhancement" do you mean making the engine more efficient (or just moving the power band) and not necessarily more powerful? Any thoughts on me using a dremel on my own with the porting?

[turboguzzi]

first of all, patience, the info is all out there in the right threads. SOHC4 is not a ready to use tuning manual, more a reference area. you need to joint the dots that you find along the way. Where would all the fun be if it was laid out for you bare?

try searching for the "gentleman's express" article/threads, explains well what to do to fit 750 pistons in a small block.

Dremel will be suitable for cleaning ports up, which might be the right thing to do considering your experience level. It's not powerful enough to really carve metal with big carbide tips.

The reason i am saying that a 650 cam is not really a high performance mod is that you might get more help by posting this in the general forum, we are all into super bumpy .4" lift cams here in HiPo  

If you want to be more scientific about it, dyno your bike before the mods and after, and you'll be able to contribute your empirical data here.

Good luck!

TG

[Ayrity]

I plan on doing just that with the dyno, got a 30 buck for 3 pulls dyno day here on may 2nd, kinda excited, never dynoed the bike before, very very curious about the numbers... thanks for your answers again, I'll leave your "big boy" section and go play in the area that is comfortable with doing 115mph haha (no thats not a stab at ya turbo, just messin around)

[turboguzzi]

I plan on doing just that with the dyno, got a 30 buck for 3 pulls dyno day here on may 2nd, kinda excited, never dynoed the bike before, very very curious about the numbers... thanks for your answers again, I'll leave your "big boy" section and go play in the area that is comfortable with doing 115mph haha (no thats not a stab at ya turbo, just messin around)

I'm good at taking stabs, no worries mate

good luck at getting REAL 115 mph (and not a reading from a 15% off 30 yrs old speedometer ) from a 550... I am not getting much more from my tuned  61 rwhp 500 racer.... maybe 120 on a good day and long straight if i am very well tucked behind the bubble with engine screaming at 11,000 rpm.

In any case, just came across this, give it a check if you havent yet:

http://forums.sohc4.net/index.php?topic=44678.0

pretty thorough me thinks

Cheers

TG