paulson_shawn
$hawn
Would running a shell 1 cam with 4th over cruzinimage pistons and base gasket delete be worth the cost of the cam and dialing in the sprocket or do I need more displacement / compression to get the advantage of the cam ?
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shell 1 or stock cam
- Thread starter paulson_shawn
- Start date
The Shell #1 will work fine in the setup you describe. Be sure to check squish clearance though. Some pistons will let you drop the deck quite a lot without trouble, others will cause grief at as little as .010" drop. With stock rods, your solder crushes should measure about .050" front and back to be safe.
Bear in mind that Joe Minton's "Better 650" article contained a few less than good ideas, and one of them was his claim that the Shell#1 could be run with stock valve springs. They'll work for a while, but the fast ramps on the Shell cam need more pressure than the stock springs deliver.
Bear in mind that Joe Minton's "Better 650" article contained a few less than good ideas, and one of them was his claim that the Shell#1 could be run with stock valve springs. They'll work for a while, but the fast ramps on the Shell cam need more pressure than the stock springs deliver.
paulson_shawn
$hawn
Thanx grizld1. I read I'll need the RD spring set. I read some post saying the cruzinimage pistons have the stock piston dimensions and some where people were able to lower deck height up to .030 with stock type pistons but I don't remember if they were using higher lift cams. I'll have to read up on solder crushes.
Camshaft lift doesn't affect squish clearance, which is the clearance between the edge of the piston and the tapered edge of the combustion chamber (squish band). If you read Craig Weeks's "XS/TX650 Engine Modification Guide" you'll see that closer clearances are specified; those figures are safe only with the use of premium rods (Carillo, Falicon, etc.). With OE pistons at 4th over you should be OK with a .020" drop, but I wouldn't take anything for granted. When you run the crushes do it with valves removed.
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racerdave
^ Gone not forgotten ^
grizld, is that to say the stock rods/pinbore/?? expand with heat or higher rpm?
paulson_shawn
$hawn
So if these cruizinimage pistons are supposed to work with a thin copper head gasket and no base gasket and degreed stock cam to get 9.5:1 CR. would the only possible issue with the shell 1 be piston to valve clearance?
paulson_shawn
$hawn
I guess I don't really need the extra performance. It will probably feel pretty peppy with the stock parts syncing and sealing good. I'm just trying to get the biggest bang for my buck on this top end overhaul.
Shawn, squish clearance has nothing to do with the cam you're using, although a high lift cam could create problems with piston to valve clearance, especially when the deck is dropped. The Shell #1 isn't a high lift cam and I doubt that the .020" drop you'd get by running with no base gasket would cause problems, but it's easy enough to check with a bit of modeling clay in the valve pockets. I'm not familiar with those pistons, but if they're made for use with lowered deck you'll probably be fine; but it always pays to check, since finding things out the hard way can be expensive!
Don't let the need for a couple of easy inspections get in your way; if you want more giddyup, the Shell #1 with a little compression boost is a fine way to get it.
Don't let the need for a couple of easy inspections get in your way; if you want more giddyup, the Shell #1 with a little compression boost is a fine way to get it.
scabber
XS650 Guru
Bang for the buck the cam is worth the cost.
A good bang for the buck would be to address the poor breathing issues of the XS head ports,particularly the exhaust port,good carburetors and exhaust system. Then if you want a more zip,install the #1 cam. Just my 2 cents.
paulson_shawn
$hawn
Im thinking I should go with stock cam and compression with the OE type pistons or do the 700cc pistons with the shell 1. I have some time to decide was just thinking ahead a little.
scabber
XS650 Guru
What Jack said on the porting. The motor down the road with the 700 pistons usually never gets built and not the best choice for a street motor. The stock cam flat out sucks little or no power off the line. With the pistons you have the cam would work great.
racerdave
^ Gone not forgotten ^
Scabber, you are the first I have seen post that the 700cc motor is "not the best choice for a street motor"? Why do you say that?
I'll chime in on this. We used to do a lot of overbore/bigbore kits. This 700 kit is an overbore, leaves you with a thinned cylinder sleeve, risk of heat issues with a daily driver (especially here in the south). It's a cost-effective option when trying to save a damaged cylinder, kinda wasteful on a good cylinder...
racerdave
^ Gone not forgotten ^
Good point twomany. It is as big as stock allows I believe. I'll have to rethink that 700 also now, although mine would only be a 40 mile or so at most at a time bike. No daily ride.
Dave, I like the dimensional stability of thicker sleeves. But, you're in cooler Illinois, which helps...
scabber
XS650 Guru
Mainly because of the added compression. It changes the characteristics of the motor. Engine braking increases and the bike slows faster. Not always desirable in slow speed traffic. This gives you on and off throttle feel, accelerate decelerate. Just going by my experience with the 750 from stock 650. I'm building a stock bore 650 motor with some headwork and #1 cam for a driver. It should fit the bill nicely. Not saying the 700 motor is a bad motor by no means. Its mostly what your ideal motor should be. 
paulson_shawn
$hawn
Porting is out of my budget... I didn't think the 9.5:1 CR would be too much fotr a street bike. I do want this to be a daily driver so would I be better off with stock deck height with the OE 4th over pistons?
Guys, I've built two 700 cc. motors, and I can tell you that they gave no grief in daily use; one has static CR slightly north of 10:1, and I reduced the CR in the next motor only because obtaining high octane fuel got to be a problem in some of the places I ride. As far as the ports go, Jack is right--if you have the ability and equipment to port the head yourself or the money to have it done right, you can get big gains. But you can improve things just by knocking off the casting flash with a paper roll in a rotary tool.
paulson_shawn
$hawn
I could prob handle just smoothing and matching the ports myself but not a real port/polish. Not as concerned with performance as being streetable, just thought if I could get some extra performance fairly cheap and easy I'd try the gasket delete and cam since I have to do a cam chain, guide and rebore anyway.
