djl here is a better picture of the piston with the part number.

 

Thanks for the update; gald you found the pistons you wanted. You have been warned twice about the 510 cam being soft n the bottom with your configuration. Maybe Bean has plans to boost compression up by decking the heads but if not, I think you can find a better cam. No trying to build your motor, just sharing information that you can do what you want with. Please do keep the updates coming.

 

Djl hello. I'm all ears. I'm not opposed to a different cam. I just don't want to have to change valve springs. Install compression release. Break starter motors, pinion gears, clutch basket gear ring, or detonate. I've been there.. I've looked at the S&S 509 but I think my riding style really reflects the 510. That being said what cams do you know of that will work well with my set up without the detonation .

 

With stock heads and those pistons you will end up with 9.37:1 static compression.

As already stated the 510 cams will result in a CCP way below what is needed for good power.

The S&S 509 with super early intake closing (18 degrees) will put CCP at 190 psi which is reasonably good for power output, and on the limit for needing compression releases.

The 509 is all about low end torque though and the fun stops at 4000 rpm. Andrews 21 and 26 are known for working well in this kind of low compression engine, slightly later closing so power band is moved a bit higher and less stress on the starter, but a bit more low end than the S&S 510.

If I understood correctly you are not planning on doing any head work like porting or increasing valve size. This limits the expectations on top end power, so you should focus on using the small ports and high velocity to your advantage by aiming for low and mid range power, so both the 509 and Andrews 21/26 make sense.

S&S claim that the 510 is designed to work well with stock, un ported heads, but you really need more compression for those, either by shaving the heads to around 80 cc volume, or using pistons with domes. The 4.6 cc Wisecos I mentioned earlier, that are cheaper than the SE ones, would set the compression perfect for the 510's at 191 psi CCP.

 

Swedishmeatball I am having head work done by Big boyz a Street Port and Valve job . How do you think the 510 cams will react with head work. I don't mind changing cams if I have to. I will look into Andrews

 

-2FX. Meatball has covered the subject pretty well and I refer to my previous posts #2 and #4 wherein I covered the compression issue in detail. The Andrews 21/26 are an improvement over stock but their intake close is just a little later and compression doesn't increase much. Beans "street" port is all about velocity, he will tell you that. The S&S 509 lower intake close event will produce off idle torque that will carry into the midrange. I don't have a dyno sheet of the 509s in a 95" configuration but I have attached a chart of an Stage I 88" motor witht the 509 cams; no head work. As you can see, the numbers are not impressive but a nice gain over stock. The thing to look at is the power curve and imagine what it would look like with more displacemant and Bean's street port. JMHO but I think you would be pleased with the results. Talk to Bean about it.

With the 509, CCP will be about 190psi, which IMHO, is on the cusp of wanting compression releases. You could get by without them but they are cheap and is used, they will extend battery and starter life. They come in handy on hot restarts at the gas pump.

 

If you are doing head work you could of course include shaving the heads to achieve a compression ratio that suits the 510 cams.

 

Hello djl it's Saturday afternoon and my package from eBay just arrived. Upon inspection everything looks good. They both measured 3.871 on a cheap harbor freight micrometer. I will be on the phone first thing Monday morning with big boys arranging for shipment. I've attached pictures. You will notice the part numbers on the box and the Pistons are different. As you can see at one time it sold for $174.95

 

OK, you are on the way now. What are you thinking about cams? If Bean is replacing the OEM valves with larger 1.9" valves, remind him to open up the valve reliefs; always a good idea. Keep the updates coming.

 

Hello everyone the build is well underway. I sent the Pistons cylinders and heads out to Big boys, Thursday. Swedishmeatball/djl the 509 looks good on paper and big boys compression calculator,





I'm open minded. I'll see what Bean says when he gets my package he says he can make the 510 work good. I'm attaching some pictures does anybody know why the rear stock piston looks brand new and the front piston is full of carbon. The bike is carbureted with 36,000 miles