For those who don't know (or won't see the thread in the troubleshooting section), I was having some weird issues with my bike. I called Dan at Hammer, and he spent about 30 minutes with me on the phone, helping me figure out what the heck was going on - he didn't pressure me to buy any particular parts, just let me know what my options were and made a few recommendations. Long story short, I needed a new higher compression piston to bring the motor's compression back up to appropriate levels to compensate for the bigger cam and ported head. I decided to send in the head at the same time, just to verify the work that had been done and let him match the piston to the head.
There was a bit of a wait (he was backlogged with work, which has since been resolved as Hammer hired additional help), but it was worth it. Getting the pieces back was like Christmas, and everything looked AMAZING. Dan did a little machine work on the head (re-cutting the squish band for a 3.563" bore) along with time-serting the spark plug hole and checking/doing a valve job. The new piston & jug fit perfectly (minor trimming of the pushrod cover, but that's normal from what I've heard). Hammer will even gap the rings and install the piston into the jug for you for a few bucks extra - a step I took since I didn't feel like messing around with gapping rings in my garage - I wanted my bike back together quicker than I felt I could do it!
The bike runs amazingly now - no more hanging idle, no more sputtering. There is still some tuning to be done (I'm running it rich during break-in to keep the temps down), but the bike is a lot more responsive and has a bunch more grunt. If you need someone to do machine work on your bike, these guys are awesome, and their prices are great too!
Last edited by piratius; 05-31-2014 at 04:28 AM.
Here's an update with LONG overdue pictures!
I don't know the weight of the new piston, as it was pre-installed in the jug and I didn't get a chance. But, judging that the wrist pin alone was 25% lighter, I'm betting the piston will be similar. It shakes a whole lot less up top now!
EDIT: After browsing Hammer's website ( www.hammerperf.com ), it looks like their piston weighs about 304g. Compare that to 433g for the stock piston - again, a weight saving of over 25%!
Stock piston & wrist pin are about 540 grams together. Hammer's piston and wrist pin are 380 grams. 540g divided by 380g gives ~1.42 - showing that the hammer stuff is over 40% lighter than stock. This is why you can rev the motors higher, and not have them come apart!
Last edited by piratius; 02-01-2014 at 05:08 PM.
I'd weigh my new one, but I don't have a cool scale like that one - nice - it is always good to start with quality parts.
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