250-500cc Another Piston Thread

I'll let ya know once I can get the jug back on. I've been screwing around with different ways to compress the rings. Don't have the proper round clamp type, don't wanna scratch my pretty piston with a hose clamp, so I'm down to a fat zip ty.

I ain't that talented. I have bent rings before and honestly am a little intimidated by that experience so I get nervous as soon as I start slipping it in there. The piston into the cylinder I mean of course...

Are you suggesting I should get pissed before I attempt to slide it in?

The good news is that I found zip ties that are fat enough to cover both rings. I'll get an early start and will hopefully have a whole bike again this weekend.

The motor is together. Fat zip ty worked great with my nervous hands. I can mess with high voltage and am steady, but give me a little engine to play with and I'm all thumbs. Should have it all together and ready to run this evening.

It's a runner folks! First 2 heat cycles are complete and she runs fine. Started first kick on the second cycle. I swear it seems that I hear less piston slap, but to be honest I'm just glad to get it back together. I'm going to take it to a local place to do the putt around sessions to finish the run in tomorrow. I'll report back after the riding tests.

Yes it is a little stiffer. The piston slap is gone, but it will still slightly protest to being lugged to low. I'm waiting for it to cool down so I can take it on a longer ride. It is much snappier than before and I am really just getting the rings settled.

I've done the manual recommend 2 heat cycles no load, then 10 min easy ride followed by the 15 minute ride I just finished. I rode a couple of easy flowing trails I usually ride to warm up mostly 2nd and 3rd gear stuff with lots of throttle variation.

Now i just need to bleed the rear brake. It seems to have developed a bubble since the last time I rode it in November. It's two pumps and an apology right now. The fun never ends...

OK, I'm game in case this helps others!

1. Lugging, but no piston slap, more like chain noise now. On the last ride I paid special attention and it was certainly not an off idle thing, I even made sure I did some slow technical climbs one gear high to get it to bog.
2. 50/50 100LL Av gas and 110 leaded Sunoco, no ethanol crap allowed in my race bike
3. The jetting is crisp, but not lean, plug is light brown, I'm not in a hurry to mess with a good thing.
4. Old piston is clean with slight brown color inside. There were zero signs of detonation and just a little carbon on top that was chocolate on the edge.

At this point I can say that if you're wondering if a forged piston is good, it works good for me so far. I get another day of riding before the National next weekend and I'm sure it will continue to improve with each run. Realizing I'm running this piston I'm being very careful to make sure I let the engine get good and warm before putting a load on it.

It is certainly a big improvement over the old piston and rings that were at the end of wear limits. I'm going to go out on a limb and say I feel at least a 10% overall power increase. I did a short burst where I really got it on the pipe toward the end of a 40 plus minute last ride today and the smile was plastered on my face.

OK, looks like I'm ready to go. Bled a bunch of air and flushed the rear brake. Much mo betta. Got my schmancy new graphics with my number slapped on today too.