MOPED ARMY

Cross hatch ok in cylinder? Had to chamfer ports in Yamaha cylinder anyway.

I'm laying in a supply of Yamaha 60cc head gaskets since they may go AWOL soon. Base gaskets same for 50 and 60cc. Should be available from Yamaha forever.

The Malossi kit is more expensive but is much higher quality, IMO. I've seen those Niche kits lose big flakes of nikasil and trash themselves.

I think he's referring to the porosity issue I described above. Its a cast iron cylinder and nikasil is typically applied to a cylinder liner thats used in aluminum cylinders. Besides, the cost of true nikasil would be cost prohibitive at that price point. (edited)

Looks like when the time comes I'll try a Niche kit. Currently $60.

2 strokes just don't live long enough to justify $200 or more top ends.

I agree.^^ Better quality can get you the option of replacement rings and over sized pistons when the time comes while reusing most of the parts from the initial kit. Try getting a set of replacement rings or oversized pistons and rings for overboring a worn out cylinder from niche. Try getting any one single part out of that kit for that matter. When something breaks, you just buy another $60 kit. Theres no right or wrong way to do this because everyone has different priorities. Some build to ride and keep forever and others are more casual and maybe have a budget. For what you get, its worth $60. I paid less 3 years ago. (edited)

Come take the trip to the Burgh sometime

Uhhh yeah it's a dumb shitty hunk of cast iron. The piston and the fit and finish is slightly better on the OEM Yamaha but not much for like 6x the price. People just have a natural desire to feel like they need to buy the more expensive thing. The Yammy is better but once it's cleaned up, installed, and ripping nobody will ever be able to tell the difference.

They should both get about the same usage. Most cast iron kits last 4-6000 miles if you have them tuned and take care of them. Even OEM service interval is about the same.

I would definitely try to figure out what's going on with the current cylinder since it doesn't sound like you've put a lot of miles on it. You can mess with putting oil in the cylinder or doing a real leak down test but it's usually way faster and easier to just pull it off. The rings could be stuck from carbon (oil injected bikes tend to run too much oil) or maybe it never got a good break in, or wasn't tuned right or soft seized.

If the bore is clean and you can find a stock oem or even knockoff piston that's probably the way to go, but if it needs bored I would just get the niche one and call it a day, maybe sell the old OEM cylinder to one of these guys that think they are magic blessed by the tuning fork fairy.

Thanks for all the replies!

So compression gets me acceleration not top speed?

So I sanded my yt60 head down about 2 mm and got my compression test from under 90 to 110 psi.

low speed pickup did improve.

I think tomorrow I'll drop down into the valley and re-check top speed if the weather holds out.

BTW: On the speedometer when it passes 30 mph just use geometry. Look at the the other end of the needle. When its a straight line pointing at 10 mph your doing 40 mph. Straight down is 45 mph with the other end pointing at 15 mph.

Instead of guessing your speed download a gps application to your smart phone. I start the app and then have it running in background, screen off while my phone is in my pocket before I take a blast.

Replace the rings. Should come up a hill with no problem. I live in NC and I have to go up a hill either way I go to get to my house. My QT has a Yamaha YT60 top end and it has no problem going up hills, not talking about gentle grades either. Not the easiest to keep cool though.

I bet you could get a set from weisco.

They do make custom rings which means you're gonna have to reach out to them for what you need. Its not gonna be listed on thier website. It means you will have to take measurements and know what type of material the rings are made of.

I've had good dealings and service from Hastings Piston Rings when I needed rings that were NLA for my Simplex . Email them with measurements . They are pretty easy to deal with .

https://www.hastingspistonrings.com

I've directed others to them and all have had excellent experiences .