Re: Just joined Forum. Have QT50

Colder air is more dense and will always have more oxygen per cubic foot .

Re: Just joined Forum. Have QT50

Jack Rutherford /

something else changed - most likely air infiltration

Re: Just joined Forum. Have QT50

Yeah, probably through my 6 headgaskets. I'm scrapping this cylinder and putting on the niche one. Should I use the whole kit (minus head) or use the Yamaha piston?

I've got time, rain through the weekend. (edited)

Re: Just joined Forum. Have QT50

Jack Rutherford /

take a ring off the yamaha piston and check clearance in new cylinder

Re: Just joined Forum. Have QT50

Similar to what I planned already. I was going to use a new Niche ring and compare dimensions betwen both cylinders.

Re: Just joined Forum. Have QT50

So it's together for the 100th time, started heat cycling/break-in.

Niche cylinder, Yamaha piston, Hobbit rings, Puch head. It's my international bike.

Niche cylinder is .001 in. tighter than the Yamaha which has almost no time or miles on it. Should work fine.

BTW: Treats has been out of the 64 cc Malossi cylinder for a while now.

Re: Just joined Forum. Have QT50

Got her up to 36 mph on my short road in front of my house. Temps now acting normal 360F running hard, drops to 320 almost immediately when you close the throttle.

Next is drop down to the flat(er) areas to get long runs. 120 main now, and that's in VM12 jets.

Screenshot_20220405-152837_DigiHUD.jpg

Re: Just joined Forum. Have QT50

Jack Rutherford /

sweet, makes me want to get my hopper out!

Re: Just joined Forum. Have QT50

Well, what are you waiting for! Get some pics too!

Re: Just joined Forum. Have QT50

Downhill Harvey (OFMC) /

Just remember the moped adage, Fast, Cheap, Reliable,,,,,,,,, pick two.

You can eliminate a lot of headaches, with high quality parts.

Re: Just joined Forum. Have QT50

We'll see, with time will tell on the reliable.

Re: Just joined Forum. Have QT50

Took her out on a good run, about 20 miles. 41 mph is all she'll do. Im OK with that. I do wonder what the bottlneck is.

Could spend another $250 on it to maybe (not likely) get 9 mph. Not going to do it.

Speedo reads low about 4 mph. When I put on a IRC tire it will be lower yet.

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Re: Just joined Forum. Have QT50

Jack Rutherford /

That next level pipe just offers more flow. You want the techno circuit or peoples pipe for more power mo speed but you’ll lose low end.

Re: Just joined Forum. Have QT50

I'm good. Around here I need low and mid range. I still slow down to 15 mph for big hills. If I can't get a full speed run at a hill it can't even climb it. At 1 T intersection it's hills both ways. I have to use 1 hill as momentum then turn around to climb the other. This ain't Ohio.

Just for kicks, will the Malossi cylinder and piston with no other changes give me more top speed or not?

Re: Just joined Forum. Have QT50

Jack Rutherford /

The Malossi has nice hill climbing power. You may have to re-jet. And it should give you a little more speed.

Re: Just joined Forum. Have QT50

Tempting...

Re: Just joined Forum. Have QT50

How long are your hills? I have a hill either way I come home, one about a 1/4 mile up a pretty good grade and mine goes faster than 15 mph. My setup was a 60cc top end, MLM Next Level pipe and stock carburetor with 100 main jet. I have since switched to an MJ bottom end and stock exhaust, same top end and carburetor. Goes up hills even better now.

Re: Just joined Forum. Have QT50

I'm a bit over the 170 lb weight limit for the QT50.

Hills are steep and long here. I'm just glad to make it now even if at 15 mph. With the rev plate mod I'd drop to 0 mph before the top of the same hill.

Re: Just joined Forum. Have QT50

For better take off, I would suggest an MJ bottom end. That 2 speed transmission really helps with take off and there’s one on eBay right now. You can use the top end you have now, as well as the carburetor. You would have to make a pipe for it. You can cut and weld a QT pipe or find an MJ pipe.

Re: Just joined Forum. Have QT50

I've had this bike since brand new. I'm keeping it like it is.

I've watched some of those 2 speeds on YouTube, I'm not impressed.

Re: Just joined Forum. Have QT50

I'm still waiting for the weather to get back to spring AGAIN for the 5th time. Last couple nights lows at 30F had snow flurries. Highs only high 40's.

I'm trying leaner on my main jet. At top speed there is a hint of 4 stroking at 41 mph. Might get higher top speed yet.

Just need at least 65F or no point in jetting experiments.

Re: Just joined Forum. Have QT50

So was at 120 main, dropped to 118, then 115. Found no change except cooler running with the 115. Maybe too cool.

Is it normal to go through 3 sizes with barely any change? Still slightly 4 stroking at max speed. seems I'm maxed out now.

4 stroke feeling might just be the max this setup can breathe at.

Tempted to go 64 cc Malossi but at $150 (on sale) for maybe 5 mph more (or no increase) it's not worth it.

I'll still want to keep the 15mm carb, stock intake, etc. I like the bar mounted choke, stock throttle cable, 15mm carb already paid for, etc.

Re: Just joined Forum. Have QT50

So just got back from abusing my QT. Must still be breaking in, climbed the one hill at 25 instead of 15.👍 Slingshoting from the other down hill of course. Only saw 380F max. Can't go leaner then the 115 main now.

I might try a compromise with the rev plate mod. 3 base gaskets and mill the cylinder down.

Wish I knew somebody smaller/lighter than me I could trust to ride it. Wonder how fast it would go.

Strangely I only get 45 downhill. shouldn't weight help then? The weight sure slows it down uphill.

Screenshot_20220510-181854_DigiHUD.jpg

Re: Just joined Forum. Have QT50

Jack Rutherford /

Now that, would’ve made a good video for the Qt50 fanatics out there.

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