Re: QT50 60cc keeps seizing.

@arlie1180

Yes, I ran a vm18 and bored out my stock intake. A lot of people on here beg to differ, but that carb setup worked perfectly. MLM makes an intake now for the qt50 that would work a lot better. Mine was the first bike on here built with a malossi kit, and to this day the cylinder hasn't been off. A lot of miles on it and still shedding 53-54 mph while still holding a crazy mid range power band that gives you a smile from ear to ear.

@triple5soul

Back when we were building a handful of malossi qt50's I tried to run one with the stock exhaust to break it in. The bike ran terrible, thats why I think you have an exhaust issue. A friend of mine had a one piece bi-turbo from a 95' tomos. I cut off the header and turned it slightly, also when I had the header off I slid on a new flange i made out of 3/16" steel. Worked perfect and Honestly besides the Jemco pipe its the best we've ran on the malossi cylinder. Also I strongly recommend a vm18. If you need a shim made to use the stock intake PM me.

Nick

Re: QT50 60cc keeps seizing.

Also I ran to base gaskets and one copper head gasket until I had a stock yt60 head machined for the malossi cylinder. I believe we were at about 160 compression after the head came back with one base and one head gasket.

Foward Motion can machine your head for you. Look them up.

Re: QT50 60cc keeps seizing.

Todd Keingeshaft Wrote:

-------------------------------------------------------

> There is a guy on here that has a YT60 topend on

> his QT with a PW80 carb and STOCK pipe, and it

> consistently runs in the high 40's. His setup

> defies the logic about the smaller header, but it

> works for him...

I wonder if you're referring to me on this one... I do run the stock exhaust on my QT's (6 between brothers and I) just to avoid drawing too much attention to ourselves. I have been running the YT60 cylinder, YT60 oil pump, QT stock head, PW80 carb and PW50 gears of course and pull mid to high 40's regularly. Only in the 50's on good days.

BUT, I just had a few YT60 heads milled down significantly and was very impressed with the performance gains. Also, running 3 Yamaha Base gaskets now (gets the full transfer port open), you really need to measure all of your gaskets to make sure they are about the same thickness as that variation is significant between brands.

Still running about 400 degrees head temp which I'm comfortable with but I am curious now about the Jog CDI, does it have any negative effects at high rpms when it retards the ignition?

Re: QT50 60cc keeps seizing.

Yt60 top end and the malossi top end are are two totally different cylinders. A stock pipe is fine for a yt60 cyl. I've ran em plenty of times like that. Put a stock pipe on a malossi and it will not run very good at all.

Nick

Re: QT50 60cc keeps seizing.

PM'D

Re: QT50 60cc keeps seizing.

Todd Keingeshaft /

Mark B****** Wrote:

-------------------------------------------------------

> Todd Keingeshaft Wrote:

> --------------------------------------------------

> -----

>

> > There is a guy on here that has a YT60 topend

> on

> > his QT with a PW80 carb and STOCK pipe, and it

> > consistently runs in the high 40's. His setup

> > defies the logic about the smaller header, but

> it

> > works for him...

>

> I wonder if you're referring to me on this one...

> I do run the stock exhaust on my QT's (6 between

> brothers and I)

<snippage>

> Still running about 400 degrees head temp which

> I'm comfortable with but I am curious now about

> the Jog CDI, does it have any negative effects at

> high rpms when it retards the ignition?

Yes Mark, it was you I was referring to. :-)

I have not noticed any negative effects by using the Jog CDI. If performance was decreased at all, I didn't notice it in my setup. The only difference I have seen was the lower cylinder head temps at higher RPMs! :-)

Re: QT50 60cc keeps seizing.

What is your before and after temps?

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account