Pulling the TZ250 motor - Sportbike Addicts

NYCSTRIPES · 11-14-2007, 12:57 PM

I have decided to send out my TZ250 motor to MCE racing in CA for a full rebuild. Despite the mechanical downtime on the 250, it is still worth riding it. I have a full rebuild kit on order and when it arrives, I will pull the motor and send it out to Kevin Murray.
Upon its return it will have a new crank shaft, new pistons, new heads, bearings, seals and other related items. I expect that with a professional rebuild like this, I should have an easier time keeping it running properly. I just got frustrated with the unexpected items crapping out on my 1995 motor and going fresh with all new parts.
Should prove to be a good thing for the bike anyway. After this I should be able to keep up with scheduled maintenance a whole lot easier.
Ken

***Cakes206*** · 11-14-2007, 01:00 PM

Cool stuff Ken. Lots of pics. Need any help let me know, be cool to check it out.

NYCSTRIPES · 11-14-2007, 01:52 PM

Be assured I will take plenty of pictures...it's the Japanese tourist gene I have... can't be helped. LOL

Ken

***carl_g*** · 11-14-2007, 02:21 PM

Nice dude!

High_Revs_17 · 11-14-2007, 06:48 PM

Is that typical? Seems like a huge labor of love. Either way you're doing it right for sure.

tommymac · 11-15-2007, 08:33 AM

Quote:

Originally Posted by High_Revs_17

Is that typical? Seems like a huge labor of love. Either way you're doing it right for sure.

He owns a TL so hes used to it

Tom

NYCSTRIPES · 11-15-2007, 10:19 AM

Quote:

Originally Posted by tommymac

He owns a TL so hes used to it

Tom

Very True...LOL

NYCSTRIPES · 11-14-2007, 07:15 PM

Not typical, but needed. Mine is a 1995 and I know it was never professionally serviced. I am still a 2 stroke newbie and my aim is to get this thing back into shape and make it reliable. Replacing all of the expendible parts at once and having qualified hands get a look inside at the same time will be something that will give me the confidence I need to run it for 2008.
It will also give me a solid timetable to run with leaving me near zero surprises. So, at 300 mile intervals I can change top ends and at 1200-1500 miles I can change out the crank. That should be the only things I need to worry about next season other than tires and fuel.

Ken

***carl_g*** · 11-14-2007, 11:20 PM

just jet it fat and you should not blow it up!

lets_racefast · 11-15-2007, 07:41 AM

Ken,

There are a few things you need to know / do when you get your motor back.

power valve cable setup
Timing
Break-in Procedure...Oil ratio change, Heat Cycles and run time.
95' Carbs?...Well then you need to rebuild your carbs if you not already done so. The parts in the carbs wear and you would not believe how much difference it makes. Your motor will not work / run as hard and you gain HP.

NYCSTRIPES · 11-15-2007, 10:17 AM

Quote:

Originally Posted by lets_racefast

Ken,

There are a few things you need to know / do when you get your motor back.

power valve cable setup
Timing
Break-in Procedure...Oil ratio change, Heat Cycles and run time.
95' Carbs?...Well then you need to rebuild your carbs if you not already done so. The parts in the carbs wear and you would not believe how much difference it makes. Your motor will not work / run as hard and you gain HP.

Thanks, I will keep that in mind. + Welcome aboard. Are you a member at www.tz250racing.com? Here are some pics from Summit Shenandoah over Labor Day.
Ken

lets_racefast · 11-15-2007, 07:28 PM

Quote:

Originally Posted by NYCSTRIPES

Thanks, I will keep that in mind. + Welcome aboard. Are you a member at www.tz250racing.com? Here are some pics from Summit Shenandoah over Labor Day.
Ken

Nice bike!

Thanks for the welcome!...Yes, I'm a member of that site as well. I've been building and racing 250's for 15 years and they're AWESOME bikes to race on.

There a few little tricks you can do to gain more reliable power. Let me know if need some help.

I also make parts for Yamaha TZ 250's...pegs, fairing ears, brembo master cyl replacement washers and knobs, cush drive etc.

NYCSTRIPES · 11-15-2007, 09:05 PM

Quote:

Originally Posted by lets_racefast

Nice bike!

Thanks for the welcome!...Yes, I'm a member of that site as well. I've been building and racing 250's for 15 years and they're AWESOME bikes to race on.

There a few little tricks you can do to gain more reliable power. Let me know if need some help.

I also make parts for Yamaha TZ 250's...pegs, fairing ears, brembo master cyl replacement washers and knobs, cush drive etc.

Sounds good, I will probably drop you a line when the motor comes back. I am just waiting for RSCYCLES to return before I can get my rebuild kit and new crank on the way.
I may have some gearing/jetting questions for you. I am trying to put together the gearing/jetting for different tracks so I can run the longer tracks as well as the smaller ones effectively.
I may be interested in getting some spare pegs..just in case.
Ken

bondo · 11-15-2007, 11:30 PM

Quote:

Originally Posted by ism409

just jet it fat and you should not blow it up!

Ken,
don't listen to Carl.
Jet it as lean as you want, especially in 40 degree weather and skip that stinky oil. Custom welded pistons are the HOT setup!

Seriously, glad to see th TZ getting some TLC. Looking forward to seeing it in the spring.

This piston was the result of too little oil (spilled some in the wind mixing in the tank) and a little too lean at 1/4 throttle. Bigger main was not enough. It ran PERFECT, plug was nice and brown. Rolled off after a bonzi fireroad blast and she locked up tight.

NYCSTRIPES · 11-16-2007, 02:04 PM

Looks like a cylinder repair will be in the works. What bike is this?