Pulling the TZ250 motor - Page 4 - Sportbike Addicts

***Cakes206*** · 05-13-2008, 10:36 PM

Here ya go Ken...bring it up to Bogie!

http://www.youtube.com/watch?v=K2zcqr0cFs4

***carl_g*** · 05-13-2008, 10:51 PM

Quote:

Originally Posted by JimRBlue

I must say this is quite the interesting post! Never owned a 2 stroke nor realized the amount of work that can be involved with them. Excellent thread!

Any purpose built race bike requires tons of maintenance. It's not only a 2 stroke thing..look at the AMA LITES class.. All 250 4 strokes. Those bikes are so on the edge they require a full engine rebuild after just 4 hours of run time.

I drool when I see pics of this bike and I am majorly jealous! Good luck with your first ride on it this season!

NYCSTRIPES · 05-13-2008, 10:56 PM

Its definitely been a learning curve. Jumping into a full on GP bike without having owned anything similar to this has been a bitter sweet experience. They were designed to be built for racing and as a track day machine, they can chalk up some expense. VP c12 (leaded) Racing Fuel is expensive, Castrol A747 two-stroke pre-mix oil is also costly. Combined, the fuel and oil comes out to about $15 per gallon. Top end rebuilds have to be performed at 300 mile intervals or every 3 track days. The good thing is that the top end is a simple task which can take about 60-90 minutes time.
Crankshafts about every 1200 miles..once a season.

I have had the bike on the track a couple of times and when I had it up and running, it was a serious blast. More fun to ride than any bike I have ever owned. I am still trying to get up to speed on having them up and running reliably. I have made some simple mistakes in tuning that has cost me two break downs so far. The good thing is that they were both common mistakes and they helped me to learn a lot about the internal workings of the bike.
There is a lot of support for them on the web which has been extremely helpful to me, being good with a wrench is a must though. Its not for the faint of heart. You MUST like to tinker to own a GP two stroke. It can be a great hobby riding and keeping one of these bikes in tune.
I have my fingers crossed for a good season, but either way, every time I have to tear it down, I wind up learning more about these amazing machines.

I just hope that they keep making parts for them.
Ken

NYCSTRIPES · 05-13-2008, 11:00 PM

Quote:

Originally Posted by Cakes206

Here ya go Ken...bring it up to Bogie!

http://www.youtube.com/watch?v=K2zcqr0cFs4

Joe
I will watch it when I get home tonight, no access to youtube or such websites through work.
Sadly I won't be making it to Canada this season. The road trips are expensive and with fuel costing this much, I will be trying to stay local this year. Summit will be the farthest I will want to go this season.
Ken

NYCSTRIPES · 05-13-2008, 11:02 PM

Quote:

Originally Posted by ism409

Any purpose built race bike requires tons of maintenance. It's not only a 2 stroke thing..look at the AMA LITES class.. All 250 4 strokes. Those bikes are so on the edge they require a full engine rebuild after just 4 hours of run time.

I drool when I see pics of this bike and I am majorly jealous! Good luck with your first ride on it this season!

You know, I am skeptical about the new 450cc 4 stroke race bikes that Roland Sands has been pushing because of the maintenance. I guess we'll see how they hold up.
I will try to put up some more current pics of the TZ after my next track outing. Once I get the bike running the way I want, I will be repainting it...so stay tuned.
Ken

NYCSTRIPES · 05-14-2008, 09:38 PM

IT LIVES...

I managed to get everything set up and fired the old girl up today and buzzed the neighborhood with the TZ250.

Turned out to be quite a productive afternoon.
Ken

***carl_g*** · 05-14-2008, 10:49 PM

Congrats dude!

NYCSTRIPES · 06-05-2008, 10:09 AM

I received a new set of heads for my bike yesterday, probably going to install them this weekend, weather permitting.
2 stroke tuner Roland Cushway machined these heads (2000 TZ125 heads) for my 1995 TZ250. The 2k TZ125cc head has a better combustion area shape and plenty of meat on the head for machining. Lends itself to be reshaped into a copy of the Kit-A leaded 1995 TZ250 heads. Should make for a nice overall improvement on power.
Ken

***Respect_My_Authorita*** · 06-05-2008, 02:34 PM

congrats

***carl_g*** · 06-05-2008, 04:08 PM

I need to update my thread.. the crank is finally coming out this weekend and being sent off to get rebuilt!

NYCSTRIPES · 06-05-2008, 04:23 PM

cool beans.
Unfortunatlely TPM isn't carrying VP race fuel anymore and I will need to find a new local source for the C12 leaded race fuel I need. Just another hurdle.

Good luck with the crank rebuild.
Ken

NYCSTRIPES · 07-23-2008, 06:27 PM

After 2 disappointing appearances at Pocono this season, I think I finally have the TZ running properly. I spent the last two afternoons working on the bike trying to eliminate possible causes for the bike not revving past 6k RPM.

I pulled the carbs, heads, exhaust valves, plugs, installed new ignition coils, and still the bike wouldn't rev properly. The bike idled OK, but anything past 4K RPM was messy and it just choked out at 6k.

I also re-checked the ignition timing which was spot on. After scratching my head over this for 2 days with FDNYDANO who lent moral support and killed the local mosquitoes with his cigar, I swapped out the CDI Ignition and Magneto set for a spare I had in the garage.

Low and behold, the bike lives again...go figure. The ignition computer shit the bed without warning.

Glad I had a spare complete ignition set that I bought used last year, the new ones are $1500.00....

So far this season I installed:
newly replated cylinders, new top end (pistons, rings, bearings, gaskets), new chain, new sprockets, new custom heads, new plugs, new tires, new ignition coils, rebuilt the carbs.

After getting the motor running again, I changed out the gearing to 15/40 for NJMSP for Friday, look out for the blue smoke. Hoping the gear selection will be good enough for that track since I am hearing about the wide open throttle sections.
Ken

NYCSTRIPES · 07-26-2008, 03:49 PM

Finally got a full day out of the TZ250
Riding at NJMSP Lightning was a thrill, definitely looking forward to riding there again now that I have a feel for the line on that track.
In the meantime I will be tinkering to get the TZ ready for Thunderbolt on Aug 4th.
Who's going?
Ken

***carl_g*** · 07-30-2008, 03:01 PM

Nice dude so it's finally running well???

NYCSTRIPES · 07-31-2008, 09:06 AM

yes, now i have to get the jetting right. Its running a bit rich now. I ordered some more Mikuni jets to help with that. It was a blast on NJ Lightning.
Ken