Tri-z seem to run way too hot

[tippmann]

Hi have a 85 tri-z with some mod... here the list
-Wrench report phase 2 done.. About 0.86mm(0.033'') (piston to head clearance)
-full dg
-38 mm keihin airstriker
-stroked crank
-v force 3 out a kx 125 but i change petal for softer
-brand new piston ring
-top and bot fresh rebuid tested for air leak
-brand new stator
spark plug br8es nice brown colour.
-About 186 psi compression ( Running with a little octane to make it run tight)

I just finished the bike and had issue about jobbber head gasket leaking into cylinder So i just installed a yamaha head gasket and the gasket didnt blow up right aways. But i notice i sound who seem to come from water pump.. but when i run the bike he leak prestone off the cap when i ride it a bit. (just some small drop) Have no prestone bottle. and no termostat. I have clear hose for prestone + i tested witout prestone cap and when i spin the bike i can see small bubble like the water pump seem to run normally.

Problem is I maybe run the bike for 5 min and cant handle my hand on the water pump cover... really hot .. the rear exhaust same thing ... really hot cant even touch it. So tested out my yz 250 09 about same riding time and touch my water pump cover and still not hot and rear pipe is cold...

Without that bike seem to be great and hes really fast. Slow idleling #1

Help me ! haha

[El Camexican]

Open the radiator cap when the engine is cold. The coolant (Prestone) should just be high enough to cover the radiator tubes, not more. If there is more than this it will leak out the cap when it gets hot.

With the cap removed from the radiator start the engine. Watch the coolant and see if it is moving. If you have no thermostat it should be flowing immediately, not just some bubbles, but some flow. If this is not the case you have something wrong. Either the hoses are in the wrong place (see photo), or you have the wrong head gasket, or perhaps it is not properly installed (I don't recall if this is possible on that engine) or the water-pump is not working. One way to test this that is very messy, but will work is to remove the hose from the top of the head and turn the engine over a few times without starting it. A bunch of coolant should come out of the head if you have the gasket installed correctly and the water-pump is good.

If the flow is good then put your finger in the flowing coolant wait and see how long it takes for the coolant to get warm with the engine running. As soon as it does get warm the water-pump should be warm too. Not hot, just warm. By the time the water-pump is hot the coolant at the top of the rad should be hot too, but not hotter than the top of the radiator as that is where the hottest coolant is. The water-pump is receiving the cooled and pumping it back into the cylinder from the front of the head, so it should be hot, but not as hat as the top of the radiator. After it passes through the cylinder and absorbs heat it comes out the top and into the left side radiator and cools before flowing back to the water-pump from the right side radiator.

Is your overheat light working? It should come on when you start the trike and then turn off for a few seconds. Do keep in mind that that particular engine does run very hot, but 5 minutes to be too hot to touch seems wrong.


After re-reading your post it sounds exactly like the WR 250 I rebuilt. The last person to work on it put the base gasket on upside down (don’t worry, yours is built differently and this can’t happen to it) and plugged the coolant flow. It was supper hot in just a few minutes of running. When the water-pump is hot put your hand on the return hose on the bottom right radiator. If it is cool or not even warm then you can be sure something is blocked.

[volfan537240]

Great advice. Let us know what you find.

[tippmann]

For now was watching the temp of rad top bot and water pump cap with a temp gun there all near same temp about 150f on operation i might be good but prestone keep spitting till the hose that get from thermostat to top of rad get halt empty (clear hose)

So i wash the bike clean then came back for a better longer test and bike were bogging at half to top throttle then switch spark been a lite better then he stalled now igniton problem dunno if stator toasted or a something disconnect im about to bring it in my home as a decoration. ,, everythin is new and i followed manual shop for everything even respected torque value

[El Camexican]

As a Canadian I actualy understand what you are saying (Just thought I'd mention that)

Tell us about your radiator cap. Is is stock? If not, how may PSI of preasure does it say on the cap? Is the rubber gasket good? Seems to me that the gasket is bad, or the cap spring is very weak. 150F is not hot at all. It should be running at least 170 to 200F so it is not heat that is making the Prestone leak out.

Let the trike dry out and maybe it will start working again.

[barnett468]

Hello Tippmann


Please answer all questions if you like but do it in line order fashion not one long paragraph, it's easier for me and some others to follow that way.

xxxxx

just finished the bike and had issue about jobbber head gasket leaking into cylinder So i just installed a yamaha head gasket and the gasket didnt blow up right aways.


What do you mean the new gasket did not blow up right away?

You may have a warped head and/or cylinder causing a small leak from cylinder into water which creates pressure in your cooling system.

Could also have the same problem at base gasket.

Suggest doing crank case leak down test or remove head and cylinder and inspect for flatness and repair as necessary. Machining may be required.

xxxxx

But i notice i sound who seem to come from water pump.


Can you either explain the sound or better yet take a video of your motor and the sound then put it on youtube.com and place a link to it here for us to listen too.

Xxxxx

when i run the bike he leak prestone off the cap when i ride it a bit. (just some small drop)


Since it is not getting hot [150f] it sounds like pressure leak at base or head gasket or bad radiator cap as El Camexican suggested.

xxxxx

For now was watching the temp of rad top bot and water pump cap with a temp gun there all near same temp about 150f


A leaking head gasket will not always heat up the prestone quickly.

How long was it running before you checked temp?

What is the longest you have ridden it then checked temp?

That seems warm enough to me at idle in Canada in the winter.

xxxxx

on operation i might be good but prestone keep spitting till the hose that get from thermostat to top of rad get halt empty (clear hose)


Don’t understand

xxxxx

So i wash the bike clean then came back for a better longer test and bike were bogging at half to top throttle then switch spark been a lite better then he stalled now


Did you spray it with a high pressure hose?

Does your spark plug still spark if you lay it on the head and kick it over?

Drain gas from float bowl into a clear narrow glass, is gas orange, is there sediment in bottom of glass, is there small WATER BUBBLE on bottom of glass? Water sinks in gas.

Xxxxx

igniton problem dunno if stator toasted or a something disconnect im about to bring it in my home as a decoration. ,, everythin is new and i followed manual shop for everything even respected torque value


Check stator coils and ignition coil with ohm meter as recommended in service manual.

Xxxxx

Leak still might just be cap as El Camexican suggested.

[barnett468]

PS -Don't wash your bike anymore.

[tippmann]

Woodruff key break here why had no fire... bike temps seem to be around 150 f.... all seem to be ok... but i keep blowing head gasket.. my head and cylinder are not bend or anything i got em both on a milling to be sure.. so its 100% tight... For this year ill use the Z as a home decoration... I still have a 250r 85 to repair.. and a 350x that working.

[Tri-Z 250]

Did you replace the waterpump seal when you rebuild the motor...shaft on impeller show any wear? As I've read your post I see you seem to think its working...Which implies to me you have not. A prefect example of the failed $2.00 part terminating a $250+ top end.

[tippmann]

new seal ,shaft is ok... where im not sure is when I start the trike with radiator cap open there lot of small bubble im thinking its the impaller that make those bubble, but im not sure since having lot of trouble with head gasket.