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clutchcargo
10-29-2006, 10:50 AM
Ok, here we go again. I'm losing anti-freeze out of the overflow on my 85 Tri-z. The water pump was bad when I bought the bike and has been replaced. The radiator cap is good. The cylinder has a fresh bore with new piston kit and gaskets. My thoughts are that the previous owner overheated it when the water pump went out and cracked a water passage in the cylinder. I don't believe that it's the head, because I swapped heads and the problem still occurs. You can ride the bike without losing too much coolant, but it gets real annoying. I just want the bike to be correct, so I can ride it without constantly smelling anti-freeze and checking the resovoir. Anybody have any input? If it's the cylinder, what swaps with a stock Tri-z cylinder or can it be repaired? Also, how can I check to see where or if it's cracked?:confused:

Kintore
10-29-2006, 10:55 AM
Are you sure the rad hoses are routed correct? This happened to my basket case Z when I totally re-did it as well.

hrc85250r
10-29-2006, 01:03 PM
blown head gasket pressurizing the radiators.

TRI-Zbrian
10-29-2006, 01:10 PM
the cylinder its self could be worped also... replaceing just the head doesnt alwase fix the problem... you may have to have the cyinder decked....but yeah like peeps say you could also have a blown head gasket.... they can be blown and not leak out side the cylinder and be visable....
drain your oil and see if it is all foamy.... if it is then you also prolly have a bad water pump seal...

TimSr
10-29-2006, 01:32 PM
TriZ is famous for head gasket leakage problems. The mfg recommended torque is inadequate, but torqing tighter often results in head warpage, but more often, the cylinder "pulls up" around the studs. If you take the studs out, tape find sandpaper to a piece of glass, and rub the cylinder (upside down) on it, you will easily be able to see the risen part. Continued "sanding" may bring it down a bit, and allow it to seal. Part of the problem is the factor steel gaskets are much harder than the surfaces they are sealing. I have found that Cometic, or Wiseco fiber type gaskets seal much better, and suck up irregularities better. I never tried them because they "looked" inferior, but when I ordered head gaskets from Wiseco with my last top end job, they sent me Cometic. I have them on both my Z's, and they are the first gasket I never had ANY trouble with, and they did not need retorqued when I checked it after installation. Also, I always use Permatex Copper Coat spray on head gasket sealer. This is NOT orange silicon!! Its a spray on carrier with copper in it specially made for automotive head gaskets. It coats like paint.

Unclediezel
10-29-2006, 07:28 PM
Isnt there a Thermostat on a Tri Z?????????

Does it smoke white?....Head gasket or Cracked cylinder would leak "INTERNALLY"
causing smoke---Or externally which would show up on your engine, not out of the bottle. HRC has a point, but when the bike cools down, the cylinder would "SUCK-IN" coolant as the pressure equalizes and either Hydro-lock or Smoke terribly on start-up.

TRI-Zbrian
10-29-2006, 07:44 PM
yeah wouldnt a falty thermastat make it over heat enouph blow blow its goooooo

TimSr
10-29-2006, 10:37 PM
Isnt there a Thermostat on a Tri Z?????????

Does it smoke white?....Head gasket or Cracked cylinder would leak "INTERNALLY"
causing smoke---Or externally which would show up on your engine, not out of the bottle. HRC has a point, but when the bike cools down, the cylinder would "SUCK-IN" coolant as the pressure equalizes and either Hydro-lock or Smoke terribly on start-up.

When a TriZ head gasket leaks, the piston pressurizes the cooling system through the gasket sealing surface, which results in it blowing a blast of coolant out the overflow each time you rev it. The radiator cap is rated at 15psi, and will not withstand piston pressure. The cylinder is very positive presssure, so coolant does not enter the cylinder, nor does it suck it back in when it cools, because the cooling system is cooling also.

The stock TriZ has a thermostat, but most have been removed because they rarely work, but they stick wide open when they fail, not closed, so you do not get overheating problems from them. Its possible, but Ive never seen it.

Unclediezel
10-29-2006, 11:26 PM
True Tim,
However , The cylinder isnt pressurized when the bike is shut down. The 15 lbs of cap rating has to go somewhere, It either cools, or if there is a leak it is forced into the first "LOWER-PRESSURE" area it can find.

hrc85250r
10-30-2006, 02:59 AM
well, i would pull the head off, reuse the old gasket dry it off good and clean everything-put a boatload of gasket shellac on everything the head gasket touches AND the head gasket, put it all back together, crank the head down good and evenly with a pattern, let it sit overnight and you will not have to worry about your head gasket ever. i run an old head on my R with 220 psi compression using a metal cr head gasket with a shaved head, never blown a head gasket.

clutchcargo
10-30-2006, 08:24 AM
Thanks for the input guys! The cylinder was machined and so was the head. New gaskets were used and torqued to 18ft. lbs in the proper sequence. The t-stat has been removed already. There isn't any white smoke coming from the exhaust. The rad hoses are routed correctly also. The coolant comes out of the overflow hose from the resovoir and pukes it onto the engine. The new water pump is still working. If Yamaha's torque specs for the head are incorrect, then what should the head be torqued down to? Also, there isn't any coolant in the trans oil. Thanks again.

Unclediezel
10-30-2006, 08:36 PM
Just for giggles----make sure your rads are clear internally. I get the point these guys are making, but Ive never seen a head gasket blown (Auto, Bike, trike, Quad) without either excessive smoke , or contaminated oil.

clutchcargo
10-31-2006, 08:23 PM
I will check that out! I didn't even think about a clogged radiator. Thanks for the tip.