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phil2k

loosing water

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Hi I am new to 4 strokes, and have only just crossed over to the dark side, I have just got myself a 2002 426, when I got the bike the guy said its had full gasket set quite recent, I got the bike home and noticed it leaking oil from the clutch cover gasket, so I opened it up and found he hadent installed the gasket correctly. I also noticed the waterpump bearing was shot, so I ordered new gasket, new waterpump bearing and seals. Now I put it all back together and I have sterted getting water in the oil. I am not getting any drips from the weep hole so I presume the waterpump seals are ok. the bike starts ok most of the time but it does loose a lot of water into the tranny. I also noticed a bit of oil floating on top of the coolant. does this sound like a head gasket problem or is there a seal somewhere I have missed, if water was getting past the head gasket I presume I would get some steam out of the exhaust but I don't get anything apart from a little smoke for the first 10 seconds after I have started it

 

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I had a 426 lose a head gasket. ..try starting it with the rad cap off and rev it to see if it blows out. Mine would blow cylinder compression out of the rad

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I had a 426 lose a head gasket. ..try starting it with the rad cap off and rev it to see if it blows out. Mine would blow cylinder compression out of the rad

yeh I can see the fluids moving about a bit and it pressurises the rad in seconds so I guess its a strip down, do I need any fancy tools to do this? im only used to simple 2ts 

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ok got those so no need to spend there. do you know of anywhere I can download a manual for it or will I have to buy one?

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Take your time and make sure you really understand the procedure in the manual before you dive in. As you realise, a  4T top end is more complex than a 2T. Shouldn't be too bad if all you have to do is lift the head and replace the gasket though. I got to be a dab hand at it on my over-bored Gilera Nordwest. That had been taken out from 98 to 102 mm and there was very little mating surface left round the cooling passages at the front of the head. Apart from catastrophic failure the first time it  then began to  pressurise the cooling system when given beans. Just blew the coolant out of the radiator in to the expansion tank.

 

The Frigerio 604cc kit used a solid copper head gasket that needed a *very* precise regime of torqueing down, with higher than OEM torque,  at assembly and after a short period of running. I then realised that I had stretched the studs in an attempt to cure it. With new studs it lasted a while, but a timed run up the 5Km hill at Lerghy Frissel on the TT course had it pumping up again. Worse than that, I started to get coolant in the oil. So for the rest of the speed hill climb season I changed the oil after every meeting (perhaps 10 minutes of running) and used to force the coolant back in to the radiator after a run by using a bicycle pump on the expansion tank.

 

My tuned 04 YZ450F runs very hot and does puke a bit of coolant out if kept waiting on the start line too long. So I've rigged up a small catch bottle lashed to the bottom of the front frame tube. That has a breather hole from which I extract the few ccs of escaped coolant with a 20cc syringe. I don't think the head gasket is starting to weep compression in to the cooling system but I'm keeping a close eye on it.

 

Anyway, good luck. I remember the first time I ever did a 4T head gasket on a bike but that was an old air-cooled AJS 650 OHV twin - much simpler ;)

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