Yamaha TRX850 Enthusiasts Forum

I was all excited this morn. i had a lisence, the bike was insured. the plan was to collect my bluespots from the post office, fit my freshly charged battery, start it up, give it a final going over and off to geta MOT. i had to push start it as it was only the second time i had started it since i had replaced the head. it started easly but was quite rattley and one of the hoses was leaking. the rattle died down after a bit, but is was still there.

I then opened the rad and found what no one wants to see oil. i refilled it hoping there may have just been a bit of oil in the water gallaries after i did the head job. but the more it ran the more oil there was.

now
i drained the oil and there is no sign of water in the oil.
i used a new head gasket, had the head plained, torqued the head to the correct settings using the correct pattern

im a bit stumped as to what it is. i did not touch the water pump so so it is hopefully not that.

the only thing i can think of is to pull the head and plain the barrels as well and refit a new headgasket. im not to happy about doing this again but i cant se another way out of it.

What else can it be. i dont want to pull it apart again.

what else can it be????????

it could be the mechanical seal in the water pump.

did you replace the base gasket and cylinder base o-rings?

is the cylinder head coolant pipe fitted properly with an o-ring? is the valve cover seal fitted correctly?

have you had the head on a surface plate and checked it is flat to within spec?

brockzila wrote:did you replace the base gasket and cylinder base o-rings?

no but i was very carefull not to pull the barrels off the case and break the seal the gaket had. would have been a smart thing to do though.

brockzila wrote:is the cylinder head coolant pipe fitted properly with an o-ring? is the valve cover seal fitted correctly?

yes and yes. i was thinking that if it was ether of these then there would also bee some signs of water in the oil.

brockzila wrote:have you had the head on a surface plate and checked it is flat to within spec?quote]

it was taken care of by a cylinder head specialst. some things i a;ways get the pros to do and that is one of them.

youngy wrote:it could be the mechanical seal in the water pump.

how hard is this to check. i would prefur to check this befor i pulled the head back off. I had a suzuki that this happened to and there was very ovous signs of oil and water in the cooling and in the oil systems. as far as i can tell i havee no water in the oil so i kind of ruled this out.

you want all the good news?

you cannot buy the seal separately. a seal from a YZF750 pump might fit, but it might not.

you cannot check the seal without removing the pump.

if you try to remove the pump be very careful. There is a shim on the pump shaft that rides against the drive gear. this shim is very unlikely to come out with the pump - it normally sticks to the gear then falls into the crankcase.

there is a seal behind the bearing, which is all inboard. it may be this seal, but on the YZF750 pump there is another mechanical seal as well.

If it's any help I do have a pump kicking around.

dam.
i will have a look at it tomorrow. but it was running sweet befor i pulled it down as it started as a valve clearence job that blew out to a full strip.

so i dont think its going to be that.

will pull the rocker cover off tomorrow and have a look under there and recheck the valves tomorrow anyway as i need to figure out the rattle.


my monotor just blew and i can only see the white bits. what else can go wrong today!!!!!!!!!!!!