Yamaha TRX850 Enthusiasts Forum

Hi, whilst trying to undo the screw Holding the water pipe to the cylinder head see pic (screw Holding part no 20), the screw had sheared off flush with the cylinder head. I do not really want to take the head off and drill the remains out, as getting the downpipes off can be a right bastard (took me three weeks on a TDM last year..). Now, when the pipe is pushed back in it sits really tight in an O-ring. Anybody know whether one can run the bike without tightening the pipe with the screw, if you get what i mean??

Here is the Picture is mentioned

No, they can be a real pain to seal, it will leak when the radiator becomes pressurised.

In an emergency and for short distances, you could ride with the radiator cap loose so pressure can't build..
But then if the join blows..you will have a lack of stability in the rear with the coolant everywhere.
The problem could get worse maybe ?

If you were clever, as the bracket only holds the pipe in place, you could braze a strap that could possibly attach to the rocker cover bolts

You may have enough movement in the motor/frame as such if you pivot the motor down on the bottom rear mount so you can remove the bolt without removing the head. You may just have to remove the front wheel and forks to give you ample space.
Save you money in engine gaskets.

Thanks for all the replies so far guys. The idea with the bracket and the rocker cover bolts is interesting...my thinking was much the same, if all the screw does is hold the pipe in place, i thought the seal of the oring would be enough to hold the pipe in and seal it. It was very hard to get out after the screw was "off"...Sadly tilting the engine forwards wont help. if i have to drill the screw out then the head has to come off....

Approx 10/12 psi pressure will soon push the pipe out - otherwise Yamaha wouldn't have bothered fitting the screw

hoyhoy9 wrote: if i have to drill the screw out then the head has to come off....

Are you sure?
Centre punch the broken screw and drill by hand. You would be best drilling the screw with the cam cover left on, pipe removed and the hole blocked to stop swarf going down, when the drilling is done vacuum the swarf out of the hole, then you would not have to worry about swarf getting into the cams/valves. soak in deisel or penetrating fluid for a day and then try extractors.

Personally as I hate screw extractors If you have access to a tig welder take the cam cover off, weld a nut to the broken screw and it should come out easily.

Thanks for the idea Rich, but i am afraid of ruining the hole if i drill it by Hand. Then having to get hold of a new cylinder head. THe idea with the mig welder would be great if the b*%ger screw hadnt sheared flush with the head...

Would pput the head on a proper stand drill and drill it with a 3mm drill bit, then soemhow try and get the gunge out so i can retap the thread..

The Trixie has done 42K Kms, so maybe taking the head off would be a reason to clean the carbs, and have a look at the valves....

I would still rather leave it on tbh, must give it all a big think.

Still taking the head off is not that difficult really - its only a bit more work than doing the valves - gaskets are quite expensive but it its do-able in a day

Mine snapped also last year,there's only one way to go,get it fixed properly,bight the bullet take the head off take it to an engineers get them to drill it out the broken bolt
and re tap the threat,

THe idea with the mig welder would be great if the b*%ger screw hadnt sheared flush with the head...

Tig not Mig, mig will splatter tig won't. Put it on DC weld a washer to the screw with a plug weld through the middle, then weld a nut to the washer. Heating /cooling cycle when welding usually breakes the seal. Don't use BZP washer or nut to weld.