400xce headgasket or water pump problem

[cOrPsE]

Sorry for so many threads about my bike but it has been sitting for god knows how long. So far ive replaced the air filter, cleaned the gas tank, bled the brakes, cleaned/unseized carb etc etc. So today was startup day and when i was draining the old oil sadly i saw coolant coming out with the oil. Even worse, the coolant has like fuckin crystallized and little white chunks all on the inside. So i got most of it out by putting oil in and draining it couple times. Anyway as a quick test i put water in the radiator, and it came out of the drain plug so something is obviously wrong. I got an RM80 back in day that had coolant in the oil and all that was wrong was an arm that moves the water pump was detached. Attached it, bike ran mint. Anyway, although this bike sat along time i dont think this guy barely even road it. The frame, swing arm etc etc have no scratches, no rust anyway really, and there is no leaks that lead to the exterior of the motor. Motor is so clean you can eat off it (exterior wise). So is it possible the headgasket is no good or maybe the water pump is seized or something? Basically just looking for some insight before i dig in.

 

[justintendo]

pull the water pump cover and see if its corroded inside...could be the water pump seal or headgasket

 

[John Archer]

 

[John Archer]

this is what mine looked like when I got it. These bikes are known for this. Not many other problems though.

 

[cOrPsE]

this is what mine looked like when I got it. These bikes are known for this. Not many other problems though.

Wow thats crazy. Thanks though ill be removing it later today.

 

[cOrPsE]

does anyone have the part # for just the water pump gasket?

 

[2premo]

the common problem was people used tap water and or a mixture of tap water and coolant, the electrolysis does this, to avoid this used the premixed coolant or at least used deionized water, if yours is an 86 it might have a magnesium cover most of the later 86 seemed to have the aluminum ones, as I recall all 86 used an o-ring and not a gasket
look at John Archers picture and you will see an o-ring,
as a tip when you have it open (and if the case is not rotten) check the bearings on the pump to see if they are smooth or that will also damage the case do to seizing, as a thought there is a seal on the bearing that can leak so if your case looks good check that, when you reassemble it be careful to not over tighten the screws

 

[cOrPsE]

i think it might be cast aluminum or something what do i do lol

PREPARE YOURSELVES

 

[86 400 XC]

Its Magnesium, later covers have a aluminium back plate JB welded in there

 

[cOrPsE]

Its Magnesium, later covers have a aluminium back plate JB welded in there

So do i need to replace this cover?

 

[86 400 XC]

I would say so. Maybe some others have tried to fix that with JB weld and it Might be to far gone.
I got a spare cover for 25 off Ebay, not worth the risk of failure or effort to fix i think.

 

[2premo]

I agree you can fix it but would be better off replacing it due to the cost of the engine you are trying to protect
as to starting the bike if you have a bug to start it go ahead, just shut it down after about a minute

 

[cOrPsE]

I agree you can fix it but would be better off replacing it due to the cost of the engine you are trying to protect
as to starting the bike if you have a bug to start it go ahead, just shut it down after about a minute

haha i do have the bug, but i dont wanna hurt this awesome bike. Just gotta save up for the replacement cover.

 

[2premo]

if you can't find one for sale contact me in about a week I work out of town
I probably have a usable one, but no guarantees

 

[cOrPsE]

if you can't find one for sale contact me in about a week I work out of town
I probably have a usable one, but no guarantees

appreciate it man, I'll be searching.

 

[roberto75015]

Hello,

this is a very common problem and true you can find a more recent alu cover but you can also fix/rebuild it with some epoxy resin: I used "Loctite 3479 Aluminium haute température" and then painted with another specific product for the inside of engines and it worked quite well.

Also, there is an husqy shop in Italy doing a thin alu layer (2mm I believe) which you can use to rebuild, first you have to machine the original plane by lowering it down of the same height of the alu bit. Not so difficult to make the same at home :-)

Here the link and a picture:

http://www.soldamoto.com/cardetail.php?id_car=54




bye, Roberto

 

[cOrPsE]

I think maybe I'll try to epoxy it 1st then roberto. Thanks for the help. Been looking on ebay there are a lot of covers, but only for air cooled bikes. That italian repair looks good but im in the USA

 

[dukkman]

Hello,

this is a very common problem and true you can find a more recent alu cover but you can also fix/rebuild it with some epoxy resin: I used "Loctite 3479 Aluminium haute température" and then painted with another specific product for the inside of engines and it worked quite well.

Also, there is an husqy shop in Italy doing a thin alu layer (2mm I believe) which you can use to rebuild, first you have to machine the original plane by lowering it down of the same height of the alu bit. Not so difficult to make the same at home :-)

Here the link and a picture:

http://www.soldamoto.com/cardetail.php?id_car=54


View attachment 32620

bye, Roberto

Thanks Roberto never thought of fixing them that way.
Don't get too disheartened corpse this is a pretty normal problem.

 

[cOrPsE]

Thanks Roberto never thought of fixing them that way.
Don't get too disheartened corpse this is a pretty normal problem.

thanks man. Just JB welded it, gonna do a bit more tomorrow.

 

[cOrPsE]

Should i put the kick start mechanism in first and the cover over it, or all together?