KR-1S.co.uk Forum

Was just running in my fresh engine (as you'll see elsewhere) - running nicely, and temperature staying at the cold end of the normal range.

After about 30 miles, noticed radiator level had dropped to the level of the core - topped up presuming just air from the re-build.

Yesterday went about 20 miles, and noticed coolant on the back wheel - header tank was full, and now overflowing.
Thought this could possible be rad cap not sealing properly, so cleaned it and gave it a run - same problem. Then added a thin rubber washer below rad cap to make sure it was properly sealed, run it again and the waterpump casing gasket blew

Again temperature didn't move while it was filling the header, or with the washer below the cap, and only shot up (as expected) when the gasket let go. So it's not running hot, but the system is over pressurising, so all I can think of is head gasket ??

Thermostat is new. I built the head onto the barrels before installing on the crank cases. Used a pattern gasket set, and a smear of Kawa-bond.

I fear the worst....................Any thoughts ?

Cheers,

Tommy

It's either the head gasket or base gasket,generally pattern base are okay but even genuine one can fail,normally you can confirm this by seeing if the gasket has "pushed outwards" around the front of the barrel.
Personally ive never had a head gasket problem even when used more than once,but ive only used genuine gaskets,for the price they are (around £20 head/£7 a pair for the base) its not worth using anything else.
Had the same problem as your having now a while a go,which was in my case caused by the base being pushed out at the front,didnt seem to be losing water (although it must have) and the plugs didnt show anything up and ran okay,but the water was rising and falling in the rad,when you revved it it got sucked down then when left to idle it overflowed.
I would just order a tyhe right gaskets from cradley and have done with it,you dont need sealant on a new genuine gasket.
ATB
dave

Tambo wrote:Used a pattern gasket set, and a smear of Kawa-bond

Hi Tommy, bad luck - it looks like a set of gaskets from Cradley are required.

Thanks guys.

The fact that it's not overheating, I can't see what else would over pressurise the system, other than combustion gasses being blown into it ?
No sign of 'white' smoke from the exhausts, so presume it's not leaking fluid into the barrel.

Do you think gaskets alone - ie no head skimming ?

Engine out again, or would you tackle it insitu ?

I'm gutted Was sooooo enjoying riding it

I doubt that any "skimming/resurfacing" needs doing unless its boiled up/ran out of water,you only have to lay a straight edge across the barrels (when bolted to cases) to see if there level (not unusual to have 1 slightly longer/shorter),if there not then they WILL need machining to same height,but although this is a renowned fault ive yet to come across it myself,worth checking though.
The head itself you can just check when off on the bench with a straight edge/rule.
Up to you wether you take the motor out,its possible to remove both barrels and head as a unit while in the frame but the only thing you may find makes this a pain is the fact that you need to clean the crankcase mating surface off of all the sealant,not to easy in situ as the angle of the motor makes bits getting into the cases highly likely (no matter how many rags/tape you use to seal it up).
my moneys on dropping the motor and working on it on the bench,it takes a leisurely 45mins to do and then you can see whats what in comfort.
Its pressurisng the system so it wont overheat,as your not losing much/any coolant,it takes alot of water to get steam out the pipe,but a small nick in the base will still pressurise the system,which is what its doing in your case.
If you have done enough miles you will notice the side with the problem,the piston crown will be very clean in comparison to the other side (bit of carbon buildup).
Just one of them things,a lesson learned.
Let us know what you find,and if in doubt put some pics up of the piston crowns.
HTH
Dave

had the same 3 weeks ago headgasket blown inside at the back of both cilinders.

rebuilt it with the same headgasket and some silicone , now it is running great.

( did check the barrels and head, rubbed them over a glass plate)

i think it happened after a good run and i didn't cool it properly after i got back home.

I had exactly the same problem when i first had mine,turned out on investigation the previous owner had not torqued the head down properly,ie the nuts were slack!I used a genuine head gasket and torqued the head down in the sequence stated in the manual with a calibrated torque wrench,this cured the problem.Hope this helps.

Rich

Best to use genuine gaskits as pattern head gaskits are rubbish unless you use sealer on them i had the same problem with mine.

Thanks guys.

So, it seems the concensus is that a genuine head gasket will be enough to cure it ? Provided I've not warped it in the failure !!

I'll drop the engine (again ) - would you take the barrels off again to connect them to the head first, or is that un-necessary as that's the way I assembled it the last time ?

Don't want to have to take it apart for a while after this !!

It's best to take of the barrels and connect the barrels to the head and then put it on the engine, if you have a slight diverence in hight in the barrels and you connect the head on the barrels when the barrels are on the engine for 100% it wil leak again.

j

Its not definite that it is the head gasket (although highly likely),it could just as easily be the base (which is what caused the same probs on mine),either way,with the motor out it would be wise to take the barrels off and fit genuine Base aswell.
You cant torque the head down on the barrels until there fitted to the crankcase,so just build it up as the manual shows (the correct way),barrels on,lightly nipped with a decent ring spanner,then torque head (18ft,lb) then finally tighten the base fully in the correct order(16ft,lb),after that its best to double check the head torque again.
The only reason you ever need to fit the head and barrels as a complete unit is if you have changed the pistons and dont need/want to disturb the head gasket.
When you put the base on (minus head) just nip them down the same amount and then check the top of the barrels are level with each other,doubt very much you have warped the head as its not been over heated.

dave32 wrote:It's either the head gasket or base gasket,generally pattern base are okay but even genuine one can fail,normally you can confirm this by seeing if the gasket has "pushed outwards" around the front of the barrel.
Personally ive never had a head gasket problem even when used more than once,but ive only used genuine gaskets,for the price they are (around £20 head/£7 a pair for the base) its not worth using anything else.
Had the same problem as your having now a while a go,which was in my case caused by the base being pushed out at the front,didnt seem to be losing water (although it must have) and the plugs didnt show anything up and ran okay,but the water was rising and falling in the rad,when you revved it it got sucked down then when left to idle it overflowed.
I would just order a tyhe right gaskets from cradley and have done with it,you dont need sealant on a new genuine gasket.
ATB
dave

Dave let me know where you get base gaskets for £7 a pair !? Normally £11.20 each and £24 for a head gasket. !?

Cheers
Kev

Hi Kev,
Base gaskets £4.20 from Cradley

http://www.kawasakioriginalparts.com/ka ... 1991&ca=GB

Cheers,
Bernie

Must have gone up a few pence since i last ordered,still not bad at £4.20,i use Cradley,always have.