Renamed, Head Gasket Leak, Solved

Biker_123

@tomimsmith1992 no problem mate! Yeah it's just the direct link as Calum runs this website of his home network. Having a little look though at this radiator cap it actually looks pretty clean I've seen worse! If you have a spare radiator cap to hand give it a try and see how it goes and if it's the same situation probably best to investigate the head gasket,the cooling system seems fairly simple on these bikes so shouldn't be hard to find the culprit .

vtrtomuk

ill try a different rad cap, if that's not the fix i'll swap out all gaskets and jubilee clips, iv purchased a second hand rad anyways, had new samco hoses a few months back so effectively should have a new system lol

Biker_123

@tomimsmith1992 Great stuff mate . Keep us posted on how you get on but I reckon you've got this covered with those parts you have..

vtrtomuk

cheers @Biker_123, still surprises me how simple these bike in theory are, yet throw up some odd things i suppose that's what you get when your bikes 16 years old lol

Biker_123

@tomimsmith1992 definetaly mate lol it's of a simple design the bike but can still leave you scratching your head! I know mines does anyway ...

vtrtomuk

just a update, replaced with known good rad and rad cap, and replaced all jubilee clips,

done a oil change while i was at it, can confirm no water in oil so water pump seal is sound,

so iv ordered a full yammy gasket set from Jacksons, my local yammy dealer so will be OEM gaskets.

i think you are right @Calum its going to be a internal gasket leak,

have remembered i never did re torque the head, unfortunately is probably to late to rectify that now 1000 miles to late lol

so in a nutshell,

rad OK
rad cap OK
waterpump seal OK
coolant pipes OK

all that remains is the gaskets in the top end so as a process of elimination that must be where the issue is

cheers

Calum

FYI Athena gaskets are perfectly good. Athena make gaskets for my Turbo motor and they are reusable sweet quality gaskets and I will be using them on my Rotax build.

I did the same a few years back on the belgarda build. Used oem but for the price it's kinda not worth it.

Unlikely, but it could be leaking around the thermostat when under load, and because the cylinder head is hot it just evaporates.

I only say head gasket because if it's not leaking and it's not the gearbox then I can't think where else.

If it was the head gasket it will pressurise the overflow

vtrtomuk

i agree have always used Athena gaskets just have a bigger budget than usual, best spent on gaskets or i'll only go and spend it on something useless otherwise ahah

i have always run my bike without a thermostat, the temp needle has sat nicely about a quarter of the way into the "running zone" no matter how much its being thrashed. full gasket set so that will be replaced as well anyways,

iv had a few head gasket failures on some of the off road bikes and the DT all usually pressurize the system eventually overwhelming and opening the rad cap and dump the coolant into the expansion tank till it overflows, can usually tell with the bulging pipes above the thermostat. and the water puddle on the floor and the exhaust fumes in the rad.

this issue unfortunately doesn't show any of the tell tale signs. possible pinhole size leak in the head maybe.

im not a fan of products such as rad weld and wonder weld etc.,... but might run a bottle through it just in case there is a pinhole leak in say the coolant pipe which runs across the front of the engine or behind a exhaust stud??

is re torquing the head a must. logic tells me once torqued correctly at cold the clamping force should only increase with the metal expanding when hot ? so surely there would be no way of it become slack ?

anyways as always thanks for the advice

Calum

Tommy, if I can give you one advice you can take away it will be this.

Always, always, always run a thermostat! It is imperative that you run a thermostat.

The reason for this is because a thermostat creates a restriction in the cooling system. This raises the pressure inside the cooling system. A cylinder head requires around 40-60 psi of pressure in the cylinder head. Failure to do so will cause stale pockets to form of hot gases in the head. This becomes increasingly hot and will warp the cylinder head and cause the head gasket to blow.

Rad weld should only be used in an emergency to get you home. It should never be used on a system you care about. It's bad for aluminium, which your engine is. It clogs up the radiator reducing the efficiency.

To be honest we may found your problem mate! Put the thermostat back in. This restriction, combined with the blown head gasket will cause the expansion bottle to overflow. Indicating that the gaskets gone mate!

Please read and take that on board. It's sound advice.

vtrtomuk

And the problem has been found @Calum & @Biker_123 you were right! tiny head gasket leak !

http://i44.photobucket.com/albums/f21/tom_smith7/IMG-20160409-WA0001_zps9vlrakjd.jpg

http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_10_Pro_zps1cmucvrw.jpg

http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_01_Pro_zpsxynp8je6.jpg

http://i44.photobucket.com/albums/f21/tom_smith7/WP_20160409_15_40_07_Pro_zps0eccyuwx.jpg

so what do you guys reckon go for another skim this heads already had 3 passes and the barrel 2 so that will be 5 thou taken of i would have thought?

also is it one of the guys on here selling the copper head gaskets on ebay? i know older engines used to have copper gaskets... are the rated highly for the use on DT's ?

as always advice aprecated

Calum

@tomimsmith1992
I have no experience with copper head gaskets but they are used in high performance engines when composite gaskets don't cut the mustard.

That cylinder head has seen better days!

As said always run a thermostat

vtrtomuk

Thermostat has been ordered from yambits, i had no idea it could cause such adverse effects ....

I'm going to go the copper head gasket route give it ago... Whats the worst that could happen

Yeah the heads a bit battered ill stick a post in the wanted section for a replacement.

Will I be ok to re skim the head do you think how far from detonation am I thats the question....

Calum

You will have to measure the squish band to really be sure. If it's that bad then you will need to double up on the base gasket to bring the compression ratio back down.

vtrtomuk

just having a thought about copper gaskets again,

i was sure copper reacts with aluminum so i had a quick search on the net.

"Aluminum will be very susceptible to galvanic corrosion in contact with copper, assuming that the two metals are also in contact with a common electrolyte (such as water with some ionic content.) Almost any text or handbook on corrosion will have galvanic series table. The farther two metals or alloys are separated on the table, faster the corrosion of the less noble of the two will be when they are in contact."

location of quote http://www.finishing.com/78/97.shtml

so surely copper head gaskets are a bad thing, also copper doesn't and wont compress like the OEM gaskets do so there cant be any imperfections on ether surface,

but then i think copper washers are used for air and water tight fittings as a "gasket" as such so copper does have its sealing quilatys

so my question is the pros and cons of copper good or bad ?? what would be the advantages over the OEM gaskets.

maybe is should start a new thread ??

Calum

@tomimsmith1992 You are right about the electrolyte stuff. But that goes the same with any two metals. So it won't corrode over night. And hopefully the gasket seals the engine so it won't have any contact with water lol.

As said I haven't used them but they are known to fix problems with gaskets blowing all the time.

vtrtomuk

after research and reading on many car forums iv decided to go with a copper head gasket with a bit of hylomar universal blue and a re skim on the head... depending on what the engineer says will double up the base gaskets. hopefully that will be the last time i hear of a leak.

with the help of the new thermostat as well

will probably take some pictures when putting it back together wont be till around the 20th of this month though

vtrtomuk

UPDATE,

had the head checked by a engineer buddy and its all flat so no warpage.

the workshops theroy for the blown head gasket.

in normal operation the thermostat regulates and pressurizes the system as @Calum stated maintaining a optimal temperature,

without a thermostat and having a free flow the "cold" coolant from the rad is being dumped into a boiling hot engine causing " thermometric" stress over time you end up with unevenly cooled parts of the head and develop hot spots "most likely over the exhaust port" this causes the aluminum to expand quicker than other parts and essentially crush the head gasket in small places. basically a slight bulge in the head surface. the engine then cools and the aluminum in the head then returns to normal, unfortunately the gasket cannot, so when you next start the engine from cold the gasket then blows past the weakest point your crushed head gasket !

i relise @Calum you have said this earlier doesn't hurt for a second opinion. but thank you i wouldn't have chased the thermostat route if you hadn't have clocked on to it

well parts should be here tomorrow including a new THERMOSTAT! so fingers crossed

cheers lads

Calum

Yeah sure mate. I do a fair bit of reading. I didn't appreciate the importance of the thermostat until I read it possibly 6 months ago. I always ran with one.but didn't know why until quite recently. What he said is true, but I doubt the head will be cold, the hot stale pockets are what I have read time and time again.

I'm sure he's right though.

vtrtomuk

http://i44.photobucket.com/albums/f21/tom_smith7/IMG-20160412-WA0001_zpsrdcpssxh.jpg

So i got all my bits and have all been fitted. went for a 40 mile ride last night no leaks and no need to top up coolant,

on the way to work today 30 mile trip let bike cool coolant is just under rad neck so possibly just working out air bubbles so probs lost 5-10ml

this is using the copper gasket with copper sealant "spray a gasket" type of stuff

see how it goes on the ride home

vtrtomuk

Update,

went to go get a maccy d's for lunch lost a bit of coolant, so im afarid its still not done anyway got a second head now so ill go get that skimmed and the barrel checked, why are these such a bast**d to seal done x amount of 2 stroke head gaskets never had a leak., yet the dt is a pain. so im just going to go on the assumption that things are warped somewhere, at least i got a geunuine head gasket floating around now. the head gasket should show where the leak is hiding .

i think its safe to say yamaha should have used O rings instead of steel gaskets like all there other 2 strokes, funny that iv never seen a AM6 or a rotax 122 (not yammys obv) head gasket leak there both oring'ed, i feel a experimental project comming on

has anyone done it before ?

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Renamed, Head Gasket Leak, Solved