Blown head gasket?

[MrMelon]

Hey,

I've been having the problem on and off where the bike would over head, and I thought that it had been fixed when I topped the coolant up, and got rid of the air block in there.. but over the last couple of weeks, the temperature's been slowly increasing, from an average of 65 degrees last week, to a bit over 80 today..

So i've been thinking that it looks like the bike might be losing coolant, and I think it might be because of a blown head gasket.

How can I find out whether it's blown or not?

[MrMelon]

Or can anyone recommend a good 2 stroke mechanic in Wellington to check it out?

cheers.

[What?]

Peter Daniells.

Sorry, no details, but should be in yellow pages under "motorcycles"

[MrMelon]

Cheers, is this guy in Wellington?

He doesn't work at a shop that goes under a different name or anything does he?

I can't find him in the yellow pages.

[Kwaka-Kid]

get hold of a radiator checker thingy majiggy... like the one in my workshop, u pump it up and put pressure into the radiation system and see if its leaking any.. thats the first step i would say.

[Motu]

Lot's of ways to check for a blown headgasket - we like to get at least a couple of positives on different tests....we need enough evidence for a conviction.Loosing water with no leaks is a good clue - give me some more.

[merv]

Peter Daniells used to run Motorad until a few years ago and he seemed to disappear into the ether after that. I'm not sure what he does now. Probably not worth trying to track him down.

Steve Dundon from Wellington Motorcycles had a lot to do with racing two strokes in the past, though I am not sure if he is still spannering these days or just cruising on Harleys. Could be worth having a talk to the guys at Wellington Motorcycles - they were Yamaha dealers once - probably about the time your bike was sold new.

AS KK says you can pressure check the system - any good bike shop should be able to do that. Otherwise check your fluid levels, ride the bike - if it loses water with no apparent leaks then its getting sucked into the motor and something is blown - could be the head gasket, could be the base gasket. Get it checked asap - water getting into the engine screws the bores, pistons and rings pretty quick even just in small doses of water.

Basically if it is losing water internally it is usually hard to tell exactly where without stripping the engine.

[MrMelon]

Cool, I'll see if I can get somewhere to pressure test it tomorrow some time.

It's definately losing coolant somewhere, but it's not smoking any more than normal, the oil doesn't appear to be milky or frothy.

The overflow tank was completely empty when I checked it this afternoon about an hour after a ride, and I know it was full 2 weeks ago... so it's gotta be going somewhere, and there are no pools of fluid below the bike when it's parked up.

[Kwaka-Kid]

hmmm/methinks it could HOPEFULLY be the overflow tank alone... i am hoping for ya dude... because ive had that happen in many vechlies.. theyget old, brittle and crack etc, and its hopefully a cheap replacement (use a coke bottle or somthing crazy if it is not going to be)

[Marmoot]

A lot of thing can cause overheating:

1. If you are sure you're loosing coolant, check every hose connection to see any seepage. Check radiator as well to see any small smoking (small leak that does not produce drips). Check the coolant overflow tank as well to see its condition. I've punctured 2 R1 radiators while they're riding behind me (those stone chips can do quite damage).

2. Make sure your 2-stroke oil is well-topped and you are using proper 2-stroke oil for that as well.

3. Air/fuel mixture ok? Tune your carburetor. If all else, it will give you better power anyway so it is worth doing.
Especially in the winter/spring/summer season changeover, air density changes due to temperature variance and some bike can get sensitive. I have to run 98 fuel in the summer and 91 in the winter, otherwise it knocks in the summer and floods in the winter.

4. Might be a blockage in the radiator and the water is not circulating properly. Might also be blockage in the water jacket in the cylinder walls (hopefully not).

5. Might be a blockage of oil passage. Hopefully not as well.

I'd give my 2cents on the air/fuel mixture and radiator condition.

[MrMelon]

Ok, Well I've checked all the coolant hoses, and they're all done up tight, there are no punctures in the radiator that I can see. The overflow tank is still in good condition and not cracked or leaking.

It's got a full litre of 2 stroke oil in it at the moment.

I've got no idea how to check or change the air fuel mix on the bike though

I took the radiator cap off again today, and there was a fair bit of light brown creamy looking gunk around the cap, so I don't think that's a good sign

It's booked into some bike shop in j'ville on tuesday to get checked out.

 

 

[merv]

Originally posted by MrMelon

I've got no idea how to check or change the air fuel mix on the bike though

I took the radiator cap off again today, and there was a fair bit of light brown creamy looking gunk around the cap, so I don't think that's a good sign

It's booked into some bike shop in j'ville on tuesday to get checked out.

 

 

If air fuel mix was a bit off it might make the engine run hot but there would be no reason for it to lose water unless it was so hot it boiled so I doubt that is an issue.

The real McCoy though is the creamy looking gunk - you gotta have a blown gasket. Booking it into the bike shop is the way to go. Friends of mine speak highly of J'ville bike shop but they aren't two stroke riders so I hope he is good with those two.

Best of luck and hope it doesn't cost too much and hope you haven't got any water damage on pistons, rings and bores.

[What?]

Originally posted by MrMelon
I can't find him in the yellow pages.

  Sorry mate, bum steer. Refer to Merv's reply. (I am old and out of touch... )

[Marmoot]

Agree. The gunk spell "o-u-c-h".
Probably will need engine rebuild.

Well, if it's a consolation, at least your bike is not four stroke 4 cylinder.

[MrMelon]

Argh, well it's in at the shop now.. I took it in there , and the dude behind the counter was like noooo not that bike again!

He reckons that it's blown up 3 times on the previous engine, so they replaced it with a 2nd hand engine, and reconditioned it with 2nd hand parts about 25,000km's ago.

He seemed to think that it would be incredibly expensive if it needed new pistons or anything.

I thought 2 strokes were reasonably cheap to rebuild