almost set fire to my 2 stroke

Ice Burger · Nova Slayer Joined: 21 Apr 2019 Karma :

Hi there,

I've been restoring a 1995 Honda NSR 125 and recently just had a full rebuild of the engine.

I went for a test-ride after receiving my bike from the mechanic. During my fateful ride, I had a loose coolant hose disconnect whilst riding.

It took me probably 4 minutes till I noticed something was wrong. The low end power seemed groggy and when I stopped at the lights it was like sitting in a bloody sauna. At this moment I panicked and caught my eye on the temperature gauge and was horrified to see the needle pinned all the way to red. I rode back home which was only 2 minutes away, on the way back I tried to use no more than 3000 revs.

The bike won't start now and lacks compression, probably the cylinder head is warped.

My question is what do i need to change? what's the damage? Can I just change the cylinder head and fix the coolant pipe?

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Take it back, to the mechanic nod explain that the fact he/she forgot to tighten the coolant pipe resulted in the engine heatseizing and fucking the rings, piston and barrel.
____________________
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Ice Burger · Nova Slayer Joined: 21 Apr 2019 Karma :

Thanks for your response Nobby,

The mechanic won't fix it because the rubber actually perished (should of specified sorry), it was more of a time bomb that took a small amount riding to break.

The engine still turns over without any odd noises and isn't seized. I'm hoping I can fix it myself.

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Ice Burger · Nova Slayer Joined: 21 Apr 2019 Karma :

Yes they didn't advise on changing it.

Sorry mate I don't know the compression I don't have the tools to measure it. I assume it's a bit shit at the moment, I might try to hill start my bike and see what happens.

St George · Borekit Bruiser Joined: 19 Feb 2019 Karma :

Have you got a decent fire extinguisher in the cave, first thing I bought.

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

It'll most likely be fucked now.
Why did you even comprehend riding an overheated bike with no coolant in it for 2minutes to get home? The way you explain it is that you didn't want to damage it further? Err hello!

The head and cylinder need to come off for inspection at the least IMO now. If your lucky it won't need a head skim or a new cylinder. I wouldn't worry about a compression test, until you've had a look at the internals and measured everything up for tolerances.

You need to say goodbye to your mechanic and either find a good shop that's a two stroke expert or else do your own engine work. On something like an NSR I'd want to have it apart every 6000-8000miles at the least, as it's got a Nicasil bore and you don't want to trash that.

Ice Burger · Nova Slayer Joined: 21 Apr 2019 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Ice Burger · Nova Slayer Joined: 21 Apr 2019 Karma :

Took my bike to a new mechanic. Compression test is 50psi!!!!

I was on the phone to them and they found out the head had 5 bolts holding it on and they were all only finger tight!

The news is suggesting the engine isn't too badly damaged, I had a lot of shoddy work and more loose connections than I first thought.