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when doing the head gasket do these need to be replaced or can i re0-use them? Thinking of doing the head gasket while ive got the motor out and trying to price up what i need.

thanks

just had a quick look in the manual and it says that the head bolts are 25 nm and 27 nm only.you only usually replace bolts if they have a angular torque meaning a setting plus a degree turn on the bolts as these as 'stretch' bolts, but these dont seem to be that i can see so ye i would say they are ok to use.maybe worth a second opinion though......cargo seems to know alot about these so he would be a good person to ask.

extonyg wrote:just had a quick look in the manual and it says that the head bolts are 25 nm and 27 nm only.you only usually replace bolts if they have a angular torque meaning a setting plus a degree turn on the bolts as these as 'stretch' bolts, but these dont seem to be that i can see so ye i would say they are ok to use.maybe worth a second opinion though......cargo seems to know alot about these so he would be a good person to ask.

I've re-used them on two engines and never had a problem, infact i had to take the head off a couple of times after i had bolted it up to put it back together again.

Depends what you want to do though really, i would imagine if the heads never been off, you will be fine, dont tighten them up much more than the 27nm though, you dont want one snapping.

Also there are stretch bolts which stretch to provide the exact force required and like you said these cant be reused. However with normal bolts, specifically head bolts that arent "stretch" bolts, you will still get threaded stretch, this can lead to less friction when re-doing bolts back up, which is why alot of manufacturers will use stretch bolts and use new ones for head bolts.

never used new ones.......................

If they've been properly torqued in the past they should be fine to reuse................

cheers guys, as far as i know its never been off and imagine the original head gasket is still in there. Still debating wheather to do it tho, more of a confidence issue really as im worried ill bugger it up, but then ill guess ill never do it unless i actually get stuck in.

I noticed you say mongo in the mini chat, the engine doesnt have to come out to do the cam chain? I was wondering why then realised i could probably undo the front engine mount bolts and tip the motor forward in the frame?

Rob if you do that you are one bolt away from getting the engine out.
Why would you want to spend you time struggling on the floor working on the engine when you could have it up on a bench with 100% access to it for the sake of one bolt ?
What is it that so many guys are afraid of? Engine out is easy nothing to worry about.

Heres a thought....................if you are a commited ZXR400 owner why not buy a second engine................refurbish it from top to bottom then spend one day swaping engines.
Your bike is only off the road for one day and you can refurbish you orginal engine at your leisure.................

Easy really

cargo wrote:Heres a thought....................if you are a commited ZXR400 owner why not buy a second engine................refurbish it from top to bottom then spend one day swaping engines.
Your bike is only off the road for one day and you can refurbish you orginal engine at your leisure.................

Easy really

You just reminded of that engine i bought a few months ago Cargo

However, that engine as far as i know doesnt run and i dont know if it has any problems or not, so its a risk. Its also at my mums in kent and im here in ipswich. Ideally id have it here but ive nowhere to keep it and i dont think my landlord would appreciate me rebuiling an engine in my bedroom.

The plan is to do it over 2 and a half days, finish work friday get to my mums, strip what i need to and get the engine out that night. Saturday, strip the motor, do head gasket, cam chain, both tensioner blades and get it in the frame. Sunday, refill with coolant and get everything back on and hopefully for it to fire straight up. Probably longer than i need but i wont be rushed and i can take my time to do it properly and get it right first time

So it' could be a head gasket race this weekend, then, except Wakka wont be running afterwards, Or at least will run, just no clutch cable or brakes on atm.
I'm still striping off the back end and refurbishing the subframe.

Yeah, I should have been more methodical.

I would put my spare engine straight in, but I know Wakka's original was ass kickingly powerful. (well 65 at back wheel) and it only needs a head gasket...

Well if your doing yours this weekend then you win not planning to do mine for another couple of weeks yet so it will be end of the month by then. If you can throw any tips my way when youve done yours they would be welcome!

Is your head gasket actually gone?


Usually you need to skim the head on them, as they do warp pretty easy. You can check by using a steel rule and feeler guages and do it lengthways across the head and between cylinders and diagoally also checking all the areas that should be flat with a steel rule (the edge of one) and try and get the feeler guages underneath.

Sometimes you can get away without removing the valves for a skim depending on howmuch it has warped, but sometimes its even good to just get it surfaced so the gasket seats correctly. You could do this yourself by using a sheet of glass and a fine grade of wet and dry, im sure ive already posted on the method for doing that for a headgasket.

No it hasnt gone yet, it just clocked over to 19K miles and i know itll be in the next 4K or 5K miles that its going to go (if its like a typical ZXR), so just thinking ahead with while ive got the engine out i may as well do the head gasket too. Id rather do it before it goes so that way i havent got to ride it 90 miles home to my mums before i can do anything about it if it does go.