torquing and retorquing the head

[spannerman]

question for those of you who are building thier own motors. are you torquing the head up and leaving it at that, or are you torquing the head and putting the engine through a couple of heat cycles then retorquing the head. the reason i am asking is last time i built it it was okay for a couple of years. this time it has gone in about six weeks of quite hard riding, more than likely the head has warped but when i checked it it seemed okay. will get another head ready but just want to know if the 400 likes certain ways of being built because i know that the kr1s i have is very particular as to how it is assembled.

[mick41zxr]

Are you sure its not the gasket that failed, can happen. I torque in steps up to specified amount in the order stamped in the head. You can crack & re torque each bolt, but never have done in the past on this motor.
regards,
MB

[cargo]

I've always done it by the book.
Not ever gone back to re-torque never had a problem either

[spannerman]

bit of a misunderstanding yes the head gasket is gone, this is what i mean, this time it has only lasted a couple of month. as for retorquing i dont mean crack them off and nip them back up i mean if the engine was to go through a heat cycle or two then just double check them again. i know that the head is probably warped ,i have built up another head and will use this one instead.

[mick41zxr]

Cracking off & retorquing head bolts is the only way to re torque the head. If you just try to check them you will get an inconsistant result.
It goes without saying that yoy use a good (usually expensive & calibrated) torque wrench, If the head has warped no amount of torquing will solve that.
Check the runout as per manual, can be corrected by a good machine shop, dont forget to check cam journal clearances as well.

[Mori Man]

A good torque wrench is paramount or having it calibrated yearly.

If your removing head time & time again , even though they are not stetch bolts I would replace the head bolts every 4th or 5th time.

I am sure Kawasaki (or any other manufacturer) didn't invisage them being removed time and time again. From industry standards the motors need to be able to be a sealed unit for 100,000Kms with out failure (observing the service schedule)

These test are in house and are left to the companies to certify themselves - I can guarentee that Honda do it all the way to 100K (or equavalant hours) with out ever servicing it.

Been a while since I stripped a motor down - is there washers under the bolt head ? I would be replacing these every time as again although not crush they will be subject to force.

Just my 2p worth.

MM!

[gavinfdavies]

i'm just about to start stripping my engine, but if i recall rightly from my first read of the service manual, doesn't access to the head bolts require the removal of the camshafts? (it might not, i've only glanced through it once, i'll go through it properly before I start.)

if so it seems alot of effort to go to to retorque the head bolts, and also i'd have thought you'd be more likely to cock up the cam timing the more often you remove the cams.

[cargo]

and also i'd have thought you'd be more likely to cock up the cam timing the more often you remove the cams.

I would have thought the exact opposite would be true..............I've had the cam shafts out that often I can put them back in blindfold.............

practise makes perfect

no telling with some folk mind you there are brain dead types that cant remember what day of the week it is

[mick41zxr]

I use a white paint pen or liquid paper when taking cams out & in, just for easy reference. A dab on the cam chain & cam gear avoids f*** ups.
Regards,
MB

[gavinfdavies]

well hopefully I won't cock it up.

know what you mean about stupid - did you hear about the dealer who sold a honda cbr400rr cheap because he thought the cam chain was shot...

dispite the stickers on the fairing reading "Cam Gear Train"!

I also know what you mean about doing it with your eyes shut. Even though I've been out of the TA for over 3 years, I can still strip, clean, and reassemble an SA80 with my eyes shut. No, really, when out on exercise you don't tend to use torches!