Is there enough metal thickness for the lid to run a tap?

I like the exhaust valve location but I all ready have the head assembled.

It's thin but will be enough to hold the probe .It only needs to be about 5-6inch/lbs torque max , I put some rvt or similar sealant on the threads and just snug them up .

Can someone please give me the head bolt torque number.
Clymer manual seems to low

Book says 18 lbs but that seems low

From factory service manual 1990 First Edition

Cyl Head
Flange bolt M8 x 1.25 = 21 ft/lb
Stud bolt M10 x 1.25 = 14 ft/lb

Bob

Never use a rattle gun to tighten any nut/bolt that has a specific torque setting.

This is basic mechanical engining.

True... One should NEVER rattle gun anything tight. Apart from perhaps a set of wheel nuts on a Transit Van :thumbup1:

However there are some very accurate (And expensive) air guns that you can use because they are limited to certain torques. On torque sensitive bolts I still wouldn't though.

In this case I think he meant use a rattle gun to remove the clutch nut which is totally acceptable.

I never use a torque wrench. But with just the slightest idea of what youre doing, I see no problem using an airgun to tighten big nuts like that. Most of the airguns (both of mine) them have different settings.

I know its not the proper way to do it, but I do what works for me, and give others the option of choosing for themselves :thumbup1:


My wr250r has something like 125Nm for the rear axle, making it just about impossible to remove with the tools provided by Yamaha. I cant figure out why they list it so high, and I've had no problem setting it way lower.

So again, for me, nothing beats real life experiences....Eventhough they are wrong if you go by the book.

Happy riding...

I couldn't disagree more with this....

There are so many torque critical components on a motorcycle that you dont know you're wrecking until many miles down the road. Theyre the kind of second hand bikes you dread buying.

Torque settings arent made up for the sake of selling manuals.

Fair enough, its pretty difficult to screw up a rear axel but if youre 'rattle gunning' engines back together then remind me never to buy a bike off you... :eek:

You are the best:thumbup1:

Put all back together and started up without drama.

Spent about 1/2 hour breaking the rings in etc, leisure driving.

Inspected bike and can hear a hiss from the head gasket doh.

Stripped down bike again
Head measured straight
jug measured straight

Cosmetic head gasket, which seems a whole lot less sturdy then OEM.

Head bolts were torqued to spec. But just didn't seem tight enough.

Gonna check threads and see if any debris in head bolt chambers etc.

Going to take head to machine shop to validate, should of done that 1st I know. Kicking myself now.

Am i missing something?
Head gasket was stock size
No copper/silver spray added on install

It doesnt make sence to me to go by yamaha specs, when nuts on the counterbalancer and crankshaft loosenes. Yamaha doesnt mentioning loctiting theese either, I did it anyway. Quite the hack job, huh? :oops2:

I havent "'rattle gunning' engines back together", I've used it on 3 nuts, 2 of them known to beeing prone to loosening up. :D

I didnt just fire up the compressor and airgunned it till the nut didnt moove anymore. I know how tight the bolts was to remove, and tightened them the same amount. I marked the nut/shaft with a marker before breaking them free, and tightened the 2 bolts proone to loosening up, just beyound that. The clutch to the same mark, as this isnt a problem. Still used threadlocker.

So should be VERY close. :thumbup1:

What difference would a couple Nm be? Its like under 10% difference. Theres probably a bigger difference in torqing the threads oiled vs not. :innocent:

I did it about 1,5 year ago, just wanted to know how much time you give me before the engine grenades. I really dont think my nuts care which tool was used to tighten them op tho'. :mchappy:

Rebuilding an engine isn't as 'back shed' as many would like.

You need those mating surfaces SPOTLESS. Or at least so smooth that you can run your thumb over it and not feel any raises or notches.

Also it sounds like your head threads are tight or damaged. You can't accurately torque down a head unless the bolts are moving freely.

Tighten down the head from opposing corners turning each bolt a few turns at a time. You can count full turns of identical size bolts and see if they are winding down similar amounts when they 'Click' on your torque wrench (book procedure is best though).

I don't mean to sound patronising but are you sure your torque wrench is set correctly ? $10 torque wrenches don't cut it on engine work either.

That's assuming everything else is straight and lined up.. Are the dowel pins seated straight etc ?

Thanks Ted

I'm going to really go over this tomorrow.
I had done a previous head gasket on this bike without problems as well as my truck.
I did something wrong obviously.
I will do a leak down test as well this time to make sure of leaks.

Pictures are cylinder after like 10 miles or 30 mins.
Front part of cylinder seems to have some wear? I can't feel anything but its smooth with no honing marks at little over 1/2 way down.

Does this look like abnormal wear?

Is it a new piston ? Was the cylinder measured ??

Those score marks arenr what you want. If everything wasnt clean in there it could be contamination. Did it smoke ??

Sent from my G7-L01 using Tapatalk

New piston, slightly larger
cylinder bored to piston size

Was taken to bike shop for machining and fit
I installed rings and piston