Yamaha TRX850 Enthusiasts Forum

any suggestions on how to do this? ta

what makes you think it is warped is it blowing gaskets

the bloke I bought it from reckoned it was warped, as it had blown a head gasket, but it looks ok to me. Just wanted to check it "somehow"!

Put it on a perfectly flat surface - a piece of glass is great. You will see any warpage.

The glass is also great to skim the head. Clamp it down, grinding paste on the head and rub in a figure of 8 motion. Crude but effective

Cheers Pete.....................any other ideas? (don't have a piece of glass to hand......)

Anything that you would regard as perfectly flat would work - a mirror?

oh hey now that's good. I like it. just off to the bathroom............

Engineers steel rule, put the edge to it and slowly rotate , also doesnt shatter if you drop it!

Dave E

try and use glass that's thicker than 4mm i use 10mm ,got it from the local window company 600*600 and it was free!!!

hmm well I don't have a decent length steel rule, and the Mrs wouldn't let me take the bathroom mirror down, so it's probably got to wait til I'm in work on Friday.....pretty sure we have a surface plate kicking around somewhere.

ah but....a cunning plan......I'm thinking that the scale on my vernier will be pretty straight and long enough. Off to the garage - thanks for the ideas!

Of course the proper way to do it (us all being proper engineers and not a load of wally's) is to use a sheet of glass, laid on a fairly flat surface (like a dining room table) with a suitable cover to absorb minor imperfections (like a cotton tablecloth), then smear a thin coat of 'engineers blue' compound over the entire gasket face and place it on the glass. Rotating the head in a figure of eight will remove 'blue' from any high spots and leave a thicker deposit in low spots. Carefully lifting the whole lot to allow you to see through the glass will reveal highs and lows.
(Wax crayons work too if you really are a wally)

Dont use 'obscura' of any description seriously though it might pay to take a trip to your friendly high street glazier who might have a spare but small piece of plate glass... it need to be thicker than glazing sheet and plate tends to be a lot flatter too...

G

Agreed with Red Rex and Greg for a perfect job, depends what you have and how much you are willing to pay, I think that I would go with the glass and the engineers blue, that way you know it will be spot on.

Dave E

I've been all over the head this arvo with a straight edge and 0.05mm feeler. Can't get the feeler under it anywhere.

Discovered we do indeed have a surface plate at work. So that will get it's first ever use on Friday.

Also remembered a mate who is a glazier - he's sorting me a piece of plate glass.

2 steel rulers, one at the front of your head, one at the back of the head.

eyeball that they are parallel.

If one ruler is lower at one end, and higher at the other end. you have problems.

*note* this is not the best way, but it gives you an indication if warpage is present. Lapping the head the way phuk said is quite effective.. Just takes time.