Cleaning up an SR400 engine cosmetically

[Spoonman]

Yeah 500 crank and bored out.

I purchased the crank new from the USA.

[darkian]

Ok great. So is the top end different, or are the 400 and 500 different only by the crankshaft? And if so, is there still enough 'meat' to bore the 400 head out?

I could look for an SR500 engine to pilfer for bits. Was an oversize piston expensive?

Thanks again.

[Spoonman]

400 and 500 barrel and head are the same. My barrel was bored 3mm over size (from stock) to 90mm. any further than that and you run the possibility of splitting the barrel.... if you want more you need to sleeve them but then that opens you up to the possibility of 600+cc on a SR500 Crank.

My maths were a bit out, seems the 90mm piston only give 535cc with the 500 crank.

http://www.motolanna.com/ourshop/prod_3304675-Piston-Wiseco-90mm-91-535cc-Yamaha-SR500-SR400-XT500-TT500.html

Lots of info on big bore kits (and lots of other info) can be found on the SR500 forum.

http://www.sr500forum.com/forum

[Overandout]

Maybe I'm over simplifying things, but wouldn't it be easier to bolt in a SRX600 engine?

[Spoonman]

Maybe I'm over simplifying things, but wouldn't it be easier to bolt in a SRX600 engine?

Sure if you want to cut up the frame to fit it but in doing so you lose the appeal of a kick start big single.

On the subject do you know where I can buy an SRX600 engine, I would like one for another project I have in mind.

[darkian]

I agree - also it's fun to make an engine a bit special. I for one am glad I don't have electric start.

Hmm, 600cc would be nice. Maybe something for further down the line.

[AllanB]

Been using Belgrom for just over a month and it is good and bad.

The bad news is that it has a very low level of abrasion, so you have to rub like buggary and it is really hard work.

The good news is that the finish is very high and it seems to last a lot longer than other metal polishes, unless you are a glutton for punishment.

So, my idea of polishing in stages would seem to be the best solution, that said cleaning in all the nooks and crannies won't be easy.

[Garry]

Walnut shot compound is best for clean blasting from my experience. The walnut shot won't damage internal components and will break down/soften in oil. Glass or plastic shot I would avoid like the plague if you have open cases and you can't barrier them from ingress of the shot.

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[yankee99]

can you but walnut shells here?

[Garry]

can you but walnut shells here?

Unfortunately for Thailand I do not know, though I haven't looked. I used walnut shot in Australia on aircraft & motorcycle components. It is very non-abrasive and takes a bit longer to work, but it is a lot more gentle on the reduced changes to the surface finish.

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[seedy]

Tried baking soda ? Is it available here in bulk ?

[dave_boo]

Tried baking soda ? Is it available here in bulk ?

Go to a big bakery and try to buy "ผงเชื้อขนมปัง" in bulk?

[taichiplanet]

maybe talk to these guys, they are in Pattaya (near Buddha Hill/Silverlake - i took a wrong turn and found them!)

http://rjsurfacetreatment.com/

[seedy]

maybe talk to these guys, they are in Pattaya (near Buddha Hill/Silverlake - i took a wrong turn and found them!)

http://rjsurfacetreatment.com/

Thanks for the link !! Good one !!

[ll2]

Walnut shot compound is best for clean blasting from my experience. The walnut shot won't damage internal components and will break down/soften in oil. Glass or plastic shot I would avoid like the plague if you have open cases and you can't barrier them from ingress of the shot.

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you scared the s..h...i..t out of my walnuts garry!