Above.....Yes, but steps get missed (routing), and employees make quality mistakes at every supplier.
Scott
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WHERE DID IT GO , IM AM WORRIED
- Thread starter funky
- Start date
Above.....Yes, but steps get missed (routing), and employees make quality mistakes at every supplier.
Scott
funky
XS650 Junkie
Right back to my engine . can someone clear this up for me ...piston rings side clearance in the book for standard piston and cylinder 16 to 31 thou then its says second with the figures 12 to 28 thou .... do they mean second size up. or second ring I thinking second ring ??? what's the "second " mean ..... Cheers
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Tomterrific
XS650 Junkie
Your oil problem was cylinder wall washing from too rich mixture. Very common on any engine. Don't automatically blame the rebuilder.
Tom
Tom
Michaelo
650Mick
Go hard on it Funky, you have the best attitude, plenty of the old boys and girls here will be available to help you. I am glad you checked the cylinder and piston clearances.
Also look at your cam chain and tensioner whilst apart, I'd not done before do it now while you have the engine out.
As far as heat goes, pretty sure that's not what the issue that caused your oil burn.
What's important is getting it right this time, so go hard at it mate, you will learn heaps too, knowing your engine and all the bits that make the beast work and sound so great you will be proud to ride down the road thinking that it was you who fixed it and breathed new life into it
Also look at your cam chain and tensioner whilst apart, I'd not done before do it now while you have the engine out.
As far as heat goes, pretty sure that's not what the issue that caused your oil burn.
What's important is getting it right this time, so go hard at it mate, you will learn heaps too, knowing your engine and all the bits that make the beast work and sound so great you will be proud to ride down the road thinking that it was you who fixed it and breathed new life into it
funky
XS650 Junkie
Thanks Michaelo.... I polished my pistons
i got another set comming so what the hell if anything they look wicked lol ...
Did them by hand no mops or dremels good old elbow grease .
i got another set comming so what the hell if anything they look wicked lol ... Did them by hand no mops or dremels good old elbow grease .
Michaelo
650Mick
Post Pictures up as you go...here was my oily knackered mess...
Michaelo
650Mick
Hey 2M wasn't that engine bored to 707? I thought I read that at some stage, would that make the tolerance different at all?
Sure, Mick. Just multiply those ring gap values by the bore ratio, 77.5/75, or 1.033. That'll add 0.001" to every 0.030"...
funky
XS650 Junkie
Thanks for that Two many..... I just noticed something 
I was told 2 to 2.5 thou piston to bore clearance,by SmedSpeed the tolerance stated on the engine spec sheet states 20 to 22 thou 
have i read that right
SmedSpeed gave me the wrong measurements ,if any thing it should be a little bigger as my piston are big bore 77.68...Spec sheet goes up to 76.00mm piston or is the the same gap for my size piston....
If he had set the clearance at 0.002 to0.0025 that was too tight which would wear the rings ????? 20 thou is bigger than 2 thou ...... Im confused
I just E-mailed him for clarification and i am going to the Yamaha engineer in my town to measure my bore and my pistons ...
Just found these I wonder ????
http://www.excessiveracing.com/WIS-7800XX.aspx
And this
https://www.alibaba.com/showroom/piston-rings-78mm.html
If you type what size you want loads come up
I was told 2 to 2.5 thou piston to bore clearance,by SmedSpeed the tolerance stated on the engine spec sheet states 20 to 22 thou have i read that right SmedSpeed gave me the wrong measurements ,if any thing it should be a little bigger as my piston are big bore 77.68...Spec sheet goes up to 76.00mm piston or is the the same gap for my size piston....If he had set the clearance at 0.002 to0.0025 that was too tight which would wear the rings ????? 20 thou is bigger than 2 thou ...... Im confused
I just E-mailed him for clarification and i am going to the Yamaha engineer in my town to measure my bore and my pistons ...Just found these I wonder ????
http://www.excessiveracing.com/WIS-7800XX.aspx
And this
https://www.alibaba.com/showroom/piston-rings-78mm.html
If you type what size you want loads come up
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funky
XS650 Junkie
Michaelo .... Nice bike
, do you want those pistons polished
I'l do you a good deal 
, do you want those pistons polished I'l do you a good deal
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Funky,Thanks Michaelo.... I polished my pistons
Mate you must have run out of elbow grease on those suckers.
Well done. Will you do mine ??
funky
XS650 Junkie
LOL Yep shure did they took about an hour and a half each started with 300
then 600 then 800 then 1200 then 2500. grit wet and dry Theeeeeeeeeen AUTOSOL All done . I shave in one of them this morning 
in accordance with the YAMAHA 650 forums grooming standards
Yep shure did they took about an hour and a half each started with 300 then 600 then 800 then 1200 then 2500. grit wet and dry Theeeeeeeeeen AUTOSOL All done . I shave in one of them this morning in accordance with the YAMAHA 650 forums grooming standards
...I was told 2 to 2.5 thou piston to bore clearance,by SmedSpeed...
...the tolerance stated on the engine spec sheet states 20 to 22 thou
Sir Funky. Calm thy mind. Breathe slowly and deeply, in thru nose, out thru mouth.
Look again at the spec sheet.
Notice the number 0.0020
That is 2 thousandths...
Michaelo
650Mick
We should revert to metric all the time, imperial has no place with these bikes. Pretty sure when we did the change over to metric it was a good thing but both UK and USA still are in the bloody dark ages hanging on to everything imperial, going through the pains of converting "thou" to metric to understand and visa versa. I was fortunate enough to go through both imperial measurement system and the metric system through my schooling years. I still find sometimes converting from one to another is common place, but when discussing precise measurements here on the forum we should (in my humble opinion) stick to the metric units to kill off any confusion ....
I can hear you going FFS, but, it's true....ha!
I can hear you going FFS, but, it's true....ha!
All I can remember is the dying centimeter.
Erg...
Erg...
Michaelo
650Mick
Looks like your going fishing
funky
XS650 Junkie
FEEEW Thanks TwoMany ......Ok this is where i am at the moment.
I took the cylinders and pistions to my local Yamaha dealer who builds drag engines for his bikes but the old singles and stuff like that. He checked one of them Pistons and cylinders as he told me to remove the rings which i did. He said that it just over the upper limit about 0.0027. Limit is 0.0020 - 0.0025.
Im thinking and tell me if im wrong that If you can see the hoaning marks from 3000 mile ago then the cylinder have not worn that much , the only possible or even reasonable conclusion is that the tolerance was up near the limit when done by Smed speed ..... What do you think
I took the cylinders and pistions to my local Yamaha dealer who builds drag engines for his bikes but the old singles and stuff like that. He checked one of them Pistons and cylinders as he told me to remove the rings which i did. He said that it just over the upper limit about 0.0027. Limit is 0.0020 - 0.0025.
Im thinking and tell me if im wrong that If you can see the hoaning marks from 3000 mile ago then the cylinder have not worn that much , the only possible or even reasonable conclusion is that the tolerance was up near the limit when done by Smed speed ..... What do you think
I grew up using imperial measurement, but then Canada changed over to metric when I was about 30. I still use both systems, but I find it easier to use thousands of an inch, when measuring fine tolerances . My micrometer measures in thousands of an inch.
Meat at the grocery store, has the price in lbs. in big 2" letters, and the price in kgs in tiny 1/4" letters. Typically canadian, we operate in two measuring systems and two languages. Its all good!
Meat at the grocery store, has the price in lbs. in big 2" letters, and the price in kgs in tiny 1/4" letters. Typically canadian, we operate in two measuring systems and two languages. Its all good!
I think .0002" isn't enough to worry about, but things might get a little loose after you've honed again to break the glaze; you'll want to measure again. 2M, chime in here please, but I'd feel comfortable if the clearance was within .0028". And right, Smed bored your cylinders to and a touch beyond tolerance. Lesson: in this age of the world, some vendors and fabricators cultivate a following of unknowing fanboys and acquire a reputation they don't deserve. Others acquire a reputation based on past good work, then get sloppy. Still others will do good work for a specific clientele (flat track racers, for example) and abuse others shamelessly; I could tell you some stories on the last sort from personal experience. It's hard to know who to trust until you've made some connections with credible people, and even then you can get a bad referral.
