Topic: 76 cb750 yoshi kit

[gizmo]

hi i'm trying to find a set of 836 yoshi piston rings can you supply any info  regards tony

[MRieck]

http://www.sohc4.us/forums/index.php?topic=12106.0

[Jerry Rxman Griffin aka MuthaF'er]

Tony,

Measure your pistons. My Yoshimura catalogue only lists 736 high compression stock bore, 748 cc 2 ring slipper kits, 810, and 826 kits. No 836. The 810 kit seems to be the most popular. It uses 64mm pistons, the 826 has 64.5mm, and if you have 65mm pistons it is in all likelyhood not Yoshimura not that this matters. If you'd like to see the Yoshimura catalogue go to SOHC4.net/gallery and search Yoshimura catalogue. If you have 64mm/810 then go to a Honda dealer and get a set of rings for a 68 to ?? maybe 72 CB350 2 cylinder (not CB360). I run the 810. I sent Hasting rings my piston. They verified this. The old CB350 rings work great. If yours is 64.5 then use 0.5mm over size 350 rings. 

Jerry

[gizmo]

i'm not 100% certain that its yoshi i've never seen anthing like it as the oil control ring is one piece not the standard three piece like the wiseco version but i got the kit of good old ebay so i'm not sure of anything apart from the pistons are in bloody good nick i'm just suspect about the rings as once installed it still burnt oil but i run her yesterday and apart from a small puff on startup there was no smoke confused or what best rgards tony          ps i've just rechecked the listing and guess what i'm now even more confused as the bore size is 63mm so what the heck did i get!!!!!!!!!!!

[MRieck]

Yosh piston say PopY or have the symbol just below and to the side of the wrist pin hole.

[gizmo]

didn't see any wording just a number but after looking at a 810 yoshi kit pistons look identical even down to valve cutaways in the crown

[Jerry Rxman Griffin aka MuthaF'er]

Bore size is 63 but what is the piston size? We can go from there. Did you find the markings as Mike Rieck mentioned? I had once used a 1 piece oil ring with my 810 also. Did not like it. Used oil. Thats when I sent the piston to Hastings for ID. The stock CB350 Honda 3 piece oil rings are MUCH better!

[gizmo]

hi can't measure the pistons as i've still got the motor running the pistons should be 0.05mm smaller if there is no major wear so allowing for the piston to bore clearance the piston should be 62.95mm i don't know if this helps with the identification but at least i'm learning a little more about them with help from you guys  regards tony

[dusterdude]

Bore size is 63 but what is the piston size? We can go from there. Did you find the markings as Mike Rieck mentioned? I had once used a 1 piece oil ring with my 810 also. Did not like it. Used oil. Thats when I sent the piston to Hastings for ID. The stock CB350 Honda 3 piece oil rings are MUCH better!

one piece oil rings suck,been there,done that.

[MRieck]

Bore size is 63 but what is the piston size? We can go from there. Did you find the markings as Mike Rieck mentioned? I had once used a 1 piece oil ring with my 810 also. Did not like it. Used oil. Thats when I sent the piston to Hastings for ID. The stock CB350 Honda 3 piece oil rings are MUCH better!

one piece oil rings suck,been there,done that.

Yosh pistons never came with a 1 piece oil ring.....garbage.

[Jerry Rxman Griffin aka MuthaF'er]

Mike is correct. Yosh didn't use 1 piece oil rings. They would be after market like mine were. You say the bore size is 63mm but it's still running and you can't measure the pistons?!. Just how do you know the bore is 63mm then? And how do you know whats on/not on the pistons?! If you did or had the kit done yourself and you're having a problem now that it's back together, the only way to find out what you have so you can find out what you need is to break it down again. Until then I don't see a way that you're going to find the answers you need. 

[gizmo]

thats the easy bit the listing said that the bore size was 63mm 2mm over stock although the two other sets of barrels i've got measure up at 60.5 with the pistons at 60mm as standard so whats at fault the listing or the fact that the barrels he had were already 1mm over before rebore or the bike had the kit fitted before he bought it ijust don't know so i thought sod it and found  a 900dohc motor to go in which gives me chance to rebuild the sohc for the future

[Jerry Rxman Griffin aka MuthaF'er]

I have a feeling what you might have is a 2nd oversize which would be 61.5mm. Stock is 61mm. I believe that you can go up to 4th oversize (but I could be wrong on this) which would give you +0.25mm  X 4 or 62mm. I don't believe I've ever seen any kits listed as 63mm. Only solution is to break it down and use a good caliper to measure. Perhaps it is the 748 Yosh slipper kit with 2 ring pistons. That should be 2nd oversize.
Break 'er down......

[MRieck]

I have a feeling what you might have is a 2nd oversize which would be 61.5mm. Stock is 61mm. I believe that you can go up to 4th oversize (but I could be wrong on this) which would give you +0.25mm  X 4 or 62mm. I don't believe I've ever seen any kits listed as 63mm. Only solution is to break it down and use a good caliper to measure. Perhaps it is the 748 Yosh slipper kit with 2 ring pistons. That should be 2nd oversize.
Break 'er down......

Yes. The only way to know is to pull it apart. That Yosh 2 ring is neat but sucks for the street...I think it took them 20 years to get rid of the KZ1000 2 ring kits.......

[gizmo]

300004594672this is the item listing which you'll have to goto ebay and put the number in so you can see the pistons and barrels you might get a better idea from this as the piston crowns are not standard as the originals are flat crowns and these are not so have a look and see what you think best regards tony

[Jerry Rxman Griffin aka MuthaF'er]

Couldn't tell anything from the EBay picture. 2 questions: What is the exact measurement of the piston and is it a 2 ring piston? If you can't provide this info then we probably can't help you. You will probably have to break it down to get the answers you need. I've never heard of a kit using a 63mm piston. IF it is 63mm then it may be home made. Also a decent picture by you of the piston might help. Might as well keep riding until winter.

[gizmo]

i'll have to let you know when i finally rip it down again! this engine has been broken down more time than i care to think about but the lesson for me is stick to what i know the next time i'll use wiseco coz they seem to keep a good lineup and they keep a stock of all the kits they supply i fitted one to a z1000 and thats just running in lovely good power and torque the guys still got the smile now but good old british weather prevails and the bikes relegated to the garage so we wait for the dry yet again