GS1000 Yoshimura camshafts

[Agemax]

Just got hold of a set of Yoshi camshafts for my GS1000, apart from the POPY there is no other markings on them. How do i know what stage they are? The total height of the cam lobe is 37.2mm on the inlet cam and 36.7mm on the exhaust.

[Nessism]

According to the FSM the stock cams have a total lobe height of 36.35mm intake and 35.80mm exhaust. Can't judge duration and lobe centers of course.

[Agemax]

According to the FSM the stock cams have a total lobe height of 36.35mm intake and 35.80mm exhaust. Can't judge duration and lobe centers of course.

yeah, i thought there would be some kind of marking on it denoting what stage they are or what the grind spec. is.
yoshi cams.jpg

[GregT]

Those figures look like stage 2. Any markings on the ends ?
Without the base circle measurement I can't get the lift figure which is the main identifying factor.

[Agemax]

Those figures look like stage 2. Any markings on the ends ?
Without the base circle measurement I can't get the lift figure which is the main identifying factor.

I cant see any markings on either one of them.

[Agemax]

just measured them and the inlet is 0.370" lift and the exhaust is 0.350"

[GregT]

Quite mild. With that lift you can still run the stock shim over bucket. Probably a good road cam set.

If you use them, I'd put them in on 107/109 lobe centers - but check valve to piston if you use stock pistons. Wisecos you'd be OK.

[Agemax]

Quite mild. With that lift you can still run the stock shim over bucket. Probably a good road cam set.

If you use them, I'd put them in on 107/109 lobe centers - but check valve to piston if you use stock pistons. Wisecos you'd be OK.

Thanks Greg, i will only be using it on the road so i was hoping they werent to wild. i have wiseco 1100cc pistons fitted so that should be ok.

[bobtail84]

I have very similar popy cams in my engine and used slotted sprockets to get the lob centres I wanted which incidentally are the same as GregT advised. I also used APE valve springs.

[Chuck78]

I have two sets of these cams that I am eager to start using this season... I believe they are the same ones. They are pretty common vs other Yoshi GS750/850G/1000/1100G 8v grinds

see if you can make out the specs on the end of this photo under the Photobucket watermark. if you need a better photo, I can find one on my phone or computer or hobble down to the basement, on crutches with broken knee and plates pins and screws surgically installed...
Hopefully in a few days I'll be down there more cleaning and organizing anyhow.

[Chuck78]

Here are more legible specs, no thanks to Photo#uck!t... at least they started allowing some sort of free image hosting again, otherwise their platform would be obsolete

Note that next to all the Japanese writing, it says 1 mm. That means that is the valve timing duration measured at 1.0mm/.040" lobe lift, so that would equate to 260 degrees duration if they're the same as yours.

You can probably search for a post on here from 2017 when I picked this first setup, I probably already measured the lift back then and posted it on here, to compare to yours. I can't remember if my intake and exhaust for the same lift or not. I had a whole topic on Yoshimura cams for our bikes

[Chuck78]

https://www.thegsresources.com/_forum/showthread.php?239452-Yoshimura-GS750-1000-2V-Cam-specs-catalog&highlight=Yoshimura+camshafts

[Agemax]

Thanks Chuck, mine are 260* duration. i am now not sure what lobe centres to set them to, and what valve clearances to set them at.

[GregT]

Thanks Chuck, mine are 260* duration. i am now not sure what lobe centres to set them to, and what valve clearances to set them at.

107 inlet, 109 exhaust. .005in inlet .006in exhaust. You'll like the strong midrange characteristics.