Shell #1 timing specs

Shell1Specs.gif
 
Yep, those were the numbers on Shell's timing cards, but they were usually not the numbers that his grinder produced; with the exhaust valves dialed in at 45/25, you'll usually see the intakes opening at ~20 and closing at 45 as on my own cam, bought in 1998.

I tried timing to the intake events, splitting the error between intake and exhaust, and timing to 100* lobe centers, but accepting late intake opening is the setting that's felt best to me; if the Shell #1 is advanced much at all, I find myself doing a lot of short shifting.
 
grizld1 said:
Yep, those were the numbers on Shell's timing cards, but they were usually not the numbers that his grinder produced; with the exhaust valves dialed in at 45/25, you'll usually see the intakes opening at ~20 and closing at 45 as on my own cam, bought in 1998.

I tried timing to the intake events, splitting the error between intake and exhaust, and timing to 100* lobe centers, but accepting late intake opening is the setting that's felt best to me; if the Shell #1 is advanced much at all, I find myself doing a lot of short shifting.
Click to expand...
This is good stuff!
 
grizld1 said:
~snip I tried timing to the intake events, splitting the error between intake and exhaust, and timing to 100* lobe centers, but accepting late intake opening is the setting that's felt best to me; if the Shell #1 is advanced much at all, I find myself doing a lot of short shifting.
Click to expand...

I've talked to both Dick and Brett about this as well as Gary Hoos . Dick it just dawned on me that you may have one of the "miss - grinds" . I , we , may have a deal for you Dick . I know it is what it is and you arn't likely to take it apart any time soon but the alcoholic could deal with the earlier intake closing . I'm not likely to be putting the red bike back together any time soon either .

Then again it could be more idiocy than epiphany and I need to just drink more and type less ...

~kop
 
"One of" the misgrinds, kop? Before I reinstalled my cam I also had a chat with Gary, and he was very up front about the fact that none of the intakes he'd seen were all that close or would improve much on what I have. (And yes, folks, Gary Hoos checks the cams on a bench motor before he sells them--what a guy!)

Anyhoo, a look at Craig Weeks' dyno numbers for the Shell #1 at different settings was enough to convince me not to go all AR over intake openings. As you know my interest isn't in balls-to-the wall power, I just want enough kick out of the apex to bounce 'er up off the springs decently (if you'd said "coil load" rather than "coil bind" when we talked I'd have understood more quickly) and a good rush up to 8K or thereabouts, and the current timing of IN 20/45 and EX 45/25 delivers on those moderate goals.

Idiocy OR epiphany? How do you distinguish between them when it comes to this disgraceful obsession with antiquated machinery? I have three very nice bikes in the barn that were made in the current century; all smooth, reliable, never ask me for more than to be ridden and to receive basic maintenance. But my time and money go into compulsive fiddling with that noisy, cranky old bitch of a Yamaha. It's a sickness. Don't bother to rationalize, don't bother to pray; we are lost beyond redemption.
 
BTW thanks for the offer, mrriggs; if and when I pull the top end again I may take you up on it.

I posted this before back at the Garage, but here it is again--anyone considering the Shell #1 should send this man a PM--he's the only source I know for accurate regrinds in that pattern.
 
It's the guys down at Oregon Cam Grinding that do the excellent work. If you just want a regrind without a re-phase then it would be cheaper to send your cam directly to them. Ask for pattern #1906.
 
Hi there!
This is an old tread.. but I need some thoughts re my timing on a Shell#1 cam. I do not have fancy timing degree equipment so I'm left with the marks only. I post a picture so you can see.. I hope it is right despite the sprocket seems to be pressed on a few degrees of the mark on the cam compared to a std cam..I would liked to have had it 1/4-1/2 a tooth more advanced..?
20190104_211034.jpg
20190103_205649.jpg
 
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mcjongs, your photo shows the head in position with no fasteners. Is this a new assembly? If so best practice is to install spacers and apply around 10 footpounds of torque to the four inside studs. Looks to me as though you could be a full tooth off. You might try moving the cam a tooth CCW, put a little torque on the head, make sure the cam chain adjuster is installed, and see how it looks. Of course you'll be assuming that the PO didn't move the sprocket on the Shell cam. I don't mean to sound harsh, but IMO there's nothing "fancy" about a set of tools (dial indicator, piston stop, and degree wheel) that can be bought for less than $100 US and could save you time, work, and money.
 
Thanks for info Grizid1!
I tightened up the cam chain believing that it would press down the cyl & head assembly enough that i could do the timing correct. But you where right. I did also yesterday a dial in check with a dial in indicator (digital) and a rough home made degree wheel to check and i got IC almost 85deg after BDC and that was for sure wrong and then I took it apart again..

20190106_170335.jpg


I also changed the cam chain to a new (not stretched) one and finally i got it right using the mark on the rear aligning 100% in center with the top surface (on the picture it could seems above but it is not) I haven't checked the valve times but now it cant be one toot out.
20190106_170344.jpg
 
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Be sure to check both intake events and exhaust events. As noted above, the Shell #1 intake opening is often ground farther retarded than specified. I get the best results by timing to the exhaust opening and letting intake events fall where they may.
 
Started up tonigjt and it responded normal or better than original. Heavy snow so cant test it just now.. only some puffing from right sylindet on idle.. maybee a smal air leak in the intake rubber or some shit in the idle jet.. as compression is same on bothcylinders New rubber intake ordered..
Jon
 
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Hi All in this old but ever relevant thread- I too have a shell#1 cam from Gary Hoos and am having a helluva time getting my top end combustion right. I am running way high on main jet trying to carb my way out of this but not getting there. Anything up around 5800 rpm and WOT the combustion will crumble and loose power. about 78mph on the taller 5th gear from Mikes. 4th gear goes about as fast as 5th actually. Plugs look ok though.

Running Gary's VM34 carb kit, Shell#1 cam, 707 biggish bore, kibblewhite titanium valve gear kit, pamco ignition, and (in focus now) the digital advancer unit for the Pamco. Main jet has climbed in testing to 210, which Gary says is crazy high. I too had a tough time nailing down the cam mark and TDC at assembly.

Big question here- does the stock, nonadjustable Pamco advancer unit need to be something it is not born to be to accommodate the cam grind?
 
Yep, with 210 mains that motor should be acting richer than Buffet, even at sea level. I don't know where the advance curve is set on the Pamco system, but it has to be close to Mamayama's 25* interval (15* retarded, 40* advanced), which works just fine with the Shell #1 (many of us find that retarding ignition timing a few degrees from factory spec is helpful). There's more to installing performance valve gear and cam than just lining up the mark on the camshaft. Installed valve spring height needs to be checked, and you'd be well advised to degree in the cam, especially if deck height has been altered.
 

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