Shim dia.

[Bigmak96]

I am going to make up some shims and wonder about the diameter. The shims that come in a Hot Cam set are 7.48 mm which is .294 Dia. I have my covers on yet so I cant check and I'm at work. Could someone tell me if there is room in the shim nest on the end of the valve stem at accommodate .002 more in diameter without any problem. I don't recall how much clearance there is. I would think an extra .002 would not be a big deal but I don't want them to fit so close that they want to hang in the stem's nest.
Thanks, Mark

 

[George]

I can't measure anything that closely.

I'm probably gonna need shims for the DRZ, gonna just go to the Suzuki shop and get what I need. There's only 4 total.

 

[Bigmak96]

I have the answer, no need to reply.
Thanks

 

[roginoz]

And the answer is? (We are a curious lot. In both senses of the word...)

 

[Bigmak96]

I just took the time to grind the pins I had down to the 7.48mm that is on the Hot Cams box. It didn't take a lot of time, it was just a step I would have avoided if I knew it would not cause any problems. So bottom line I guess I don't know if the added .002 would have been an issue. I would still guess not.

 

[Kevin_56]

Years ago my brother, the tool maker, made me a set of shims for our Suzuki's. Still have them for the early GS series. Shim on top is so much easier to change out. They were about the diameter of a quater. The good ole days.

Mark, get that girl buttoned up, riding season is getting near.

 

[Bigmak96]

I hear you, just need to rebuild the forks and rewire some stuff (read-everything ) ;>)

 

[okmurdog]

From the sound of it, I presume you are taking a standard pin gage and cross-slicing to produce the shims?

If so...I'm curious, any hardening needed on the cross-sliced pieces before use?

 

[Bigmak96]

Nope, I'm using QB pins. They are in the high 50s Rc and are through hard. Wire cut then surface ground. So there is not enough heat to change their original Rc durring the making of them.

 

[okmurdog]

Ok, thanks...hence the reason I asked - I know someone who made a custom thickness shim by trimming down a 1.60 mm shim to 1.58 mm. By utilizing a 3/4" thick piece of glass as a flat surface and very fine diamond paper, the shim was trimmed to the needed thickness (and the ends were kept parallel). It's a little bit of gamble re compromising the hardness, but given the method and amount that was taken off, coupled with the relatively large contact surface area onto the shim on both sides, I don't think there is much risk.

 

[W0QNX]

Just out of curiosity I measured a couple of my Hot shims, .2945 with my calibrated .0001 reading mic.

Raymond

 

[okmurdog]

Just out of curiosity I measured a couple of my Hot shims, .2945 with my calibrated .0001 reading mic.

Raymond

7.48 mm = 0.29448"
7.5184 mm = 0.296"

When I changed the shims on my bike, I seem to remember there not being much 'slop' room around the shims when in the depressions of the Valve Retainers. Not sure an extra 0.002" (0.0384 mm) would fit.

I just zoomed one of my existing shim pics...looks kinda tight -

 

[Bigmak96]

I feel good about taking the time to grind in the OD I went with a +.000 -.001 tol. for that so there will be no issue with interference.

 

[Bigmak96]

On an unrelated topic while in the cam neighborhood. I was amazed that there were no bushings to carry the cams. Anybody else surprised with that?

 

[Tdinova]

On an unrelated topic while in the cam neighborhood. I was amazed that there were no bushings to carry the cams. Anybody else surprised with that?

nope My '81 cb750c was like that. Oil keeps the clearance

 

[Bigmak96]

yep, and it does an amazing job too. I would have guessed it would have had some brass.

 

[acedantinne]

Nope, I'm using QB pins. They are in the high 50s Rc and are through hard. Wire cut then surface ground. So there is not enough heat to change their original Rc durring the making of them.

Mark, used old valve stems.

 

[Bigmak96]

Ace, are you saying you cut off bits of valve stem and ground them to thickness? I would think the stems would be a softer yet tougher Rockwell. That's just a guess tho.

 

[acedantinne]

Yes, cut valve stem ends off about inche. Then made shims. ground as needed. It worked fine.


I was cheap. used to grind (orginal) shim down to get clearance needed. Diamond stone.

Bought Hot Valve shim Kit.