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Discussion Starter #1
does it matter if i do a tach install before i do a cam upgrade? a somewhat knowledgeable friend of mine suggested i look into that question before doing work. second question, looking at webcamshafts.com i noticed two different kinds of valve spring kits. one comes with a perfomance single ovate beehive spring and the other comes with performance dual springs. is there a gain to having one spring or two?
 

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Stiffer/ dual springs have a few downsides, including considerably increased valve seat, stem and cam wear. They're mostly for all out motors where long term reliability isn't the main driver.



The point of them is to prevent valve float with high lift cams. The beehives and titanium retainers are mostly to counter the effects of the weight of the additional components in the valvetrain. Again, nice to have, but mostly for all out, high-rpm racing.



I'd stick to the 40a and single springs for the street. The higher lift cams require valve guide trimming and double springs. Pgilles runs his 40a with stock springs and reports no issues. If you decide to go this route make sure your stock springs are on the high end of spec.
 

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I've never installed one, but I'd imagine the tach calibration wouldn't change unless you changed the size of the cam sprocket. Different springs will still have to move at the same speed, I think.
 

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The tach won't care. It just counts RPM off of the coil or the plug wire. It has nothing to do with the cam.
 

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The tach won't care. It just counts RPM of the coil or the plug wire. It has nothing to do with the cam.


Yeah that makes a lot more sense. I thought he was installing some sensor by a lifter or the cam or something. Never fooled with those, really.
 

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TeeWee is running a cam.

Superdave is running a cam.

Macbig2k1 is running a cam.

And I am as well.

Probably others, but I can't think of them right now.



I have over 1000 miles on it (grind 40a, aka "stage 1") with stock springs. No issues. I spend a lot of time at higher rpm's winding it out because of the speed I cruise at. So far so good. When I purchased the cam their website only stated springs were RECOMMENDED, not REQUIRED. I'm not going to advise against what they say, but I can say my stock springs have held up. Maybe this winter I could take the head off and do a measurement on the springs to see where they measure.



I do own a DRZ now so the TW has been sitting quite a bit (and I really did ride it that much last year due to traveling for work). Citiots (city idiots) in cagers were a concern for me locally so I got something bigger that can keep up and get out of the way without batting an eye. The power of the 400 is so nice, but I miss really leaning the TW around the corners and the small, nimbleness of the TW. I just might sell the DRZ next year and big bore/stroke the TW...I have some ideas floating around.
 
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