how can i tell if it is hotcam?

[exrider23]

Ok i bought my quad used and they said it had a cam....im going to take the valve cover off and take a look....how can i tell its a hotcam?

[enduro400rider]

why not take their word for it, it would save you some trouble, there is a little hot-cam logo on the cam, you probably wont be able to see it with out pulling the cam out its a pretty small logo. if you dont know much about motors dont take it out you will end up screwing up your timing unless you know what your doing

[1fst400]

ya, when you take your valve cover off you need to re-set the cleerences. the rockers are attached to the cover.

But you can usually tell if it is aftermarket if the valves are loud. stock valve trian tends to be fairly quiet. once you throw an aftermarket cam in there they get loud. Loud ticking sounds. so compare to a stock 400 if you know of a kid that has one.

[GPracer2500]

All cams should have an identifying mark or number etched/scratched/machined on to it somewhere.

Another indicator that a cam is not stock is to see if the auto-decompression mechanism has been removed. It's a mechanical device that rides on the cam between the cam sprocket and the end (right exhaust valve) cam lobe.

You should be able to see if the auto-decomp is there or not by looking into the valve adjust access caps on the valve cover. You'll probably need a mechanics mirror and a flashlight to see in there.

Here's a pic of two cams, one with the auto-decompress (left side, completely stock) and one without (right side, WB regrind of stock cam). The one without is also without a cam sprocket--don't let that throw you. The auto-decompress mechanism is the part between the last lobe and the fitting the cam sprocket bolts to.

http://img338.imageshack.us/img338/1460/p10100083no.jpg

Most aftermarket cams do away with the auto-decompress--even regrinds of the stock cam. The HRC cam is the only contrary example I can think of. No Hotcams cams have the auto-decomp.

If I were you, I'd try looking into the right/front valve cap with a mirror and look for the auto-decompress. You shouldn't have to dissassemble anything to look in there--easy. That should tell you if the cam is stock or not. Then, when it's time to do a valve adjust (right now is always a good time to adjust the valves on a "new" used quad) just go ahead and take the valve cover off so you can look for identifying marks. It shouldn't add more than 20 or 30 minutes to the valve adjust.

Just be sure to use the proper torque values on the valve cover bolts! The service manual is a little confusing on that point--all the 8mm hex head bolts (6mm thread, large flange) only get 9 ft/lbs. The larger one in the middle gets 17 ft/lbs.

[400exrider707]

Originally posted by 1fst400
ya, when you take your valve cover off you need to re-set the cleerences. the rockers are attached to the cover.

But you can usually tell if it is aftermarket if the valves are loud. stock valve trian tends to be fairly quiet. once you throw an aftermarket cam in there they get loud. Loud ticking sounds. so compare to a stock 400 if you know of a kid that has one.

Why on earth would you have to reset clearances by simply removing the valve cover???

Yes they do get very loud with hotcams! Pop it off and look, if the decompression mechanism isn't there, then you can assume its an aftermarket cam. Most people dont run the HRC cam on the 400 because its nearly $400

[400exrider707]

Originally posted by GPracer2500
All cams should have an identifying mark or number etched/scratched/machined on to it somewhere.

Another indicator that a cam is not stock is to see if the auto-decompression mechanism has been removed. It's a mechanical device that rides on the cam between the cam sprocket and the end (right exhaust valve) cam lobe.

You should be able to see if the auto-decomp is there or not by looking into the valve adjust access caps on the valve cover. You'll probably need a mechanics mirror and a flashlight to see in there.

Here's a pic of two cams, one with the auto-decompress (left side, completely stock) and one without (right side, WB regrind of stock cam). The one without is also without a cam sprocket--don't let that throw you. The auto-decompress mechanism is the part between the last lobe and the fitting the cam sprocket bolts to.

http://img338.imageshack.us/img338/1460/p10100083no.jpg

Most aftermarket cams do away with the auto-decompress--even regrinds of the stock cam. The HRC cam is the only contrary example I can think of. No Hotcams cams have the auto-decomp.

If I were you, I'd try looking into the right/front valve cap with a mirror and look for the auto-decompress. You shouldn't have to dissassemble anything to look in there--easy. That should tell you if the cam is stock or not. Then, when it's time to do a valve adjust (right now is always a good time to adjust the valves on a "new" used quad) just go ahead and take the valve cover off so you can look for identifying marks. It shouldn't add more than 20 or 30 minutes to the valve adjust.

Just be sure to use the proper torque values on the valve cover bolts! The service manual is a little confusing on that point--all the 8mm hex head bolts (6mm thread, large flange) only get 9 ft/lbs. The larger one in the middle gets 17 ft/lbs.


Im almost positive that you can have the auto decompression mechanism pressed off of your stock cam and then repressed onto your hotcam...no one does it though because its completely un-necessary.

[GPracer2500]

Originally posted by 400exrider707
Im almost positive that you can have the auto decompression mechanism pressed off of your stock cam and then repressed onto your hotcam...no one does it though because its completely un-necessary.

That's true.

You DO need to re-check and/or re-adjust the valve clearences after removing (or even just un-torquing) your valve cover. The rockers are bolted to the top of the valve cover. When you remove and reinstall there is every chance in the world that the clearances have now changed. .001 inches isn't much and things like the valve cover gasket squishing, bolts stretching, or +/- a single ft/lb of torque on the bolts could make that difference.

It might not always change, but I'd venture to say chances are good that it will change a little.

[exrider23]

thanks alot for all your help...does anyone now the clearence with a hotcam?

[GPracer2500]

Originally posted by exrider23
thanks alot for all your help...does anyone now the clearence with a hotcam?

stock is:
.004 intake
.005 exhaust

Hotcams recommends:
.005 intake
.006 exhaust

[Resq]

Upon setting clearence on my 400 ex, the intake tappet cover, on the starter side, at TDC , my cam is clearly marked with a hotcam logo. Very easy to see with a flashlight. Looking for GPracer's chart to see if it is stage1 or stage 2.

R.