It takes the aftermarket a good while to make stuff for a recently revamped motor. In a year or two I suspect you will see hot cams, big bore kits, and stuff like that.

Regarding the overhead cam thing, utility atv's generally make power at fairly low RPM so there's really no disadvantage to having a bit more mass in the valve train. The thing isn't going to float the valves anyway. Failure of the cam drive is often the first thing that requires significant engine work on many overhead cam motorcycles. Push rod engines also allow the overall height of the engine to be shorter, so a quad can have a lower center of gravity relative to its ground clearance. Many large truck engines are pushrod- and intended to see upwards of a million miles between overhauls.

 

TLC is just upset that Honda doesn't make a "cookie cutter OHV belt drive machine" just like every other company out there....just like his Polaris. He knows that his Polaris is of dubious quality, so he wishes that Honda would build him one instead....

I am sure glad Honda marches to a different drummer, instead of copycating eachother just like all the other companies do! Different competing designs are good for the market!

 

Hi Jeff.
Thought I would mention the fact of valve springs on higher lift cams. Not really an issue of the valves floating but the valve spring diameter will limit the distance the valve can open and bind when over-revved. Higher lift cams, kind of a rule of thumb, of over .550 lift will require smaller wire valve springs to promote higher lift cams. Not really an issue normally, lets say if you put a cam in that is .560 lift exhaust and .540 intake as opposed to the stock .480 lift cam, generally the overrevving issue will not come about under accelleration as the rev limiter on the CDI will not give you problems with .010 over lift, but decellerating can be the issue as the rev limiter will not affect how many RPM the engine will turn if dropped a gear too low when downshifting etc... that will cause the springs to bind. I haven't messed with cams on the 420 yet and Honda does not give me a base circle diameter in their specs. It just has a cam measurement of 1.41 from heal to toe of the lobe. My specs above are shooting from the hip since I don't have a base circle spec, so I used them as examples.
Looking at the cam profile, I think I could alter a stock cam by changing the approach angle of the intake for better performance, but as far as altering the key-way or notches where the cam gear bolts to the cam I would have to get the engine on a dyno to find the power realm of the stock cam grind before adjusting it's timing accordingly.
You may see some cams for these 420's more readily available in the future after some of these larger cam manufacturers do some research. The 420 motor is capable of more than Honda has set it out as in it's showroom models.

Chat with you later my friend

----- Gimpster -----





<div class="FTQUOTE"><begin quote>Originally posted by: JeffinTD

It takes the aftermarket a good while to make stuff for a recently revamped motor. In a year or two I suspect you will see hot cams, big bore kits, and stuff like that.



Regarding the overhead cam thing, utility atv's generally make power at fairly low RPM so there's really no disadvantage to having a bit more mass in the valve train. The thing isn't going to float the valves anyway. Failure of the cam drive is often the first thing that requires significant engine work on many overhead cam motorcycles. Push rod engines also allow the overall height of the engine to be shorter, so a quad can have a lower center of gravity relative to its ground clearance. Many large truck engines are pushrod- and intended to see upwards of a million miles between overhauls.</end quote></div>

 

Well the only performance mod I have are in my signature, but I'm happy with the power gain of the HMF pipe and PCIII. Right now I'm looking for a place to get my PCIII Dyno to see better results then the factory map they supply. Also I love the loudness of the HMF pipe! I can't complain at all its a reliable bike and that's why I bought a Honda and not another brand.