wondering about 1981 head mods, camshaft exchange

[brian weir]

Hello all,



I'm going on sunday to look at a basket 81 cbx. The engine is out, with the head off and camshafts out. 30,000km ago the owner died after taking it apart, then it was bought by a Honda collector who didn't get to it.

If I can get it at a good price then I have to check the entire motor, and if I could I'd like to repalce the camshafts for higher horsepower, but I have no idea if that is possible.



Any suggestions on what to check for on the engine would be welcome- Also if anyone sees this that previously wrote me could you please send again as my email was trashed.

thank you

Brian

[Mike Barone #123]

hi brian



belated welcome to icoa and our site



79 cams will fit the late model engine and are avail at reasonable cost from various member sources (see icoa want ads and xpress want ads)....if this does not work e me



>>>>



i am not sure if you need both 79 cams ....or if one of the cams in the 79 and late models are the same.... and as such you would need only one 79 cam. i think most sellers want to sell 79 cams in pairs



can anyone else help on this





mike

[Jeff Dean]

Brian,

Welcome.

Sorry I didn't get a chance to reply to you e/m. However, if memory serves me, this was a Canadian model?? My 1st thought went to import requirements. I didn't see where you lived. If not in Canada, check the old post on getting a non-US model across the border.

Also, are you looking to make this thing a rider, or a showpiece? JJD

[sr71cbx]

Brian,

The hot setup for max horsepower would be a set of '79 cams with the '79(422)advancer unit,this will make great top-end power but at the expense of minor low-end losses.

--79 cams had the most aggressive lift & duration of the 4 years,the 81-82 cams have the same lift & duration but lobe centers are set wider and in different positions for better midrange.Stay away from '80 cams,they were lower in lift and duration to satisfy the U.S. EPA yo-yos and they cut usable power.

--Hope you score a deal!

[Guest]

Cams alone will most likely not yield any improvement that you will be able to feel. The difference between 79 and 81 was 105 to 98 horsepower. But this difference did not occur at the same rpm, nor was it made by cams alone. The carbs, the exhaust and as Mark said, the ignition were different. I am surprised, that all the authorities here leave you to believe, this is a thing to do.

[EMS]

Brian: The overall tuning of the later models was intended to provide more "useable" power, while the max hp rating was reduced. We have that discussion ever so often, here too. Many people are obsessed with hp numbers, but horsepower is not what you feel as performance. That would be torque. Torque accelerates a vehicle from standing and when rolling on the throttle. Horsepower expresses the ability to sustain a maximum speed. If you consider, that in North America you may have very little opportunity to go over 100 mph, I would stay with the stock 81 set-up. If you can maximize low end torque, that would be an improvement. 79 cams will not be.