Ok , I´ll post the exhaust mod over the weekend .

 

Motion Seconded!

 

Thank You !

 

I´m glad your mule acts more like a horse now ... Yehaaa
Enjoy !

 

We need writeup !!!!


With lots of pics.

 

How much of a difference does just changing the intake valve timing over doing both exhaust and intake.

 

For my 1000th post, I would like to be the second to second the motion on the floor to name this the"The Marcelino Cam Mod"

 

I want to be the second to DO the Marcelino Cam Mod!

Again, awesome job and thanks for the re enforcement Zomby wolf.

David

 

Is the ACR pressed in with a super tight interference fit?

For pressing out the ACR, what is the I.D. of the exhaust cam? Haven't had the valve cover off yet to check it all out.

 

First things first, you can and should make a bit on this. You should either buy a set of new cams or get a set of cores and start selling the work. A rider sends you his cams with sprockets, you sent them a set of cams with compression release pre-set and sprockets either clearly marked for bolt on or already bolted on.

I don't know if both sides of the sprockets are marked, but if you distinctly mark the sprockets for the timing positioning on the cams and in the engine, bolt them on the cams if possible, reposition the compression release and send out the set up for a drop in installation, that would be the trick.

For a nearly 20% gain in hp it could be worth doing as long as the core set of cams are in good shape when you get them. Or just do the work on their cams. I have to think sprockets wouldn't be hard to mark in some distinct way and they can't be that expensive to pick up a few sets. Toughest part would be shipping in general. I know from my cam chain tensioner sales, that it is $13.95 to send parts by USPS flat rate in the small box to Europe, sprockets would have to be off the cams, 12 day delivery. Depending on the cost to send back, it could be maybe $40-50 in shipping total for both directions.

You do the mods for whatever cost on their parts, then send them back. 5 hp (actually 25% increase) for a total including shipping being under the cost of a new cam and far less than a carb or header. Could be worth it in the winter during down time for some riders. How much would you charge to do a rider's cams and what would be the shipping cost back to the U.S. and around Europe?

Now back to the technology. I'm not that up on things,but I remember a thing about the Honda Nighthawk S that Joe Minton, a well recognized authority on motorcycle mechanics in the 1980s, did on Dr Harry Hurt's Nighthawk S (yes, that Dr. Hurt).

The S had the cams at something like 133, optimum was either 103 or 108, I forget. Minton did the work slotting the cam bolt holes and got them positioned properly gaining a lot of power through most of the range. He actually lost about 3 hp at the top, but what it did for the powerband was well worth the loss at the top, which was his goal - ridability and gaining power where it was best to gain. He mentioned not being overly fussy about a degree or so in timing, it was all about the big chunk. Cam timing is definitely science and clearly you know what you're doing.

Think about that cam service thing. It could make a couple of bucks for you to help with your bike play. Then there's the help for those who can not do the work either for lack of skill, time, or equipment. That's part of my cam chain tensioner thing. It isn't for the guy who can and will make their part, it's for the guy who, for whatever reason, won't make the part, but is willig to pay a fair price for it. Same could be done with your cam mod. If nothing else at least in Europe.