Well I finally got tired of waiting for someone else to try it. I was going on a 1000 mile trip so I found the time to swap cams. I searched and although others have done the swap and everyone knows it will fit, I could find no good report on how it ran. Most people do it with other mods, or do it and never report back. It still amazes me that after more than 25 years its not common knowledge??
Enough ranting,.. it works really well. This was the only modification made and its resulted in a real solid noticable improvement. Much more than any bolt on mod like headers, air filters, ignitions etc...
My bike is a 75 CB550 with hooker header and foam pod filters. I spent a lot of time to get the jetting right and it really ran well before the swap. For those who don't know, running pods will cost you a little low end power compared to the stock airbox. but presumably help a little on top? The hooker header slightly intensifies the normal 5-7K rpm surge of the stock bike. Like I said it ran great before the cam swap.
Now it just runs better, I would guess maybe 15% improvement under 4000 rpm and 10% more up to redline. The normal 5-7K sweet spot is maybe 4-7K now. The tach won't work now but it surely comes on a full 1000 rpm sooner. Don't get me wrong, its still an old slow bike but it sure is more fun to ride now with better low end and fatter mid range. It feels healthier all the way to redline but no huge gains on top. Even after 1000 mile ride, I still notice it runs better than stock and I've owned 12 CB500/550's over the years including a couple full Yoshimura powered racers.
This is an excellent choice for a daily driver, its roughly equivilent to a stage 1 street cam and you can find them on ebay cheap.
Here's the best part, its a drop in replacement, just use the 550 sprocket and time it like normal. no need to degree the cam and forget all you hear about swapping coil wires, and different firing orders. Its made from the same blank as a 550 cam with all lobes in the same place. No jetting was required and it even made the exhaust note a little sharper.
The only minor issues are the different tach drive ratio and some people report needing to clearance the head for the taller lobes.
The tach drive issue can be dealt with by removing the plastic driven gear and plugging the hole (use an electric tach) or use the 650 driven gear and a 650 tach. Don't use the 650 cam with the 550 gear or it will destroy the plastic gear.
I checked several heads I had and always had at least .030 clearance between the lobes and the casting. Just lay the cam in place and spin to check clearances. If yours hits it will only need slight scraping with a pocket knife to remove a little aluminum from the top edge of the oil reservior walls,.. No big deal and I wouldn't make a big mess with a dremel.
So there ya go,.. plug and play, its worth the trouble.
