Topic: would you put in a big bore kit and a hot cam if you had the chance?

[Tews19]

With my 650 cam I can feel the difference. It may be aubtle.but you also get it in your head that it adds performance. Kind of like changing a stock exhaust to a loud zoom zoom one.

[b5rider]

With my 650 cam I can feel the difference. It may be aubtle.but you also get it in your head that it adds performance. Kind of like changing a stock exhaust to a loud zoom zoom one.

That's what I was thinking. 
I figure,  from the posts,  the 650 cam won't hurt performance,  only enhance it. Whether this enhancement comes at the mid range or the top end is probably subjective without a real dyno test. I'm not discounting anyone's opinion that the 650 makes a positive enhancement to the bike's performance

[mrfish2]

I figure,  from the posts,  the 650 cam won't hurt performance,  only enhance it. Whether this enhancement comes at the mid range or the top end is probably subjective without a real dyno test. I'm not discounting anyone's opinion that the 650 makes a positive enhancement to the bike's performance

Let's put it this way: you could always start out with a 650 cam that can be had for >$150, and if you get tired of it or decide you need more power to pull that sidecar aroud then you could sell the 650 cam rather quickly and put that money towards a Webcam or a Dynoman cam.

[b5rider]

I found a 650 cam for "decent" money (125 shipped). Only thing I couldn't find was a new set of the 'D'connecting rod bearings. I'll have to reuse the old ones.

So the conclusion was to go ahead and put in the 650 cam and the 603cc kit. Will report back when it gets put back together...

[mrfish2]

I found a 650 cam for "decent" money (125 shipped). Only thing I couldn't find was a new set of the 'D'connecting rod bearings. I'll have to reuse the old ones.

So the conclusion was to go ahead and put in the 650 cam and the 603cc kit. Will report back when it gets put back together...

Did you get a tach drive with that cam?

[b5rider]

I found a 650 cam for "decent" money (125 shipped). Only thing I couldn't find was a new set of the 'D'connecting rod bearings. I'll have to reuse the old ones.

So the conclusion was to go ahead and put in the 650 cam and the 603cc kit. Will report back when it gets put back together...

Did you get a tach drive with that cam?

Nope.  Do I need the gear at the engine,  or at the wheel?

[flatlander]

at the engine. the one at the front wheel is for the speedo - or did i misunderstand the question?
you'll also need a tach from a 650 or 750 if you want the indicated rpm numbers to be correct.

[b5rider]

Lol I misunderstood.  I have an aftermarket tach that isn't the correct ratio for my 550.
I'll start sourcing the tach gear which mates with the camshaft.  Probably as elusive as the conn rod bearing...

[Tews19]

I actually like the 650 tach on mine.

[SOHC4 Cafe Racer Fan]

If you are sidecar-ing, keep this in mind: this is a small-bore engine. This means it can make plenty of HP above 6000 RPM, but torque will not be its long suit. To make torque in it, you need larger inlet ports (not too much larger, or other troubles will appear) like the 650 head has, polished valves, a PROPER air filter intake tract (i.e, NOT PODS!), slower spark advance curve, higher compression, and higher base-weight oils (like 15w-something or 20w-something) to keep the bearings slick under low RPM loads. Adding a longer spark duration will also help: this means using either OEM coils or something like the 5-ohm Dynas, plus either 10,000 ohm plug caps or the typical 5,000 ohm caps AND resistor plugs, to make the most duration possible.

Look into using the ND sparkplugs X22ES-U, too, for their longer-reach tip. While you have the head off, look through the fins to find (and remove) flash metals that are blocking air flow, and cut it away. Mill the head and cylinder decks about .010" each, maybe a bit more if your new pistons don't have high domes on them.

Finally, look "out" the exhaust ports (with valves removed and head shiny clean) and remove the tiny step blockages that abound in the 500/550 heads. When you make an exhaust, get something with backpressure, don't run it open or with real low restriction: you will need the crossover buildup in the chamber during overlap time.

Cams like the 650 make their HP at much higher RPM. Instead, consider slotting the cam sprocket and advance your stock cam about 3-5 degrees. This will move the torque curve downward in RPM and make it feel more "on tap" than having it all start up above 5500 RPM like the stock 500/550 usually does.

Insightful as to the intended purpose of the thread.

[b5rider]

Just received the pistons

[Tews19]

Quick update. I received my tach cable and I am not sure why but I can fly past 10k rpms like nothing. The bike seems to get stronger the closer I get to 10k and I still have more to go. I need to hit up Mrieck and ask if this is fine for my bike. I did do the stage 2 head work with him.

[b5rider]

Quick update. I received my tach cable and I am not sure why but I can fly past 10k rpms like nothing. The bike seems to get stronger the closer I get to 10k and I still have more to go. I need to hit up Mrieck and ask if this is fine for my bike. I did do the stage 2 head work with him.

Wow! I might break in the engine without the sidecar attached

[Tews19]

If I had a go pro I would show it. She screams. I get to roughly 62mph in second gear no problem... Not verified by the old speedo but the wife's mini van. I hit 95 and if I am recalling correctly I was around 6k. Still room to play.  I did change the AF needle to 1 1/8th turns. I was at 2.5 and she would bog while driving normal then trying to gun it. Updates to follow.

[b5rider]

Got the 603cc kit and the 650 cam installed.  She fired right up, but haven't ridden her yet

[b5rider]

just a little bit bigger than stock!

[Tews19]

Wow that was fast work! Now the #$%*ty part.... Tuning.... what's your plan for jets and rest of the settings?

[b5rider]

I plan on letting the mechanic figure it out

[Powderman]

I found a 650 cam for "decent" money (125 shipped). Only thing I couldn't find was a new set of the 'D'connecting rod bearings. I'll have to reuse the old ones.

So the conclusion was to go ahead and put in the 650 cam and the 603cc kit. Will report back when it gets put back together...

Did you get a tach drive with that cam?

Nope.  Do I need the gear at the engine,  or at the wheel?

Now you sound dangerous.

[b5rider]

I found a 650 cam for "decent" money (125 shipped). Only thing I couldn't find was a new set of the 'D'connecting rod bearings. I'll have to reuse the old ones.

So the conclusion was to go ahead and put in the 650 cam and the 603cc kit. Will report back when it gets put back together...

Did you get a tach drive with that cam?

Nope.  Do I need the gear at the engine,  or at the wheel?

Now you sound dangerous.

Yeah,  that's why I stick to working on humans.  Luckily,  I have a really good mechanic

[Tews19]

If you are paying someone to tune. At least start w 105 mains. 40 slows. 2 notch. Tuning can take a away and cost a lot.

[b5rider]

I'll let Andrew (mechanic)  know,  Thanks

[b5rider]

Here's what Andrew said on the first 10 mile test ride. 
'Has a ton of torque.. pulls hard. Took for long test ride now'

[Tews19]

Awesome!

[DaveBarbier]

Man, this is really making me want to do some power upgrades...it never ends!


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1978 Honda CB550K