Topic: Patina Hyena - 550/650 674cc Hybrid Cafe Build

[SOHC4 Cafe Racer Fan]

If memory serves me correctly, I went with Mike's gasket recipe.

[DaveBarbier]

That will work well. If you think the gaskets will pull down a tad under torque, then that 0.033" (gasket & 3 thou below deck) shrinks a little, and that is too tight for stock rods.

Wait, sorry, are you saying that the .030" will work well or that it could be a little too tight when things are all torqued down?

[DaveBarbier]

If memory serves me correctly, I went with Mike's gasket recipe.

I feel like I'm going insane with head gasket thickness, haha. If I had realized what I was reading when I first read Mike's email...maybe it would have saved me some craziness

[bwaller]

If you use a 0.010" base it brings the piston compression shoulder to within 0.003" of the deck. A 0.030" head gasket gives 0.033" total less a little under torque. When you clamped the cylinder down to check piston height it wasn't under torque, you will ultimately be less than 0.033" when cinched down. Too tight for stock rods/bolts.

The 650 combustion chamber is 60mm wide and your pistons are 62 so it's not like the piston is smaller.

However my feelings cannot be hurt,  ask Mike for his opinion and get it straight.

[DaveBarbier]

Ah, ok I get it. Yeah, I'm sticking with the .010" and the .040" and leaving it at that. I'll save my insanity for the second degreeing process. I don't want to hurt your feelings

[sinister902]

stupid question, the pamco you're using....is it simply this one:

http://4into1.com/pamco-electronic-ignition-honda-cb500-cb550-cb750/

or is it a new specific cb650 one that's not online for direct purchase yet?

[DaveBarbier]

Not a stupid question. Yes, it's the same one. There isn't a 650 ignition. Pete isn't sure he's going to make one.

The PAMCO will work just fine, but to fit it there needs to be some modification.

First, you need to mount the electronics on a plate that fits the bike. That means either machine down the plate that the PAMCO comes with or mount the PAMCO bits on your existing ignition plate. Drilling and tapping the holes properly. Two 8-32 holes and two 4-40 holes.

Second, fitting the supplied PAMCO rotor to the advancer mechanism. The 650 advancer has two different ODs on the shaft that the rotor spins on.

My crap drawing:


The supplied rotor fits perfectly over the top OD (15mm I believe) but doesn't go over the second OD (15.75mm I believe)

So either, machine the supplied rotor to fit, machine the shaft of the advancer mechanism to fit the rotor, or possibly use an advancer from a 750 or 550 because I've been told they fit the 650 and will definitely fit the PAMCO rotor.

Hope that helps!

(Edit, I ended up buying the C5 ignition. I screwed up the plate and didn't want to fiddle with it anymore)

(Edit edit, the C5 wasn’t working for me after about a year of figuring out why my bike was shutting down after an hour of riding. I modified a Dyna S to fit and it’s working perfectly. See link in the table of contents on the first page of this build thread.

[SOHC4 Cafe Racer Fan]

It's only money, right? I opted for the C5 unit because it allows you to easily ditch the weak-link CDI boxes, and I like the technology behind it. 

[sinister902]

Oh, I'm going C5 but I just wanted to ask for continuity. You never know who's gonna bump into this info somewhere down the line and have that same question.

[DaveBarbier]

The C5 looks pretty awesome. And the optical-ness is cool. But still, at over $500 I'm all set. The PAMCO gets rid of the CDI boxes too and will hopefully work out nicely. I also like that Pete is a member here.

Anyway, I machined the rotor to fit the advancer and it slides on perfectly. I also machined down the outside of the plate so the screws lay flat when tightened.

[SOHC4 Cafe Racer Fan]

The C5 looks pretty awesome. And the optical-ness is cool. But still, at over $500 I'm all set. The PAMCO gets rid of the CDI boxes too and will hopefully work out nicely. I also like that Pete is a member here.

Anyway, I machined the rotor to fit the advancer and it slides on perfectly. I also machined doen the outside of the plate so the screws lay flat when tightened.

Great to know that the Pamco can be adapted to the 650.  Maybe with all of the new 650 motor builds, Pete will release a 650 version.

[MRieck]

I was just reading about the gasket thickness and I was getting a bit confused. If the piston is down in the hole use -.003. If it is above the deck it is .003.
I also didn't know if the base gasket was in place when taking deck height measurements. I don't use the base gasket when checking....just torque the cylinder down a bit using PVC pipe over 4 studs. Measure over the wrist pin.
 .040 squish is good for stock rods. If you are -.003 deck height with no gaskets/cylinder torqued down a bit you can use .010 base and .032 head MLS gasket. Total squish would be .045

[DaveBarbier]

I was just reading about the gasket thickness and I was getting a bit confused. If the piston is down in the hole use -.003. If it is above the deck it is .003.
I also didn't know if the base gasket was in place when taking deck height measurements. I don't use the base gasket when checking....just torque the cylinder down a bit using PVC pipe over 4 studs. Measure over the wrist pin.
 .040 squish is good for stock rods. If you are -.003 deck height with no gaskets/cylinder torqued down a bit you can use .010 base and .032 head MLS gasket. Total squish would be .045

Yes, sorry. Pistons currently are -.013" in the hole with the base gasket installed. Yes, that's negative thirteen thousandths. That's with an OEM base gasket which is .020". To replace my current gaskets I bought a rubber coated steel base gasket at .010" thick as well as a .040" MLS head gasket. Both are coming on Tuesday I believe.

That means that my total squish should be around .053", right? No idea if that's good or not, but that's what I'm going with .

Thanks Mike!

[MRieck]

I was just reading about the gasket thickness and I was getting a bit confused. If the piston is down in the hole use -.003. If it is above the deck it is .003.
I also didn't know if the base gasket was in place when taking deck height measurements. I don't use the base gasket when checking....just torque the cylinder down a bit using PVC pipe over 4 studs. Measure over the wrist pin.
 .040 squish is good for stock rods. If you are -.003 deck height with no gaskets/cylinder torqued down a bit you can use .010 base and .032 head MLS gasket. Total squish would be .045

Yes, sorry. Pistons currently are -.013" in the hole with the base gasket installed. Yes, that's negative thirteen thousandths. That's with an OEM base gasket which is .020". To replace my current gaskets I bought a rubber coated steel base gasket at .010" thick as well as a .040" MLS head gasket. Both are coming on Tuesday I believe.

That means that my total squish should be around .053", right? No idea if that's good or not, but that's what I'm going with .

Thanks Mike!

Dave....squish will be .043 with the .010 base and .040 head gasket. Replacing the .020 base with the .010 will bring the piston up to .-003 . add .040 for the head gasket and you have .043 which is right where you want it.

[DaveBarbier]

Perfect! I'm curious where my valve clearance numbers will fall. I'm getting antsy to button this thing up and get it in the frame!

[MRieck]

Perfect! I'm curious where my valve clearance numbers will fall. I'm getting antsy to button this thing up and get it in the frame!

You should have plenty of clearance on both sides

[DaveBarbier]

New deck height is about -.002". The base gasket is about .012". Seems good to me! Hopefully will make more headway tomorrow. Day off!

[DaveBarbier]

Question on torque for the MLS when I'm degreeing the cam/checking valve to piston height. Should I just snug the head bolts down, or go a bit further and torque to something like 10ft/lbs? I'm going to be removing the head again to swap springs and possibly add clay to the pistons.

I can easily see with a CFM gasket that a good snug is all that's required, but the MLS gaskets have embossing that keeps the head off the surface. Enough where on the ends I can see light through the gasket layers. Should the head be fully seated or a good snug is all that's needed here too?

[RAFster122s]

Dave, ask Brent W. or Mike R.  I would be interested in knowing the answer too.

[DaveBarbier]

It would be most accurate to test under full torque. But I torqued to 12 ft/lbs (my final torque is going to be 20ft/lbs). And that seems very close and since I'm dealing with relatively wide valve to piston clearances I feel safe it won't put me in the danger zone. I will obviously be torquing to full torque and degreeing when I'm ready to button up the motor.

[DaveBarbier]

Speaking of degreeing...the numbers are in of my final valve clearances.

I degreed my cam so intake was 104.625° and exhaust was 104.75°. I felt that was within tolerance. Hope that's ok! My cam card says to be 104.5°. It's not easy to get it exact.

My smallest intake clearance (ATDC) was at 10° and was .070". My smallest exhaust clearance (BTDC) was at 8° and was .118"

That .018"-ish difference from last time pretty much makes sense because I reduced the overall gasket thickness by .020".

Thoughts from the smart ones? I'm very happy with it and with actual final torque it'll be a hair tighter. Building motors is fun! Makes me want to do another, haha.

[RAFster122s]

Webcam is known to not have super accurate figures, you are very close and I wouldn't worry at all with those figures. Sometimes you get lucky and you can get it evenly split so both are equal (provided they should be of course...)
I rarely have heard of anyone getting Webcam's numbers spot on.  You have a very small number between them... 0.125 = 1/8 inch...
So, mapping the curve of opening and closing and duration of each would show you their overlaps... Color the curves from the base circle outward to map the rise beyond that circle...expanding the graph scale so it is larger than it actually is above the circle.  Just doing one cylinder is all it takes...to show overlap. If you wanted to go crazy you could do them all and map it and digitally overlay them if they were transparent.  In effect you would have a view of the lobes rise and fall as if looking at the end of the cam but, without the effect of distance messing with your perception of size, allowing you to compare them within the 360 view of the cam from the end...
It won't really tell you anything that plotting the numbers on a graph wouldn't...just doing it visually.

I am by no means a smart one...

This 550 cam photo attached is one of ebay's finest for sale...I think it looks a little roached.
I think I have one that's likely to look similar with the uneven wear, not the blueing from overheating. Have some play in the top cover.

[bwaller]

Sounds good.

[DaveBarbier]

Sounds good.

Would you use the clay method with this too? I'm just trying to think how it would be done. I'd take the head off, put clay on the domes, out head back on and degree it which involves spinning the motor. That would put impressions in the clay before the cam is set right, which would throw results, no?

[bwaller]

You don't need the cam for this part. Spray a little `non stick`(Pam) on the head & pistons, add your clay and bolt on the head. Turn it around a couple times then break it apart to measure. The chamber is 60mm, your pistons are 62mm so place your clay accordingly. On the outer edge should be the tightest area but place some up the dome angle as well to be safe.