Hemi Build #3 -Boogie Woogie Woogie

[ezcome-ezgo]

You did the right thing. Now let's get on with it.

 

[bob58o]

In about an hour I will call Dynocams, ask for Randy, and see how they would work the stock valve seat for me if I send them a 28.5mm valve. If they can do the work for cheap, I will send the head off.

If not, I'll look for quotes elsewhere. Maybe NR or I know a few guys on FB.

I have been reading about people with jetting issues using the inverted manifold. We will see.

 

[bob58o]

Randy at Dynocams is going to....

Mill 0.035"
Seat for 28.5mm SS Intake Valve (Either larger seat or work the stock seat, I'll let him choose)
3 Angle Valve Job on intake and exhaust
Seat - Bowl Blending (Matching the seat to the bowl) Intake Only

Dynocams
PO Box 400
Delco, North Carolina
28436

 

[bob58o]

Here it is....
28.5mm Intake, 25mm Exhaust
10.97 :1 SCR
8.5 :1 DCM
0.875" AVG Intake Port Diameter
2.5" Port Length
33.6 Flow % Efficiency

0.87" Runner Diameter
10" Long Intake Runner Length (Head to Air filter opening)
85% Flow Efficiency
88cfm

22" Long Exhaust
0.87" ID Exhaust
85% Flow Efficency


220 (0.050") Duration
0.280" Lift
104 ICL
116 ECL
110 LSA
1.2 Ratio Rockers

I have to input 110 Octane for the program to NOT retard ignition timing.
Check out that VE!!!
Guessing that comes from the really high Theoretically Cranking Pressure.
I get positive Overlap Tuning at every RPM except for 4500 RPM.

 

[bob58o]

I think this is the spot AKG says to put a vent or pulse fitting.
Nicely tucked away so it isn’t easy for oil to get splashed out.

https://affordablegokarts.com/pages/fuel-pump-setup
The pic with the fitting is AKG's

 

[bob58o]

1/8 NPT x 1/4 Hose Barb 90 Degrees

 

[Desertduler]

When may I ask is the launch date for this engine?

 

[bob58o]

When may I ask is the launch date for this engine?

Head is in the mail to Dynocams. I shipped it cheap. 5 day. When it comes back, I'll break in the the cam as suggested by NR. Not sure how long it will take for me to get it back. Two weeks?

While I'm waiting I'm trying to design how I want to set up my crankcase/valve cover venting and catch can.

I guess I'm about finished. But in no hurry because I don't have the bike yet. I'm trying to make one last order with all the stuff I might want. Catch Can, Maybe some check valves, Tall Valve cover or valve cover spacer,...

 

[Desertduler]

Head is in the mail to Dynocams. I shipped it cheap. 5 day. When it comes back, I'll break in the the cam as suggested by NR. Not sure how long it will take for me to get it back. Two weeks?

While I'm waiting I'm trying to design how I want to set up my crankcase/valve cover venting and catch can.

I guess I'm about finished. But in no hurry because I don't have the bike yet. I'm trying to make one last order with all the stuff I might want. Catch Can, Maybe some check valves, Tall Valve cover or valve cover spacer,...

Got ya.

 

[bob58o]

If I only use the 1.2 Rocker on the intake and use the stock rocker on the exhaust...
I don't really lose anything, plus I can use the other 1.2 Rocker on a future Hemi build.

Even after enlarging the intake valve to 28.5mm the program is telling me the exhaust to intake flow capacity ratio was somewhat large. 80%, which is higher than the 75% Rule of thumb.

The % Exhaust to Intake Flow Capacity 'Total Exh/Int %' is 80.5 %.
This is somewhat high, and indicates you could be opening the
exhaust valve too early or you could improve performance by improving
intake valve flow and intake cam profile. The most common 'rule of
thumb' is to design for around 75% EXH/INT flow capability.


If I only use the 1.2 on the intake, I no longer get any notice, meaning it is good I suppose. Better option would probably be to increase intake flow, but this will be fine.


Where would you guys try to engage if using a CVT for off-road, non-racing use?

3300 or 4000 RPMs are the options I consider. I want the shift to happen around 5200 or 5300 RPM, which also changes depending on the garter springs in the Driver unit.

3300 RPM might be just below pk TQ, but HP down around 10.5.
4000 RPM might be just past pk TQ, but HP is up above 13.

3300 RPM would give me more RPMs at higher TQ, but might take longer to rev to pk HP.
Might be harder to tune for a 5300 RPM shift if engagement is at 3.3k??

4000 RPM would render 700 RPM of really good TQ useless, but would rev to pk HP quicker.
Might be easier to tune for a 5300 RPM shift if engagement is at 4k?

 

[bob58o]

OK, Here's the catch....


Going to run 1/4" line from the valve cover and side cover. Both to a "T".
Then from the "T" to the side input of the catch can. One of these detergent/chemical pickup filters on the top connected with 1/4 hose.
.
https://www.ebay.com/itm/Go-Kart-Ra...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

https://www.ebay.com/itm/General-Pu...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I like the petcock drain for the catch can. Hope the plastic doesn't leak. Teflon Tape? High Temp Thread Sealant goop?

I'm hoping this type of pickup filter will work better than a paper fuel filter for the Catch Can vent.
Also going to put one on the fuel tank vent.

I like how RBG mounted the can.
https://www.youtube.com/watch?v=RTHDeAMrjO4

 

[bob58o]

Do they have these at the local hardware store????
Expensive online with shipping.

1/16 NPT x 1/4" Hose Barb 90 Elbow

https://www.ebay.com/itm/1pc-1-4-ID...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

Hoping a 1/16 NPT tap will fit the governor hole in the top of the block.
It should, but the hole wasn't exactly centered from the factory.

I want to run a line to the valve cover (closed with no vent).
I want extra oil to splash around on the valve train. Make it rain.
The governor hole in the top of the block will probably have a decent amount of oil being flung up at it. Maybe some of it makes its way to the valve cover.

And since I don't want the lifter / pushrod cavity to fill with oil, I enlarged the oil return hole. And I think there is a piece of hair in the cylinder.

 

[Randy H]

Looks like a gray (cougar) hair. Did you change age groups?

 

[bob58o]

Speaking of catch cans as seen on RBG...

 

[KartFab]

Where would you guys try to engage if using a CVT for off-road, non-racing use?

2k rpm.

Anything higher and it LURCHES ask me how I know? haha poor midas geta a good launch. Anything above the stock 30/40 series engagement is going to give you a rev then a lurch with less than full throttle.

If you want to avoid the lurch,, you just get a crazy fast launch at full throttle/peel out in dirt.

 

[bob58o]

2k rpm.

Anything higher and it LURCHES ask me how I know? haha poor midas geta a good launch. Anything above the stock 30/40 series engagement is going to give you a rev then a lurch with less than full throttle.

If you want to avoid the lurch,, you just get a crazy fast launch at full throttle/peel out in dirt.

Not sure what you mean by LURCH.
Can you try to explain it? I could guess at what I think you mean. Like it "jerks" forward?

My minibike now has 4k RPM engagement.
I have to slowly roll into the throttle or else when it engages it just throws me off the back.

I like it better when I set the idle to 3600 when using the 4k springs.
There is less of that slow revving period where I'm wondering when the clutch will catch. But it takes off smoothly at 4k with part throttle. Haven't noticed a lurch at part throttle, and haven't been able to get a WOT launch do to the lack of wheelie bars and gear ratio.

 

[ezcome-ezgo]

Not this...

 

[taotao110d]

Did you ever decide on a carb? I might have skipped over it.
I am really liking your hemi build, and am thinking about a pz20 carb for my low/mid hemi build instead of a 'ikuni 22 most high rpm guy are using

 

[bob58o]

I went with the OKO 21 (which measures 22mm). Knockoff of a Keihin PWK Carb.
I needed a rubber boot adapter thing to make it work with the manifold. The manifold is for a flange type carb and my carb is a spigot type carb.

Carb seems kinda heavy on the end of the manifold. Heard stories of the manifold cracking.
Thinking about bracing to support the weight of the carb.

About $21-$22 for the carb.
https://www.aliexpress.com/item/26m...w7SNcgiu_ZF62yl_eHwaAq2UEALw_wcB&gclsrc=aw.ds

Maybe $7 for the rubber boot adapter.
https://www.ebay.com/itm/28mm-Carb-...m=262804452237&_trksid=p2047675.c100005.m1851

 

[bob58o]

Did you ever decide on a carb? I might have skipped over it.
I am really liking your hemi build, and am thinking about a pz20 carb for my low/mid hemi build instead of a 'ikuni 22 most high rpm guy are using

20mm, 22mm whatever it takes.

lol

People told me to look at PZ carbs. Said they were a cheap alternative to the Chinese knockoffs I was using. They said they found China carbs difficult to tune, due to the shotty machining or what have you. I, of course, ignored the advice and got the carb I wanted.
https://www.youtube.com/watch?v=iX3kxAA2L4Q