News:

Mat Oxley 1986 IOM TT


click above to read more about Mat.

Main Menu

'How To' stuff on RD's

Started by SUPERTUNE, August 25, 2019, 11:46:20 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Czakky


Greaser Greg

Every day above ground is a good one.
'71 R5B "Rusty"  '71 R5B "Decaf"   '99 KZ 250
'97 XL1200S "The Vibrator"   '08 XL1200N  "Greenie" (totalled)
'78 CB750F "The Skunk"   '74 CB550 "Blackie"    '78 Honda Hobbit

SUPERTUNE

So let's take this a bit further in theory...
Once you get the head cut, you then have to CC the head volume to get the compression ratio in your target range if running on pump gas or race gas...
You will always have to figure in how big the bore is as that can make a big difference in the final compression ratio

Here is the formula to reach this factor...we need to know how big the engine displacement is.
We have to know what the displacement of the engine is, specifically 1 cylinder.

Take the bore size and multiply by itself.
Example a RD350 at 65.00mm of bore and a stock stroke of 54mm.

Bore squared is: bore x bore.
So, bore x bore x stroke x .7854  divided by 1000 will equal the cc's for one cylinder, then x 2 will give total displacement of the engine.
65mm x 65mm x 54mm x .7854 divided by 1000 = 179.19 cc per cylinder.
Now 179.19 x 2 cylinders we get 358.4 CC's of engine total displacement.
Now that we know the displacement is 179.19 CC'c per cylinder we are now ready to mock up the engine and do a CC fill volume of the combustion volume with the engine together to get what we call Fill Volume (F.V.)

Mock the engine together, using  some grease to seal the piston at TDC. (top dead center) grease with light coat on the headgasket and then put on the head and hand tighten the head bolts, not critical as we are not checking for squish clearances which do require a torque value .

to be continued...time for bed! Sorry I'm beat from the FL. summer heat! :thumbs:
Chuck
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

Czakky

Do you recommend every time a cylinder is bored that the CC should get profiled?

SUPERTUNE

No, I try to set the up for 2-3 more bores.
Yes, if going over 1mm from when there done the first time.
Bigger bores up the cylinder volume, so the compression ratio goes up.
Chuck
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

Hardy

TBC? The suspense is killing me! :cheerleader:

SUPERTUNE

OK.
The racing season just got done at Barber Vintage Festival...was really busy with racebikes and now the backlash of work missed while gone for a week.
C
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

Hardy

When you have a moment, any chance of the next chapter?

SUPERTUNE

Hardy,
I'm sorry...been everything I can do to keep up lately due to my Ford F-150 deciding to break the transmission for no reason...turns out to be a Ford manufacturing issue with a bad forward clutch drum breaking in thousands of F-150's!
Their goes $1900 out the window for no reason other I bought a Ford instead of a Chevy!  :umm: :bang: :help:
Wish I would have known before buying a Ford.
Motor runs great, gets good fuel mileage and doesn't use a tic of oil...
Front brake pads will out last front rotor permanent sealed wheel bearings too! Found that out in December!  :eek:
Oh crap...time to go home from shop it's 11:15....
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com