Author Topic: Timed a DP295 today  (Read 1465 times)

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Offline PeWe

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Timed a DP295 today
« on: August 14, 2020, 12:47:33 pm »
I'm sure that there are others that are curious about DP295 cam data. I have been for years! :)
I helped a friend to time his DP295 cam today. I focused on IN open and EX close

I compare with my cam installed in my K6, RC295 scratched in the washer end.
Mega cycle official data added too since its numbers look not that far from the possible timing of DP295.

I timed my cam and the DP295 at 0 lash.
Dial indicator reset on valve retainer when adjuster screw has just started to move the valve.
DP295 has some lift! 10.12 mm (0,3984") checked several times to be sure.
(My cam has been dialed in at 9.98mm with other cam holders)
 

Edited/corrected the chart. It was not readable on Tapatalk so pdf added.
My "RC295 marked cam timing added with running lash to give a picture what that lash will change.

CAM:                        DP295           DP295 (alternative timing)
Lift In/Ex                  10.12/9.22mm
                                (0.398/0.363”)     
IN Open/close          25.5/58.5‎°       27/57‎°
Duration                   264‎°                264‎°
EX Open/Close        51.5/24‎°          53/22.5     
Duration                   255.5‎°             255.5‎°
LC In/Ex               106.5/103.75‎°     105/105.25‎°
Overlap                     49.5°              49.5‎°

DP295 Open/Close at running lash. 0.1/0.15mm (0.004/0.006")
21,5/ 55‎°     
49,5/19‎°   

CAM:                        ”RC295”        ”RC295” at running lash (0.004”/0.006”)
Lift In/Ex                  9.93/9.18mm‎        9.7/9.0mm
                           (0.391/0.361”)     (0.382/0.354”)     
IN Open/close          25/54‎°          22.5/52‎°
Duration                   259°                254.5‎°
EX Open/Close        56/21‎°          53/18‎°
Duration                   257‎°                251‎°
LC In/Ex               104.5/107.5‎°     104.75/107.5‎°
Overlap                   46‎°                    40.5‎°

               
CAM:                       Megacycle 125-70/75  official data
Lift In/Ex                  0.400/0.375”
IN Open/close         26/56‎°
Duration                  262‎°
EX Open/Close       53/24‎°
Duration                  257‎°
LC In/Ex                  105/104.5‎°
« Last Edit: August 25, 2020, 05:20:45 am by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline MRieck

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Re: Timed a DP295 today
« Reply #1 on: August 14, 2020, 06:22:56 pm »
Thank you for the solid info Per. I gave up on "zero" clearance a long time ago when measuring cams. As you said.....running clearance will change the numbers. I like to see actual lift etc with the lash in there.
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Offline johno

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Re: Timed a DP295 today
« Reply #2 on: August 15, 2020, 03:18:01 am »
I agree, it also gets past the opening and closing ramps to make the inlet open and exhaust close points more definitive when measuring for the advance / retard cam setting figures. cheers for the info PeWe as I run the 125/75 as well and like to see what your up to.
cheers Johno
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Offline PeWe

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Re: Timed a DP295 today
« Reply #3 on: August 15, 2020, 06:23:12 am »
Yes, agree with you guys. I told my friend to verify numbers with running lash.
I was eager to see the cam only data.
The lower In valve lash relatively Ex will advance it a little bit more and maybe to equal LC.

Compare In open versus Ex close to see advanced or retarded is a detail I found on this site, written by you Johno. Thanks for that quick check. ;)

I also had Bears good result using 125-75 5 degrees advanced in my mind too. No need to rev after 8000 rpm. Lots of power earlier. >1100 cc might have helped too.


Almost equal LC won, 836 very modest porting with stock valves.
The numbers look in disorder on Tapatalk, PC better.

But you always check the cam with 0 lash first to verify cam data. Final setting with running lash, right?

If you have timed a certain cam type several types, final adjustment wirh lash direct to not waste time is understandable.

EDIT:
You measure all valves, fine adjustments with different lashes to get all IN/Ex at same numbers, right?
Correct cam grinders lobe differences and rocker arms/shafts differences.

It must be a few ponies hidden there ...
« Last Edit: August 15, 2020, 06:41:11 am by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline PeWe

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Re: Timed a DP295 today
« Reply #4 on: August 15, 2020, 06:25:24 am »
It would be fine if you have timing values of a 125-70/75 to compare with.

Official numbers/cam cards  seem to differ some.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline MRieck

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Re: Timed a DP295 today
« Reply #5 on: August 15, 2020, 07:05:33 am »
It would be fine if you have timing values of a 125-70/75 to compare with.

Official numbers/cam cards  seem to differ some.
I'll see if I can dig some up Per. That being said I have seen generous #'s and shy #'s with the hardwelds.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Timed a DP295 today
« Reply #6 on: August 15, 2020, 08:41:04 am »
125/75

.040" lift checked with zero clearance

Intake:
open 26 btc 
close 56 abc
lift .400"
duration 262
LC 106
lash cold  .005"

exhaust:
open  53 BBC
close  24 atc
lift  .375"
duration  257
LC  104.5
lash  .005"
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline PeWe

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Re: Timed a DP295 today
« Reply #7 on: August 15, 2020, 01:40:47 pm »
Jerry, that is the cam card data, right?
The real data when timed a cam should be interesting. The cam card data and physical measurement on a cam in an engine can differ some.
The data measured at 0 lash followed by the real data at running lash should be very interesting.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline johno

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Re: Timed a DP295 today
« Reply #8 on: August 16, 2020, 08:38:45 pm »
Gerry,
For goodness sake ! please post some pics of your bike so we can see your baby and bits, its driving me crazy. ;D
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Timed a DP295 today
« Reply #9 on: August 16, 2020, 10:28:40 pm »
Pewe, numbers verbatim right off the 125/75 cam card

Johno, which one of the 750F's?  ;)  blue or orange? I'll be out playing with them tomorrow and I'll try to remember to get both.   

As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline johno

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Re: Timed a DP295 today
« Reply #10 on: August 17, 2020, 01:07:02 am »
Good onya mate, I'm looking forward to seeing them.
cheers Johno.
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Timed a DP295 today
« Reply #11 on: August 17, 2020, 03:44:06 pm »
As requested Johno. Hacking Pewe's thread. It's Johno's fault Pewe  ;D ;)

As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline johno

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Re: Timed a DP295 today
« Reply #12 on: August 17, 2020, 05:36:58 pm »
Well PeWe, we finally get to see Jerry's bikes after all these years. Griff they look SENSATIONAL you should be flashing them around a lot more. Id love to know more about the mods and PeWe is a techno head so Im sure he would like to know as well  ;D
Thanks Jerry.
Johno
GRASSHOPPER SOHC HONDAS ARE THE MEANING OF LIFE.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Timed a DP295 today
« Reply #13 on: August 17, 2020, 10:22:58 pm »
Thanks Johno. Really appreciate it.

I just responded to Terry on the "what did you do to your bike today" thread as to not continually jack up this thread since I did not use a 295.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline PeWe

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Re: Timed a DP295 today
« Reply #14 on: August 18, 2020, 12:18:54 am »
No problems guys!
I hope to add the timing measurements at running lash of the DP295 when my friend has measured it without moved the degree wheel.

I guess the difference will be like my "RC295" cam numbers.
IN 25/54  -  22.5/52
EX 56/21 -  53/18

Each open or close  2-3 degrees less. Diff In open vs Ex close increased a little due to Ex bigger lash than in.

So this DP295 (at 0.004/0.006") can be something like:
IN:  22/56
EX: 49/21
Lift reduced by lash and a little bit more.  - 0.15/0.2mm (0.006/0.008")
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline mark ward

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Re: Timed a DP295 today
« Reply #15 on: August 18, 2020, 06:45:45 am »
I probably should've taken Mike's advice..... Originally chose not to degree my Megacycle 12565, when I 1st installed in 1985; and found strong power from 6000-10,000.
     This past year's rebuild, with same cam, (degreed at 0 lash);  and now find less power surge until later rpm range; 7500-9500.
 Although, I am still getting carb tuning dialed in; since my old VM29's have pushed me towards the RS realm.

Offline PeWe

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Re: Timed a DP295 today
« Reply #16 on: August 18, 2020, 09:48:14 am »
If you have frame kit, not that much work to time it again with engine in frame.

Advance it some degrees. I heard 3 degrees as a "normal" value before. A little bit more seems to work too.
With running lash to see the correct timing.

I used 0 lash to measure cam and compare with other cams at 0 lash.

It feels fine to have good response earlier on a street bike.
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline mark ward

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Re: Timed a DP295 today
« Reply #17 on: August 18, 2020, 12:21:46 pm »
Thanks Per for that suggestion. Perhaps I'll try advancing 3 degrees as weather turns cold here, since I did install the frame kit this past year.
       You're right about gaining power-surge sooner in the rpm range for street riding.

Offline PeWe

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Re: Timed a DP295 today
« Reply #18 on: August 25, 2020, 05:23:48 am »
The DP295 cam timing verified at running lash too.

DP295 Open/Close at running lash. 0.1/0.15mm (0.004/0.006")
@ 1mm (0.04") lift
21.5/ 55‎°     
49.5/19‎°   
Overlap 40.5°
« Last Edit: August 25, 2020, 11:19:35 am by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967