Author Topic: Salt Racer CB 750 OZ style  (Read 169689 times)

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Offline scottly

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Re: Salt Racer CB 750 OZ style
« Reply #1200 on: April 01, 2015, 06:48:49 PM »
I can assure everybody there was no vacuum leak secondary to the head on that cylinder. First off all the ports are vacuum checked on the Serdi after cutting and lapping the seats.
 
I didn't really believe a leak in the head was an issue, Mike, but was more thinking out loud about any conceivable cause. ;) I have experienced a case where a fault in the casting of a big block Mopar head caused a coolant leak into an exhaust port after surviving over 100,000 miles, when a simple valve job and cleaning operation were done.
I have seen some serious damage done to both man and machine by "erratic" ignition on my buddy's
XR500: sheared kick-start shaft, (also broke the foot of the 250 lb guy that was kicking it at the time) and a blown head gasket when we tried to pull start the bike with a truck. Turned out the ignition trigger wires had been crossed with the lighting coil, which created a random, rapid series of sparks for every revolution of the crank.   
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1201 on: April 01, 2015, 07:58:09 PM »
Cheers Bear.... dont worry this time dyno will be my middle name  :)

Billy ......your truly amazing   8):o   its just not true what the other blokes say about you ;D ;D
I'll have easter off for a break and catch my breath then contact you to sort out a deal on a couple of pistons, hope you can hold off for a week.
cheers johno
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Offline Bill/BentON Racing

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Re: Salt Racer CB 750 OZ style
« Reply #1202 on: April 01, 2015, 08:21:14 PM »
Johno,that works, gotta ship Retro some stuff, just let me know. You get it it right on all 4. ....record time! K, Bill
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Offline Retro Rocket

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Re: Salt Racer CB 750 OZ style
« Reply #1203 on: April 01, 2015, 11:48:18 PM »
Johno,that works, gotta ship Retro some stuff, just let me know. You get it it right on all 4. ....record time! K, Bill

I may have a seat being sent to you to on ship mate... :o, I'll let you know... ;)
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Offline hotdog

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Re: Salt Racer CB 750 OZ style
« Reply #1204 on: April 02, 2015, 08:28:23 PM »
Bear, yes you and mike are correct the MSD looks good, guess I'm just shooting off my mouth as I can only imagine how johno feels about this x 2. Can't help but think there would have been less issues with a pamco or dyna s.....
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1205 on: April 02, 2015, 10:31:14 PM »
Johno,that works, gotta ship Retro some stuff, just let me know. You get it it right on all 4. ....record time! K, Bill

I may have a seat being sent to you to on ship mate... :o, I'll let you know... ;)

No worries mate, easy peasy just let me know.
If anyone in OZ needs something to go to Mike let me know as I will be sending him OUR FORUM head to tidy up.
cheers Johno
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Offline bear

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Re: Salt Racer CB 750 OZ style
« Reply #1206 on: April 03, 2015, 02:25:45 AM »
Bear, yes you and mike are correct the MSD looks good, guess I'm just shooting off my mouth as I can only imagine how johno feels about this x 2. Can't help but think there would have been less issues with a pamco or dyna s.....


I think you will find that Johno is a kindred spirit.
"Old School is Cool" ;)

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Brian
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Offline MRieck

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Re: Salt Racer CB 750 OZ style
« Reply #1207 on: April 03, 2015, 08:06:15 AM »
Bear, yes you and mike are correct the MSD looks good, guess I'm just shooting off my mouth as I can only imagine how johno feels about this x 2. Can't help but think there would have been less issues with a pamco or dyna s.....
Me too.
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Offline sohc boy

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Re: Salt Racer CB 750 OZ style
« Reply #1208 on: April 03, 2015, 08:44:46 PM »


Hmmmm Mikey , lets look at the head ????????
.. Geeeeses... Johno .. bet you sat down quietly n had a few beers after discovering that
« Last Edit: April 03, 2015, 08:50:25 PM by sohc boy »
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1209 on: April 04, 2015, 03:39:48 AM »
Hi Pete,
I passed your regards onto Afflick, he said he hasnt seen you for awhile and wanted to know what your up to. I said "retired' ;D ;) ;D
cheers Johno
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Offline bear

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Re: Salt Racer CB 750 OZ style
« Reply #1210 on: April 04, 2015, 03:54:23 PM »
Hey Johno,

Did Steven Finn put down a 157 before it ventalated? :o

Cheers,
Brian
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Offline MRieck

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Re: Salt Racer CB 750 OZ style
« Reply #1211 on: April 04, 2015, 05:15:59 PM »


Hmmmm Mikey , lets look at the head ????????
.. Geeeeses... Johno .. bet you sat down quietly n had a few beers after discovering that
I did.
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1212 on: April 04, 2015, 11:07:36 PM »
yeh sorry Bear, was too busy feeling sorry for my wallet to report on the racing.

As it turned out the battle between Finny and I was good racing.
Ol finny come very prepared this year, had a good crew,  a reed valve motor and a piston port motor, the spare motor syked me out as he built a amazing perspex crate and had it on display in his / our pit .    Was good enough for a coffee table in the house.
On the Monday run he run a 157 mph first up but not allowed as the wind was a roaring cold southerly 22MPH directly behind him.
After him We had our first qualify run  ( safety run ) at 100mph bike handled straight, motor was running easily,  we almost had to deal with crowd control at the start line with people so enthused with an ol Honda it was almost a problem.  Plus with the rollers it was like an entertainment circus.

Tuesday ..Next day conditions perfect , cool slight tail breeze,  Finny had a run first again but popped his engine in second gear not far from the start line,   We had our run in morning as well, bike sounded good had to do the 125mph licence run and be plus or minus 5MPH or repeat, we set up a GPS and Jamie nailed it at 124.9 for a full mile then he accelerated at full throttle for a burst up to around 135 to 140 approx before backing off and braking so he didnt break out his limit 125mph,   with the smaller 16 front tooth sprocket.
At this stage we got a bit excited, Jamie was confident it would pull to 150 mph plus  ( he is a Honda mechanic at local dealer so has a good feel)   so we went back to pits changed the front sprocket to 17 / 43 and rejoined the que ready for another run while conditions were perfect.  Unfortunately lots of incidents on track to delay and we got within 10 positions from start before they stopped racing for the day.

Wednesday, we qued the whole day but no run, Finny changed to his piston port motor and went to the practice track to run it.

Thursday.. up super early to get a morning start, weather perfect again, salt hard and dry. We thought this record will happen today , finny or us will get it, hopefully its close for both of us.
Finny ran first and seized his second motor with no time, then we ran Jamie hit the first timed mile at 8,300 RPM but motor popped just as he was entering the mile,    the official timing van do a first quarter mile time at the start of the mile and had him at about 140MPH as he was  deaccellerating.

Shared a beer with Finny and his crew ( ol Bob Voumard was with him 4 times Aust motocross champion , poor ol Bob on his last legs with the big C) then we packed up and started the drive home.

Frankly I have learnt a lot this year, its so different from other forms of racing and it has taken me time to adjust and get my head around it, the forum boys have really really helped, it feels like being part of  the worlds biggest race team 8) 8)

Deep down in my mind I feel we have an engine that can run 150mph, naked on the salt and that has always been my goal. To emulate the Factory CR 750 at 150 plus mph with full fairing on bituman BUT to do it naked on loose salt was the challenge for me and I think we can do it.   That would mean the ol sohc forum combined has produced something as good as a works bike, a big challenge.

The other thing that has made me happy was just as the CR 750 had standard swing arm,  so too our bike ran straight and true with std wheelbase and no lead as compared to other bikes in class carrying 150 kg of lead with long swing arms and I cant help but not want to go there.   Currently no need , as the old stocky runs on rails and still lets the rider get his bum over the back wheel.

Better stop raving and get working for next year, the old saying , when the green flag drops the bull #$%* stops.
ciao johno
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Offline Bill/BentON Racing

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Re: Salt Racer CB 750 OZ style
« Reply #1213 on: April 05, 2015, 05:59:59 AM »
Way cool. Yes we are part of Team SOHC4 !! Next year we'll be writing about your new record.K, Bill
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Offline Old Scrambler

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Re: Salt Racer CB 750 OZ style
« Reply #1214 on: April 05, 2015, 08:36:06 AM »
Johno.................good story..............and the feeling is mutual about how GREAT it is to be part of the SOHC/4 TEAM :) :) :) :)
Dennis in Wisconsin
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Offline Medyo Bastos

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Re: Salt Racer CB 750 OZ style
« Reply #1215 on: April 05, 2015, 10:27:53 AM »
what ignition was this?

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Salt Racer CB 750 OZ style
« Reply #1216 on: April 05, 2015, 11:08:40 AM »
Get at it Johno.

Now it's time to go SOHC4 drag racing with Bill and the boys.  :D

Dennis, you're up next.  ;) Start your staging.
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1217 on: April 07, 2015, 04:29:43 AM »


Not sure if this will work but a short video of the old mechanic and the young jockey ;)
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1218 on: April 15, 2015, 04:19:49 AM »
So I have been doing my thinking on the detonation problem I have.

Putting it very simply my feeling is the ignition system has a problem.   Lots of things cause detonation but in this rebuild anything that could effect detonation was changed or altered  ie complete fuel system from Pingal valve, fuel lines,  carbs, jetting, air cleaners, pulled timing back to 32 deg , changed piston design, etc etc , in real terms it was a different engine except for the ignition, previous engine I felt it was the cause of deto problem and when I checked it was.  It had the wrong software loaded on to suit different type of coils  and other things like that so I thought I rectified that and reduced the total advance just in case.

However the 3 pics I will upload will show it has the identical problem it originally had.   Its difficult to diagnose a computer system but the variation between the cylinders combustion are distinct and too varied to be anything simple as fuel or timing issues.
 the variation between the cylinders is the key to identifying its not sparking when it should be  and the pics will show that.

Statically good strong spark on all cylinders.
When running the cyl 1 & 2 exhaust gets hot quickly, cyl 3 & 4 take a lot longer to warm up with number 4 being the coolest by far.
Low RPM Runs fluffy like its too rich low down cos it is  at 11 : 1  but crack the throttle and good responce clean and sharp.
Carbon on pistons and chambers.
Number 1 cyl, about where it should be.
Number 2 is where it should be then bang detonation    (possibly at around 7,000.RPM)
Number 3 is totally fuel washed chamber
Number 4 is flat black rich carbon

With two different complete fuel systems and piston shapes but identical combustion problems just leaves the spark. Its like two different ignition systems on the same engine 1&2 then 3& 4 :o
What worries me is Power arc insist on it being a non wasted spark system but its not. He says he wastes the spark on the next exh stroke on the same cylinder which is what I was trying to avoid by purchasing his system.  I believe his programming is out of cinc and it is not doing what it should be.  I could continue to work with the company to try and solve his problems but I am the person paying the bills not them.  After everything I have been through by giving the power arc system a second chance you will forgive me for giving up on this system and will go conservative by running a Dyna 2000 or a MSD    might save a lot of money and time ;)

Pics to follow.
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1219 on: April 15, 2015, 04:21:29 AM »
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1220 on: April 15, 2015, 04:22:53 AM »
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1221 on: April 15, 2015, 04:25:49 AM »




Read about your little groovy  camera. Dont worry about your pistons Den , they will be fine if you treat em OK, this issue is about spark control.
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Offline johno

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Re: Salt Racer CB 750 OZ style
« Reply #1222 on: April 15, 2015, 04:32:56 AM »
Last comment by me.
I did check what I could on the ignition,
re software curves and settings I sent to Power arc for confirmation all was good.
I check the plug leads for resistence,
changed several sets of plugs
Check the 4 coils for primary resistance and the secondary for earthing , all same all good,
Checked every wire connection, all good
Checked the battry voltage several times and changed battery as well.
Checked the engine  & frame earthing.

This is done for me !
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Offline Medyo Bastos

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Re: Salt Racer CB 750 OZ style
« Reply #1223 on: April 15, 2015, 04:46:08 AM »
what did gary at powerarc have to say???

Offline hotdog

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Re: Salt Racer CB 750 OZ style
« Reply #1224 on: April 15, 2015, 05:09:06 AM »
Definitely groundhog day symptoms there.....would msd or dyna do a sponsorship thing.?

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