Author Topic: Hi comp and big bore  (Read 4798 times)

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toecutter

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Hi comp and big bore
« on: September 22, 2009, 12:00:50 am »
Hi folks

id like to pep up the old girl as it will be raced in some classic events next year (nothing to serious ) what do you guys suggest ,i have been told cg 125 pistons have a higher crown for more compression on the 500 ,or just fit 550 barrels and pistons
advice would be great
cheers
 [img=http://img10.imageshack.us/img
i hope the photo comes out  ,it never does hey ho

Offline KB02

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Re: Hi comp and big bore
« Reply #1 on: September 22, 2009, 03:42:12 am »
here you go:


Sweet looking bike!
1978 CB750K Project
2000 Ducati Monster
...and a pedal bike

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My project thread Part I: K8 Project "Parts Bike"
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Offline Bill/BentON Racing

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Re: Hi comp and big bore
« Reply #2 on: September 22, 2009, 05:22:22 am »
Nice bike,what are your class limitations? Lots of options up to Paulages's 718cc!! Bill
I ran a Yosh 553cc,then went up up 590cc.
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Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #3 on: September 22, 2009, 12:51:02 pm »
Hi folks

id like to pep up the old girl as it will be raced in some classic events next year (nothing to serious ) what do you guys suggest ,i have been told cg 125 pistons have a higher crown for more compression on the 500 ,or just fit 550 barrels and pistons
advice would be great
cheers
 [img=http://img10.imageshack.us/img
i hope the photo comes out  ,it never does hey ho

Welcome to the forum toecutter, nice looking bike you have there, looking a tad wet though, north west England perhaps?

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

toecutter

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Re: Hi comp and big bore
« Reply #4 on: September 22, 2009, 02:38:04 pm »
Thanks for posting up the photo ,i still cant figure out these new fangled things (computers )

any way yep she is a nice little bike ,since that photo ive done lots of work to her .It started life as Rickmans development bike for their first road race chassis ridden by Don Rickman and raced by allan Barnett. A Matchless G50 was in the bike at the time and it won its debut race at Mallory park in 1966 and this bike being the first in the world to have dual disc brakes ,front and rear, running 41mm forks (yes 41mm cerani forks in 1966) Jim redman and Tommy robb both recognised the bike at the festival of 1000 bikes as they both raced againsed it ,so i was chuffed when they both signed the tank for me .

 
Rickman fitted the 500/4 motor in 1969 it again was raced but not much is known about it from then till the early 80,s when Roy parker and seven others began the forgoten era race series ,its then been used as a parade machine ,then relegated to the back of a garage till i got my grubby little hands on it
I belive the  motor has a road /track cam ,has had some mild tuning but untill i pull it to bits this winter im not sure what ill find ,the bores are fine (no smoke ,no oil loss etc but you can tell she is a bit tired .I dont want to go to mad (700 odd cc )may be a bit much and i dont think crmc would allow it
cheers

toecutter

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Re: Hi comp and big bore
« Reply #5 on: September 22, 2009, 02:43:23 pm »
ooo
and no im not in the north but in the midlands ,where everyone moans about everything but does nothing about it
(i can hear canada calling me )

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #6 on: September 22, 2009, 02:50:37 pm »
I was in Coventry on Sunday, it was nice and sunny but I had problems understanding the language. ;D ;D ;D ;D ;D
What's your name and where do you race?

Sam. ;)
C95 sprint bike.
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CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

toecutter

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Re: Hi comp and big bore
« Reply #7 on: September 22, 2009, 03:07:42 pm »
Rob
and this along with my z1100r will be raced at the crmc race meetings next year with a bit of luck and a tail wind with a bunch called Team jam who all have original race and endurance bikes

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #8 on: September 22, 2009, 03:16:10 pm »
Rob
and this along with my z1100r will be raced at the crmc race meetings next year with a bit of luck and a tail wind with a bunch called Team jam who all have original race and endurance bikes

YOU'LL HAVE TO LET US KNOW IF YOU GET TO ANY OF THE NORTHERN CIRCUITS, sorry for shouting ;D ;D ;D pressed the caps key.

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

toecutter

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Re: Hi comp and big bore
« Reply #9 on: September 22, 2009, 03:27:40 pm »
will do
any way any info would be greatly apreciated ,i guess id like to keep it under 600 cc ,i know there were some 610 kits about  but havent seen any for a while and thats new liners .mind you for crmc i belive the Honda 4,s have to have a twin leading shoe front brake for originality but mine has always had the discs so i dont even know if they will accept it yet
Job tomorrow ,do some grovelling

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #10 on: September 22, 2009, 03:37:16 pm »
Rob, I would think if you got in touch with Rickmans and they gave you a letter that the bike is as you claim, I can't see that the CRMC could refuse you.

Sam. ;)
C95 sprint bike.
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CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline BLUE71TURBO

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Re: Hi comp and big bore
« Reply #11 on: September 22, 2009, 07:51:46 pm »
Hey Sam !  When did you get promoted to moderator ?  Or have i been blind all this time !   :D   ;D
Remember; Before you can be old and wise, you must first be young and stupid !

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #12 on: September 22, 2009, 08:13:40 pm »
September 17th @ 04.05.25.  ::) ::) ::) ::) ::) or there abouts :D :D so behave yourself ::)

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline BLUE71TURBO

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Re: Hi comp and big bore
« Reply #13 on: September 22, 2009, 09:28:31 pm »
CONGRAT'S  " MR BIG SHOT MODERATOR " MIKE !   I promise "finger's crossed behind back"  to be a good and faithful member as long as i live !!  Pinky swear !!   ::)
Remember; Before you can be old and wise, you must first be young and stupid !

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #14 on: September 22, 2009, 09:31:59 pm »
 :D :D :D :D :D :D :D :D :D :D :D to be honest, I didn't know it had happened untill I got a congrats PM from another member......must pay more attention ;D ;D ;D ;D ;D

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline paulages

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Re: Hi comp and big bore
« Reply #15 on: September 22, 2009, 11:10:34 pm »
nice bike!

what exactly is the motor, as the production 500/4 hadn't come out yet in '69, but you're referencing parts vailable for the production model.

welcome to the forums!
paul
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Offline bwaller

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Re: Hi comp and big bore
« Reply #16 on: September 23, 2009, 03:25:22 am »
Yes, how'd be we peel back that body work for a look-see.  ;D

Cool bike.

Offline Rod

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Re: Hi comp and big bore
« Reply #17 on: September 23, 2009, 07:33:22 am »
I wouldn't even begin to consider changes to the spec until you have been in contact with the eligibility officer at CRMC - http://www.crmc.co.uk/ Better still go along to Cadwell next month (last race of the season), you can chat to other 500/4 racers and also get a steer from the club officials.

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #18 on: September 23, 2009, 11:30:50 am »
nice bike!

what exactly is the motor, as the production 500/4 hadn't come out yet in '69, but you're referencing parts vailable for the production model.

welcome to the forums!

Spot on Paul, I didn't pick up on that one.  :-[ :-[ :-[  The 500 came into the UK about June 1971.
I was working as a Honda tech at a local dealers when the first 500 came my way for pre delivery check.

Rob, you'll have to check out the history on that one.

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline Bill/BentON Racing

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Re: Hi comp and big bore
« Reply #19 on: September 23, 2009, 08:00:00 pm »
WOW,Moderator,I knew him when he was Sam the Sham,and Al's other brother,Drew hold the presses ,we got to change the T shirt,and book Sam on Letterman show! ;D ;D ;D,CONGRATULATIONS,Bill
BentON Racing Website
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Over 35 years of experience working on vintage motorcycles, with a speciality in Honda SOHC/4 with a focus on the CB750 and other models as well from 1966 - 1985.
______________________________________
1993 HRC RS125 | 1984 NS400R | 1974 Honda CB750/836cc (Calendar Girl) | 1972 CB 500/550 Yoshi Kitted 590cc | 1965 Honda CB450 Black Bomber | 1972 Suzuki T350 | 1973 88cc | Z50/Falcons Pit Bike | 1967 CA100| 1974 CB350 (400F motor)...and more.
______________________________________
See our latest build 'Captain Marvel' CLICK HERE

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #20 on: September 23, 2009, 08:23:19 pm »
Yeh, but I'm still on the same money though, Glenn is a right tight fisted so and so.  ;D ;D

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline turboguzzi

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Re: Hi comp and big bore
« Reply #21 on: September 24, 2009, 12:17:27 pm »
+1 Rod, check the rules and calsses,

1. I seriously doubt if they'll allow you to run it as an overbore in the first place
2. If they do, you might end up racing against serious 750's like triumph and BSA triples and you might be even less competitive.

I remember that peterC from the UK told me that the CRMC requires 500-4's to run with a front drum!!!! (and of course a rear one too).

That said, your prototype bike just proves how silly this rule is.

The only off-the-shelf hi-comp pisotns for a 500 are XL125's, CG's are too low and require milling the block

You will have to remove some material from the XL125 piston domes otherwise compression will be too high

Other comment is that the bike seems to sit very low on the back, you might want to raise it for quicker steering.

Last, like others here, i'd love to see the frame, without tank and fairings

TG

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #22 on: September 24, 2009, 12:24:38 pm »
TG, it's probably sitting low because it's strapped on a trailer.

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

Offline voxonda

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Re: Hi comp and big bore
« Reply #23 on: September 24, 2009, 01:01:40 pm »
+1 Rod, check the rules and calsses,

1. I seriously doubt if they'll allow you to run it as an overbore in the first place
2. If they do, you might end up racing against serious 750's like triumph and BSA triples and you might be even less competitive.

I remember that peterC from the UK told me that the CRMC requires 500-4's to run with a front drum!!!! (and of course a rear one too).

That said, your prototype bike just proves how silly this rule is.

The only off-the-shelf hi-comp pisotns for a 500 are XL125's, CG's are too low and require milling the block

You will have to remove some material from the XL125 piston domes otherwise compression will be too high

Other comment is that the bike seems to sit very low on the back, you might want to raise it for quicker steering.

Last, like others here, i'd love to see the frame, without tank and fairings

TG

Agree with TG about the rules, it's like that in Holland too. This is one of my favorit, a really fast 500 with builder/rider Frank Lemstra.


Rob
Better sorry for failing then for the lack of trying.

Offline Sam Green Racing

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Re: Hi comp and big bore
« Reply #24 on: September 24, 2009, 01:09:42 pm »
Nice looking bike Rob. 8) 8) 8) 8)

Sam. ;)
C95 sprint bike.
CB95 hybrid race bike
CB95 race bike
CB92
RS 175. sprint/land speed bike
JMR Racing CB750A street ET drag bike

 

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