Author Topic: cb750 to 900cc -- I need one 67mm big bore Henry Abe piston (Read 19756 times)

Soos · « **Reply #50 on:** March 29, 2009, 07:07:21 PM »

I would assume so based on the info I have found so far.
As the info I have coma across the crank journal is 35mm, but the big end on the rod is 38mm.
At the below listed site, it refers to the "connecting rod bearing insert selection" and goes on to list the 3 sizes of bearing inserts offered.
http://books.google.com/books?id=U331HAv2b4cC&pg=PA144&lpg=PA144&dq=GSX-R1000+connecting+rod+measurements&source=bl&ots=NZ4eoWg-0o&sig=h7Hw76ukndNIy-cwoJPdQvi1ius&hl=en&ei=_JbPSYW1NqHaswP8roGhAw&sa=X&oi=book_result&resnum=1&ct=result#PPA155,M1

But I am going to go ahead and contact either carrillo, of falicon and find out the last bit of info I would really like to confirm before buying a set of rods off Feebay(unless someone here has a set they wanna sell?)...
The center to center is the only thing I cannot find (multiple) sites that state the info.
AND they all list the same info...

I can see one website being wrong, but 6?
I dunno......

As they say the proof is in the puddin, and i'm eager to dip in if this will work!

l8r

Soos · « **Reply #51 on:** March 30, 2009, 09:36:41 AM »

Well I got ahold of Falicon.

They confirmed it does use shell bearings and they also confirmed the 15mm pin bore for the '05-'08 year of production GSX-R 100 bikes only.
Not '04 and earlier.
They also confirmed the width of the big end, 20mm, (0.785) as well as the 38mm big end.
The kicker......
They REALLY DO have 111mm center to centers!!!!!!!

If I had the $$, I would DEFINATELY go for a set of their -2mm rods for the stroked GSX-R 1000 crank they offer, as it would get the deck height of these GPZ750 pistons down to where the stock cb650 pistons are at.

Well, that arises another thing, the stocker rods on Fleabay are a option for stronger rods now!

I am gonna at least scrimp up some money somehow to get a used set of GSX-r 100 stock rods.

l8r

fang · « **Reply #52 on:** March 30, 2009, 09:55:04 AM »

Quote from: Soos on March 30, 2009, 09:36:41 AM

Well I got ahold of Falicon.....
They REALLY DO have 111mm center to centers!!!!!!!

Well, that arises another thing, the stocker rods on Fleabay are a option for stronger rods now!
I am gonna at least scrimp up some money somehow to get a used set of GSX-r 100 stock rods.

Very nice detective work.... Now if only we can find something like this for the SOHC CB750!!!! That would be amazing!
-steve

Terry in Australia · « **Reply #53 on:** March 30, 2009, 03:39:02 PM »

Yep, very good work mate, out of interest, what is the "centre to centre" length for the CB750 rods?

fang · « **Reply #54 on:** March 30, 2009, 06:47:04 PM »

Yeah Soos,
Do you know all the spec numbers for the CB750 rods?

Big Jay · « **Reply #55 on:** March 30, 2009, 11:33:42 PM »

Quote from: Terry in Australia on March 29, 2009, 03:37:56 PM

G'Day Soos, hasn't the GSXR1000 engine got a roller bearing crank? Cheers, Terry.

No

BIKE · « **Reply #56 on:** March 31, 2009, 07:00:55 AM »

When I took my engine apart, to my surprise I had Henry Abe pistons, marked HAINST 890cc.

Also to my surprise, one of them had a crack in the skirt.

I ended up sourcing a new top end. IM me if you are interested in any of the pistons/jug.

Soos · « **Reply #57 on:** March 31, 2009, 07:03:32 AM »

Quote from: fang on March 30, 2009, 06:47:04 PM

Yeah Soos,
Do you know all the spec numbers for the CB750 rods?

here is a post I put some measurements up for cafebob...

Quote

The mill I was going to use to dial in the bores and give you a exact bore to bore measurement is down...So using some digi calipers, I come up with 4.566 center to center.
In Metric thats 115.976 mm
I'm guessing 116mm is stock.
I did re-measure, and the second time I came up with 4.567.(116.002mm)

While i'm at it.... stock DOHC cb750 connecting rod center to center length I measure is 4.507(114.478mm).
touching lightly I come up with 4.508 (114.503mm)

Hope this helps.

Cannot remember the big end diameter, but I know both the DOHC and SOHC rods have 15mm pin bores.
I remember that the DOHC and SOHC rods have the same big end diameter... but what that is...dunno.

http://forums.sohc4.net/index.php?topic=28495.msg292416#msg292416

If you look at this post on the second page BigJay posts the Center to center is 4.570.
Or a hair over 116mm.

here is a post on more info on DOHC rods if interested....
If one were to use the data, they could find alternative rod/piston combo to make a larger bore motor cheap.

http://forums.sohc4.net/index.php?topic=28401.0

l8r

Soos · « **Reply #58 on:** March 31, 2009, 07:34:37 AM »

With the cb750 rods, the 2 measurements I am unsure of are the width of the big end of the rod and the bore of the big end.
Anyone got those measurements offhand?

If you are wondering how on earth I found this info for the GSX-R 1000('05-'08 only) rods...
I did a internet search for "rod 38mm"
I just followed up until I found one with a 15mm pin bore.
Then I called Falicon.
And confirmed the last bit of info I was unsure about, as well as all the other measurements.

l8r

DRMR · « **Reply #59 on:** March 31, 2009, 05:00:34 PM »

The rods I have measure;
Big end width,
Stock CB750=.895
Falicon CB750=.901
Carrillo DOHC750=.903
Big end I.D. of Carrillo rod 1.5356 printed on spec sheet
Big end of Falicon using dial caliper 1.535

fang · « **Reply #60 on:** March 31, 2009, 07:02:27 PM »

It would be spectacular if some modern sports bike has rods that are a direct swap.

Soos · « **Reply #61 on:** March 31, 2009, 08:34:46 PM »

thnx there DRMR...

I get a bit of time i'll search those out.
Probably this weekend.

I really need to focus on my garage.
Got a KZ1000 nearly all put back together, and I need to start moving on my cb650....

l8r

Soos · « **Reply #62 on:** April 04, 2009, 09:32:02 PM »

Ahhh...
Not alls well on this front of my 66mm project today.
I got the pistons, look great and all.....
But now I have the rings as well.

Too bad that I found this info too late, could have ordered GPZ rings, not realizing the KZ rings would not suffice without needing mods...

Quote

Spectre/GPz pistons have higher domes (also part of the gain in c.r.) To reduce friction the pistons have thinner rings, 1.0mm steel for the top ring, 1.2mm cast iron for the center ring, while the standard KZ uses 1.5mm cast iron rings for both.

Found this info at:
http://www.motorcyclespecs.co.za/model/kawasaki/Kawasaki_Z750N%20Spectre.htm

Damn.
Now the real question is, do I re-sell the KZ rings, and go out and shell out $45/set for the GPZ rings.......or mod the GPZ pistons to take the KZ rings?
I'm not past modifying these pistons by any means.
I intend on lopping 1.5mm off the top, and 2.5mm off the deck height, as well as valve pocket mods(possible there, not sure yet).

And then there is the option of simply grinding the 1.5mm middle rings down to 1.2mm....
The GPZ 1.0mm steel top ring would probably have to be re-used IMO as the KZ top ring is cast iron, and I think 1mm thick is really pushing it for a cast iron ring.
Seems harder than opening up the ring grooves though.

As a side note... Notice it says the GPZ pistons and the Spectre pistons have a higher dome compared to the KZ pistons....
One could extrapolate from that the KZ pistons would just be the better route for a cb650/750 overbore then.
Less(or none) to lop off the top to get CR within sane limits, dunno I don't have any KZ pistons.

What to do, what to do....

I hope the '07 GSX-R 1000 rods I (hopefully) an going to win on Feebay will work without needing mods!

l8r

Terry in Australia · « **Reply #63 on:** April 07, 2009, 04:46:52 AM »

Oooer, so the CB750 big end ID is 39mm? Hmmmnnn, I wonder if the GSXR1000 rods would still work with thinner plain bearings, or a hone, perhaps? I just bought a really nice 4 stone hone that should work ok?

Quote from: BIKE on March 31, 2009, 07:00:55 AM

When I took my engine apart, to my surprise I had Henry Abe pistons, marked HAINST 890cc.

Also to my surprise, one of them had a crack in the skirt.

I ended up sourcing a new top end. IM me if you are interested in any of the pistons/jug.

Sold! (if they're still available, of course)

Soos · « **Reply #64 on:** April 07, 2009, 07:00:34 AM »

Quote from: Terry in Australia on April 07, 2009, 04:46:52 AM

Oooer, so the CB750 big end ID is 39mm? Hmmmnnn, I wonder if the GSXR1000 rods would still work with thinner plain bearings, or a hone, perhaps? I just bought a really nice 4 stone hone that should work ok?

Not sure what the '04 and earlier were, or if they offered the GSXR in '09 let alone if there were any more changes to the rods.
I know the 111mm center to center applies to the '05-'08's though.
The material they used (from what I have read) is chrome-moly steel.
Now what type of chromo-moly... dunno.
If it has a high nickel content, it might load your stones up.

So a "stock" cb750 rod is 116mm center to center, so you would loose 5mm by putting 111mm center to center GSXR 1000 rods in there.
But if you drop in a set of pistons that are 5+mm taller than the stocker cb750 pistons you should be good.
But thats for the deck height.

I can't wait for my GSXR1000 rods to arrive....
Bought a set off Feebay.....

l8r

DRMR · « **Reply #65 on:** April 07, 2009, 05:42:30 PM »

Question for Soos and Terry.
What about the 2.95mm difference in rod width if used in a 750?
What is the allowed side clearance for the rods?

Rods might be a good candidate for a stroker crank,welded up and ground
to width and journal size of the GSXR rods, +5mm longer stroke???

Dreamin again.

Soos · « **Reply #66 on:** April 08, 2009, 08:03:29 AM »

With 5mm shorter rods, you would need a +10mm stroked crank to make it up.

It would pull the pistons down 5mm more and up 5mm more. So in a way it ends up 5mm, but you gotta thing in diameter not radius.
You would end up with a 73mm stroke.
So thats.....853cc's with 61mm pistons..... with a 836 kit(65mm pistons), you get 968.9cc!!!!!.

With a stroked +4mm crank and the DOHC rods(-2mm compared to SOHC rods) you would get 67mm stroke...
I'm really surprised no one has done a stroker crank using DOHC rods.
(or I just haven't heard of it anyways... who knows it may have been done already)
That gives 783cc with 61mm pistons, and with a 836 kit, you get 889cc!!
Mabey someone ought to see if APE would stroke a CB750 crank?

l8r

Soos · « **Reply #67 on:** April 18, 2009, 06:09:09 AM »

Well......

Having checked what I have... these GPZ pistons MIGHT be useable in a 650...
But it would make one REALLY high compression motor.

I made the mistake of buying KZ750 piston rings, not realizing they would not work.

GPZ pistons went to not only a higher deck height and taller dome(from what I have read), but also to thinner rings...
top ring 1.0mm, 2nd ring 1.2mm on the GPZ.
The KZ pistons have 1.5mm top and second rings.

So I went ahead and bought a set of KZ750 pistons off E-bay today.
I'll post the differences between the 2 piston types for those interested.
I'm seriously thinking the GPZ pistons would work, but the availability of those rings are worse than the KZ750 rings are.
Kawasaki dealerships quoted me $40 a set for GPZ rings.
OUCH!

$40 for a set of pistons is better IMO.

After I get the KZ pistons, I will probably offer these GPZ pistons for the same deal I was offered, at cost of shipping.
Any takers?

l8r

MRieck · « **Reply #68 on:** April 18, 2009, 06:43:27 AM »

Quote from: Soos on April 08, 2009, 08:03:29 AM

With 5mm shorter rods, you would need a +10mm stroked crank to make it up.

It would pull the pistons down 5mm more and up 5mm more. So in a way it ends up 5mm, but you gotta thing in diameter not radius.
You would end up with a 73mm stroke.
So thats.....853cc's with 61mm pistons..... with a 836 kit(65mm pistons), you get 968.9cc!!!!!.

With a stroked +4mm crank and the DOHC rods(-2mm compared to SOHC rods) you would get 67mm stroke...
I'm really surprised no one has done a stroker crank using DOHC rods.
(or I just haven't heard of it anyways... who knows it may have been done already)
That gives 783cc with 61mm pistons, and with a 836 kit, you get 889cc!!
Mabey someone ought to see if APE would stroke a CB750 crank?

l8r

With a 10mm stroke I'd be thinking of rod angle. I don't see why APE couldn't or wouldn't stroke a CB crank.

Soos · « **Reply #69 on:** April 24, 2009, 05:16:36 PM »

IMO from what I have measured found about kawasaki GPZ and KZ pistons I believe the following:
1.) GPZ kawasaki 750 pistons are usable in a 650, but definitely will lead to a SERIOUSLY high CR.
2.) KZ pistons are (approx.) 2.25-2.5mm shorter than the GPZ 750 pistons.
3.) KZ pistons have 1.5mm rings in the top 2 ring grooves on the piston, GPZ pistons however have a 1.0mm top ring and a 1.2mm 2nd ring.
The ringsets are not compatible.
4.) KZ pistons run from '78(?'79) through '82(81?) or so.
5.) GPZ pistons AND Spectre pistons ('82-??) are the higher compression pistons.
5.) GPZ pistons rings are HARDER to get ahold of than the KZ750 rings.

I will definately be using the set of KZ750('80) pistons I have now.
I checked out the GPZ pistons, and besides the fact I had a KZ piston ring sets, the CR would end up crazy high.
Having checked out the KZ pistons, With a little material removal a 650 overbore can be kept near stock, or (guessing here) go to about 10:1 to 10.5:1 or so.

Definitely pleased with the purchase of my KZ pistons.

Hey terry, you still interested in trading those high compression 61mm pistons for these 66mm GPZ pistons?

l8r

Terry in Australia · « **Reply #70 on:** April 25, 2009, 04:39:50 PM »

Quote from: Soos on April 24, 2009, 05:16:36 PM

Hey terry, you still interested in trading those high compression 61mm pistons for these 66mm GPZ pistons?

l8r

Yeah mate, they're just sitting in a box doing nothing.

fang · « **Reply #71 on:** September 26, 2012, 09:27:36 AM »

I had a question about these pistons, so BUMP.

P.S. I am no longer looking for a piston, and I resolved the problem buy just buying a few additional sets of the Henry Abes as they popped up cheap or incomplete on eBay.

-Fang

Don R · « **Reply #72 on:** September 26, 2012, 11:16:59 AM »

did you find rings yet?
http://www.sohc4.net/index.php/ringsforthehenryabe900ccpistonkitscb750/

fang · « **Reply #73 on:** September 26, 2012, 01:29:40 PM »

Yes. Thank you! Jerry and I did lots of talking about that stuff several years ago.... He did all the leg work, and I bought a set.

Alan F. · « **Reply #74 on:** November 13, 2020, 07:57:12 PM »

I'm not sure if this info will be useful but the SOHC Honda twin cylinder 400 and 450 connecting rods use the same bearings as the DOHC Honda fours 79-83 and have a center to center length just under 100mm.
The 400 little ends are 17mm and the 450's are 18mm.

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Author Topic: cb750 to 900cc -- I need one 67mm big bore Henry Abe piston (Read 19756 times)