Author Topic: Re: 650 overbore/550 engine hybrid underway...final stages (Read 69123 times)

paulages · « **on:** September 10, 2006, 11:24:15 pm »

okay, i thought i'd start a thread independent of the other one discussing this idea, since i now have both engines ready to disassemble, compare and begin modifying.

first off, i still need to acquire heavy duty studs, 65mm pistons (or possibly larger?), 550 and 650 gaskets, etc. any help with sources appreciated.

i will post pictures of both engines disassembled with measurements to help with questions many people have had concerning compatibility of parts. anyone with ideas/suggestions, and especially those who really know what they are doing ( $:-\$ ) please chime in...

scunny · « **Reply #1 on:** September 11, 2006, 12:31:10 am »

I don't know what I'm doing, but I await further posts on this subject with interest. the 650 is 59.8mm bore, what's the 64mm pistons from.... 750 ?

paulages · « **Reply #2 on:** September 11, 2006, 12:56:38 am »

here's the link brianj provided before.

http://www.sohc4.us/forums/index.php?action=dlattach;topic=12765.0;id=11111

written by thayes, but i don't know if he's around any more. would be a great help if so. he says 64mm pistons will result in a 718cc displacement. i haven't done the math myself. first order of business for me is to pull both engines apart and compare the innards.

bryanj · « **Reply #3 on:** September 11, 2006, 01:04:50 am »

Teds going one better than that now--HOW ABOUT 763----

Bol dor 900 shortened liners with the outside two move inwards by 1mm to keep the oil passages good, then i think he said 66mm Kawasaki pistons!!

GOD HELP THE GEARBOX!

scunny · « **Reply #4 on:** September 11, 2006, 01:32:36 am »

cheers for that link, that is an interesting post. might try that with engine number 2, first things first tho, get present project mobile.

paulages · « **Reply #5 on:** September 11, 2006, 09:55:18 am »

brianj: get him on this thread!

Ibsen · « **Reply #6 on:** September 11, 2006, 11:32:52 am »

Is there a reaon why that link doesn't work??

Pinhead · « **Reply #7 on:** September 11, 2006, 12:25:08 pm »

Quote from: bryanj on September 11, 2006, 01:04:50 am

Teds going one better than that now--HOW ABOUT 763----

Bol dor 900 shortened liners with the outside two move inwards by 1mm to keep the oil passages good, then i think he said 66mm Kawasaki pistons!!

GOD HELP THE GEARBOX!

Now we're talking! 763cc out of a 626cc?!? He needs to post here!!

bill440cars · « **Reply #8 on:** September 11, 2006, 01:14:09 pm »

paulages,

All I can supply you is encouragement while I watch with enthusiasm. I hope to do the same thing someday but,later. So, I'm hoping to gather all the info I can on the subject. It'd be cool to have sleeper bike like that. Carry on and I'll catch you later on, Bill

paulages · « **Reply #9 on:** September 11, 2006, 04:00:48 pm »

i do know how to google (

), but if anyone knows a good source for heavy duty studs, liners, and pistons let me know.

Pinhead · « **Reply #10 on:** September 11, 2006, 04:51:10 pm »

Wouldn't 750 liners work? If so, you could use a couple overbore sizes for the 750 ("836cc kit"). I could see oil galleries, etc. getting in the way. What would be the easiest way to find this stuff, other than tearing the engine down and ruining it?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #11 on:** September 11, 2006, 06:18:26 pm »

There should be a few 750 liners floating around and matching pistons. I will eventually have a set when I get my 900 kit installed hopefully later this year. If you could use these let me know.

Jerry

paulages · « **Reply #12 on:** September 11, 2006, 08:03:10 pm »

liners should be easy to come by (dohc's are supposed to work fine), and regular 750 pistons should be no problem...as a matter of fact, i have some junk ones laying around. i'm just not sure yet what i should use. aren't the 750 valves offset, and the 550/650 valves opposite of each other? i'd love to try an 836 kit, but i'm afraid that might be a bit too much for the drivetrain/frame. i'll find out how much clearances i have once i get the 650 torn apart. the 550 definitely doesn't seem to have too much room to spare...

Pinhead · « **Reply #13 on:** September 11, 2006, 09:44:32 pm »

This may have a bit of usefull information...

http://home.wi.rr.com/kgebauer/cb650mods.htm

bryanj · « **Reply #14 on:** September 12, 2006, 04:05:53 am »

I dont think Ted would mind if i reproduced his mail to me so here goes

G'day again Bryan.
It is a 550 gearbox that i am using and cases.What my mate has done,he has
fitted some shortened
Bol'dor liners (900cc) in a set of 650 barells.Now this is where it becomes
a little difficult! when he bored the cases out for the Bol'dor liners he
moved the 2 outside spigott holes in 1mm so there was no damage to the oil
supply to the head,and when he machined the barells he did the same.
So now 1 and 4 cylinders are offset towards the centre by 1mm.These will be
bored to 66mm and i have a set of Z750 Kwaka pistons 66mm and with the 650
crank should go well.Mayebe i should say a quick prayer to the god of
gearboxes.
Regards Ted

paulages · « **Reply #15 on:** September 12, 2006, 08:11:50 am »

maybe i'm picturing this wrong, but wouldn't moving the outside two cylnders inward affect the placement of the rods in relationship to the crankshaft?

ElCheapo · « **Reply #16 on:** September 12, 2006, 08:45:58 am »

Ok now you have my attention... I always thought of the 650 as the dirty red headed step child of Honda. But now, I can have some fun with all those parts sitting in my piles of 650 parts.

mlinder · « **Reply #17 on:** September 12, 2006, 09:28:44 am »

Quote from: paulages on September 12, 2006, 08:11:50 am

maybe i'm picturing this wrong, but wouldn't moving the outside two cylnders inward affect the placement of the rods in relationship to the crankshaft?

That would be my guess, too....

Pinhead · « **Reply #18 on:** September 12, 2006, 10:49:54 am »

I was thinking the same thing.

Tommy Neimeyer · « **Reply #19 on:** September 12, 2006, 10:54:34 am »

On the large bore 550 I've seen, the oil line from the bottom was plugged and a SS line was ran from the galley to the ends of the head.

Cheers, Tom

mlinder · « **Reply #20 on:** September 12, 2006, 11:25:20 am »

Quote from: TomN on September 12, 2006, 10:54:34 am

On the large bore 550 I've seen, the oil line from the bottom was plugged and a SS line was ran from the galley to the ends of the head.

Cheers, Tom

That's a nice, elegant solution.

paulages · « **Reply #21 on:** September 18, 2006, 11:42:50 am »

tom, do you know where those lines are being fed from?

BTW, i did the math, and wiseco 65mm pistons would result in a 740cc displacement. that's the route i'd like to try if i can sort out the logistics, i.e.: compatibility of the connecting rods, finding heavy duty studs and primary chain, etc...

Pinhead · « **Reply #22 on:** September 18, 2006, 11:50:20 am »

740cc displacement out of a 650 block? Now that'd be a sleeper!!

bryanj · « **Reply #23 on:** September 19, 2006, 09:38:07 am »

Heavy duty primary chain dont exixt as its a Hy-Vo type, As to the offset bore there should be no problem as there is more than 1mm play sideways between the rod small end and the pin boses in the piston, OK force will not be entirely straight but the pin should absorb this, and anyway we are talking aboout a "race" engine not a 100,000 mile reliable "street" one!

Tim. · « **Reply #24 on:** September 19, 2006, 10:06:25 am »

Quote from: TomN on September 12, 2006, 10:54:34 am

On the large bore 550 I've seen, the oil line from the bottom was plugged and a SS line was ran from the galley to the ends of the head.

Cheers, Tom

I'd love to see/read more about the bike in the picture - links to more info?

News:

Author Topic: Re: 650 overbore/550 engine hybrid underway...final stages (Read 69123 times)

Ibsen

ElCheapo