Frankenstein Build

F

FolsomShredder

Location
NORCAL
Hey everyone Im looking to build up my first frankenstein motor starting with a 61x ported cylinder freshly honed. It came with pistons that Im not sure are in condition, I will post pics of them shortly. I have a whole 650 motor that I was going to just drop the 61x on to, buy an msd enhancer, and high comp head. I have done a lot of searches on these builds but im still not sure what I will need. From what I know everything will bolt up just the case and exhaust mani have to be bored? Please help im looking to do this as soon as I can get some solid advice:beerchug:
 
extreemthrottle

extreemthrottle

freeride junkie
Location
north palm beach
maybe im wrong, but i thought the 61x and the 650 cases were the same, only diff was the bore on the cylinders.

thought a frankenstein motor was 61x cases with 62t top end..
im sure someone will correct me if im wrong.
 
sjetrider

sjetrider

615 Freeriders are addicted to T1 madness.
Location
in the 615 (Nashville)
650 cases are (6M6) NOT (61X). Running a ported 701 cylender on those cases is a total waste of $$$ and time. I strongly suggest to spent the $75 on a set of 61X cases. The intake, carb and crank from the 6M6 will work fine in the 61X cases. I would replace seals too.
I do not believe the 701 cylender will just slide down on the 6M6 cases anyway, I think the cases have to be bored (but not positive of that).

So your gonna run the stock pipe?????
 
F

FolsomShredder

Location
NORCAL
Ya im thinking I might as well build a whole 61x motor If im pulling everything out anyways. Sjetrider I will be putting m coffman sizzler on the 701. So let me know if Im wrong but I will need these parts in addition to my cylinder; 61x case, 701 after market head, cranks, and exhaust mani. Again, Im not sure because this is my first motor build. From what iv read I think the stator, flywheel, bendix, and starter from my 650 will switch over no problem. I appreciate all the input guys.
 
kevbo

kevbo

Location
dfw
Don't worry about the 650 case. I have used the same ported 701 cyl on both 6m6 and 61x cases and could feel no difference. The same carb ran slightly richer in the 6m6 case. Your choice in pipe and prop are far more important.
 
skithis

skithis

X
Location
Belleville/ Coldwater, MI
kevbo said:
Don't worry about the 650 case. I have used the same ported 701 cyl on both 6m6 and 61x cases and could feel no difference. The same carb ran slightly richer in the 6m6 case. Your choice in pipe and prop are far more important.
Click to expand...

Most likely because the 6m6 cases don't flow as much air. I am mad right now because I just checked my cases after reading this thread and found the big "6M6" stamp on the bottom even though it has 61x cylinders. Will the 61x cases be stamped with 61x? I was under the assumption that 61x cases and 6M6 cases were 1 in the same.
 
chriselmore_1

chriselmore_1

high on resin
Location
san jose ca
yes 61x will be stamped. 6m6 and 61x cases are different.61x reeds have, i think, 1 more reed pedal per side than the 6m6 (650).also, you will have to do a little grinding on the 6m6 cases to fit a 61x cylinder. their a was guy not to long ago selling 61x cases for 45 bucks or somthin not too long ago. do a search and find him.
 
kevbo

kevbo

Location
dfw
skithis said:
Most likely because the 6m6 cases don't flow as much air. I am mad right now because I just checked my cases after reading this thread and found the big "6M6" stamp on the bottom even though it has 61x cylinders. Will the 61x cases be stamped with 61x? I was under the assumption that 61x cases and 6M6 cases were 1 in the same.
Click to expand...

All 650-701-760 bottom case halves are stamped 6M6. The difference in actual reed area between 650 and 701 single carb is 10%. Dual carb 701-760s have 25% more reed area than a 650.
 
J

jdowell

What exactly is a 6m6 Frankenstein Build? i have a case from a 6m6 650 that has a welded reed cage from a kawasaki 750. I used this set up about 10 years ago, dont use it anymore but i remember that only a 6m6 cyl from a 650 will work not a 61X or 62T.
 
sjetrider

sjetrider

615 Freeriders are addicted to T1 madness.
Location
in the 615 (Nashville)
FolsomShredder said:
Ya im thinking I might as well build a whole 61x motor If im pulling everything out anyways. Sjetrider I will be putting m coffman sizzler on the 701. So let me know if Im wrong but I will need these parts in addition to my cylinder; 61x case, 701 after market head, cranks, and exhaust mani. Again, Im not sure because this is my first motor build. From what iv read I think the stator, flywheel, bendix, and starter from my 650 will switch over no problem. I appreciate all the input guys.
Click to expand...

you are correct. If the Cofmans pipe is from a 650 I would grind/ port out the exhaust manifold where it meets the cylender to match your new gasket before installing. All other parts will work, you will need a 61X intake mnfld but the 44mm carb from the 650 will work. Dont pay more that $90 for the cases and manifold and reeds, they are cheep. If your looking to go cheap you can always use a milled stock head instead of investing in a billet head. If you stay on pump gas 185psi or under on compresion then there is no need for the aftermarket billet head unless you tear your motor down for inspection alot as it does eliminate a $20 gasket. Your elects will bolt right up as well as starter and bendix, bed plates and motor mounts. YOU WILL BE PLEASE WITH THE GAINS. jUST LOOK AT THE PORTS ON THE 61X VRS THE 6M6.
 
F

FolsomShredder

Location
NORCAL
Awesome thanks for everyones help, I keep hearing the debate whether it is a waste with a ported cylinder to use a 6m6 but I might use my 6m6 case and use the money for something I really need. I have never taken apart a yami 650 so I have no idea how much dremeling I will have to do one the case. Parts checklist for frankenstein; 61x intake mani, aftermarket head (or mill the stock one I have), msd enhancer, gasket kit? Im planing on dremeling my intake mani just so it is smooth and flows better. Again, thanks for all the help guys.
 
W

waxhead

wannabe backflipper
Location
gold coast
sjetrider said:
650 cases are (6M6) NOT (61X). Running a ported 701 cylender on those cases is a total waste of $$$ and time. I strongly suggest to spent the $75 on a set of 61X cases. The intake, carb and crank from the 6M6 will work fine in the 61X cases. I would replace seals too.
I do not believe the 701 cylender will just slide down on the 6M6 cases anyway, I think the cases have to be bored (but not positive of that).

So your gonna run the stock pipe?????
Click to expand...
You will need a different intake
the carb will work the intake is different
 
F

FolsomShredder

Location
NORCAL
So I have reeds, cages, intake mani, 61x case and triton head on the way! Looking for modded cdi or msd enhancer and gasket kit. Thinking I will need to rejet my sbn44 with the new powerplant.
 
ryan

ryan

Location
baldwin ny
the 6m6 exhaust manifold will not work on a 701 cylinder. match up the gasket and you will see what i am talking about. it will leak water into the exhaust port. it may work for a few rides. trust me it will fail.
 
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