Identifying a 701

[alex_hockey]

Hey guys i got a quick question, im going to look at an engine tommorow, cant tell if its a 650-701 engine. It has riva ported cylinders and he the owner cannot find any 61x/62t markings. But i got him to measure the bore on the cylinder and it reads 81mm which is stock for a 701. I just want to know if a 650 cylinder can be bored out to a 701? The pistons have no markings on top to suggest an oversized piston. Just want to make sure im not getting a 650 engine before i make the drive.

 

[john zigler]

it should have numbers on the cases also. either 61X ( 701) or 6M6 ( 650).

you can also put 61X clys, on a 650 case, so make sure it is ALL 701.

if he cannot see the numbers on it, i would say it sounds "fishy" as they are easily read.

 

[jetx]

hey alex...who's motor are you looking at..maybe one of us knows the guy or ski??

I sold a Sn with a 701 w/riva ported cylinders to a guy in st.catherines...maybe it is the same guy?

 

[alex_hockey]

Not seeing the numbers, but not knowing where to look i guess would have been a better statement. How much is a riva ported cylinder worth anybody got any ideas? Im picking up the motor pretty cheap so even if it does have 6m6 cases its not a big deal, i will just swap them out. I just want to make sure 650 cylinder cannot be bored out to 81mm like a 701

 

[john zigler]

i think 79mm is the biggest you can take a 650, without re-sleeving.

 

[snowxr]

i think 79mm is the biggest you can take a 650, without re-sleeving.

I have a 650 cylinder (Riva ported, too) bored to 81.5mm

The cylinder would have the "6m6" or "61x" cast on a little spot between the cylinders on the intake side.

 

[Nuklear6]

As snowxr said 6m6 cylinders can be bored to atleast 81mm and use a stock 701 piston but are restricted on size and width of the exhaust port. if you try to widen the exhaust port like you would on a sport port for a 701 you would prob gring into the water jackets. plus the 6m6 transfers are a little different. If the marks on the cylinder are ground off chances are its a 6m6 that someone trying to pass off as a 61x. take notice how thin the steel sleeves are the 6m6 bored to 81mm would be pretty thin.