What have I got??? 750?? 900??? or ???

Posted: Sat May 22, 2010 1:22 am

Hmmm. Got to doing some work on the 79 750 I bought for 500 bucks last weekend (Look what 500 buys you in Milwaukee link) and discovered this

So, what is this engine? A 750 with a 900 top end? What else could be lurking inside?
Any ideas or thoughts?

Vin number does not match the block number.below..not even close Vin #RC04-2007086

Posted: Sun May 23, 2010 1:22 pm

Interesting. Looks like nobody else knows what you have either. Definitely 900 cylinders, I don't know how to tell a 900 head or carbs from a 750. Someone should know the case numbers, I don't either. I see some gasket goop at some of the joints, looks like a motor question mark.

Posted: Sun May 23, 2010 3:13 pm

Looks like you have a 1981 CB900C engine ....... according to this (taken from here http://www.z1enterprises.com/bike-list-honda.aspx) >>>

1980 CB900C
- Frame: SC04-2000046
- Engine: SC04E-2000035 [more]
1981 CB900C
Japan:
- Frame: JH2SC040XBC100004
- Engine: SC04E-2100004
USA:
- Frame: 1HFSC0406BA100004
- Engine: SC04E-2100004 [more]

1981 CB900F
- Frame: JH2SC0101BM000011
- Engine: SC01E-2200950 [more]
1982 CB900C
- Frame: 1HFSC0409CA200101
- Engine: SC04E-2200001 [more]
1982 CB900F
- Frame: JH2SC0107CM100003
- Engine: SC01E-2300001 [more]

Posted: Sun May 23, 2010 10:03 pm

Petrat,
I do believe you have made the identification.
Thanks very much,
A 900 engine all around!!
Barry

Posted: Mon May 24, 2010 1:46 pm

petrat wrote:

Looks like you have a 1981 CB900C engine ....... according to this

How do ya like the shaft drive? Laughing

Posted: Mon May 24, 2010 2:35 pm

I don't think the 9C was a shafty, only the 1000

Posted: Mon May 24, 2010 3:57 pm

Nope. 900C was a shaftie. It had the two-speed transfer case to get the drive over to the right side of the bike.

Posted: Mon May 24, 2010 4:39 pm

Maybe someone did a shaft to chain conversion on it?

Posted: Mon May 24, 2010 4:52 pm

Can you post some pics of the output shaft?

Posted: Tue May 25, 2010 11:25 pm

headless wrote:

Can you post some pics of the output shaft?

Only in CTDY.

Smile

Posted: Fri May 28, 2010 3:44 am

WisconsinF wrote:

Maybe someone did a shaft to chain conversion on it?

not likely. unless someone in this engine's past was a frustrated machinist with LOTS of time. that is a lot more work than you might think.

Posted: Fri May 28, 2010 6:24 am

rtabish wrote:

WisconsinF wrote:

Maybe someone did a shaft to chain conversion on it?

not likely. unless someone in this engine's past was a frustrated machinist with LOTS of time. that is a lot more work than you might think.

I thought it was a matter of swapping the output shaft?

Please show more pictures of the front sprocket area.

Posted: Fri May 28, 2010 8:31 am

Probably did the conversion. I don't recommend it, the cases have different strengthening bosses in them for the different loads they need to manage. But there is plenty of metal on the shaft drive output shaft to machine a sprocket holder.

Might just work OK for an other than full on balls out bike.

Posted: Fri May 28, 2010 9:16 am

i have never actually seen anyone do this conversion. finding a 900 F engine is usually a lot less work. interesting if it is one. Wink

Posted: Sun May 30, 2010 5:41 pm

Looks to be a shaft to chain conversion.
only 1 of the 4 cover bolts line up.

Posted: Sun May 30, 2010 6:40 pm

and everything lined up properly...chain, wheel, sprockets...? hmmmm.

Posted: Sun May 30, 2010 7:45 pm

That 461 on the case is the code for cb900c like 438 is the code for cb900f.

Posted: Sun May 30, 2010 11:48 pm

still_bluenoser wrote:

petrat wrote:

Looks like you have a 1981 CB900C engine ....... according to this

How do ya like the shaft drive? Laughing

Who likes the shaft drive now huh?! Razz