Author Topic: K8 motor in a K1 frame (Read 3470 times)

Industrial Cafe · « **on:** March 15, 2009, 09:51:58 AM »

so,
I'm getting a K8 motor from byrdmancafe on Monday or Tuesday.
I'm starting the thread now, so I don't forget.
I put a DOHC swing arm on and it's 2.5 inches longer.
http://forums.sohc4.net/index.php?topic=46599.msg491591#msg491591
I need the linkage and a drum lever (broke it) for the back brake off an 80's bike, and a 116 link chain.

I think that's about it.
gotta go, scooby doo's on.

mrbreeze · « **Reply #1 on:** March 15, 2009, 10:21:24 AM »

Scooby Doo?

?..............WTF?

I dunno......is the swingarm and wheel all you need to line up with that motor? People here should know.Now go get some Scooby snacks and get yer a$$ in front of that TV!!!!!

Industrial Cafe · « **Reply #2 on:** March 15, 2009, 10:35:48 AM »

the swingarm was just cause I wanted a longer swing arm without those hideous seams for a 21'' wheel project I have lined up.
the chain lines up with the motor I have now, so it shouldn't be different, should it?
guess I'll find out.

GammaFlat · « **Reply #3 on:** March 15, 2009, 11:30:35 AM »

You're probably aware, but the K8 engine "wants" a 630 chain. The sprockets that fit on that engine (at least most available ones) are 630. Pre-77 are 530 (from the factory). Here's a thread with pictures that clear up what's going on: http://forums.sohc4.net/index.php?topic=37174.msg384249#msg384249

Industrial Cafe · « **Reply #4 on:** March 15, 2009, 12:52:06 PM »

great, thanks!

Industrial Cafe · « **Reply #5 on:** March 15, 2009, 02:13:07 PM »

that thread is kinda the opposite of what I'm doing, but I get the picture.
I have 2 different cb750 front sprockets here, one that is flat and one with a dish in it.
I'll fiddle around with that issue when the motor gets here.

mrbreeze · « **Reply #6 on:** March 15, 2009, 02:23:32 PM »

Yeah....the 77-78's run the 630 chain and won't just line up with the older motor.CycleX sell the offset sprocket.I haven't done this yet but am aware of it. Should be lots of folks here that can tell ya the whole story.

Industrial Cafe · « **Reply #7 on:** March 15, 2009, 02:40:14 PM »

Yeah, I've seen that, I was thinkin' about that too.

Industrial Cafe · « **Reply #8 on:** March 15, 2009, 02:45:09 PM »

if I put that kit on, wouldn't that make both sprockets out of line still?
or would i need the drive sprocket only. $:-\$

Patrick · « **Reply #9 on:** March 15, 2009, 02:51:37 PM »

The rear sprocket carrier on the later (77-78) bikes is taller than the earlier carrier. I think you might need the carrier from a later bike to get the chain to line up. I did the reverse, K2 750 in an F3 frame, and got the chain to align with the K2 carrier.

Patrick

Industrial Cafe · « **Reply #10 on:** March 15, 2009, 03:00:20 PM »

couldn't i just shave the end off of the carrier?

mrbreeze · « **Reply #11 on:** March 15, 2009, 03:08:57 PM »

One thing I heard was putting a kit on the newer motor that takes the chain down to a 530. Maybe thats what I was thinking about with the offset sprocket.The cool thing there is you get plenty of clearence to run an O ring chain.

Industrial Cafe · « **Reply #12 on:** March 15, 2009, 03:23:21 PM »

all will be unveiled when i get the motor in a day or two!
I'm running an x-ring chain now.
it's in good shape, 100 links if anyone wants it. pm me

Patrick · « **Reply #13 on:** March 15, 2009, 03:24:46 PM »

I don't remember the exact difference in height between the carriers, but I know it would entail a bit more than "shaving" to get them equal. Anyway, with the later motor I think you are going to need the taller carrier. Shaving is not on option.

Industrial Cafe · « **Reply #14 on:** March 15, 2009, 03:36:12 PM »

thanks for the help,

Quote from: Industrial Cafe on March 15, 2009, 03:23:21 PM

all will be unveiled when i get the motor in a day or two!

and I'll post pics 'O' plenty.

moham · « **Reply #15 on:** March 15, 2009, 05:19:33 PM »

I can't speak to the offset issue to fit a later swinger, but you can cartainly fit 18/48 sprockets to a 78 to accomodate a 530 oring chain. There is a write up in the faqs dealing with this exact issue, complete with part nos. etc...

Industrial Cafe · « **Reply #16 on:** March 15, 2009, 05:39:40 PM »

the dual cam swing arm has been "done" so everything lines up just as stock, except for the 2.5 inches of stretch.

moham · « **Reply #17 on:** March 15, 2009, 06:45:39 PM »

Here's the 530 conversion faq I referred to...

http://forums.sohc4.net/index.php?topic=372.0

Industrial Cafe · « **Reply #18 on:** March 17, 2009, 11:16:57 AM »

the motor got here around noon today, dirty dirty dirty.

here's the sprockets I have.

and look at this

I put the thin one on the shaft, and some of it sticks out.
I don't know what this means until i get the motor in the bike though.

Industrial Cafe · « **Reply #19 on:** March 17, 2009, 11:27:35 AM »

I cleaned it up, but it looks like I'll need to spray it down with some aircraft paint remover.

look at the teeth on these gears, straight and tapered.

Industrial Cafe · « **Reply #20 on:** March 17, 2009, 12:52:21 PM »

ok, so the k8 motor has 0.360 inches from the mount on the case.
K8

and the k1 has 0.400 inches from the mount on the case.
K1

hmm... thats .040 inch further out on the k1.

if you look at this picture you can see that the sprocket on the k1 sits back 0.250 inch.
K1

0.400 on the K1
-0.360 on the K8
0.040 out on the K1

0.040 K1 shaft
-0.250 sprocket inset on the K1 shaft
0.210

the K1 sprocket sticks out 0.100 inch on the K8 shaft.

after all that B.S. it looks like there isn't going to be a line up problem.
we'll see when i get it in the frame.

SOHC4 Cafe Racer Fan · « **Reply #21 on:** March 17, 2009, 01:04:04 PM »

With the DOHC's longer swingarm, does that translate to a lower rear ride height or some adjustment to the rear shocks?

Industrial Cafe · « **Reply #22 on:** March 17, 2009, 01:49:18 PM »

Yeah its lower in the back by a little over an inch with the DOHC swing arm.
I have CB1100f shocks, which are about 15 inches eye to eye, so they're too long to begin with.
I tightened the shocks all the way up until I get some mounts welded to the swingarm.
It seems to be around stock height now.
we'll see when the motor is back in, it might drop to the ground.

mrbreeze · « **Reply #23 on:** March 17, 2009, 11:50:28 PM »

I wouldn't sweat it.................like you say....once the motor is installed...you will figure out what will be needed to make it work.Happy buildin' dude!!!!....It will work!!!!

Industrial Cafe · « **Reply #24 on:** March 18, 2009, 10:04:38 AM »

uncle sam took my entire tax return check.
so this thread is gonna hafta be on hold....

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Author Topic: K8 motor in a K1 frame (Read 3470 times)