Topic: 1977 CB750K Cafe Racer Project - $$ Can't Take It With You

[BRAD CHIEDUCH]

I've been working a lot lately and finally had a chance to come up for air and get back on my project.  Spent the day putting the transmission gear clusters back together, changed all the bearings and circ-clips, checked all the gear/shaft clearances and everything seems okay.  I got race cut gears and a refurbished chain wheel cush drive (including balance with clutch hub) from CycleX.  It ain't much but it's still progress.

[BRAD CHIEDUCH]

I am doing a GXSR front end conversion and here's a before and after pic of the forks after refurbishing.  Story goes, I picked up a set of 2006 GSXR 650 forks from a wrecker and gave them a complete overhaul.  The inner tubes checked out to be straight but the gold outer tubes were beat up pretty bad so I scoured the country and found a pair of new outer tubes from a 750 (black).  The lower fork legs also had some cosmetic damage so I bead blasted them and sprayed them with some VHT caliper paint and baked them in the oven to cure.  Changed all the o-rings, seals, and installed inner guide bushings - good as new!

[BRAD CHIEDUCH]

Today I put the crank into the case to check main bearing clearances for the final time.  The crank was previously lightened and balanced by APE and connecting rods are super-rods from CycleX.  I couldn't pry my wallet open to spring for Carillo rods but this a street application and not an all out race bike - at least this was what my inner voice of sanity was telling me.  Previously, I checked the main bearing clearances with the original bearing sizes but found I had to go one size tighter on all the bearings with exception to the main bearing closest to the alternator in which case I had to go two sizes smaller (from green to black).  Now all clearances check out on the plus side of 0.0015" and less than 0.002".  It's tough to interpolate the exact clearance but I am closer to 0.0015" than I am to 0.002".  So I think I have it nailed down.  I will torque the main studs incrementally will turning the crank to make sure there's no tight spots.

[SOHC4 Cafe Racer Fan]

That's a nice crank/rod combo.  You should be just fine (without Carrillos) for aggressive street riding - it's not a race bike.

[754]

You asked about Ceriani  if you are talking 35mm GP style, it's a chore to mount big calipers. Unless you go to wider trees  iv you want more modern the bigger Cerianis may be a better choice.
 I like that self centering vise, are you using that ?

[slikwilli420]

That's a nice crank/rod combo.  You should be just fine (without Carrillos) for aggressive street riding - it's not a race bike.

Where does the thought that the Cycle X rods aren't up to race bike standards? The Cycle X AHRMA race bike used these rods and made a load of power and was pushed very hard. I'm using them in my race bike and have no reason to believe they wont be up to the challenge.

[SOHC4 Cafe Racer Fan]

That's a nice crank/rod combo.  You should be just fine (without Carrillos) for aggressive street riding - it's not a race bike.

Where does the thought that the Cycle X rods aren't up to race bike standards? The Cycle X AHRMA race bike used these rods and made a load of power and was pushed very hard. I'm using them in my race bike and have no reason to believe they wont be up to the challenge.

slik,

I think my post was either unclear or just plain stupid.  I don't think that Super Rods are not up to the task of racing. What I meant to convey is that they are plenty robust enough for aggressive street riding and that (perish the thought) Carrillos were not necessary for that task.  I think that the APE, Super Rods and Carrillos are all great parts and a huge upgrade from 40 year old stock rods.

[brandEn]

This build is off to a great start. I'll be tagging along for sure.

[BRAD CHIEDUCH]

You asked about Ceriani  if you are talking 35mm GP style, it's a chore to mount big calipers. Unless you go to wider trees  iv you want more modern the bigger Cerianis may be a better choice.
 I like that self centering vise, are you using that ?

Thanks for the information on the Ceriani forks but I'm committed to the GSXR front end conversion - something to keep in mind for the next project.  As for the vise, I use it regularly on my milling machine.  I think I got it at Busy Bee a few year back.  Self-centering vises are nice to have but for shade tree mechanics like me they can be pricey.

[BRAD CHIEDUCH]

That's a nice crank/rod combo.  You should be just fine (without Carrillos) for aggressive street riding - it's not a race bike.

Where does the thought that the Cycle X rods aren't up to race bike standards? The Cycle X AHRMA race bike used these rods and made a load of power and was pushed very hard. I'm using them in my race bike and have no reason to believe they wont be up to the challenge.

slik,

I think my post was either unclear or just plain stupid.  I don't think that Super Rods are not up to the task of racing. What I meant to convey is that they are plenty robust enough for aggressive street riding and that (perish the thought) Carrillos were not necessary for that task.  I think that the APE, Super Rods and Carrillos are all great parts and a huge upgrade from 40 year old stock rods.

I think we are all on the same page here.  I certainly never meant to imply that the Super Rods weren't up to the task for a race application but if one was looking to wring every pony out of an engine and have it rev quicker and higher then I think we would all agree that Carrillo rods would be favored.  However, I'm just a working stiff putting my knees in the breeze and all I compete with is the open road, so the cost/benefit of the Carrillo rods wasn't justified.

[BRAD CHIEDUCH]

I have to buy new chain and sprockets.  Sprocket ratio I'm going with is 17T/48T and 530 chain.  I like RK chains and am leaning towards a 530GXW chain.  Any suggestions or comments from everyone are greatly appreciated.

[BRAD CHIEDUCH]

I’d like to share this little problem with everyone and hopefully get some feedback.  Way back when I stripped the bike down I noticed that the upper shock mounts are not horizontal (angled upwards approximately 5 degrees).  As a result, this swings the bottom of the shock outwards away from the swingarm.  With reference to the attached pictures, I ran a straight edge along the lower mount on the swingarm and you can see how it lines up with the upper mount.  The issue IS NOT related to the custom swingarm as the dimensions are identical to the stock swingarm.  The shock mounts and frame are not bent and I am confident that Honda purposely angled the upper shock mounts to get the shocks in semi-alignment with the swingarm.  My concern is that if I leave things the way they are, the shock will not perform correctly because it will start to bind as the swingarm travels upward.  I could cut away the old upper shock mounts and modify to get the shock in alignment (perpendicular) to the swingarm - the boys at Cognito Moto have a clean aftermarket shock mount.  This problem is the same on both the left and right side of the bike.  Any suggestions here are greatly appreciated as always.

[slikwilli420]

My upper mounts are the same way. Not sure why buy don't notice any suspension issues. The shocks have an offset clevis so the apparent misalignment is really a non issue. Build is looking really good.

[BRAD CHIEDUCH]

My upper mounts are the same way. Not sure why buy don't notice any suspension issues. The shocks have an offset clevis so the apparent misalignment is really a non issue. Build is looking really good.

Thanks for the feedback Willie.  This gives me some piece of mind but I'll just have to fit the new shocks and see how things line up.  I might be concerned over nothing.

[BRAD CHIEDUCH]

Took a little break today and went for a ride on the big V-twin.  Trying to enjoy what few riding days are left in Edmonton.  Let's just say the scenery was spectacular.

[SOHC4 Cafe Racer Fan]

Let's just say the scenery was spectacular.

Yes, it was.

[BRAD CHIEDUCH]

So here is an interesting problem/question that I have encountered and very similar to what another forum member posted (http://forums.sohc4.net/index.php?topic=106600.25).  While stripping the engine down I found the final drive shaft sprocket gooped up with red Locktite and there was a 1.8mm shim washer behind the sprocket.  The shim washer does not show up on the Honda micro-fiche and I don't think it's supposed to be there.  If the shim washer is removed the sprocket is not tight on the  final drive shaft and slides left-to-right approximately 2mm.  Is the sprocket supposed to have the ability to float left/right on the final drive shaft??  It seems the PO didn't think so and added the shim washer and lathered things up with Locktite; he also torqued the mounting bolt excessively and dished the washer under the bolt inwards - so this will have to be replaced.  I  also question if the sprocket was mounted in the right direction; it was installed with the raised flange facing outwards.

All this being said, I am converting from a 630 chain to a 530 chain.  The original 630 sprocket is 10.7mm thick and the new JT 530 sprocket is 12.7mm thick.  So left to my own devices, I would eliminate the 1.8 mm shim washer (mentioned earlier) and simply bolt on the new 530 sprocket - since it is thicker by 2mm everything should be tight.  Someone tell me if this makes sense - I think it does.

[calj737]

I concur with your diagnosis and plan.

[SOHC4 Cafe Racer Fan]

It would appear that the PO by mounting the sprocket backwards, created the slop issue and the need for a shim.

[BRAD CHIEDUCH]

It would appear that the PO by mounting the sprocket backwards, created the slop issue and the need for a shim.

Actually, I think the PO found that the sprocket was loose without the shim washer which seems to be normal   Then the PO added the washer to tighten things up.  By reversing the sprocket and adding the shim washer the centerline of the sprocket remains unchanged.  It kind of all makes sense but it puzzles me why Honda would have designed the sprocket to float on the final drive shaft to begin with?  Bit of a head scratcher!

[slikwilli420]

It would appear that the PO by mounting the sprocket backwards, created the slop issue and the need for a shim.

Actually, I think the PO found that the sprocket was loose without the shim washer which seems to be normal   Then the PO added the washer to tighten things up.  By reversing the sprocket and adding the shim washer the centerline of the sprocket remains unchanged.  It kind of all makes sense but it puzzles me why Honda would have designed the sprocket to float on the countershaft to begin with?  Bit of a head scratcher!

Not sure why they made it float but it makes for a very forgiving system that is very secure and easy to switch sprockets on. Rather than a big nut on the end with a safety tab.

[BRAD CHIEDUCH]

Finally had some free time over the holidays to make some progress on getting the engine cases together.  It's taken awhile to get to this point but I've never been accused of rushing anything (except maybe my first marriage but that's another story) .  Everything seemed to go together without major issues which was a relief. Just a special thanks to guys like Hondaman and Mike Rieck for answering my many questions as I was putting things together and making sure I was getting everything right the first time.

Also, a plug for Hondaman's book, I really found it to be a wealth of information which can't be found in any of the Honda manuals.

To everyone else, thanks for your support and feedback over the year and I wish you all a happy and healthy New Year!! 

[JoeCooley]

That's one really nice engine. It's so clean! :drools:

Good luck with the build. It's gonna be super cool when it's all together.

[BRAD CHIEDUCH]

Thanks Joe.  The engine was vapor blasted and then numerous hours spent buffing with Scotchbrite pads to get it to what you see.  I wrestled with the thought of painting the engine but I like the satin finish and the nice thing is I can always buff out dings and scratches easily.

[Stev-o]

+1 motor looks great! 

I love vapor blasting, did it on my last Kawasaki engine project.
But I didnt buff it, the finish came back beautiful.

Was buffing it with scotchbrite necessary?