Topic: CB550 Cafe build - 1st bike build, but not 1st build

[Tintop]

Dang that is shaping up really nice Tin..

.: Scott :.

Thanks Scott.  Front end goes back on Saturday for the last time.  Then I can fit the pipes.

Tank and seat maybe ready late next week.  Getting closer to that sound video you want.

[Syscrush]

The PD's are not CV carbs, just the 'emission' version of the previous mechanical slide carbs.  The carbs I'm familiar with that use vaccum to lift the slides (needles), all take their 'signal' from the intake maifold side.  Can't see how it would work from the air box side.  You won't get a pressure drop in the air box (vaccum) until the slide moves, and you need the pressure drop to make that happen.   However on the manifold side, as soon as you open the butterflys there is an intake pressure change that starts the slide lifting (SU's).  With a CV carb it is the pressure difference between ambient (one side of diaphram), and manifold pressure drop on the other that lifts the slide (Zenith Stromberg).  Can't see that bike CV's operate any different, but I stand to be corrected by the forums knowledge base.

I'm sorry, I thought that the stock carbs are CV's, aren't they?

And even if the vacuum signal for lifting the slides comes from the manifold side rather than the airbox side, I don't think that there's any question that removing the airbox will have an effect on the vacuum signal.

My old Katana 600 with CV carbs would barely even idle with the stock carbs when the airbox was off, it was almost impossible to even start it.  The intake & jet kits for that bike all kept the airbox, and I've seen a lot of posts on here about the difficulty of tuning the 550's stock carbs with pods, so I assumed that there was something going on with CV carbs that's sorted out by going to roundslides.

[Tintop]

The PD's are not CV carbs, just the 'emission' version of the previous mechanical slide carbs.  The carbs I'm familiar with that use vaccum to lift the slides (needles), all take their 'signal' from the intake maifold side.  Can't see how it would work from the air box side.  You won't get a pressure drop in the air box (vaccum) until the slide moves, and you need the pressure drop to make that happen.   However on the manifold side, as soon as you open the butterflys there is an intake pressure change that starts the slide lifting (SU's).  With a CV carb it is the pressure difference between ambient (one side of diaphram), and manifold pressure drop on the other that lifts the slide (Zenith Stromberg).  Can't see that bike CV's operate any different, but I stand to be corrected by the forums knowledge base.

I'm sorry, I thought that the stock carbs are CV's, aren't they?

And even if the vacuum signal for lifting the slides comes from the manifold side rather than the airbox side, I don't think that there's any question that removing the airbox will have an effect on the vacuum signal.

My old Katana 600 with CV carbs would barely even idle with the stock carbs when the airbox was off, it was almost impossible to even start it.  The intake & jet kits for that bike all kept the airbox, and I've seen a lot of posts on here about the difficulty of tuning the 550's stock carbs with pods, so I assumed that there was something going on with CV carbs that's sorted out by going to roundslides.

Thanks for the thoughtful reply Syscrush.

I think the 650 was the 1st to get CV carbs (& 79 750?).  You are right, there definitely appears to be a problem when you remove the air box on the 550.  However I don't think it is the loss of the air box, but of the rubber 'stacks' that join it to the carbs that is the root cause.  That is the reason I am being so finicky about refitting stacks.  To my mind just adding Pods makes the situation worse.  They do nothing to replace the lost low engine speed intake air velocity that the stock 'stacks' provide.  To me this is were the jetting problems become intertwined.  You now need to rejet for the less restricted air flow, but also deal with a low speed flat spot caused by low intake air velocity, causing poor fuel atomization.  Re-jetting will fix the 1st issue, not the 2nd.

The other thing to keep in mind is that, compared to the 750, the 550 has long, double bend, intake runners.  These also contribute to poor low speed throttle response.  I keep looking at those, and wondering what it would take to shorten them, and then re-space the carbs to fit.

[traveler]

The easy fix is:

Keihin CR 29 Carburetors.

~Joe

[Tintop]

The easy fix is:

Keihin CR 29 Carburetors.

~Joe

Joe does this build look like I choose to take the 'easy' path?

I've known for quite awhile that going with PD's was fraught with problems.  I have been through the FAQ's, and followed yours and other 500/550 threads .  Thing is carbs are my gig, and I enjoy the challenge, and would rather solve the problems.   If they don't to work to my satisfaction in the end, I'm more likely to look to an 'out of the box' solution. Like I did with my remote oil filter.  That's the way I am.   It's because CR's are an 'easy fix', that they are down the 'solution list'.

[Flying J]

Im think of building my own air box that uses a large flat K&N filter but retains the stock rubber stacks.

[Tintop]

Im think of building my own air box that uses a large flat K&N filter but retains the stock rubber stacks.

That's a direction I discussed with Hondaman.  I was looking at the small flat filters they use in cars now.  Basic idea was to make an inverted 'V' (alloy or glas) with the filter under the seat front / tank back area.  The stacks would be at the bottom of the 'V'.  Planned on a radius at the bottom to 'feed' the stacks.  Check out - ITG @ http://www.itgairfilters.com/, and Piper @ http://www.pipercross.net/competition/index.asp.  Both offer ones that are small enough to fit nicely.

My problem is that I didn't include an air box in my original 'vision' , so space is now an issue.   It's why I've decided to concentrate on getting the bike up and running 1st.  Let me/us know how you make out.  Maybe an alternative air box design that uses the stock stacks, and a flat filter, is something Frankenbike might take on.

[bwaller]

Tintop I used the PD's on wifeys 592 with the stock plenum & a single large K&N (twice the surface area compared to stock). It accelerates hard, but runs out of air at a measured 115mph. Stock 22mm just isn't big enough for full potential of the larger engine, but there won't be any flat spots, I think you'll have fun.  

Anyway the stock plenum is tiny and the airbox is smaller, but space is limited and I couldn't think of a better solution while maintaining all the other stock gizmos.

A larger box would be a cool solution for certain apps.

[Flying J]

  Maybe an alternative air box design that uses the stock stacks, and a flat filter, is something Frankenbike might take on.

Now thats an idea!

[Tintop]

A larger box would be a cool solution for certain apps.

Hey bwaller, how was Indy?

It would be nice to have a box that worked with the 'open triangle' look, and stock stacks.  Would solve a lot of carb issues that people face when they go that way.

Seems ffjmoore also likes the idea, so will put some serious thought into a design.  As you mentioned it would have to flow more than the stock setup (with K&N) to be useful to those doing a displacement increase.  ITG had one that was about 8x5, which would fit cross ways between the upper frame rails.

[bwaller]

The GP weekend was great as usual, the MotoGP race itself a bit of a yawner.

A horrible loss of one young rider hangs a dark cloud over the event, but no-one ever said there wasn't risk.

[Raef]

The guys on the 600's were really going after it, you could tell they were riding at the limit many were unable to keep their bikes under them.

[bwaller]

The guys on the 600's were really going after it, you could tell they were riding at the limit many were unable to keep their bikes under them.

Indeed, with forty odd riders things get nuts fast. I was following Roger Lee & the Schwantz/Erion deal all weekend but Jason DiSalvo made an even better showing finishing 9th after qualifying 27th.

I met him in a restaurant later Sunday evening and both he and Al Ludington were pretty happy to beat the American Honda contingent.   Jason's a real nice guy.

Sorry Tintop.....back to regular programing.

[Tintop]

It's OK I enjoyed the commercial break.  Does sound like a good time was had by all though.

Now back to the build.

Got down to the shop today with a box of parts.  1st up was installing the front end, with tkat's 'made to measure' fork brace.  I wanted the triangulation, he wasn't sure; I think it came out great.   Everything slipped together beautifully, and the flat wiper seals look, and fit great.  Also installed the 'other caliper'.  Took bwaller's advice and had the pivot pin machined.  Worked great, caliper and pads lined up perfectly.





Next up was the remote oil filter system.  Finally I had all the pieces, plus hose parts in the same place.  1st to go on was the newly anodized adapter plate.  Didn't polish it because its in behind the pipes; but had a 'gloss' anodize put on the machined metal.  Came out as a dark satin finish.  After installing the NTP to AN fittings, I cut my hose lengths and attached the fittings.  Still need to run the hoses through a guide.  It will be attached using the right side upper mount bolt.  You'll also notice that I had a slight design change made to the filter mount.  Added some cutouts to lighten the look.  What do you think Terry?   Its off to be anodized.

Adapter plate mounted, with new hoses fitted.  Had to see what the pipes looked like, so I attached the headers.  The engine mounts are temp.  Have alloy ones, but need to P/U long bolts, as the current ones are a touch short.


Filter mount end with new hoses fitted.  When the guide / hose clamp is installed they will be together and down closer to points cover.


Last item on the list for today was the oil pressure gauge.  Made up the hose, but with only a fitting at the gauge end so I can easily try different routing's.  Not sure if I like it with the hose going between the other gauges, or below the dash panel.


It's a long weekend so Monday back to the shop, and wiring.  Tomorrow though will be spent re-posting the pictures that Photobucket has pulled because of 'bandwidth'.

[Flying J]

i really like those oil filter lines. Looks clean. here is a rough idea for my air filter. I think i would build mine from sheet metal or alloy.
Im not sold on this set up yet. I would like to hide the filter a little more but i do like the amount of surface area.

[bwaller]

It would be much better to have a larger plenum, the problem of course is fitting around the frame tubing.

Tintop you could get away with much smaller tubing to the gauge if you so desired.

[Tintop]

It would be much better to have a larger plenum, the problem of course is fitting around the frame tubing.

Tintop you could get away with much smaller tubing to the gauge if you so desired.

The frame tubes are the big headache , not as much room as the 750.  I was thinking of it laying horizontal & crossways, rather than vertical like ffjmoore pictured it.  Flush with the bottom of the frame rails.  The air would come in from the top of the plenum.  That way you can shape the bottom to try and equalize pressure across the stack mouths.  Volvos with SU's had a filter box that tapered from front to back, so the rear carb got the same air as the front one.  The frame tubes make it harder to get 'equal' air to 1 & 4.

Not sure how much smaller I can go bwaller.  Those are Aeroquip 04 fittings & hose.  The 90 on the gauge is female 1/8 NTP to male 04.  03 stuff is very limited, especially adapters.  I think the camera makes it look bigger.  Also the gauges are only 2 1/2", and the oil 1 1/2".  The more I see the picture the more I think I'll route it under the dash, and lower the gauge.  Haven't made a mount yet.

[Tintop]

i really like those oil filter lines. Looks clean. here is a rough idea for my air filter. I think i would build mine from sheet metal or alloy.
Im not sold on this set up yet. I would like to hide the filter a little more but i do like the amount of surface area.

Thanks for the compliment and picture ffjmoore.  As I posted in my reply to bwaller try - 'photoshopping' the filter to a horizontal position parallel to the top rails above the original air box position.  I think this would give a cleaner look.  Alloy would be my preference too.

With the filter in that position I was thinking you could hide ducts under the tank, and get some ram air.

[Flying J]

[Tintop]

Great work with the picture ffjmoore.   That is more like the shape I was thinking of.

The shape should probably be a wider at the top (closer to the size of the filter) for better flow.  Maybe push it forward so the front edge is in more under the back of the tank.  Because of the frame tubes, it seems like the bottom of the box will have to be shaped like the stock one.  I'm wondering if you could cut the stack attachment face off the stock box, and then incorporate that into an alloy box.  Maybe reuse the whole part that bulges around the tubes? 

Don't have a stock box to play with, sold my good one, and the 78 didn't have one.  Will try a borrow one to play with.  Looks like it's right direction though ffjmoore, for that 'open triangle' cafe look.

[Tintop]

ffjmoore - Took another look at your picture.  If you changed the backside shape to more of a smooth radius than a 'kinked L', and rounded the bottom I think that might be it.

[Flying J]

Also installed the 'other caliper'.  Took bwaller's advice and had the pivot pin machined.  Worked great, caliper and pads lined up perfectly.

So you machined down the pin instead of the fork like i did?  That sounds a lot easier.

[Tintop]

Also installed the 'other caliper'.  Took bwaller's advice and had the pivot pin machined.  Worked great, caliper and pads lined up perfectly.

So you machined down the pin instead of the fork like i did?  That sounds a lot easier.

No kidding!

[Tintop]

Don't have any pictures, but a quick explanation of how I aligned the 2nd caliper.  My calipers are reversed, but this should work either way.

Install just the caliper arm on the 'out of alignment' side.  Lightly tightened the pivot bolt, and only finger tightened the 2 upper mounting bolts.  At this point there is a gap beween the upper fork bosses and the upper mount.  Alternately tighten / loosen these bolts until the gap is equal at both ends of the top mount.  Now take a straight edge and place it against the disk; move the arm against the straight edge.  Adjust using the upper bolts until the caliper mounting face is true to the straight egde.  Double check that gap is still equal at both ends of the mount.  Measure gap / record.  Now measure the space between the arm at the pivot & the fork.  If the gap at the top is smaller than the space at the bottom, machine the top amount off one side of the pivot pin.  If it is greater (shouldn't be) you can only remove the smaller bottom amount less some for 'swing clearence'.  In my case the top amount was 2.4mm, and the bottom was 2.6mm+.  Removed the 2.4 and fitted everything back together.  Got perfect pad alignment, and the adjuster lock nut is on the outside.

Again, many thanks to bwaller for this method.

[Tintop]

Got a lot done on the wiring today.  Bike now has a charging system / a start system / and most of the HID components are now wired.  Ignition system is almost done.  Just need to finish wiring in the Hondaman ignition box to the coils.  Did a quick test of the tail light; boy is it bright.

From there it's the dreaded headlight bucket, and the control switches.

Have to replace the rear brake light switch.  Seems the working one I saved 2 years ago from the 77 is now seized.

Stopped by the paint shop to check out the progress.  Tanks looks great with the little dents gone.  Seems it had 4 () coats of paint.  All the body pieces are now in primer and sanded, paint goes on next week.  Just have to finalize the graphic's sizing and placement.

Looks like it should be ready for its 1st startup in about 2/3 weeks.