Topic: CB550 - CR29s is this the best it gets? Will CR26s be better street carbs?

[turboguzzi]

losing you a bit, what set of carbs can you get your hands on? stock 500/550 are keihin 22mm. with your state of tune i'd say they will be limiting all over and defeat your purpose. VM26s or a set 28s off a 750 are a nice compromise and above all have decent idle circuits (which CRs dont..)

[bwaller]

My wifes 592 runs with stock PD carbs. Mind you she doesn't ride it on the edge. It idles perfectly, makes 51rwhp and has a really fun power band.

These 22mm carbs are part of the restriction granted, but compared to the 29's I'll bet this one is far more streetable! If you can't stomach stockers CR26's are a better choice. For $40... try them, what have you got to lose?

[akabek]

My wifes 592 runs with stock PD carbs. Mind you she doesn't ride it on the edge. It idles perfectly, makes 51rwhp and has a really fun power band.

These 22mm carbs are part of the restriction granted, but compared to the 29's I'll bet this one is far more streetable! If you can't stomach stockers CR26's are a better choice. For $40... try them, what have you got to loose?

Aside from the big bore on your wife's bike which cam are you running and are you using pods? 

I will give the stock carb a try.  I can always revert back to the CRs is the stock ones don't work.

[bwaller]

I used the smaller Web in it, 58a I believe. On the intake side I kept only the stock plenum and use a single large oval K&N. I really only did minimal porting but also more than just a casting flash "clean-up".

Agreed if the stock carbs don't make life easier, you have a backup.

[Godffery]

These are set up ready to go and come with everything you need:
http://www.power-barn.com/servlet/the-1072/Keihin-CR26-Carburetor-Kit/Detail

[akabek]

These are set up ready to go and come with everything you need:
http://www.power-barn.com/servlet/the-1072/Keihin-CR26-Carburetor-Kit/Detail

I am familiar with that kit but the CR26s still seem to have a problem with idling.

[Retro Rocket]

These are set up ready to go and come with everything you need:
http://www.power-barn.com/servlet/the-1072/Keihin-CR26-Carburetor-Kit/Detail

I am familiar with that kit but the CR26s still seem to have a problem with idling.

They are a race carb...    Have you thought about a set of stock 750 carbs..?

[akabek]

These are set up ready to go and come with everything you need:
http://www.power-barn.com/servlet/the-1072/Keihin-CR26-Carburetor-Kit/Detail

I am familiar with that kit but the CR26s still seem to have a problem with idling.

They are a race carb...    Have you thought about a set of stock 750 carbs..?

Trust me I get it.  I will give some CB550 carbs a try.  Worst case I put the CR29s back on or get some CR26s

[Tintop]

These are set up ready to go and come with everything you need:
http://www.power-barn.com/servlet/the-1072/Keihin-CR26-Carburetor-Kit/Detail

I am familiar with that kit but the CR26s still seem to have a problem with idling.

They are a race carb...    Have you thought about a set of stock 750 carbs..?

akbek, I have a set of SOHC 750 late model carbs.  The ones with the accel pump.   They are in Kingston, and I can get them delivered to Toronto for for free (p/u @ my sister's).  They'll need going through, but are clean.  $100, let me know.

[akabek]

akbek, I have a set of SOHC 750 late model carbs.  The ones with the accel pump.   They are in Kingston, and I can get them delivered to Toronto for for free (p/u @ my sister's).  They'll need going through, but are clean.  $100, let me know.

Tintop, what is the venturi size of the 750 carbs?

[Tintop]

akbek, I have a set of SOHC 750 late model carbs.  The ones with the accel pump.   They are in Kingston, and I can get them delivered to Toronto for for free (p/u @ my sister's).  They'll need going through, but are clean.  $100, let me know.

Tintop, what is the venturi size of the 750 carbs?

28 if I remember correctly.  I'll take some pictures of them for you.

[akabek]

It is the middle of December and I am starting to think about bike tinkering again.  I bought a set of stock CB550 carbs but they are stuck and will require time and patience to free up and rebuild.  From the sounds of it they will not help my case.  Now I am thinking of trying the CR26s.  I use the factory stacks with filter socks so clearance is not an issue with the CR29s.  Power-Barn offers a complete bolt on kit but is there any benefit to using this kit if I am using the stacks with filters?  Are the CR26s the same physical size as the CR29s so spacing should not be a problem?  I was speaking to Sudco and their base line for CR26s with a CB550 is 26s- 105 mains, 65 slows, P151 needles in the 2nd, 2.0 slides and 220 main airs.  Anyone know what a P151 needle is, I am use to using " eg. YY8" needles?

I have my CR29s jetted so I can go WOT at any point it the motor does not bog down.  Should these carbs be jetted so the throttled is rolled on?  I was trying to mimic a modern day bike but I don't think CR carbs should be jetted this way.

[Godffery]

Hey akabek,
I did the R&D for the Power Barn CR26 Kit (Including 3 days of Dyno time) while I was building and tuning Café Overkill.
http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Cafe+Overkill/

Part of the problem with the set-ups you get direct form SUDCO (or any of their other dealers) is they don’t really make a proper Spigot to adapt smoothly to the CB500 / 550 intake manifolds. Among other things, there jet & needle settings are way off from where you will need to end up; the Kit from Power Barn http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/95/Keihin+CR26+Carburetor+Kit+for+1974-1978+Honda+CB550/ will come set much closer and will come with 2 extra sets of High & low speed jets for fine tuning. (Basically because it is imposable to predict the performance specs on every application).

BTW: the factory stacks with filter socks will be fine for track days but using something like that every day on the street will eventually tear up your motor; the socks don’t provide nearly fine enough particle filtration to keep evil grit out.

[akabek]

Is there anything special about the intakes in that package deal?  My intakes have the syncing ports and they are ported to match the head already.

[Godffery]

Yes, this kit uses the shorter 1977 / 78 model intake manifolds; the profile is also a bit different and utilizes the same late model intake rubber boots.

[Kemp]

Godffrey, do you have a dyno sheet published on your build. Were you working with a stock motor or modified when you designed your CR26 kit?

[Godffery]

I don't have a Dyno sheet; a friend was helping me (using his Dyno) and I never thought to bug him for a data sheet;  It was enough that he was willing to let me burn up 3 days on it.  = ]

The motor was stock bore & a Mild street cam form WebCam with a little porting just to clean up the casting and transition from intake to head.

[akabek]

Yes, this kit uses the shorter 1977 / 78 model intake manifolds; the profile is also a bit different and utilizes the same late model intake rubber boots.

Is the main benefit for these manifolds to get the pods to fit?

[Godffery]

That was one of the main concerns but the Spigots also have a better transition between the Carbs to the intake boots because they are tapered to match.

Another of the unexpected results was a firmer mount between the Carbs & manifold resulting in far less racking movement of the Carbs while running down the road.
When running no air box, there is no support to the back of the Carbs so they tend to sag down & bounce under their own weight.

[akabek]

Looks like the CR26s will be back in stock next week.

Godffery, how is the idle on Cafe Overkill?  I know CRs are race carbs but do you find you need to have a high idling RPM?

[Godffery]

It's a bit higher then stock (about 1500 idle) But the motor was also Cam'ed.
here is a link to a Vid of it running:
Honda CB 550 Cafe racer Start up " Cafe Overkill "

[Retro Rocket]

It's a bit higher then stock (about 1500 idle) here is a link to a Vid of it running:
Honda CB 550 Cafe racer Start up " Cafe Overkill "

Love that swingarm set up Godfrey....

[akabek]

It's a bit higher then stock (about 1500 idle) But the motor was also Cam'ed.

I am running a CB650 cam so it is a little more lift than stock but your idle is still better than I was dealing with.  I am going to order the Power Barn kit except I am going to keep the stacks and the ITG socks.  I am comfortable running the ITG filters for street purposes as the filter material is thick.  I am also going to swap out my Dyna S ignition for the Pamco ignition and coils to see if there is a a difference.  With some tuning experience now under my belt I will hopefully be riding more than tuning this summer.  At some point I plan to run the bike on a dyno to see what is going on.

[Godffery]

Sounds like you have a solid plain!

BTW; for anyone in the Midwest US.
I was invited to show "Cafe Overkill" at a local show, here's the skinny:

http://mamatriedshow.com/

Would be great to see some of you guys there!

[akabek]

http://mamatriedshow.com/

Great video, especially 2:25 of the video.......LMAO