Topic: MotoGPWerks Pipe CB550 (Jetting and video)

[Stev-o]

Hey Joe......seems like slapping in the 650 would be the way to go.

Or, maybe it's time for you to step up to a 750!

You shut your whore mouth!  LOL I love my 550, and I don't want a 750. 
When you are used to the nimbleness of a 550, the 750 feels like wrangling a hog.

Yeah, the 650 engine seems like a good idea.  Might start working on it.

Not saying get rid of your 550, what you've been through with it, you never should.

Nothing wrong with havin a 550 AND a 750....

[hellraiserDLX]

I will say this...tews' bike revs really quick and makes good power up top. My 650 is stock, less the exhaust and intake. The gearing is set up in the stock 550 configuration so it is pretty tall. Im pretty sure it would do 130ish topped out and doesnt really get out of the whole like the 550 or like tews 605, but it has enough bottom end tourque to pull right on through it. Im super impressed by the stripped down version of my new ride with the added power. There is a bunch of little #$%* that goes along with the swap though. If you need more info hit me up. Too much to type on my phone and its in the wrong thread O.o

[joeyvans]

Sorry to bring this thread back from the dead, but I wanted to add my final settings to the list:

'76 CB550K
Un-oiled UNI foam replacement filter in stock airbox (unmodified, with all tubes connected as they should be)
MotoGP Werks 4-1
900 ft elevation
No known engine mods.  I say "no known" because I've never cracked the motor open to verify.

087a carbs
110 mains (100 is stock)
38 pilots (38 is stock)
Needle clip in 3rd position (middle) - (4th down is stock)
Air screws 1.33 turns out

With a stock airbox, it seems that most people end up at 105 mains and needle clip in the middle or stock position.  This did not work for me.  There was fairly considerable off-idle hesitation with the 105's and needle in middle or 4th positions.  Tried the 110's and got good deposits on the WOT chop... but still hesitation off idle with needle in 4th position.  Moved clip to 3rd position with the 110's and got nice 2/3 throttle plug deposits.  At this point, hesitation off idle was almost completely eliminated.  Some minor adjustments on the air screws has eliminated off-idle hesitation.  Smooth and solid acceleration all the way up through the throttle ranges now.

Went for an 85 mile ride (half of that on a windy interstate between 75 & 80 mph) and got 35 mpg.  I am completely happy with that MPG..... considering I never short shift.

Time to finally enjoy the ride!

Thank you to all previous posters for the information!  This thread gave me a decent starting point, but in the end.... EVERYTHING must be verified on your own bike.

[mrfish2]

'76 CB550K
Un-oiled UNI foam replacement filter in stock airbox (unmodified, with all tubes connected as they should be)
MotoGP Werks 4-1
900 ft elevation
No known engine mods.  I say "no known" because I've never cracked the motor open to verify.

087a carbs
110 mains (100 is stock)
38 pilots (38 is stock)
Needle clip in 3rd position (middle) - (4th down is stock)
Air screws 1.33 turns out

You've got the exact same setup as me, un-oiled UNI filter and all. My carb settings are all the same as well, except I've got 115 mains in right now and it does run a tad on the rich side, just haven't had the time to swap in the 110's and try them out.

[joeyvans]

You've got the exact same setup as me, un-oiled UNI filter and all. My carb settings are all the same as well, except I've got 115 mains in right now and it does run a tad on the rich side, just haven't had the time to swap in the 110's and try them out.

I had 115's ready to go too, but settled on the 110's. Looks like you and I are at the same elevation too. However, I thought I've read that unless you encounter large weather changes or altitude swings over 2000 ft, you should be fine. I bet you'll be good with 110's. I was getting quite a bit of popping on decel with 1.5 turns out on the air screws, so brought them in a little and have very little intermittent popping now... still with no hesitation off idle.

Hope you get to enjoy your brown bomber this summer as much as I have enjoyed mine. Cheers!



Sent from my iPhone using Tapatalk

[riverfever]

Hmmmmm. Glad you are in a happy place Kyle. I just put 105 mains in my carbs and am very anxious to see how things go. I'm basically starting from scratch with the cc increase and all the head work but I'd rather be there than where I was last year fouling out plugs every other day. Always good times tuning this old bike wayyyyyyy up here. 

[joeyvans]

Hmmmmm. Glad you are in a happy place Kyle. I just put 105 mains in my carbs and am very anxious to see how things go. I'm basically starting from scratch with the cc increase and all the head work but I'd rather be there than where I was last year fouling out plugs every other day. Always good times tuning this old bike wayyyyyyy up here. 

... speaking of crazy weather and elevation change! Here's to hoping you are close with the 105's and especially the needles. I got pretty good at changing the needles with the carbs still on the bike.

Good luck to you, Chris! Can't wait to hear that beast fire up!


Sent from my iPhone using Tapatalk

[SF]

Bump

[Winters]

Thought I’d post here instead of starting a new thread.

069A carbs. Swapped to K needles. Stock Airbox, Emgo filter, 650 cam.

110 Main Keyster
3rd Clip
38 Pilot
IMS @ 1.3 turns out from seated

Minor popping on decel. Runs great plugs show great color. Tried to get a wideband on it and it looked good on free idle but not while rolling. Shimmed needles and got a stumble at low throttle. Put back to third clip. Not sure if I want to try to go to 105s and shim the needle or go down to 4th clip or swap back to f needles since it runs good. Might have to do a dyno session one day to verify AFR.