Topic: New guy-74 CB550FourKO

[surfrider74]

Jon here from So Cal-surfrider 74 because i surf  and ride a lot and my bike is a 74-I have a 2015 KTM 350 excf plated dual-sport and my wife has the Husky FE 350S. But i missed that feeling you only get from just cruising down PCH on a vintage bike.
Trolled for a while like most and found some great info so I'm jumping in.
Found bike on CL and bought it for 2k-i think its a screaming deal-it ran-had 20k miles-so about 500 a year seems reasonable-compression tested and went over it before i bought it. Pretty clean and almost completely original. Ill post pics later. Boss Maroon/black and non original seat-previous owner remounted key ignition between gauge cluster on bars-came with a really nice RC (Russ Collins-famous 70s drag bike guy that had his own pipe) 4 into 1 pipe-i hear these are relatively rare and it has such a nice throaty burble! I pulled the old packing-it was trashed-and about a pound of rust out of it.  VIN-Engine numbers all lined up-clean title. Pretty stoked with this bike for price.
Bought mainly to wrench on with my oldest son who is in USAF-eventually i will give it to him as he probably wants to go Cafe route and i will search for another as i am more original/vintage minded. He deploys soon so I'm replacing leaking seals and gaskets and overhauling carbs (stupid CA Ethanol garbage) and the usual things you do. We will discuss build over face time while he's in Kuwait and ill pretty much keep it like it is so we can get more serious about build when he returns.
Thanks for listening and looking forward to wrenching and discussing with all here...

[MD]

Welcome from snowy Minnesota.

-MD

[RAFster122s]

Welcome Jon, look forward to some photos or links out to them. Sounds like a nice bike.  If the pipes are solid you may wish to have them cleaned out and coated on the inside.
David

[surfrider74]

Thank you Sir!

[surfrider74]

Thanks im in the middle of a PC meltdown and on wifes Mac for this forum so no photos but ill get some uploaded soon-the RC pipe is super cool and was a bit of a bonus for a CL find. Has a great sound to it! Looks like the rust was pretty mild and pipe is solid, thanks for the suggestion though.
Tackling Clutch case gasket and kick start seal leaks next. Plus when i turn on the blinker the Horn goes off!
New tires coming for it and with recent new fork oil and new seals its riding nice.
Id like to think about a brighter headlight but not sure what that would entail....

[surfrider74]

Update-
I was the victim of the dreaded but apparently fairly well known blocked- gas -cap -vent -she -died -on -me -going -70 -down -PCH scenario!
Finally figured it out and i could have just drilled the vent hole out a bit more since it dosent go all the way through cap and that would have probably solved it but the original cap was pitted and a bit wonky so i ordered a NOS and its on its way.

Then i woke up one morning to a puddle of raw gas on the ground-checked the usual suspects-along the way i found my petcock was not completely turning off. I had completely rebuilt it except for a new pre-loaded crush washer behind the diaphragm and plate and no matter how bottomed out my two screws were she still dripped in the off position. I was going to shim the diaphragm out a few centimeters by adding a glob of 1184 behind the diaphragm where it mounts to the disc-effectively popping out a bit to allow more crush force on the diaphragm but i didnt like the now squishy feel of the petcock lever and decided to just buy an NOS one-problem solved no more drip.

Now i believe ive got a bad needle/seat in one of the carbs-possibly two. With the petcock leaking the needle and seat should seal and stop flow into the bowls-i believe its leaking past and filling up the bowls and into the drain-ive got wet tips on 2 of my float bowl drain hoses!. I am still a newb and the carbs are rather intimidating so i think i may need to buy 4 carb re-build kits, bribe my brother and have him come help me with those-probably only need to rebuild one or two but gonna do them all, it is a 42 year old machine and im pretty sure the carbs have only been cleaned as needed and never rebuilt. Besides i have a noticeable flat spot in the powerband around 4500 rpm and im thinking the carbs were never re-jetted when the previous owner slapped on this cool RC 4 into 1 pipe. Think i definitely need to upsize the main jets.

Well thats it for now-man this is a big forum!-thanks for reading and please feel free to offer any tips or suggestions!

[surfrider74]

waiting for new petcock and gas cap-decided first gear was a bit tall with the 17 tooth front so im going to install a 16 tooth and new chain.
I had a clutch case gasket leak and in the process of replacing that somehow the spring inside the case cover that adds tension to the clutch rocker arm slipped under the cam on the clutch arm-well that took a second to figure out but revealed itself when the clutch arm outside the case was just flopping around. I neglected to check it until about an hour of dry time with the new gasket.
So off came the clutch cover aaaaaaaaaannnnnnddd naturally i tore the new gasket !
Went back in the house after almost launching the case cover across the garage....
Came back and scraped everything clean and luckily had another gasket-AFTER i fixed the tension/spring problem i reattached everything and no leaks!
After this i will look into the possible bad needle and seat(s) in the carbs. It gives me an excuse also to upsize the main jet to deal with the flat spot i mentioned.

[surfrider74]

well turns out the original front 17 tooth sprocket is not completely flat and has two approximately 2mm mounds on each side and overall is 10mm thick, the 16 tooth i bought has no mounds and is 6mm thick. Ya think they could have told me that after i went through 60 amazon pages to find a supposedly OEM 16 tooth sprocket and the one i bought showed the mounds...

Ok so off to the hardware store to get two decent 2mm washers and shim it into the same place on the spline it was originally to make sure everything lines up. Finding rear washer for behind sprocket no big deal but could not find one for the front washer that had a small enough outside diameter to not get into the way of the two bolts that attach the locking plate to the sprocket.
If i had a real garage with a vice and a grinder i could have looked harder and at least found one close and then ground out two small little half moons to allow bolt passage...., but i dont so because i dont NEED to replace the sprocket i said hell with it and kept the original.

Installed new chain and got within one link on the first try. New chain looks good and now just waiting for the new petcock and gas cap to get her operational before my son shows up from Idaho to ride her over xmas holiday. He gets deployed soon and will be gone 6 months so i wanted to get her running so he could at least ride her a few times before he leaves. While hes gone i will keep her running and original and when he gets back and moves back to socal upon discharge from the Air Force we will start to plan what we want to do with her. Hes leaning more towards the hipster hack up and i like original. I did buy it for both of us to work on so we will probably end up somewhere in the middle... Hmmmmm... how do you make a bike that looks and functions well thats between vintage and hispter-hack?....  Time will tell....

[surfrider74]

well i installed the new petcock and gas cap and had my son in town and after installing both i fired her up and...........
she still runs terrible!
Started up but would not idle-same thing it was doing when i had the blocked gas cap vent issue.
Im beginning to think i may have a bad coil....
However i cant completely rule out carbs but a stuck needle and seat out of the blue dosent make any sense-it was running great from day 1.
Gonna give it a rest for a few days and test coils to make sure i dont have a bad coil-at some point i will need to go through all the carbs-clean-adjust and probably go up a main jet size. Pretty sure the last owner did not up the jet when he installed the 4 into 1 and when shes running she has a noticeable flat spot at about 4k.
I doubt these carbs have really ever been gone through in their over 20k mile lives so i may just rebuild and upjet soon.

[calj737]

I doubt its the coils, probably the plug caps if you are having spark issues. Measure each cap for their resistance value. Should all be less than 5k Ohms. If they're outside that range, replace them with new NGKs.

Have you tested the fuel level in your carbs? Use the Clear tube method. This may explain the leaking carb, the "flat" spot, and generally inconsistent performance. You should also consider fresh plugs and perform a WOT plug chop. Warm up the bike, install new plugs. Ride somewhere that you can safely hold the bike at 6,000 RPMs for about 1 mile. Pull the clutch, hit the KILL switch, and safely coast to the side of the road. Pull the plugs and shoot a picture of them. That will tell the most/best about the Main jets.

[Scott S]

 You should start a thread(s) in the main forum or Projects forum. Definitely get more views there.

[Stev-o]

I doubt its the coils, probably the plug caps if you are having spark issues. Measure each cap for their resistance value. Should all be less than 5k Ohms. If they're outside that range, replace them with new NGKs.

Replace em, they are about $6 ea.  And snip off approx 7mm of the plug wire before installing the new cap so you get a good connection.

[RAFster122s]

Welcome to the Forums and definitely start a thread in the Projects section...  maybe capture and paste the thread after the intro into your new thread...

David

[surfrider74]

wow go away for xmas vacation and i missed all the good stuff!
Thanks for all the hints and tips-im not very good at this and some of your replies echo some of the guys over at Caferacer.
They are a salty bunch but everyone pretty much knows more about this than me.

Good call on starting a new thread in Projects section-will do now that my introduction is over.
Man there is a ton of good info on this site-appreciate all your help!