BRAT build

one pic at a time
 

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Diagnosis help! A week ago while on the ride back from work I started to get a loss of power and some weird sounds upon acceleration after stopping at a stop sign. I cranked the gas, it jumped back to power and I kept driving home. Hoping it was just a one time thing ( little hic-up) , yeah right. So two days ago its starts doing it again, but wont hic-up back to normal power. In fact I had to keep it throtlled to 2000 rpms at stops just keep her going. Conked out on me 6 times on the way home. Sound is totally different. No pur, sounds like a fucking outboard motor all of a sudden. Carbs should be fine, did a full re-haul 8 months ago. Have driven it everyday since. Had some battery issues a couple months ago, but that's sorted and shouldn't be related. Pulled plugs just now and they where pretty bad, all black. Am changing the oil now. Any sugestions on where to go from here. Ideas on possible issues please
 
work9to5 said:
Diagnosis help! A week ago while on the ride back from work I started to get a loss of power and some weird sounds upon acceleration after stopping at a stop sign. I cranked the gas, it jumped back to power and I kept driving home. Hoping it was just a one time thing ( little hic-up) , yeah right. So two days ago its starts doing it again, but wont hic-up back to normal power. In fact I had to keep it throtlled to 2000 rpms at stops just keep her going. Conked out on me 6 times on the way home. Sound is totally different. No pur, sounds like a fucking outboard motor all of a sudden. Carbs should be fine, did a full re-haul 8 months ago. Have driven it everyday since. Had some battery issues a couple months ago, but that's sorted and shouldn't be related. Pulled plugs just now and they where pretty bad, all black. Am changing the oil now. Any sugestions on where to go from here. Ideas on possible issues please

Black with Oil or Sooty from unburned fuel? Guessing Fuel Fouled may be your running issue. Didn't see a rejet or Vacuum Gauge treatment in you previous posts to know if the Pods, exhaust and tune are the problem. Pic of what the plugs look like may help some of the wizards around here.
 
Oil seemed fine. I had changed it last 2 months a ago. Was dark but nothing worrying about it. I rejetted the carbs during the rebuild, had to when i put on the new exhaust. (should be ok i ajusted according to manufacture's recomendation). pic of plugs
 

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oh and if i pull the choke, the engine dies as well (keep in mind i'm throttling the whole time it's running).
 
Too rich. Need to back off the fuel. Either the pods are too restrictive or you missed on the jetting. Pulling the choke just blocks off air and makes it even richer. You are getting too much fuel either way.
 
Nothing has changed though. Ive been driving it like this for 8 months (with new jetting/pods/4into1 pipes). Taking apart carbs today i guess
 
bump!!!!

bike problem- need advice!!!!


symptoms-
problem started where i could drive it out- has worsen'd to where bike will not drive up any incline
loss of power, cant get it above 10mph
sound has changed drastically- still even and balanced but tone and pitch are different
have to keep it rev'd to 2000 rpm even while braked at a stop or in neutral
if i dont give it gas it shuts off
pulled plugs- they where all black
changed oil- nothing out of the ordinary
if i pull choke bike shuts off
all sparks are firing- all pipes getting hot
no problem with fuel getting to carbs, checked all lines
dont understand that this could be a carb problem- i rebuilt them 8 months ago

its a 78' honda 550 with 20,000 miles roughly
was running fine for the past 8 months before the clean-up/rebuild
 
work9to5 said:
bump!!!!

bike problem- need advice!!!!


symptoms-
problem started where i could drive it out- has worsen'd to where bike will not drive up any incline
loss of power, cant get it above 10mph
sound has changed drastically- still even and balanced but tone and pitch are different
have to keep it rev'd to 2000 rpm even while braked at a stop or in neutral
if i dont give it gas it shuts off
pulled plugs- they where all black
changed oil- nothing out of the ordinary
if i pull choke bike shuts off
all sparks are firing- all pipes getting hot
no problem with fuel getting to carbs, checked all lines
dont understand that this could be a carb problem- i rebuilt them 8 months ago

its a 78' honda 550 with 20,000 miles roughly
was running fine for the past 8 months before the clean-up/rebuild

Try a new set of plugs. If it runs fine then you know its an issue with either the plugs, heat range or fuel jetting. Your jetting may still be on the rich side and the longer you ride the more fouled the plugs get until they cannot be effective.

If you put new plugs in it and it still has no power then you can dig deeper into the issue.
 
work9to5, did you ever find your problem for this? I looked through your build again and didn't see any jet settings. It looks like you've gone through the carbs a couple of times since the problem has started and you may have changed something there. The black spark plugs if they aren't oil fouled seems to be a problem of being too rich, the PD46C carbs have an air mixture screw on the bottom of the carbs that you turn out to richen the mixture and turn in to lean (If I remember correctly.) If it was my bike, I'd start at the beginning, check compression, check valves, check carbs again.

good luck.

btw, i'm running pods and 4 to 1 exhaust on my 78 cb550k and here are my carb jetting settings.
Main jets: 100
slow jets: 42 (stock)
Needle setting: 3rd (stock)
float height: 14.5mm (stock)
Idle mixture screw: 2.5 turns out
 
Thanks steak. I ended up finding the problem. Engine needed a full rebuild. Whole top end was carbon and black. Needed a gasket change and valve job. I went full top to bottom, took me two months to do. Just finished two weeks ago. Bike is back on the road with no mayjor probs right now. My carb settings are a bit different than yours. My pipes are open ended four into ones. Bigger main, small differences on everything else. I'm about to start so major cosmetic changes soon (paint, gadgets, etc). When I finish that ill tie all my posts together so everyone can seen the beginning to "end".
 
those mirrors aren't that bad, they're just hanging the wrong way. If they are are up above the grips they should work much better. Like Napoleons..
 
Hey, so I've run into a new problem and would appreciate help diagnosing how far I have to go to repair it. I'm having trouble finding neutral when not at speed or not rolling. I can find it easy when bike is off. I've adjusted my cable top and bottom and it gets better but a day later i'm in the same spot. This has been going on awhile and I've been dealing with it fine. Just by holding N lever at stop, but gets annoying. When the bike is really warm and I've been driving awhile it is eaier to find neutral for some reason. Something new popped up today though. From take off in first im finding the bike hesitating. It takes a second to find the gear, way too long and I could see it putting me in a unsafe position on the road. This hesitation has been getting gradually worse. When I got home today I changed the oil to see if it improved the situation at all and it did a bit. These two things related? I understand the first problem a little bit. I can't find neutral because the trans is still moving. The bike thinks i'm moving still and skips past neutral? What are reasons for this? The hesistation...is that the springs loosing their give? I've never worked on a clutch before but looks like that's happening soon. Gonna order new friction plates and springs tomar but does anyone have any recommendations for me. Also what tools do I need for this? I moved recently and am down to a tool rool which is stocked correctly but anything I don't have is gonna be a looong walk to the auto store after I open her up.
 
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