Carb problems?

[SthrnSqrl]

A few days ago, I had a problem with the octy being a leaky p.o.s. I removed it and replumbed the fuel system. My first problem was with the crappy yellow, thin *fuel* line the parts store had. It will collapse and block off the flow with the slightest bend. I fixed that by hitting the tractor supply and getting real fuel line.

I cleaned the carbs *COMPLETELY*. I cleaned the plugs. I teed the fuel feeds into 1 line and filtered it, feeding off 1 petcock. I adjusted the idle screws. I synched the carbs. Bike runs like a dream sitting on the stand.

When I start off, there is a VERY slight stumble. I can live with that. When I hit about 5-6 grand, the engine sounds like it's about to **** itself. Cutting out, bucking, vibrating, uneven ignition, won't accelerate any more. It sounds like it's starving, maybe, I'm not sure.

It's not the pickup coil wires. I checked. They are still like new, because apparently, the vacuum advance hasn't worked in ages. The vacuum module leaks. I replaced it with the one from my spare engine. It seemed to make things worse, so I disconnected it and plugged the vacuum port on #2 carb.

I am at a loss here. I could really use some help.

Skwerl

P.S. this is what my plugs looked like when I did the plug cut:

[CatatonicBug]

Those plugs look really strange... They almost look rusty! Do you know if the fuel cap vent is clear? Might be clogged just enough to slow the flow of fuel at high RPMs. Have you sync'd the carbs lately? What about float height? If the floats are too lean, that will starve the carbs at high RPM.

[DGXSER]

Do check the float heights, they should probably be within spec. But also look at your mains. The slight stumble at take off and the lack of top end points to fuel starvation. On the carbs from the 78 model, the mains feed the entire carb. Both low and high end circuits. With the 4-1 exhaust, and you do not mention if your running pods or the factory airbox. You could easily be running a bit lean.

[natemoen]

Do you use any fuel additives? Additives can turn the plugs a pinks orange color.

[soccer4m]

vacuum it could be

With the vacuum advance, your bike needs it, I would recommend getting another good, if not new, advance from somewhere. If the advance is not advancing due to the vacuum, then your high rpm problems are the bike is not producing the correct spark at those rpms. Maybe bikebandit.com or our sites parts guys, andreass, should have a good one for you. Also check the carb manifolds to the carbs and engine head, spray some wd40 or carb cleaner around them while its running to check for leaks, and the engine will noticibly change speed if there is a leak. I am suprised it only happens at higher speeds, maybe a member can chip in here on the scientific reason for the vacuum advance................anyway get a good vac. modulator asap,,,,,,,Mike in Ca

[dbeardslee]

Whenever I do work on a bike and subsequently have 'new' problems, my first suspicion is always what I've just done. You just changed your fuel feed from two petcocks to one, and now your experiencing what sounds like fuel starvation. Hmmmmmm. I'd be taking another look at that plumbing. Might not be flowing enough fuel from one petcock to satisfy your carbs.

[bikerphil]

Make sure the gas filter you just installed is in properly. It should have an arrow with fuel flow direction on it. If it is one of those small lawnmower type filters, it just might be too small. JAT

[SthrnSqrl]

The carbs aren't any issue any longer. Thanks for the help, but the engine is fried now. Copper in the oil filter. Filled with new oil, and the oil light won't even go out. Also, the slap/knock is still there, so it looks like it's time to pull the engine and scrap it. I just need to get the second engine ready to go into it. No more bobber project bike. Now, the Special will just be a scrap donor bike.

Again, thanks for the help.

If I can get the other engine in it and get it right, this thing will be for sale. Gonna try to find me another Honda, I think.

[CatatonicBug]

Copper? Where is there any copper in the engine? Do yourself a favor, and before you junk-pile it, take the right side cover off the engine, remove the clutch basket, and look at the oil pump idle gear. That gear uses the spinning of the clutch to turn the oil pump, thereby turning off the oil light. The gear has a tendency to loose the circlip on the end of the shift fork shaft, and it can "walk" off the end of the shaft, making a real mess in there. However, it IS repairable/replacable.

[SthrnSqrl]

The copper, I'm assuming, is from the bearings that have been shredded, causing the knock/slap.

Why would the oil pump come apart like that, without the engine even turning? This occurred while the bike was parked overnight, and with oil drained. The light was going out when it was parked, but on refill, it does nothing but sit there nice and bright.

Even if the oil pump gear is loose, the knock/slap in the front of the engine is there. Nothing is making that go away.

[DGXSER]

Honestly, these engines have proven to be VERY stout, so it is odd for one to lose a bearing like your suggesting. Not unheard of, and you seem to know what your talking about, as the bearings are the one copper piece in the engine.

The oil pump idler gear does take engine power from the primary to the oil pump. The primary gear turns the outer basket of the clutch assy. The outer basket has two sizes of gears on it, one to interface with the primary gear, and another to drive that oil pump idler gear. For reasons I can not explain, I have twice now seen the C-clip loose and the gear not engaged or off the shaft, and therefor no oil pump turning and no oil pressure.

If you had no oil pressure, it could lead to the knocking, but yes, typically once the knocking is there, it is a matter of time until a rebuild or a thrown rod whichever comes first.