Bike bogs down at high rpm's

[Splittie]

Ok so I am on my way home from work and my bike died on me.
I checked the fuses and two of them were blown.
I changed them out (Once my wife came and picked me up)and tried to start it, but all it did was crank.
I pulled the plugs one at a time to check for spark and it was there.
After cranking it and choking it for a bit, it started up, buuuuttt the right two (3&4) cylinders weren't firing. The bike was running crapy and the two headers (3&4) were still cold and (1&2) were hot.
Any ideas???

[TheCafeKid]

Ok so I am on my way home from work and my bike died on me.
I checked the fuses and two of them were blown.
I changed them out (Once my wife came and picked me up)and tried to start it, but all it did was crank.
I pulled the plugs one at a time to check for spark and it was there.
After cranking it and choking it for a bit, and it started up, buuuuttt the right two (3&4) cylinders weren't firing. The bike was running crapy and the two headers (3&4) were still cold and (1&2) were hot.
Any ideas???

Quite possible what ever took your fuses out took a coil out with it? Or maybe the coil itself took the fuses out. Bust out the multimeter and start testing. Check the stator and RR too, as a overcharge could have started the whole process i suppose.

[Splittie]

Thanks Kid,
The debate begins--Tomorrow I will drive my gas guzzling 4x4 Suburban to work, then after I will pick up gaskets that came in today for my 75 CB750 and come saturday one of these bikes is gonna get on the road come monday.
Thanks for the info

[TheCafeKid]

Thanks Kid,
The debate begins--Tomorrow I will drive my gas guzzling 4x4 Suburban to work, then after I will pick up gaskets that came in today for my 75 CB750 and come saturday one of these bikes is gonna get on the road come monday.
Thanks for the info

Yanno, and this is just a theory, but if you were experiencing that bogging prior to all of this happening, its possible that your coil was the cause, and when it finally bit the dust, it caused this other stuff to blow too. I would start at the battery, then the rest of the charging system, and work my way around the ignition system to see whats going on. Its possible you have a short or an open causing this too.

[Splittie]

its possible that your coil was the cause, and when it finally bit the dust, it caused this other stuff to blow too.

Would I still be getting spark at the plug if the coil(s) is bad?
I pulled the plugs to check for spark and it was there.

[Pacman]

I wouldn't expect to see a good spark at the plug if the coil is bad. Also, the coils should run 1&4 on one coil and 2&3 on the other. So a bad coil shouldn't have 3&4 out because they run on two seperate coils.

Because you had a really bad flat spot and then it died completely but had spark when it wouldn't start I would have bet money that you had a restriction in fuel delivery. If 3&4 aren't running then pull the float bowls to see if you have fuel there. If no fuel in the float bowls on 3&4 but you do have fuel in 1&2 I think you have found at least part of the problem.

The thing that bothers me is probably the same thing that bothers you and that is the fuses blowing. What I would be interested to learn is which fuses blew and what they supply current to? If they supply current to your turn indicators then it would seem to just be a coincidence.

Chris

[Splittie]

So now I'm flippin' confused...
After I put new fuses in the bike on friday, it started up, and was running on all cylinders.
I didn't have time to mess with it during the weekend but last night, I found out I would be needing to ride to work this morning. Fired it up and lowandbehold it started up just fine. Threw my helmet on and went for a ride. Went up through the gears and when I got into the 5k-6k range... that's right smooth as could be?????
What gives with this? I made no adjustments whatsoever and it just started running fine.!!

[TheCafeKid]

So now I'm flippin' confused...
After I put new fuses in the bike on friday, it started up, and was running on all cylinders.
I didn't have time to mess with it during the weekend but last night, I found out I would be needing to ride to work this morning. Fired it up and lowandbehold it started up just fine. Threw my helmet on and went for a ride. Went up through the gears and when I got into the 5k-6k range... that's right smooth as could be?????
What gives with this? I made no adjustments whatsoever and it just started running fine.!!

sounds like you are starting into some electrical gremlins. I would suggest in your spare time, start going thru all the connections, and cleaning them up and using dielectric grease on them. The fuse replacement and suddenly better running bike is generally a sign that your connections are getting cruddy. Obviously, you took care of the worst ones, but preventative maintainence is ALWAYS a good thing on these bikes.

[Splittie]

sounds like you are starting into some electrical gremlins. I would suggest in your spare time, start going thru all the connections, and cleaning them up and using dielectric grease on them. The fuse replacement and suddenly better running bike is generally a sign that your connections are getting cruddy. Obviously, you took care of the worst ones, but preventative maintainence is ALWAYS a good thing on these bikes.

What (In your opinion) would have been causing the bike flattening out at the 5k-6k rpm?

[Big T]

I agree with TCK. If your problem "suddenly" vanished, it can "suddenly" return. Start with the connections in your headlight and near your battery. You may be shocked at what you find.

Get some good spade connectors and heat shrink tubing and just replace the bullet connectors. You'll be glad you did.

Clean the block connectors unless they're really corroded.