Bike acts like it has a rev limiter in around 5000 rpm

[derrick woods]

Also, you noted that 2 different carb sets were used, both recently overhauled, so carbs might be able to be ruled out. Fuel delivery under load is a different story. The carbs can only put out the amount of fuel delivered to them.

So, if you get into 5th gear and slowly raise the throttle as you reach highway speeds, can you creep up past 5000 RPM? If not, then I would assume gas delivery to the carbs is being either restricted or starved. New gas lines by chance?

You can get past 5000 rpm with throttle slowly but it has difficulty. Yes all rubber is new fuel lines etc

 

[mcgovern61]

Assuming the fuel pump is working correctly, I would suspect possible issue at the fuel pickup inside the gas tank, or possibly even the fuel petcock seals being swollen. Easy way to check the pickup. Close the petcock, take the gas line off the filter, insert the end of an air pump hose (tapered type), open the petcock and send compressed air into the tank (I would not use more than 12 lbs of air pressure.) Reconnect the gas hose and take the bike for a ride right away. If no immediate difference, you can at least rule out a clogged pickup screen.

 

[derrick woods]

Assuming the fuel pump is working correctly, I would suspect possible issue at the fuel pickup inside the gas tank, or possibly even the fuel petcock seals being swollen. Easy way to check the pickup. Close the petcock, take the gas line off the filter, insert the end of an air pump hose (tapered type), open the petcock and send compressed air into the tank (I would not use more than 12 lbs of air pressure.) Reconnect the gas hose and take the bike for a ride right away. If no immediate difference, you can at least rule out a clogged pickup screen.

I've finally figured it out it showed its face. I was at my ol motorcycle buddy's house were I shut it off , then he said start it and drive by his house at full throttle so he could hear it. So I cranked the bike took off and it didn't do it , turned around and launched that bike absolutely screamed down the road then the bike started dying . Looked down and realized the petcock was off causing bike to run leaner. So the problem was I'm running rich at full throttle so I'm gonna drop the float level to 16mm instead of 15.5, although it could be weak spark at higher rpm

 

[derrick woods]

Well droping the float height helped a lot but it is still present however you can pull out of the problem area. I set the float height to 16 mm, I guess I could set it to 16.5 I'm afraid I'll make it run too lean has anybody ever had a problem with the needle Jets and those carburetors being worn is it just seems Rich at 3/4 throttle

 

[derrick woods]

Anyone? I'm still at a loss on this

 

[mcgovern61]

Up to this point, you mentioned two different carb sets performing the same way. Can the needle get worn? Yes. Are they aftermarket needles? (Notorious for not working correctly.) If they are original needles, have the tips been sanded? Have the seats been sanded cleaned and reseated? (I am only posing questions for a rethink and not guessing your carb rebuild skills.)

My experience rebuilding 1100 carbs has seen a few notable items. One of the common issues is not getting the sync correct on the bench. The carbs cab be synced to each other even if two of them are only balanced to each other, but higher than the other two. The side to side balance can be attained, but when at higher RPM, you lose power. Again, I am assuming you have great skills and experience rebuilding carbs based on your previous posts. But the 1100 carbs can be real tricky once fully separated, cleaned and reassembled. If you want to discuss these points any further, I am open to that. If you are sure the carbs are not the issue, I will respect that also.

 

[derrick woods]

I've actually thought of that and wondered but I use a manometer instead of vacuum gauges that way I can make absolutely sure one is not pulling more than the other because it sucks against one another the interesting thing is when I get to that stutter spot if I just barely let off the throttle and then gun it again she'll take off and rip on up to 8,000 RPM it's very strange it's almost like I'm getting flutter in the vacuum slides but I have polished them they slide freely they vacuum test correctly this one has got me absolutely stumped. Also thank you very much for helping I don't want people to ever think that I know it all my problem is I'm an absolute perfectionist and the least little thing drives me insane

 

[mcgovern61]

When you cleaned the carbs, did you check to be sure the accelerator jets were clean?

 

[derrick woods]

When you cleaned the carbs, did you check to be sure the accelerator jets were clean?

View attachment 50342

• Today at 3:09 PM
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• #29

Yes sir they all shoot a nice flow of fuel it honestly acts like it's running a bit rich in the 4000 rpm area no where else though plugs are perfect I'm starting to think I might be the mufflers are restrictive or could be that electronic ignition even though it test fine the mufflers are the same ones I use an all the GL's i run factory Rd king mufflers. If I can't get this out of it soon I'm gonna put some 76 heads on it and ditch that obsolete pulse generator it has

 

[DaveO430]

Synch problem with the throttle wide open, NO. Accelerator pump problem NO. Someone needs lessons on how these carbs work. Is the air intake all original? Sure of the cam timing?

 

[derrick woods]

Synch problem with the throttle wide open, NO. Accelerator pump problem NO. Someone needs lessons on how these carbs work. Is the air intake all original? Sure of the cam timing?

• 28 minutes ago

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• #31

Cam timing is perfect and really someone needs a lesson on these carbs? I've been building Honda carbs for about 20 years now I don't get on these sites to be insulted get plenty of that out in the real world that's why I'm on this thread because it's got even me stumped ...it acts like it's something in that crappy spark advance system that these bikes have. And not only do I sync them I use a manometer and then I use a vacuum gauge just to make absolutely sure like I said it's either a spark problem do to the pulse generator cuz it's the only thing I can find or it's running a little rich at 3/4 throttle ,because once you let off the gas a bit when it starts studdering then power it on again it takes off and a run all the way up to 8,000 RPM or when your at a dead stop and take off full power never missing a beat through entire rpm range . It only happens if your cruising and then power it hard into the 5000 rpm range everything is original except for the OEM factory Rd king mufflers because the originals where rotted, I've used these mufflers on every gl I've ever had because they are quiet and have decent back pressure

 

[mcgovern61]

When you installed the mufflers, did you remove the 1100 cross-over tube? Also, if the mufflers were rotten, there is a chance the inner pipe on the headers might also be rotten. Ultimately, it could be the spark advance. '81 1100 are normally pretty darn peppy through their whole RPM range. I had both an '81 and an '82. Both were standards. The '81 was a real seat in the pants ride! The '82? I nicknamed her, "The Slug". Speaks for itself.

 

[derrick woods]

When you installed the mufflers, did you remove the 1100 cross-over tube? Also, if the mufflers were rotten, there is a chance the inner pipe on the headers might also be rotten. Ultimately, it could be the spark advance. '81 1100 are normally pretty darn peppy through their whole RPM range. I had both an '81 and an '82. Both were standards. The '81 was a real seat in the pants ride! The '82? I nicknamed her, "The Slug". Speaks for itself.

I put a set of 76 manifolds on it i like them better because the exit end doesn't have a steep angle easier to put mufflers on and yes the cross over tube is gone. Ive actually wondered if that could be the problem. Bike runs like a scalded dog if you give it full throttle from a stop through all gear no problem hitting higher rpms. It's only when cruising part throttle then you go full throttle in the 4500 to 5000 range, if you let of the gas when it stumbles for a brief second then hit it full throttle again it has no problems. Just when coming out of cruising almost like it's fuel loading. I even set the floats to 16mm just to see if I could lean it up a bit it helped some

 

[mcgovern61]

I wonder if the accelerator pump is dumping too much gas when you hit it at that range while cruising? From a stop to full throttle you have no issue. (My head hurts thinking this through and I do not have a bike to even reference anymore.)

When rebuilding the carbs, were the springs in the slides all the same height? I seem to remember that weak springs can also cause a bog with the sudden change in vacuum.

 

[derrick woods]

I wonder if the accelerator pump is dumping too much gas when you hit it at that range while cruising? From a stop to full throttle you have no issue. (My head hurts thinking this through and I do not have a bike to even reference anymore.)

When rebuilding the carbs, were the springs in the slides all the same height? I seem to remember that weak springs can also cause a bog with the sudden change in vacuum.

Accelerator pump to much gas now that's a thought I've not considered maybe I will bend the stop tab a bit see if a change and the spring height is same but I've never measured the spring resistance wonder if there is a way to accurately do this

 

[mcgovern61]

There used to be a tutorial on the forum for checking the spring tension. Don't know if I can still find it. (From many years ago.)

 

[mcgovern61]

Checking the spring tension, if I remember correctly, with the slide and covers on the bench, after checking the springs are all the same height, put the spring in and the slide, then tap the slide(s). They should easily go all the way down and right back to the same height with little to no effort.

 

[DaveO430]

• 28 minutes ago

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Cam timing is perfect and really someone needs a lesson on these carbs? I've been building Honda carbs for about 20 years now I don't get on these sites to be insulted get plenty of that out in the real world that's why I'm on this thread because it's got even me stumped ...it acts like it's something in that crappy spark advance system that these bikes have. And not only do I sync them I use a manometer and then I use a vacuum gauge just to make absolutely sure like I said it's either a spark problem do to the pulse generator cuz it's the only thing I can find or it's running a little rich at 3/4 throttle ,because once you let off the gas a bit when it starts studdering then power it on again it takes off and a run all the way up to 8,000 RPM or when your at a dead stop and take off full power never missing a beat through entire rpm range . It only happens if your cruising and then power it hard into the 5000 rpm range everything is original except for the OEM factory Rd king mufflers because the originals where rotted, I've used these mufflers on every gl I've ever had because they are quiet and have decent back pressure

Wasn't replying to you. Should have used the reply button. 1st of all the accelerator pump is only in effect until about 1/2 throttle. 2nd you couldn't get the synch far enough out to matter at WOT. Sounds like there is not enough fuel supply, when you let off the throttle it lets it catch up and fill the bowls then it will go on. I have 4 running 1100 engines right now, only one has a good vacuum advance and they all run just fine. The one with the good advance runs better of course.

 

[derrick woods]

Wasn't replying to you. Should have used the reply button. 1st of all the accelerator pump is only in effect until about 1/2 throttle. 2nd you couldn't get the synch far enough out to matter at WOT. Sounds like there is not enough fuel supply, when you let off the throttle it lets it catch up and fill the bowls then it will go on. I have 4 running 1100 engines right now, only one has a good vacuum advance and they all run just fine. The one with the good advance runs better of c

I checked fuel pump it flows correct measure I also tried raising the needle 1mm just to see if there was improvement but made it run worse it caused the studder to come in at 3500 instead of 4500 which lead me to think it could be rich at that rpm I'm gonna try to run a direct wire to my coil pack on a new switch see if I'm maybe getting weak spark at that rpm to eliminate the weak spark theory . If you take the top of the filter box off you can actually hear the vacuum slide chatter a bit when it's studdering. The slides all move freely under vacuum test when off bike. I tried a different set of slides too just to see with still same results,and I always keeps slides and caps matched I'm well aware of the problems that come with this. The only thing I've not considered is the spring tension on slides Anyway much thanks for the help so far

 

[derrick woods]

I think I might have found the problem not sure yet but I found an thread about slide scuffing and how to fix it my slides were a bit scuffed but I polished them up but did not fix the root problem. The thread said to use a file on the bottom side where the slide and carb throat intersect when I originally done these carbs I just polished them and polished the slide bores not reading into more of the route problem.while it might not effect the slides under vacuum test This could very well be what's causing issues when onder load because of suction pressure. I'll give an update sometime after this weekend as I've got a list of clients mowers and weed eaters I've got to get to first but I'm very hopeful in this because it seems logical to the problem