Bike wont rev over 4k

[phatman1969]

Hi again to all. I am asking for help on my rpm issues again. I have 1982 xs400 DOHC. The bike will run and idle now. Cleaned carbs 5 times trying to get it right. I am running pod filters so I put the new 140 main jets in it the other day. Prior to that it had a 125 and a 115 in it. When I rev the bike up either in gear or out of gear at around 4k-5k it starts popping and wont go any higher. Same when I ride, it accelerates slowly and then max out at the same rpm. I have cleaned and cleaned these carbs. Any ideas? Here is the checklist i have gone through:
Coils Good
Pick Up coil good
New plugs
Carb boots not cracked and tight
New Battery
Clutch switch bypassed
TCI module good
New Float Needle valves
New 0 rings on the float needle housing

Please help. Desperate.

 

[1979XS4002-F]

Have you done a plug chop and confirmed main jet is proper? Have you sync'd yhe carbs as the manual describes? Does the 82 xs have a rev limiter? Is your float height correct?

 

[DanMach]

Vaaaaaaaaaaaaaaaaaaaaaaaaaaaalves! Check your intake valves.

 

[jmd_forest]

Check the timing.

 

[bcware]

What brand of pod filters?

 

[DanMach]

So.. to conclude. Check compression, fuel, and spark. lol

 

[phatman1969]

Dont know what brand of pods.They look like emgo pods but cant be sure. PO put them on. Valves are good, float heights is good, compression is good on both, i have electronic ignition so timing should be fine, and yes carbs have been synched. not sure about a rev limiter on it. Never thought about that.

 

[bcware]

If they're emgo pods directly on the carbs that could be the problem; I could never get my bike to run right on them. When I switched back to stock I had no issues.

 

[bentwrench]

Here's the trick with jetting - sometimes you need to try a couple to get it right. Your jets could be too small or too large. What do your plugs look like? The exhaust colour?

 

[bentwrench]

Scratch that - it happens in neutral too, so it's unlikely jets.

Try running it with open carbs in neutral - no pods at all. Could be they're starving your engine.

 

[phatman1969]

I want to first start by thanking everyone who continued to help me on this bike. I just came back from a kick a++ ride on her. Without all of your great advice this would not be running. I did learn something and admitting it will be embarrasing but maybe it will help the someone else out there.
Evidently the xs400 will run with plug leads reversed. Float Height was too low, once i set it where it should be I took her out and same slow acceleration and low rpm. I then came home and she would not start only pop and backfire. I got pissed and then took a chance due to the backfiring and switched the plug wire sides. BAM fired up and drove the squat out of it.
So yes, sadly I screwed up the plug wires when changing a coil. Live and learn. At least I know now.
She still drops out a little around 8k rpm so I guess i gotta mess with the screws a little.
Either way thanks to all who helped. Including HoughMade and drewpy as well as all you guys on this thread.

 

[1979XS4002-F]

Well done glad to hear

 

[drewpy]

another bike on the road