Rpm question

[Larrydplummer]

Morning guys, I searched a few old threads before i posted. Before i put her away, i noticed i could not get the engine to go over 5000 rpms. I am guessing that I am responsible. She came with the original air boxes and filters. They crumbled when i removed them. I removed the rest of the paper element material. The cages cleaned up like new, so I foamed and oiled them (basically made two pod filters). I did the same thing with an SR250 and that bike loved it!. She runs great No hesitation, no back fires, runs great. Just maxs out at 5000rpm
. (note, i ride like an old man) Tried to read the plugs but was only able to put just over a mile on her. My guess is that she runs lean now? or i have a vacuum leak. Oddly? from a riding point? it does not bother me. I am thinking perhaps SHE needs higher rpms at times. Replacement filters are probably the answer. just fiquired id throw this out there

 

[Charles13]

Does it free rev in neutral? Does it just fall flat or struggle under load?

 

[TX650A Van Islander]

What does your timing light tell you as in where does the full advance end up with the timing light? Perhaps the timing is set up too retarded?

 

[Larrydplummer]

Thank you,I never hit it from a timing angle. I had "mixture tunnel vision". I will give that a try. hopefully that idea can save me $100 on air filters. still thinking, I did a really nice job on foaming those air filter cages lol and I did not ride untill i did that . I was concerned about debris being sucked in to carbs. Define...."old age"...... " own..a timing light" thank you and yes,i own one

 

[Larrydplummer]

Does it free rev in neutral? Does it just fall flat or struggle under load?

no she does not, 5000 rpms and she's done. runs great...except for that

 

[YamadudeXS650C]

Don't worry about your air filters unless you soaked them heavily with heavy weight oil. Light application of Marvel Mystery oil (3w) works good.


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[Charles13]

no she does not, 5000 rpms and she's done. runs great...except for that

Wow does not rev past 5000 in neutral! Has to be spark because even with little fuel it will still rev in neutral

 

[5twins]

Check your carb diaphragms, they may have small holes in them. If that happens, you only get a partial vacuum formed, the slides will only lift so high, and the bike won't rev up past a certain RPM. Hold the slides up to a good light and gently stretch the diaphragm away from the slide. Look for the small holes where the diaphragm meets the slide.

 

[Larrydplummer]

Good morning folks, worked on my RPM issue yesterday and located the problem. Embarassing as it is, I found the problem. I almost wasn't gonna post this. But It may help someone else out so, here it is... My tachometer cable was slipping once it got to 5000rpms. I had failed to tighten the connecting knurl nut after I serviced the cable. ( at the tach) In my defense, I did do a really good job on all the cables and only put less than two miles her?? It took only 5 minutes after she warmed up untill i fiquired this out. I had tunnel vision. why i never picked up an the rpms audiobly climbing but the tach bottoming out? ..Tunnel vision..beer? All is well other than i have brand new set of K70s mounted, shes begging to go...and its winter. I do thank everyone who responded. Did I ever mention that I do believe my wife was jealous of that thing for a few months. could have been the "going to see your other girlfriend" as I snuck downstairs comments. Once more thank you

 

[Lou_TX]

Thanks for the follow-up, Larry. Glad you found your problem and happy that it wasn't anything serious.
And no worries, it's easy to miss a small detail and cause ourselves a headache like that. It gets worse as we age. LOL (don't ask how I know)
In all aspects of life, if something gets worse, a good troubleshooting step is to undo what you just did. Or check ALL that you've done recently.
Hence my usual approach: change one thing at a time. The more I change at once, the higher the chance that I won't know the root cause if something goes wrong.
And tunnel vision is real. In that case, I step back and take a break and come later with a fresh mindset and hopefully without tunnel vision.
Anyway, glad she's running fine and it was just an indicator problem.