Topic: 79 cb 650 stalling out at higher rpms ***issue resolved***

[artistry06]

Here's a video to my issue.  I also took a quick view of the engine, fuel line, not sure of everything there is supposed to be there.  Looking for some expertise on this matter,  I'm a total noob when it comes to indivdual parts so bare with me.

Yesterday night while on the highway going about 65-70 mph, i noticed a slight lack of power while holding the throttle.  Felt "laggy", loss of power, like it was having trouble sending gas efficiently, though i could be wrong.   (i have known of this issue before.  This is my second motor.)  As I exited the highway, the engine shut itself down.  Had to wait a few minutes & started up again.  Still laggy but i made it home. 

Sometimes it rides fine, somethimes it doesnt & I am forced to pull over and wait.  I've seen and read some of the forums with similar issues but no one has hit it spot on. 

****updates****
Tried starting it today, won't even crank over and idle now.

[HondaMan]

Check your gas tank's vent? There may be a vent hole in the gas cap that is plugged.

[Mantree]

And the screen in the petcock I had a 650 that I chased my ass on for weeks before rebuilding the petcock

Sent from my ME302KL using Tapatalk

[artistry06]

Check your gas tank's vent? There may be a vent hole in the gas cap that is plugged.

I blew into the top hole of the gas cap, air seems to still flow through, it's a bit rough but not sure if its suppoed to be that way. 

[artistry06]

Tried starting it again today, now it wont even get to ideling stage.  $1400 down the drain still not working. 

[HondaMan]

Tried starting it again today, now it wont even get to ideling stage.  $1400 down the drain still not working. 

$1400 on what?

On the 650, this symptom could also be due to bad (dirty) contacts on the CDI module that runs the coils. They are [in]famous for corroding and being cruddy, usually from carwash soap that an over-aggressive owner got into the connector(s). Maybe take a look generally at all the connectors? And, check the battery voltage, as the sparks quit altogether at about 7 volts or so.

[artistry06]

Tried starting it again today, now it wont even get to ideling stage.  $1400 down the drain still not working. 

$1400 on what?

On the 650, this symptom could also be due to bad (dirty) contacts on the CDI module that runs the coils. They are [in]famous for corroding and being cruddy, usually from carwash soap that an over-aggressive owner got into the connector(s). Maybe take a look generally at all the connectors? And, check the battery voltage, as the sparks quit altogether at about 7 volts or so.

$600 on a different motor, ended up using the same carbs though. $700 on labor. 
As far as the contacts, what should i look for?  & where exactly? I did end up riding in the rain the same day.  But rode fine until after it sat for a few hours.  Symtoms occured after when i was headed home.

[harisuluv]

The pod filters are a new thing recently?

You have the CV variety of 650 carbs.  They don't work very nicely with pod filters.  They really need to be set up properly.  Those carbs don't have slides that mechanically go up and down, they just do based on air intake, putting pods on completely changes everything.

[artistry06]

The pod filters are a new thing recently?

Yes, came with the motor.  I had the uni pod filters before, but regardless same issue.  Different motor or not.  Before the bike started having the same symtoms, it ran great with the new used motor.  I would suspect my issue is greater than using different pod filters, but i'm no bike mechanic.  What addtional the thought process of why you asked me about the pod filters may i ask?  & what do you suggest?

[HondaMan]

Tried starting it again today, now it wont even get to ideling stage.  $1400 down the drain still not working. 

$1400 on what?

On the 650, this symptom could also be due to bad (dirty) contacts on the CDI module that runs the coils. They are [in]famous for corroding and being cruddy, usually from carwash soap that an over-aggressive owner got into the connector(s). Maybe take a look generally at all the connectors? And, check the battery voltage, as the sparks quit altogether at about 7 volts or so.

$600 on a different motor, ended up using the same carbs though. $700 on labor. 
As far as the contacts, what should i look for?  & where exactly? I did end up riding in the rain the same day.  But rode fine until after it sat for a few hours.  Symtoms occured after when i was headed home.

The CDI box is under the seat/left cover. It has a connector on it that can be unplugged: inside there you will see the Blades and Receptacles that are likely cruddy, dirty, and corroded. Most bike shops never look at this stuff when working on them, I have discovered....

[HondaMan]

Also, how are your fuel lines to the carbs routed, since everything was removed recently? The hose(s) must run straight from the fuel petcock down or horizontally to the carbs, never down under and then back upward. The latter will cause  very many fuel feed troubles.

[artistry06]

Ok, will do.  I'll check tomorrow morning and give an update.  It's almost midnight where im at.

[cb650]

sounds like cam chain tensioner is in wrong.

[artistry06]

I had another local mechanic take a look at it this evening & turns out that the crud inside my fuel tank was blocking passage to the petcock.  Smh..... Just drove it after he cleared it out, it drove just fine.  I know now  the new engine replacement was unecessary,  $1500 lesson.  Something so simple can be so costly.

[artistry06]

I don't want to look down on my mechanic, but how can someone call himself a "mechanic" when he didn't even look at the most simplest places first.  Jeeze.  I have patience but this was rediculous.  I don't want to think that he did it knowingly my issue, but did it for his own personal gain.  Because it would be out of his busines's best intrest.   

[harisuluv]

Because dishonesty, incompetence, and easy money.

[artistry06]

Because dishonesty, incompetence, and easy money.

Sound about right.

[Deltarider]

I don't want to look down on my mechanic, but how can someone call himself a "mechanic" when he didn't even look at the most simplest places first.

I know what you mean. The only time I took my Goldwing to a workshop (in the US) for a sqeaky sound, the mechanic returned from a testride saying that the engine had to be taken apart to find the culprit. I insisted it came front the front. Turned out to be some sort of a ring near the front axle that produced the sqeak. Completely harmless. I've the impression that in the US there are more adventurers wrenching in shops whereas many mechanics around here are in businesses that went from grandfather to father to son and they hate to loose a good reputation. One time I was conned however (1981) and I decided to do most myself.

[Bailgang]

I've the impression that in the US there are more adventurers wrenching in shops whereas many mechanics around here are in businesses that went from grandfather to father to son and they hate to loose a good reputation. One time I was conned however (1981) and I decided to do most myself.

Unfortunately you're about right on that. Finding a really good bike mechanic (even auto mechanic) in the US isn't always easy. My sons friend had an early GPZ Kaw 600 that didn't run when he first bought it so his friend took it to a shop that was owned by a friend of his father that supposedly knew sportbike engines really well. That shop messed with that bike for over a month and was unable to get it running and eventually insisted that it needed a new engine, my son told his friend to let my son and I look at it first before he went to any extreme like getting another engine and within 2 days of process and elimination we found the problem was nothing more than a nasty vacuum leak. Once that was taken care of the bike started and ran fantastic.

[HondaMan]

I don't want to look down on my mechanic, but how can someone call himself a "mechanic" when he didn't even look at the most simplest places first.  Jeeze.  I have patience but this was rediculous.  I don't want to think that he did it knowingly my issue, but did it for his own personal gain.  Because it would be out of his busines's best intrest.   

This problem here in Colorado is over-the-top terrible. Almost all of the bikes I see arrived because some shop wrench (with one of your mechanics behind it) did something incorrect, uniformed, lazy, or stupid to the bike, and neither he nor the shop would admit it. Sadly, it is about the same with car mechanics here, too.

I met a [marginal] BMW (bike) mechanic a couple of years ago, because he had some SOHC4 pipes for sale. His ad stated, "In great shape, came from a running CB750 that was parted out." When I saw the pipes, they had rust holes big enough to fit my little finger through. After talking with him a while, I asked how he became a BMW [master!] mechanic: he said that when he interviewed, they only asked him one question: "Which way tightens a bolt, and which way loosens it?" He told them, "Righty-tighty, lefty-loosey", and they hired him on the spot. They then told him to go see the Service Manager, because they have computers to plug the bikes into that will tell him what to fix, so he could learn how to use them.

Honest.

OMG...

[calj737]

I know plenty of great mechanics, and plenty of dopes too. It takes some time, and money spent to determine which are which.

The problem with today's breed of mechanics, is they must rely on engine computer diagnostics and have essentially been mentored to do what the computer tells them to. They have lost all their fundamental understanding of internal combustion engines, electrics, and vacuum operated components, and as a result, their diagnostic skills SUKK!

The best part of the bikes is they are simple machines and easy enough for the average person with a modicum of patience and literacy to service. Armed with some decent tools, a computer to surf the forum, a few pages from a manual, you can do most everything to make and keep your bike running.

At least you now know to visit this forum when you encounter a problem. Spend the next $1500 on a decent set of tools and garage space

[artistry06]

I figured it out after talking to people, it seems like the older mechanics  in their late 40's and up seem to be more legit when talking about certain issues, especially about these older bikes.   Tools would definitely  be my next investment especially since winter is coming up.  I have the original motor and another motor i bought from the owner which he gave me  to play with.  I have a general base knowlege about motors and whatnot since my older brother works on cars (especially older hondas) but these older motorcycles are definitely another ball game. 

I didn't know carborators were soo sensitive when it comes to reliability.  Good learning experience, just didn't wish it cost me that much.  Lol.