TOPIC:

old_kaw wrote: Usually, when my bike starts running progressively worse, I am running out of fuel. I know it's time to switch my petcock to reserve. (the carbs start running out of fuel) Your buddy obviously didn't fix anything, and to tell ya the truth, if something doesn't run after ANY repair, it really wasn't "repaired" at all. The main thing is that he didn't make things even worse.
Loosen up the bowl drain screws to check for fuel in the carb bowls, better yet, use a clear tube to check for fuel levels while checking. You can bypass the vacuum petcock by switching it to prime to check for fuel.

I appreciate your comment but the type of "progressively worse" I experienced is NOT low fuel in the tank.

We have yet to identify the issue but I will let you know how it turns out. I have 6 other bikes and I put the KZ650 in the garage and will come back to it. Today Im on this:


Thanks.

Sweet CB900F Super Sport. This was mine. (now sold) It had the "big bore kit". I couldn't keep the front wheel on the ground at closing time, but then again when it was hot on a nice warm day, it ran like crap. I attribute this to it having too high compression ratio, so that it only ran good when stone cold on a cool night. BUT in everyday riding it would sputter and ping / pop, My 99% stock old Kaw is faster 100% of the time than my modified CB900F SS. It will flat eat the loud and slow bikes.


With the running progressively worse would indicate something restricting fuel. Carbs, filter, screen, petcock, etc. Valves are also a possibility, as well but would get worse over an extended period rather than minutes. There are actually two coils, so one effects 1,4 and the other fires 2,3. Not knowing the general condition of the bike, cleanliness of the tank / fuel etc, it's even more of a guessing game, than your buddies who can actually see the bike.
There are some great folks on this board, and they give some solid advice. that reflects on their personal experiences with their own bikes. Much like myself.

Anyway, good luck on the repair.

Inspect the H/T leads at the spark plug caps. Sitting out in the moist elements can cause corrosion at the connections. If you see green or white crap snip off 1/4" and put the caps back on. Water can get in anywhere and cause problems.
That's why I built Bossie's shop.
Steve

Steve, speaks truth!
Sitting in the elements is not good for cats, dogs, lawnmowers AND motorcycles for many many reasons.

Electrical is a big one. So is fuel contamination.

I never did find the reason for my voltage drop on the brown wire to my voltage regulator, so I took the "band aid" approach and added in a relay to stop overcharging.

old_kaw wrote: Sweet CB900F Super Sport. This was mine. (now sold) It had the "big bore kit". I couldn't keep the front wheel on the ground at closing time, but then again when it was hot on a nice warm day, it ran like crap. I attribute this to it having too high compression ratio, so that it only ran good when stone cold on a cool night. BUT in everyday riding it would sputter and ping / pop, My 99% stock old Kaw is faster 100% of the time than my modified CB900F SS. It will flat eat the loud and slow bikes.

With the running progressively worse would indicate something restricting fuel. Carbs, filter, screen, petcock, etc. Valves are also a possibility, as well but would get worse over an extended period rather than minutes. There are actually two coils, so one effects 1,4 and the other fires 2,3. Not knowing the general condition of the bike, cleanliness of the tank / fuel etc, it's even more of a guessing game, than your buddies who can actually see the bike.
There are some great folks on this board, and they give some solid advice. that reflects on their personal experiences with their own bikes. Much like myself.

Anyway, good luck on the repair.

Hey! Thanks for this good message.

I laughed when I read about the "ping and pop" on the 900F. Same thing happens to me, and the bike LOVES when its cool out.

In re the KZ650 I have an opportunity to swap the KZ650 for a KZ1000 +$1000 to the seller. Not sure what im going to do.

650Dude wrote:

old_kaw wrote: Hey! Thanks for this good message.

I laughed when I read about the "ping and pop" on the 900F. Same thing happens to me, and the bike LOVES when its cool out.

In re the KZ650 I have an opportunity to swap the KZ650 for a KZ1000 +$1000 to the seller. Not sure what im going to do.

We cause spitting and poping and pinging ourselves by "improving" things to the point that the motor no longer runs properly. Pod filters, 4 into 1 exhaust, removing the air box, "big bore kits" all should be marketed as "go slow parts", because the everyday joe has no idea how an internal combustion engine runs, let alone the math involved to make it run properly.

I see your CB900F SS has pod filters, and a 4 into 1 header with whatever other "improvements" it has been blessed with. If that bike were 100% stock, it would be hard to keep the front wheel on the ground.

I recently put a Delskevic SS exhaust on my Kaw. I did not remove any baffles just for this reason. (had it out in ~60 F weather last nite). I assure you I won't be upping the CR or removing the air box anytime soon. My bike is still an animal.

old_kaw wrote: ..................... We cause spitting and popping and pinging ourselves by "improving" things to the point that the motor no longer runs properly. ..........

Exactly. When the bikes were new and stock they ran fine, but after folks improve them they often run poorly if they run at all.

What always amazes me is that the millions of R&D dollars and the efforts of the very highly skilled engineers working for the motorcycle manufacturers are ignored by folks who are going to "improve" performance by screwing on some aftermarket gadget. If it was that simple wouldn't the manufacturer simply use that same gadget rather than blowing time and money refining the engine and its components? Ed

old_kaw wrote:

650Dude wrote:

old_kaw wrote: Hey! Thanks for this good message.

I laughed when I read about the "ping and pop" on the 900F. Same thing happens to me, and the bike LOVES when its cool out.

In re the KZ650 I have an opportunity to swap the KZ650 for a KZ1000 +$1000 to the seller. Not sure what im going to do.

We cause spitting and poping and pinging ourselves by "improving" things to the point that the motor no longer runs properly. Pod filters, 4 into 1 exhaust, removing the air box, "big bore kits" all should be marketed as "go slow parts", because the everyday joe has no idea how an internal combustion engine runs, let alone the math involved to make it run properly.

I see your CB900F SS has pod filters, and a 4 into 1 header with whatever other "improvements" it has been blessed with. If that bike were 100% stock, it would be hard to keep the front wheel on the ground.

I recently put a Delskevic SS exhaust on my Kaw. I did not remove any baffles just for this reason. (had it out in ~60 F weather last nite). I assure you I won't be upping the CR or removing the air box anytime soon. My bike is still an animal.

Your post is full of assumptions

You think my bike was better/faster stock? Nope. After my mods, the bike was dyno tested and puts out 107 hp with the CR carbs and a few other things I did. I have all the paperwork and graphs. Stock is 95 and im at 107. it IS hard to keep my wheel on the ground. I did 140 yesterday out on long island.

SWest wrote: If the valves have never been adjusted, the engine will run worse and worse until it doesn't run at all.
Steve

BTW it wasnt the valves. It was the carb floats put back incorrectly and two stripped coil wires. Bike is running great now.

650Dude wrote:
Your post is full of assumptions

You think my bike was better/faster stock? Nope. After my mods, the bike was dyno tested and puts out 107 hp with the CR carbs and a few other things I did. I have all the paperwork and graphs. Stock is 95 and im at 107. it IS hard to keep my wheel on the ground. I did 140 yesterday out on long island.

Yep, it is full of assumptions. What does anyone have to work with on this big ole internet guessing game with little to no info, except a pic and what little bit of info you spoon feed a little at a time? I think you missed the main point. When it is spitting and sputtering, it is no longer faster / better than stock, and is actually slower and less dependable than stock when the spitting and sputtering starts. Love this cool fall weather. My bike was fast in the hot summer weather, now it's even faster.

You say it spits and pops, and sputters yet dyno's impressive numbers. Of course not all the time, just under certain conditions. (another assumption) Stock runs good all the time, in most all conditions. The warranty work would be a nightmare. Everyone here is making assumptions what is wrong with your ride. I wasn't talking record dyno numbers, I was talking about a daily rider. Take it for what it costs you.

old_kaw wrote:

650Dude wrote:
Your post is full of assumptions

You think my bike was better/faster stock? Nope. After my mods, the bike was dyno tested and puts out 107 hp with the CR carbs and a few other things I did. I have all the paperwork and graphs. Stock is 95 and im at 107. it IS hard to keep my wheel on the ground. I did 140 yesterday out on long island.

Yep, it is full of assumptions. What does anyone have to work with on this big ole internet guessing game with little to no info, except a pic and what little bit of info you spoon feed a little at a time? I think you missed the main point. When it is spitting and sputtering, it is no longer faster / better than stock, and is actually slower and less dependable than stock when the spitting and sputtering starts. Love this cool fall weather. My bike was fast in the hot summer weather, now it's even faster.

You say it spits and pops, and sputters yet dyno's impressive numbers. Of course not all the time, just under certain conditions. (another assumption) Stock runs good all the time, in most all conditions. The warranty work would be a nightmare. Everyone here is making assumptions what is wrong with your ride. I wasn't talking record dyno numbers, I was talking about a daily rider. Take it for what it costs you.

Im glad the weather is cooler and your bike is faster now. But what does that have to do with anything? Not bieng confrontational, just saying.....

The popping noise i was referring to is the METAL expanding and contracting, something the reviewers mentioned back in 1982 when the CB900F came out, not any sputtering from carbs, electrical or anything like that. Im talking about PINGING from the engine getting hot as was the habit with this particular bike.

So you know, the bike runs fast and I beat the PANTS off a friend on a 77 KZ1000 the other day. I mean absolutely destroyed him. My chin was on the tank so I have no idea how fast I was going ( was tucked from 120MPH on) but when we slowed down and he caught up to me, he was like "dude that bike is a MONSTER! The acceleration is brutal!!! Brought a smile to my face!

FYI NONE of my bikes are daily riders because I have FIVE of them and rotate them. No one bike gets ridden into the ground. Thats they way I planned it.

That's great you have a collection. I'm jelly.

The reason cooler weather makes a bike faster is relevant because.. the cooler / denser air carries more oxygen which increases the intake charge, and the mixture is leaned out slightly,. Lean is mean, but it also blows sh!t up. +the bike runs cooler, which also adds HP.

I have 1 dependable rider. (don't have the room) It starts, runs and rides extremely strong all the time. I have yet to have anyone outrun it, although some have come close, I do not lay down on the tank. Looking at the gauges is pointless. (85mph speedo) Even the newer crotch rocket kiddies seem surprised when the old kaw is still hanging. (with the exception of splitting lanes and acting the fool on public highways)