carb jets?

[richmccolman]

Does anyone have a source on carb jets for late model 600 carbs?
Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
Richard

[Chas]

Hi Richard,
With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
Chas

--- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> Does anyone have a source on carb jets for late model 600 carbs?
> Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> Richard

[Don Laughton]

The 600s have "simultaneous" coils. That means they fire off both ends of the windings, on each revolution  this eliminated the need for a distributor. There was one minor drawback. One end of the coil fires positive to negative. The other fires negative to positive, delivering a weaker spark. Under normal operating conditions, this was not a problem. However, not getting the engine up to temperature, prolonged idling or improper/prolonged used of the choke could lead to fouling at least one plug being fouled. Hope this helps.
Don B. Laughton Sent from my iPhone

On Sep 28, 2012, at 6:29 AM, "Chas" wrote:
Hi Richard,
With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
Chas
--- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> Does anyone have a source on carb jets for late model 600 carbs?
> Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> Richard

[richmccolman]

The plugs that are in the engine now only have a few hundred to 1,000 miles - I installed them a few months back - but I take your point, Chas. (I was just curious about carb jet availability, in the event I ever got to the point of eliminating other possibilities.)
Thanks,
Richard

--- In
2cylinderhondas@yahoogroups.com
, "Chas" wrote:
> Hi Richard,
> With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
> Chas
> --- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> > Does anyone have a source on carb jets for late model 600 carbs?
> > Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> > While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> > Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> > Richard

[richmccolman]

Interesting, Don.
I don't know if it's set up with the same internal configuration, but the coil installed on my coupe isn't OEM - it's a part for a Harley, supplied by Mike O'Connor. But I'll bear this in mind.
Richard

--- In
2cylinderhondas@yahoogroups.com
, Don Laughton wrote:
> The 600s have "simultaneous" coils. That means they fire off both ends of the windings, on each revolution this eliminated the need for a distributor. There was one minor drawback. One end of the coil fires positive to negative. The other fires negative to positive, delivering a weaker spark. Under normal operating conditions, this was not a problem. However, not getting the engine up to temperature, prolonged idling or improper/prolonged used of the choke could lead to fouling at least one plug being fouled. Hope this helps.
> Don B. Laughton
> Sent from my iPhone
> On Sep 28, 2012, at 6:29 AM, "Chas" wrote:
> > Hi Richard,
> > With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
> > Chas
> > --- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> > > Does anyone have a source on carb jets for late model 600 carbs?
> > > Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> > > While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> > > Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> > > Richard

[feltonminicycle]

There was only ever 3 different carb jets used on the standard 35HP USA Mainland N600. The early carbs with steel tops held on with 4 screws had a 135 main jet. The later N/Z 600 carbs with aluminum dome tops had either 150 or 160 main jets. I have had good luck even using a 135 in a later carb they all interchange.
Also keep in mind the 600's don't have valve guide seals and you could be sucking in extra oil through worn out intake guides making your plugs black or you could have bad rings or you could just install a hotter plug and just drive the car until you do a rebuild.

--- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> Interesting, Don.
> I don't know if it's set up with the same internal configuration, but the coil installed on my coupe isn't OEM - it's a part for a Harley, supplied by Mike O'Connor. But I'll bear this in mind.
> Richard
> --- In
2cylinderhondas@yahoogroups.com
, Don Laughton wrote:
> > The 600s have "simultaneous" coils. That means they fire off both ends of the windings, on each revolution this eliminated the need for a distributor. There was one minor drawback. One end of the coil fires positive to negative. The other fires negative to positive, delivering a weaker spark. Under normal operating conditions, this was not a problem. However, not getting the engine up to temperature, prolonged idling or improper/prolonged used of the choke could lead to fouling at least one plug being fouled. Hope this helps.
> > Don B. Laughton
> > Sent from my iPhone
> > On Sep 28, 2012, at 6:29 AM, "Chas" wrote:
> > > Hi Richard,
> > > With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
> > > Chas
> > > --- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> > > > Does anyone have a source on carb jets for late model 600 carbs?
> > > > Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> > > > While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> > > > Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> > > > Richard

[richmccolman]

Thanks for the input, Miles.
I haven't put many miles on the coupe since I bought it, and supposedly the previous owner rebuilt the engine not long before selling the car. The thing is, I don't know how good or complete the rebuild was - for instance, whether the valve guides were replaced, or were in decent shape, when he rebuilt the engine.
I'll keep working with it.
Thanks again,
Richard

--- In
2cylinderhondas@yahoogroups.com
, "feltonminicycle" wrote:
> There was only ever 3 different carb jets used on the standard 35HP USA Mainland N600. The early carbs with steel tops held on with 4 screws had a 135 main jet. The later N/Z 600 carbs with aluminum dome tops had either 150 or 160 main jets. I have had good luck even using a 135 in a later carb they all interchange.
> Also keep in mind the 600's don't have valve guide seals and you could be sucking in extra oil through worn out intake guides making your plugs black or you could have bad rings or you could just install a hotter plug and just drive the car until you do a rebuild.
> --- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> > Interesting, Don.
> > I don't know if it's set up with the same internal configuration, but the coil installed on my coupe isn't OEM - it's a part for a Harley, supplied by Mike O'Connor. But I'll bear this in mind.
> > Richard
> > --- In
2cylinderhondas@yahoogroups.com
, Don Laughton wrote:
> > > The 600s have "simultaneous" coils. That means they fire off both ends of the windings, on each revolution this eliminated the need for a distributor. There was one minor drawback. One end of the coil fires positive to negative. The other fires negative to positive, delivering a weaker spark. Under normal operating conditions, this was not a problem. However, not getting the engine up to temperature, prolonged idling or improper/prolonged used of the choke could lead to fouling at least one plug being fouled. Hope this helps.
> > > Don B. Laughton
> > > Sent from my iPhone
> > > On Sep 28, 2012, at 6:29 AM, "Chas" wrote:
> > > > Hi Richard,
> > > > With all due respect, I think that you are theorizing so much that it may adversely affect your actual diagnosis. I like to take these problems one step at a time, and to really dig until I am confident with a particular diagnosis. The problem with theorizing faults and diagnosis, is that as you chase these theories, and try to repair them, you ofen introduce new variables, which can complicate or alter the actual problems, and that can make the proper diagnosis even more difficult to accomplish. Black plugs could be improper jetting, or could be caused by many other things, including a previous owner who installed used blackened plugs. If you are concerned about the color of the plugs, either start with a fresh set of plugs and see how they burn, or invest in a color tune device to actually watch the flame. Take a careful step by step procedure to test your theories before repairing anything or changing things which could complicate and confuse your diagnosis.
> > > > Chas
> > > > --- In
2cylinderhondas@yahoogroups.com
, "richmccolman" wrote:
> > > > > Does anyone have a source on carb jets for late model 600 carbs?
> > > > > Just speculating at this point, but I wonder whether the carbon buildup in my coupe engine could possibly be due, at least in part, to a previous owner re-jetting the carb too rich.
> > > > > While I suspect that at least some of the carbon buildup could be due to other factors, I did notice that the plug electrodes were coated black when I removed them a few days ago, rather than the "normal" tan color. This leads me to think that perhaps the air-fuel mixture could be a bit too rich.
> > > > > Mind you, I haven't even gone inside the carb as yet, so all of this is pure speculation at this stage. I just thought I'd find out if there's a source for jets for this vintage Keihin carb - just in case.
> > > > > Richard