Question About Carb. Rebuild Kit for 1987 KZ1000P

Nessism wrote:

jackleberry wrote: Nessium,

I'm talking about one of these: www.harborfreight.com/spring-loaded-center-punch-621.html

Works like magic, no need for a hammer or a socket... Just a well placed paper towel to catch the pin when it rockets out. Can do it without having to ungang the carbs.

Yeah but the carbs should be unganged for reasons mentioned. And I'd rather not put any side stress the post. Way too many people snap off the posts that way.

If it's not leaking from the fuel pipes, and you don't need to mess with the enricher valves, what is the reason to ungang them? Seems like a lot of unecessary work and potential to break things to me.

The beauty of the automatic punch is that the force is small but concentrated just where you need it. I think you're far more likely to break something with a hammer.

jackleberry wrote:

Nessism wrote:

jackleberry wrote: Nessium,

I'm talking about one of these: www.harborfreight.com/spring-loaded-center-punch-621.html

Works like magic, no need for a hammer or a socket... Just a well placed paper towel to catch the pin when it rockets out. Can do it without having to ungang the carbs.

Yeah but the carbs should be unganged for reasons mentioned. And I'd rather not put any side stress the post. Way too many people snap off the posts that way.

If it's not leaking from the fuel pipes, and you don't need to mess with the enricher valves, what is the reason to ungang them? Seems like a lot of unecessary work and potential to break things to me.

The beauty of the automatic punch is that the force is small but concentrated just where you need it. I think you're far more likely to break something with a hammer.

The only way to properly clean the pilot passages is by soaking the carbs. Also, the fuel interconnection O-rings are the ones that are typically the most deteriorated. How do you change them without unganging the carbs? You advocate keeping 30 year old rubber O-rings in the carbs?

Oh, and you will not find the proper O-rings to rebuild the carbs in a generic Harbor Freight O-ring kit. I posted a link to a very complete carb rebuild tutorial that apparently nobody bothered to open. Inside you will find the actual O-ring sizes you need.

I am doing this right now on my P Bike.
You don't need the rebuild kit. Save your money. partzilla has the O-rings you need and so does Z1. partzilla is slightly cheaper.
The only thing you need to replace are the O-rings and the bowl gaskets.
PM me if you have any questions. It's an easy job but you have got to be thorough.

Nessism wrote:

jackleberry wrote:

Nessism wrote:

jackleberry wrote: Nessium,

I'm talking about one of these: www.harborfreight.com/spring-loaded-center-punch-621.html

Works like magic, no need for a hammer or a socket... Just a well placed paper towel to catch the pin when it rockets out. Can do it without having to ungang the carbs.

Yeah but the carbs should be unganged for reasons mentioned. And I'd rather not put any side stress the post. Way too many people snap off the posts that way.

If it's not leaking from the fuel pipes, and you don't need to mess with the enricher valves, what is the reason to ungang them? Seems like a lot of unecessary work and potential to break things to me.

The beauty of the automatic punch is that the force is small but concentrated just where you need it. I think you're far more likely to break something with a hammer.

The only way to properly clean the pilot passages is by soaking the carbs. Also, the fuel interconnection O-rings are the ones that are typically the most deteriorated. How do you change them without unganging the carbs? You advocate keeping 30 year old rubber O-rings in the carbs?

Oh, and you will not find the proper O-rings to rebuild the carbs in a generic Harbor Freight O-ring kit. I posted a link to a very complete carb rebuild tutorial that apparently nobody bothered to open. Inside you will find the actual O-ring sizes you need.

I find squirting carb cleaner through the pilot circuit to be sufficient. The stuff that *really* blocks up these passages isn't soluble anyway, it's solid grit.

If that 30 year old rubber doesn't leak, then why not keep it? It would be quite obvious if it did leak there, and it also would be unlikely to affect performance (which is why people generally clean/rebuild carbs). I'm sure the o-rings are brittle, but as long as you don't disturb them they'll probably hold that seal for another 30 years. If you ungang the carbs, then yeah, you'll need to replace them. I just don't see the point.

And I do disagree about the *big* (blue) HF o-ring assortment. It has o-rings to fit everything in BS34-CV carbs except the idle mixture screws. $8.99 buys you enough to do probably a dozen rebuilds.

You can rebuild the carbs right or you can do it half ass. Each person has to make the choice for themselves. The half ass rebuilds often result in the person having to do the job again, sometimes several times. Cleaning the carbs properly one time, by breaking them down and soaking the parts in carb dip, is a time saver for many people in the end.

Problematic area to watch out for are: pilot jets plugged, choke tubes plugged, pilot circuit plugged, choke tube passage in the float bowl plugged, weak float valve springs, brittle interconnection tube O-rings, float seat O-rings, and others but this comes to the top of my mind.

OEM Nitrile (Buna-N) O-rings have a shelf life of 15 years. At 30 you are in trouble. GOOD LUCK if you don't change them.

Regarding the O-ring sizes to properly rebuild a set of Mikuni BS (CV) carbs is concern, I've listed the sizes below. Make sure that Harbor Freight kit has these sizes or you are using the wrong O-rings. Sometimes, you can take an undersized O-ring and stretch it and shove everything together, but that O-ring will be under stress and will have a shortened service life. Who knows what the quality of those HF O-rings is anyway. Again, do what you want, but if you want to do the job right, you need the proper size O-rings. Cycleorings.com sells a nice kit for a very nominal price. Purchasing in bulk from McMaster Carr is what I did. Viton O-rings are more chemical resistant than Nitrile but more expensive.

O-rings (thick X ID)
Choke plunger: 1.5mm X 10mm
Drain bolt: 1.5mm X 5mm
Float Needle: 1.6mm X 7.1mm
Fuel Tubes: -10 size (1.8mm X 6mm)
Pilot Screw: 1.13mm X 2.70 mm

Nessism wrote: You can rebuild the carbs right or you can do it half ass. Each person has to make the choice for themselves. The half ass rebuilds often result in the person having to do the job again, sometimes several times. Cleaning the carbs properly one time, by breaking them down and soaking the parts in carb dip, is a time saver for many people in the end.

Problematic area to watch out for are: pilot jets plugged, choke tubes plugged, pilot circuit plugged, choke tube passage in the float bowl plugged, weak float valve springs, brittle interconnection tube O-rings, float seat O-rings, and others but this comes to the top of my mind.

OEM Nitrile (Buna-N) O-rings have a shelf life of 15 years. At 30 you are in trouble. GOOD LUCK if you don't change them.

Regarding the O-ring sizes to properly rebuild a set of Mikuni BS (CV) carbs is concern, I've listed the sizes below. Make sure that Harbor Freight kit has these sizes or you are using the wrong O-rings. Sometimes, you can take an undersized O-ring and stretch it and shove everything together, but that O-ring will be under stress and will have a shortened service life. Who knows what the quality of those HF O-rings is anyway. Again, do what you want, but if you want to do the job right, you need the proper size O-rings. Cycleorings.com sells a nice kit for a very nominal price. Purchasing in bulk from McMaster Carr is what I did. Viton O-rings are more chemical resistant than Nitrile but more expensive.

O-rings (thick X ID)
Choke plunger: 1.5mm X 10mm
Drain bolt: 1.5mm X 5mm
Float Needle: 1.6mm X 7.1mm
Fuel Tubes: -10 size (1.8mm X 6mm)
Pilot Screw: 1.13mm X 2.70 mm

Good info. In my experience the OEM o-rings don't even last 5 years, depending on where they are in the system (the ones soaked in fuel last a lot longer, IME than the ones exposed to oxygen and heat). The harbor freight ones are fine. I also get things not found in the cheap assortments from mcmaster. One generally doesn't know what one is getting in carb kits either... That being said, o-rings in static situations don't just usually start leaking just because they're old. If they held a seal before they hardened, then they'll likely continue to hold it until disturbed.

There's a difference between half-assing and just fixing what's broken. It's always a balance between doing a good job and risking further repairs. The deeper you disassemble something, the more you increase the potential for something to break. Plenty of people think that rebuilding carbs requires replacing all the brass too, because to do otherwise is half-assed. I also think that's silly.

Thanks to everyone for their time and replies. I will order those o-rings!

Hi I just want to thank everyone again for the help and replies. This place is great. I hope that someday I can offer assistance to people the way that you guys have helped me out.

Also, I did read through the carb rebuilding PDF that was posted it was very informative.

Having said all of that I think I found what the problem was with my carburetor. I removed the bottom float bowl on the carburetor that was giving me trouble and found this sitting in the bottom of it.

I assume that this part needs a new O-ring. Is it just held in by friction after the O-ring is replaced?

I hope this explains why gasoline was flowing through my carburetor boot and into the airbox of my motorcycle.

That's the pilot jet plug. It does not explain gas in the airbox but a bad oring there may make it run rich.

OK Thanks a lot. I think it was just rolling around in the float bowl. If I put in a new o-ring it's just held in there by friction?

When the float bowl is installed it shouldn't be able to come out. The if the o-ring is bad/missing then too much fuel can get to the pilot jet.

Man, that would be great if that's all it is.