Some carb ?'s

I started a disassembly/cleaning/inspection/rebuild project on the carbs from my '80 KZ1000B4 and have a few questions.

First, the manual states that I have VM26SS Mikunis (with the accelerator pump) and the picture in the manual correlates to what I have on the bike. I assume that means they're 26mm throats but, I measure closer to 28mm ID on the engine side. Is that where the measurement is supposed to be or is it inside where the slide is?

Next, as I'm not the original owner of this bike, I was curious as to what jets they had in them as the plug readings I've been getting seem to be a bit rich. The jets are 115's. For stock the manual lists 102.5. I'm running the stock airbox (with K&N element) and a Kerker 4-1 exhaust. Anyone running this combination that could give me a jet size more appropriate?

Also, one of my jet needles seems to be a bit pitted down near the tip. I can barley feel it with my finger nail. Would this affect performance much or should I try to find a replacement?...and, where would I find one?

Guess that's enough questions for now,... stand by for more though.

Sonny

Sopme carb parts websites:

1. www.nrp-carbs.com
2. www.motorcyclecarbs.com
3. www.dropbears.com

if you can get some pictures up we might be able to help you better it kind of sounds like they might be carb's from a 900 i've done that before worked pretty good too.

I took some before I started to disassemble...

The back side....

Measure the carbs on the engine side. Inside diameter on the carb. There should be a number on the outside of the carb down near the float bowl. It is hard to see.

Wired George's probably has a carb I.D. section on his site. Roy

wern't z1-r carb's 28mm. any way the jets you might want start out with are 117.5 mains and 17.5 pilots and i usallay put my clips in the 3 rd position

roy-b-boy-b wrote:

Measure the carbs on the engine side. Inside diameter on the carb. There should be a number on the outside of the carb down near the float bowl. It is hard to see.

Wired George's probably has a carb I.D. section on his site. Roy

That's where I measured with my calipers. Don't have an inside micrometer but, it's definitely bigger than 26mm.

Looked all over the carb with a magnifying glass...couldn't see a number.

Couldn't find the carb I.D. section on WG's site either.

Thanks,
Sonny

timebomb33 wrote:

wern't z1-r carb's 28mm. any way the jets you might want start out with are 117.5 mains and 17.5 pilots and i usallay put my clips in the 3 rd position

117.5? I'm running 115's now and it looks to be rich. I'm confused.

Sonny

sbulla wrote:

timebomb33 wrote:

wern't z1-r carb's 28mm. any way the jets you might want start out with are 117.5 mains and 17.5 pilots and i usallay put my clips in the 3 rd position

117.5? I'm running 115's now and it looks to be rich. I'm confused.

Sonny

If not already done, would first assure ignition and compression are up to specs before blaming carbs.

Good Luck!

[/quote]If not already done, would first assure ignition and compression are up to specs before blaming carbs.

Good Luck! [/quote]

Oh yeah, compression is OK and I have battery voltage at the coils with good spark. There really is no big problem that instigated this tear down. I just purchased the bike and was curious as to what I had and figured a good cleaning was probably in order.

My plug readings show just a bit on the rich side and the idle was set too high as the idle screw was screwed all the way out so, I thought after a valve check, I'd pull the carbs and clean them, do a bench sync, and start from there.

Sonny

Your manual is wrong. 26 pumpers were used in the first part of 79 and only on the LTD model then they switched to 28 pumpers as are on all the other KZ1000s. The carbs pictured are VM28SS w/accelerator pump. They should measure 28.7mm ID on the engine side venturi.