1986-87 32mm carburetor jets and needles

[Yamahawk]

I just got into my carbs, and found the main jets were 110. I know these are larger carbs, but would this be the stock size for the early pregens? The needles are different also, with the ID# being N52I instead of the N61I in the 88-07's. I am going to install 115 mains, because it is for racing and it will be using an aftermarket 2-1 header with it. The pilot jets seem to be standard 35's also.
Does anyone have the stock specs for the 86-87 32mm carbs?
I think the needles are really close to the 5DP7's I run in the RD350 Mikuni carbs too, with the 5DP7's needing some shimming to get them lifted up a little, as the lower notch is on par with the stock 86-87 needle length. The 5DP7's also have a taper like the Factory pro and Dyno Jet needles do. Hmmm... they might be worth a try!

EDIT: I found the factory specs, and yes the stock jets were 110! So, I think the 115's should be a good place to start. I do have 118 and 120 mains also, and can always swap them in if it needs more fuel.

[ducatiman]

i happen to have a '86 32mm Keihin carbset for sale in the forum marketplace.

I can confirm stock is 110 main, 35 pilot and N52H and N52I needles (differ left and right) as mine are so equipped.

Metal slides, correct?

[Yamahawk]

Originally Posted by ducatiman

i happen to have a '86 32mm Keihin carbset for sale in the forum marketplace.

I can confirm stock is 110 main, 35 pilot and N52H and N52I needles (differ left and right) as mine are so equipped.

Metal slides, correct?

Yep, metal slides with keyed 'wings' on either side. I am thinking these carbs should be pretty good runners for racing, the original 86-87 engines had different specs for cam timing and compression, and, I believe the ignition timing is better also. I''m going to try the 115 mains to start, and then go up from there. need to set the float levels also, and if I remember the manual, it is 15mm height.

[ducatiman]

15 a good starting point, tweak using wet tube method, if I may be so bold to suggest

[Somchai]

Charlie I think @ducatiman is a good address to talk about carbs.
Maybe here can you could find also some information http://forums.ninja250.org/posting.p...&t=80222&tro=1
Note: "current setting for the cvk32's
main: keihin 112's (most likely best, i will try 115's)
pilot: keihin 38 (staying put)
needle: factory pro 4th groove (i will try one washer under)
fuel screw: 3.5 turns out (i'll try another 0.25-0.5 turns out)
as for "is it more powerful?" i'd have to say yes."

[Mohawk]

Originally Posted by ducatiman

i happen to have a '86 32mm Keihin carbset for sale in the forum marketplace.

I can confirm stock is 110 main, 35 pilot and N52H and N52I needles (differ left and right) as mine are so equipped.

Metal slides, correct?

If you have these off the bike, can you check something for me please ?

I just stripped checked cleaned my pre-gen ZZR250 carbs, the book says these are 30mm carbs & the outlet is 30mm. But looking at the venturi area, the bore is stepped, so only 28mm at the venturi !

Can you look in the outlet of the 32mm carbs with the butterflies open & see if there is a step on the bore to the venturi area ?

Thanks

[ducatiman]

I'll post a pic up, would that suffice? just waking here in the US, watching moto 3.

Give me a bit.

[Yamahawk]

Originally Posted by Mohawk

If you have these off the bike, can you check something for me please ?

I just stripped checked cleaned my pre-gen ZZR250 carbs, the book says these are 30mm carbs & the outlet is 30mm. But looking at the venturi area, the bore is stepped, so only 28mm at the venturi !

Can you look in the outlet of the 32mm carbs with the butterflies open & see if there is a step on the bore to the venturi area ?

Thanks

Ok, I just measured my carbs, they are 32.1mm ID and there is no step, to speak of inside past the butterflies. There is a hairline where the slide area is, on the butterfly side, but I could hardly feel it with a fingernail. Hope this helps!
Charlie

[ducatiman]

I'll go out on a limb and submit 30 and 32 are/were produced from the same basic body, just bored out by Keihin.

pic 1..30/32 side by side, notice wall thickness
pic 2...32mm...no step past the slide bridge

dimensions already supplied by Yamahawk, so i'll forego.

[ducatiman]

this thread prompting me to compare 32 vs 30 for my own knowledge base.

The 32 will bolt right on any 30 application...the OD of both head side and air filter side are identical, as is choke linkage and fuel inlet.

So for all you racer boyz out there, with correct setup...the 32's may offer some advantage in place of 30's.

So somebody buy the damn things from me already...https://www.ninjette.org/forums/showthread.php?t=257648

[Yamahawk]

Originally Posted by ducatiman

this thread prompting me to compare 32 vs 30 for my own knowledge base.

The 32 will bolt right on any 30 application...the OD of both head side and air filter side are identical, as is choke linkage and fuel inlet.

So for all you racer boyz out there, with correct setup...the 32's may offer some advantage in place of 30's.

So somebody buy the damn things from me already...https://www.ninjette.org/forums/showthread.php?t=257648

think you're right, brother. The 32mm carbs will flow more, and properly set up will outperform the stock 30mm carbs. I am amazed that Kawasaki didn't keep them, perhaps emissions prompted them to downsize, as on the later newgen, they reduced the header size also.
These might be an economical alternative to the $480 Keihin CR31's out there...

[ducatiman]

i'm gonna continue some research, comparisons with some other Keihins I have for a different application.

Adding to the information bank is always good policy.

Why not? Too cold to ride here anyways (speaking for myself)

[HoneyBadgerRy]

The cvk32s would likely be better than the cvk30s, however, they are still CV style carbs, and a race style carb where the throttle cable is attached to the slide will have better throttle response, and should outperform the cvks.

CVK is great for a manufacturer, because it makes it easier to pass emission, and it creates a smooth friendly throttle, but when in the game for power, CV carbs aren't the way to go.

[ducatiman]

all according to your application, wants and needs, budget

So, whats on YOUR bike?

[HoneyBadgerRy]

Originally Posted by ducatiman

all according to your application, wants and needs

So, whats on YOUR bike?

Currently the CVK30s, but only because I haven't ponnied up for fuel injection with the ninja 300 throttle bodies yet.

Once my Yoshimura arrives, I want to go efi and play with cam timing, then my bike will be complete.

[ducatiman]

^ price, all told?

[HoneyBadgerRy]

Originally Posted by ducatiman

^ price, all told?

I haven't really figured it out yet. I could go the microsquirt route, and I would have no idea how complicated it would get. Or I could get the $500 ecotrons kit and a $50 used throttle body. As far as the cam timing I just need to lope the can gears, so free.

[Mohawk]

Thanks for the pics, appreciate the effort. Where the venturi is around the slide, you can se the step I was talking about, OK might only be a 1/2mm but still restricts the intake area slightly.

Quick question, do the 32mm carbs have carb heaters & coast enricher ?

Re the CV -V- Slide carbs, from some testing done by a British engineer using a flow bench his calculated difference, was that a CV needed to be 2mm larger than a slide carb to flow the same air flow, this is due to the butterfly valve which does NOT exist is slide carbs.

A well tuned CV will work as well as any slide carb, if its sized correctly. Most CR carbs etc only work better due to having an accelerator pump & a short intake track which allows the throttle to be pinned without bogging, a cheap slide carb does not have a pump. And peak power can be made at slightly higher rpm due to a shorter intake track length.

You can get CV carbs with accelerator pumps & a slide vacuum hole that is larger &/or with weaker slide springs to reduce the response time to equal slide carbs. You can also reduce the length of the intake stubs to get the same inlet track length. But as that negates most of the user friendly advantages of a CV carb, most people opt for a slide carb which is a known entity in racing !

YMMV