The Great Restriction Thread - a discussion of !

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Mori Man
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The Great Restriction Thread - a discussion of !

Post by Mori Man »

When I have been reading through the forum I have been getting a bit lost on what's what about the restrictions of the bike :smt017

Easily done as I am a bit oldman

However, while reading Japanese articles the confusion thickened more shocking

So today I delved my nose into the service books for the models and a veil has been lifted. Most of it I now understand as being the majority of you use an L model.

What I have just now is the H information but will add L in a day or so's time.

Carburators:
ZX4 = 30mm CVK
ZXR400H1 = 32mm CVK-D32
ZXR400H2 = 32mm CVK-D32
ZXR400J1 = 32mm CVK-D32
ZXR400J2 = 32mm FVK-D32 (These should be on your want list)
ZXR400L1 = 30mm CVK (1990)

CDI:
H1 & H2 rev limiter 15,000 RPM

Speed restrictor:
All Japanese bikes 180KPH

Compression ratio:
H1 = 12
H2 = 12:1
J1 = 12:1
J2 = 12:1

Horsepower (PS) Crank:
H1 = 59 @ 12,000 RPM
H2 = 62 @ 12,500 RPM (E , I , Ar)
H2 = 60 @ 12,500 RPM (F)
J1 = 59 @ 12,000 RPM
J2 = 59 @ 12,000 RPM

I'll stop there as it's easier to scan the sheets in and post up.

Now here's a thing, the H was never an official import yet the Kwak book doesn't specify it as (J) for Japan as it does with the L models and indeed you can see above that there was specific models for Italy and France.

They all use 32mm carb's and wasn't until the 1990 L1 that they dropped them back to 30mm, I think the L5 still had them but not the L5A (I'll confirm later)

H CDI's have no lower rev limiter in them - explains why my bike goes until 15K and why I have read on Japanese sites that the H isn't restricted (Just speed). So if your L is rev limited below 15K then an H CDI will open it up - it does not need to be a UK spec box !

From what I can gather power output varies between jetting, base gasket thickness and transmission ratio's.

Strangely enough the J2 seems to have been de-tuned yet it was the "Sports Production" - they had the outer cylinders running 102 mains with the inners at 98.

main jet:

H1 = 102
H2 = 98
J1 = 102
J2 = 102/98

My SP carb's from an M also had this 102/98 combination.

Anyhoo, oodles of stuff on the sheets to look through so I'll get them scanned in.

MM!
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Re: The Great Restriction Thread - a discussion of !

Post by masterofinsanity »

intersting thread as i always thought all the models had 32mm carbs even tho there has been a lot of confuddling going on about these on the forum.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.
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Re: The Great Restriction Thread - a discussion of !

Post by Mori Man »

Here's the H data:

ImageImage

ImageImage
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Re: The Great Restriction Thread - a discussion of !

Post by RedexRobB »

where on earth did you find all that?
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Re: The Great Restriction Thread - a discussion of !

Post by Mori Man »

The Kawasaki Workshop service data manual - saves having to buy a "Haynes" for each model as this gives you all the essentials

I'll get all the L pages up after the New Year.
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Re: The Great Restriction Thread - a discussion of !

Post by cargo »

I hate to rain on Mori mans party but most of that information is in the workshop manuals which can be read in full on ZXRworld here...............

http://www.zxrworld.co.uk/zxr400/manual.html

Including the race supplement



I have the H manual and the L supplement saved as a pdf and am more than happy to supply copies on disc...................I'm sure there are still people selling these manuals on -e-bay because there is NO Hayes manual for the ZXR400.............................and there is NO Clymer manual either.
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Re: The Great Restriction Thread - a discussion of !

Post by Mori Man »

Agreed, but this was to show a very easy quick "ready reckoner" of the differences between models.

Simpler for me as i have the printed sheets side by side (and things need to be simple :smt002 )

However, no amount of reading in the available manuals showed me that the H2's are the most powerful :smt003 and I never got an incline as to which models have 30mm & 32mm carb's on them.

But me and reading don't mix well so I am not saying it's not there to be found.

There is the controversy about European H's though ! shocking

Maybe they were planned for release so hence the full power CDI's but market forces determined to keep them for the home market confuddled

Anyhoo, I'm "happy bunny" as I have an H2 (of sorts) and is the best of both worlds Image
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Re: The Great Restriction Thread - a discussion of !

Post by zimm »

whats interesting in that lot is the cam timing ..

H1's and J1's have the same inlet cam timing (ok the J will have an adjustable sprocket) of 35" btdc to 65" abdc 280" duration as specced in the F3 kit manual .. as opposed to the later 23" btdc to 65" abdc 268" duration used in all other models..

and i finally know where my N36Y needles came from (H/J1)... and why my H1 likes #102 mains ... cos they're the stock size ..

The H2 hasn't been "de-tuned" as such where the staggered jets are concerned .. more "refined" ... the needles are different too (N77C) aswell as some other difference in the carbs .. my guess having tried the H1 (N36Y) needles in several bikes and never getting satisfactory results is that the changes on the H2 are simply a factory attempt at a "dynojet kit" to cure the nasty glitches and flatspots that were present


oh .. yeh... H cdi's wont "derestrict" an L .. cos they wont plug into the loom ! well, they will but all the pins are different and toad... whatever .. it wont work without a patch lead or similar. been there.. re-loomed my whole bike to take an L cdi

its only a few hundred rpm anyway.. and the later cams/intake wont let the engine breathe properly up there anyway.. the only restriction that matters is the 180kph one.
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Re: The Great Restriction Thread - a discussion of !

Post by Mori Man »

Got the rest of the spec' sheets up to an L4 I think. Need to start scanning them in now :smt015

So, If you have a Japanese import L there is one major upgrade you should do 1st and foremost:

Change the camshafts as they are robbing you of probably 4~5BHP as the grind is a lot milder , changing the carb's from D-30 to D-32 should gain 3~4 more. Overall they are 6PS down on a UK spec'd bike.

Still can't see where a "full power" UK CDI changes the performance on an import as the cam's are killing any chance of getting close to a UK bike :smt017 To me all it will do is remove the speed restriction only and there is a lot cheaper way's to do that.
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Re: The Great Restriction Thread - a discussion of !

Post by Mori Man »

While I'm on I'll shove up the cam grinds:

Japan 59PS (CVK-D30)
L1/L2/L3/L4/L4A/L5: IN 256 EX 256

UK 65PS (CVK-D32)
L1/L2/L3/L4/L4A/L5: IN 268 EX 265

SP (M) UK Bikes 59PS Japan Bikes are 6PS down but all spec's are the same - CDI retarded ?
M3/M4: IN 280 EX 265

SP(M) All same power at 59PS
M1/M2: IN 280 EX 265
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Re: The Great Restriction Thread - a discussion of !

Post by Neosophist »

Mori Man wrote:While I'm on I'll shove up the cam grinds:

Japan 59PS (CVK-D30)
L1/L2/L3/L4/L4A/L5: IN 256 EX 256

UK 65PS (CVK-D32)
L1/L2/L3/L4/L4A/L5: IN 268 EX 265

SP (M) UK Bikes 59PS Japan Bikes are 6PS down but all spec's are the same - CDI retarded ?
M3/M4: IN 280 EX 265

SP(M) All same power at 59PS
M1/M2: IN 280 EX 265

Interesting there.

Are UK cams plug & play with the JDM CDI? I presume they all fire in the same place? Wouldn't the H1 cams yield more power? IN 280 / ex 265 over the UK cams? (268 / 265) I have access to both types.. I want to know what to put in over my L1 JDM cams...

Any idea on where the 32mm carbs with half of the needle holder cut-away come from?

As for Overlap..

H1 / M1 / M2: Overlap of 62.50 degrees. The Inlet Cam has an Installed Centerline of 105.00 degrees ATDC. The exhaust cam has an Installed Centerline of 105.00 degrees BTDC.

H2: Overlap of 50.50 degrees. The Inlet Cam has an Installed Centerline of 111.00 degrees ATDC. The exhaust cam has an Installed Centerline of 105.00 degrees BTDC.

Is the H1 / SP exhaust system any different from the other models as with such high overlap it'd surely have been designed with cylinder scaveging in mind, that'd be my first concern putting H1 / SP cams into my motor.
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Re: The Great Restriction Thread - a discussion of !

Post by zimm »

ignition timing (non sp models) is assumed to be the same across the board, at least until proven otherwise by those out there with test rigs.. at least any differences are likely to be marginal, slight tweaks to the limiter rpm perhaps ? differing advance at either end of the rpm range .. nothing a seat of the pants dyno (or even a real one) can see

yep, early cams (or SP ones) give more power at the topend at the expense of a peakier delivery (like there's any midrange to lose ! :pmsl )

no, the exhausts are all the same... well, no they arent but it doesnt really reflect H1/SP cam profiles .. there was the H exhaust which had balance pipes (maybe closed off and just to strengthen the headers ?) running 1-4 and 2-3, and the L exhaust which err ... didnt. Ive swapped from one to the other and noticed no difference.

If you've got H1/SP/UK cams fit them,, you wont notice the smaller midrange, the topend just feels nicer as it kicks in (bit like a stroker) and it'll hold the power closer to the redline

.. just remember that any move away from a known OE configuartion will/can make carb setup fun unless you have all the rest of the parts for that setup. (but really, in your case, you pretty much do)

like H1/SP cams with an L airbox and CVKD-32 carbs :smt017 (sp's used the cams and airbox, but had flatslides .., J1's had the carbs and cams, but different airbox, and differing carb innards)

as an example, I had to move the ZX-4 to a ZXR airbox to get crisp fuelling through the midrange after fitting 32mm carbs (30mm stock)

then again .. a bit like binning the base gasket.. its a known mod thats been done on countless bikes over the years.. so while it "could" cause problems, we wouldnt all do it, if it did.

I believe millameter had a zx4 engine in his L-foo, which is essentially an H1 engine mated to import carbs and an L airbox with uk ignition and an aftermarket pipe ? but without the kbatl clutch
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