NC30/NC35 gearbox and clutch technical questions

[Psychosomatic88]

I have been half heartledly skimming around the net at race prepped 30's/35's. I remember when I bought my first NC30 and was told it had a slipper clutch, It did kind of feel like one but wasnt the best. So I was skeptical on it.I have since found people writing articles saying the '30 did have a slipper clutch, and other people saying the '35 did not have a slipper clutch. Another article says they use essentially the same clutch parts bar different plate thickness's across some model years.

So... Can it be clarified on what should and should not have a slipper clutch? I didnt really have the oportunity to use it on my last RVF so dont remember, and my current one I have never ridden.

I also think Id like to put a close ratio box from a '30 into my RVF. Has anybody done it successfully? I presume it is possible. Is there any major known pitfalls? Worth the hassle? I quite like the near 70 mph firdst gear and the rest being very close, I missed it on my last '35.

[Spike16]

iv never heard of 30's having slipper clutches and i know for sure mine dosn't (i love getting it sideways going down the gears on my way up to roundabouts)

but the close ratio box is good and iv heard of people swapping it into rvf's especially for racing

[RickOliver]

Both the NC30 and 35 have slipper clutches, albeit fairly unsophisticated ones. In simple terms the clutch centre is split into two halves, one of which (and with it half the clutch plates) disengages on the overrun.

The NC30 and 35 gear clusters are interchangeable although the selector mechanisms are somewhat different on the two models.

[simmo]

ill tell you this for free,

the nc30/35's slipper clutch is 100 times better than the zxr400 one.

[Spike16]

i stand corrected by the master himself

is there any way of adjusting the slipper clutch Rick?

[Cammo]

I much prefer the nc30 gearbox ratios, to me it adds to the feel of the bike (I like the long first gear).

But the rvf 'box is much better for race starts which count for heaps in short sprint races, although the ratios between 3rd and 4th gears is a bit wide.

The nc35 hrc manual recommends the nc30 gearbox.

[Psychosomatic88]

Thanks for the info guys.

I much prefer the nc30 gearbox ratios, to me it adds to the feel of the bike (I like the long first gear).

But the rvf 'box is much better for race starts which count for heaps in short sprint races, although the ratios between 3rd and 4th gears is a bit wide.

The nc35 hrc manual recommends the nc30 gearbox.

I can appreciate that. I have a copy of said manual but has some scrawl over the gearbox section

Would I be really naive in assuming if I can get a complete 'box (and selector system) that it will bolt right in?

[RVF]

The way you alter the slip on a sprag style slipper is to adjust the thickness and number of plates.

I can't recall in the F3 manual if it lists all the different thickness of plate but normaly in a RC30/45 they tend to list 3.

Sprag style slippers do work very well though they do tend to overheat the center "slipping" plates. Anyone ever tryed to get undo the clutch center nut only to find the sprag slips? Thats the slipper clutch working when you dont want it too!

[Psychosomatic88]

The way you alter the slip on a sprag style slipper is to adjust the thickness and number of plates.

I can't recall in the F3 manual if it lists all the different thickness of plate but normaly in a RC30/45 they tend to list 3.

Sprag style slippers do work very well though they do tend to overheat the center "slipping" plates. Anyone ever tryed to get undo the clutch center nut only to find the sprag slips? Thats the slipper clutch working when you dont want it too!

Like this?

"Here is a summary of the plates used for each bike. See the second table below for more specific details and some cross referenced parts available in the USA. I measured several plates and averaged the result to get the thickness.

Bike Model Fiber Plate Thickness Fiber Plate Quantity Metal Plate Thickness Metal Plate Quantity
NC30 - K ?
2.94 mm 8
2 1.58 mm 9
NC30 - L, N 3.06 mm 10 1.58 mm 9
NC35 - all 3.06 mm 9 1.98 mm 8

Note the NC30 L and N, and NC35 all use the same fiber plates (3.06 mm). The NC35, however, uses a thicker metal plate (1.98 mm for NC35 vs. 1.58mm for the NC30 - all years). The NC30 K model bike used 8 fiber plates of one thickness and 2 of another. I don't have the thickness of the 8 fiber plates because I don't have an example I can measure, but the 22201-166-000 fiber plate (qty 2) has been superceeded by Honda with the VTR250 plate, part number 22201-GF6-000. I measured the VTR250 plate as 2.94 mm, so I assume the VTR plate is a similar thickness. I don't have any details (other than part number) on the other fiber plate (qty 8) used for the K model NC30, the 22201-MLO-781, so I don't know the plate's thickness.

For my NC30 (model L and N), I have used Barrnet HP62-16 metal plates, and I have used Honda VTR250 fiber plates, all of which are easily obtained in the US. But, this was the wrong stackup. More recently, I started using the original Honda fiber plate for the NC30-L,N because of the slight thickness difference between the VTR plate and the NC30 plate. For street use, the thickness probably doesn't matter, but for the race track, the slightly thinner VTR250 plate doesn't offer as good of a clutch feel for launches at the starting line.

The table below summarizes the different plates, what they are used for, quantities, and plate thicknesses. (Update Dec 17, 2006: I had the quantities wrong for the NC35 clutch plates - this has been updated.)

Manufacturer Part Number Type Usage Thickness Notes
Honda 22201-MR8-000 Fiber NC30-L,N - qty 10
NC35 - qty 9 3.06 mm '90-'93 VFR and RVF use this plate.
Honda 22201-MLO-781 Fiber NC30-K - qty 8 '89 VFR uses this plate
Honda 22201-166-000 Fiber NC30-K - qty 2 '89 VFR uses this pate
Honda 22201-GF6-000 Fiber VTR250 2.94 mm
Honda 22321-KE8-000 Metal NC30-K,L,N - qty 9 1.58 mm All VFR use this plate
Honda 22321-KE7-000 Metal NC35 - qty 8 1.98 mm All RVF use this plate
Barrnet HP62-16 Metal NC30-K,L,N - qty 9 1.58 mm Barrrnet plate for all VFR

NC30 Date Codes
K = '89
L = '90-'91
N = '92-'93"
"

[CMSMJ1]

That is from Mike Lohemeyer's page isn't it?