nc35 cams vs nc30 cams?

[scooble]

I was under the impression that the RVF developments improved all round power characteristics, driveability and mid range. I've hear of a few racers who have used VFR carbs and heads, but also using RVF cams in that it gives better top end power at the expense of midrange.
I am sure that Honda in their ultimate wisdom put a lot of thought into their development, but you must also consider what it is they were trying to achieve for a road bike and the market to which they were trying to sell it to at the time.

[CMSMJ1]

I reckon the reported power and the peak power were not the same.

The RVF carbs are better than the NC30 - for road use.

I reckon unless you are making a bitsa motor then a little bit here and there is not going to make the difference.

[speedy231278]

Didn't I read somewhere that RLR's TT winning RVF400 had RVF carbs, but bored out to or beyond the size of NC30 ones? Or was it NC30 ones bored out? Whichever it was, that must have been an interesting job!

[Cammo]

The change in the head might be a factor, but in my ignorance I can't see a tiny difference in the port diameter robbing 10% of peak power.

Whether or not it was exactly 53hp, power does appear to have dropped compared to the nc30. I personally believe the standard rvf exhaust system was responsible for most of the power difference, as evidenced by dyno results from peeps on here that have changed just the exhaust system to an aftermarket system (usually gain around 5hp).

It would be interesting to cut open an rvf system to see whether there's any sort of baffling or reduction of diameter inside (I do have a spare...). The standard rvf muffler is also more restrictive than the standard nc30 muffler (very different internal designs).

Didn't I read somewhere that RLR's TT winning RVF400 had RVF carbs, but bored out to or beyond the size of NC30 ones? Or was it NC30 ones bored out? Whichever it was, that must have been an interesting job!

Yes, they bored the nc30 carbs out to 34mm. It made 85hp - probably the world's most powerful 400cc rvf engine. I can't find the page on the net anymore, RLR might have pulled it.

This is my 2 pence worth, rvf's make more power once fettled for racing that's a fact.

I agree, and so do most race engine tuners. The rvf engine as a whole (bottom end included) is superior to the nc30, but this is probably only important to tuners looking to extract every last drop of power.

You'd probably gain a couple of hp at most bolting on the rvf cams and heads to an nc30, but if you feel like doing this then I say go for it.

[VFRkieran]

Been having a think about this and i will comapre the weight of the RVF and VFR cams to see how much weight is saved there, its reportedly about half a kilo So surely the lack of weight there is going to make a noticeable diffrence alone! Supposedly even removing the quietening gears makes a diffrence and they weigh hardly anything.

Im not looking for huge improvement by fitting 35 cams, its mainly due to the fact that i got given a blown 35 motor for free and i cant justify making any money on it by selling parts, so i may aswell fit them to the 30 even for a small improvement and so i can do a bit more willy waving if anyone asks me what work has been done to the bike. Once i get the bike back on the road i will get it dynoed and see what sort of HP we are looking at with freshly overhauled heads, RVF cams and a full system.

Here is what Rick O told me when i asked him about fitting RVF cams and removeing the quietening gears:
"RVF cams - the inlets have exactly the same timing as the NC30 ones,
the only difference is that they have a very slight `quietening ramp`
on the leading edge of the cam lobe. The NC35 exhaust camshafts have
the same amount of lift as the NC30 ones but more duration so swapping
those will improve performance.

Removing all the quietening gears (from the cassettes as well as the
camshafts) will gain you a theoretical bhp or two, but it will also
make the engine more mechanically noisy and I`m not really convinced
that it`s worth the time and effort involved unless you are trying to
squeeze the last drop of power out of a full on race bike"

So for me words from the guru's mouth are enough to make me decide to fit them and i think unless we get some hard proof of BHP figures then its anyone guess as to weather there is an improvement or not...

[Drunkn Munky]

Im not knocking anyone for swapping in RVF cams, just a shame to ruin a RVF motor for little gain, unless its blown

Im pretty certain the RVF system itself isnt restrictive as tuners and racers cut the final link pipe off and make shotgun and SP1 systems using the rest of the pipework, my bet is its in the can if anywhere.

85bhp! we need me info on this!

[VFRkieran]

Im not knocking anyone for swapping in RVF cams, just a shame to ruin a RVF motor for little gain, unless its blown

Im pretty certain the RVF system itself isnt restrictive as tuners and racers cut the final link pipe off and make shotgun and SP1 systems using the rest of the pipework, my bet is its in the can if anywhere.

85bhp! we need me info on this!

Oh yea i agree it isnt worth taking a good motor off the road just for the camshafts. If im not mistaken Fonty's race bike has a chopped shotgun style 30 system fitted, not sure if his is a bitsa or if he fitted the 30 system because its better positive i asked him at brunters but i cant remember what he said!

Id love to know whats been done to that 85hp RLR motor! Christ that must be more than the tt-f3 RVF motors where putting out, do you know what HP that TS engine of yours produced Tony?

[Drunkn Munky]

You gota be running oversized pistons and seriously lumpy cams to warrant even boring the carbs out to 34mm, someone must know the details?

F3 motors made about 78 i think, TS also did some extra work on that motor inc machining the valve pockets deeper but its tired now, be nice to see it in the high 70's after a refresh.

[speedy231278]

85bhp! we need me info on this!

And probably a five figure budget! lol

[webby16]

thanks for the help and suggestions everyone! really good arguements for and some against i think il stick to the vfr cams and just get tyga system and configure a ram air system with a hrc tray and carb setup cdi map, hrc copy with cbr up rated shock nc35 front end uprated, cbr 600 calipers and master cylinder ebc discs. and ebc race clutch plates and springs...

anyone used a scottoiler on the vfr or rvf by the way i know its going off the subject of cams?