V4 Camshafts

[TeamDragon]

Rebuilding my RVF 400 engine at the mo. To cut a long story short I have snapped a camshaft while tightening down holders. Read the manual, tried to be as careful as possible but was in a rush....crack one of the dowels hadn`t seated correctly, exhaust camshaft of rear head snapped clean in two. I am a fool.
Anyway my question regards the Cams themselves.
Is there any difference between the Cams of each head?
Could an exhaust cam from the front cylinder head be used in the rear head?
They are marked front and rear but as far as I can see and measure they are the same.
Reason I ask is I`ve found a second hand front cylinder head and wondered if I could pinch the cam out of that?

Thanks

[CMSMJ1]

I would be worried..but if you are prepared to try it

The fiche has them as different asssemblies..but seeing as you could fit the equivalent NC30 camshaft I expect you might want to try the replacement NC35 one..

Can you take the 35 one out of your bike and see if you can physically fit it and that the lobes are in the same place etc?

[Neosophist]

Hmm.

As Mark has said they are listed as different assemblies.. not sure if the timing is any different as the rear heads get hotter than the front, which is why there run slightly richer.

You could always try it.

Did you damage the cam-cap? there machined at the same time as the journal in the head (matched) so if your chopping and changing things might be worth checking clearances with some plastigauge

[TeamDragon]

Can you fit the NC30 cams into the RVF head?
I have an old NC30 lump in the corner of the garage from years ago, had a look but they look very different? (Drive gear, lobes, journals, caps etc)
Cam Caps are undamaged so was just looking to swap cam.
Was worried about the timing/lobe position differences which is why I asked first.

Spoke to Bristol Honda (fowlers i think) earlier. Parts guy said the Cams should be the same, different part numbers because they are sold as an assembly. But couldn`t say for sure

Anybody got a rear head exhaust cam they want to sell? lol

Thanks for the input

[hunter]

How soon do you need the cam i could find you one,
and i'm not far from you.

[RoninZX-10R]

Sorry, but I had to laugh when I read your post because I'd done exactly the same thing last year. Checked all my valve clearances, worked out what shims I needed, orered and installed new shims, re-measured my valve clearances, feeling quite proud that I'd done the job properly. When I was tightening up the front exhaust cam journals I heard a crack, thinking/hoping it was just the dowels seating into position, then I noticed one half of the cam could turn freely while the other half remained solid.

Thankfully a mate of mine had a spare exhaust cam, although neither of us knew if it was for the front or rear head. I personally think they would be exactly the same, I certainly hope so since it's run without a problem since I installed it

[Mananon]

I suppose the profile might be a tiny bit different but I'd doubt it. Timing must be the same mustn’t it?. Driven by the same crank with the same number of teeth on the gears so...
As the bloke in the garage said, as an assembly, they are different but we're just talking about the cam.
I'd be pretty confident of a front cylinder cam working correctly on the rear cylinders.
VFR and RVF cams are interchangeable but, being slightly different in profile, you'd have to replace both RVF exhaust cams with the VFR exhaust cams so that both heads are matched.

[TeamDragon]

I heard a crack, thinking/hoping it was just the dowels seating into position, then I noticed one half of the cam could turn freely while the other half remained solid.

Exact same thing mate, would of been funny if I wasn`t cursing and punching thin air so much

I cannot see why they would be different as said above so I will try an exhaust cam from front or rear, whatever I can get. Didn`t realize NC30 could be used in 35, cheers

Hunter, if you can find one mate it`d be awesome.

Cannot thank you all enough.
Been on a few good car forums over the years but never found one for my bike, think I`ve found a new home

[hunter]

Sorry i'v been so long getting back to you on this mate,
i have looked high and low for these cams and after tearing the place to pieces i remembered a mate of mine had the 35 stuff of me about 18 months ago.sorry mate.

[TeamDragon]

No worries mate, thanks for looking.
As it happens it was an intake Cam I was looking for Too many projects on the go....
Anyway, got a front head off of ebay. Nicked the cam, timed up and fitted a okay.

TIP - If fitting the rear cams, set front-head cams so timing marks are pointing straight down. (Makes rear cams far easier to fit due to lobe orientations !!)

Engine assembly finished and refitted in frame (pic later LOL ).
Starter Motor, Wiring, Exhaust, Thermostat housing etc all refitted + new oil filter.
Tomorrow is Carbs, Cables, Airbox + Tank. Then cross fingers and

Original reason for strip down was because of a very sick gearbox. Got 2nd hand set and refitted.
Original crank bearings, oil and water pumps even head gaskets have been reused

Will probably grind to a halt not long after startup but it is nearly in one piece instead of in multiple boxes all over my garage!!!! Happy Days!!

Anyone help out with basic procedure/checks for starting up & running in a half arsed rebuilt engine?

Thanks