Yamaha TRX850 Enthusiasts Forum

Primarily a question for Phuk and Honk, and anyone else with Kent cams.

I am thinking of regrinding my cams, and thought I'd let Kent Cams do it. Now on their web-site, they only offer TDM re-grinding. Is this what You have put in? (I have understood this will give more omphh than peak power, which suits me fine.)

I asked them about adjustable sprockets, and the short and simple answer was "No", but as I recall it, Honk is supposed to have adjustable sprockets in his mean machine?

Would it be a bad idea to buy another set of used cams and let them regrind those, instead of mine? One reason not to, would be the matching wear of the cams and the head, but I don't know if it matters. A bit scared of the cams getting stuck, it has killed one too many TRX lump...

The cams I've got are for a TRX (although I wouldn't be surprised if they were the same as the TDM)

They are designed to increase midrange not peak power

Slotted sprockets were offerred to me (although I didn't deal directly with Kent) and Honk (who I believe did)

Best thing to do is to phone Kent and ask them. Otherwise email http://www.tts-performance.com or http://www.holeshotracing.co.uk or http://www.2ktt.co.uk

Not sure it makes any difference if you grind new cams or old ones tbh?

I seem to recall on a recent post that Honk did have slotted cams but it didn't really make much difference to the power and so left the timing as standard.

Yes he (Honk) does have slotted sprockets.

earywig wrote:I seem to recall on a recent post that Honk did have slotted cams but it didn't really make much difference to the power and so left the timing as standard.

That's not entirely accurate.... When I adjusted the cam timing I ended up within a Gnat's snatch of the standard positions; so for me slotted sprockets didn't gain me anything, but another engine may well be different....

Same story with me.

I decided to set up first and see if sprockets needed slotting - they didn't and I knew that there was no way I would change the timing so I left them as is.

honkdawillydahonk wrote:

earywig wrote:I seem to recall on a recent post that Honk did have slotted cams but it didn't really make much difference to the power and so left the timing as standard.

That's not entirely accurate.... When I adjusted the cam timing I ended up within a Gnat's snatch of the standard positions; so for me slotted sprockets didn't gain me anything, but another engine may well be different....

Honk, where did You get the sprockets from? The mail response I got from Kent was a clear 'No, we don't have them'...

HansJ wrote: Honk, where did You get the sprockets from? The mail response I got from Kent was a clear 'No, we don't have them'...

I had my standard ones machined out.

Honk, How can you say that slotting your cams didn't gain you anything. Just think of the weight !!!

I was hoping it wasn't the same guy that did his heat sink...

No !! I was being serious. If you think about it logically (and I have) by reducing the weight of cam gear you will automatically reduce the centifugal forces of the cam gear, which will result in lower energy-sapping loads on the valve gear train, thus increasing available power to the back wheel. Reducing the centifugal forces will reduce the gyroscopic forces which resist directional changes, thus improving steering response through corners and needing less rider input. The fact that the cam gear is carried high in the engine, any lightening in that area will lower the centre of gravity to further enhance stability and steering.
All in all I think slotting the cams is a very worthwhile exercise even if it has no effect on engine tuning the side effects are enormous, as I think I have just proven. After all if weight saving is not a big factor in modern motorcyle design why do all the major manufacturers insist on making their petrol tanks hollow? I rest my case.

why do all the major manufacturers insist on making their petrol tanks hollow? ooh ooh I know this one.So the fuel will fit in

twolfe wrote:why do all the major manufacturers insist on making their petrol tanks hollow? ooh ooh I know this one.So the fuel will fit in

I think you got a bite there Red Rex! Looks like a fighter too!

Max wrote:I was hoping it wasn't the same guy that did his heat sink...

Nope. I did that. And it works just fine in case anyone was wondering.....

honkdawillydahonk wrote:

Max wrote:I was hoping it wasn't the same guy that did his heat sink...

Nope. I did that. And it works just fine in case anyone was wondering.....

really.......