YX 160 cam upgrade worth it?

[tormentandglory]

the lifts I've quoted in the specs above are at the valve.

 

[sean01]

Well I should have checked the stock cam before buying a new one!! I loaded both cams into an engine tonight and measured them.

Tb #0304 cam

inlet
lift - 6.35mm
duration @ 0.020" lift - 245deg
duration @ 0.005" lift - 309deg

exhaust
lift - 6.47mm
duration @ 0.020" lift 248deg
duration @ 0.005" lift 340deg

lobe separation 123deg



Stock dirtmax yx150 cam

inlet
lift - 7.55mm
duration @ 0.020" lift - 263deg
duration @ 0.005" lift - 297deg

exhaust
lift - 7.55mm
duration @ 0.020" lift - 269deg
duration @ 0.005" lift - 332deg

lobe separation 117deg


I like the stock cam better, more lift, faster acceleration, smaller lobe centre angle. Spec isn't much different to the cams in the V2 heads.

that is very strange that the TB cam has a larger lobe separation...
its a pretty well know fact among engine tuners that these engines like around 110deg lobe sep..

TB stuffed that up big time...

well look on the bright side... at least you have a perfect cam now for forced induction....lol

also i have a dirtmax 160 here and i just measured the standard cam..
it only has 7.00mm(closest lobe to cam flange) and 6.45mm lift on at the cam lobes...
also it has YX2106 as a part # stamped on it.

either they used different cams between the 150's and 160's or the rocker ratio isnt 1:1 as i was told.
but i was also lead to believe that the larger engines cam should overpower the smaller engines cam in specs..

i also got a V2 roller cam here which i was told was s25 profile(no markings on it)
it has 6.32mm(closest to cam flange) and 6.25mm lift..
whats the rocker ratio in a V2 head?

T & G can you please measure the lift at the lobe to confirm rocker ratio..

 

[ClassicHonda50]

TB Cams

Hi All

The TBW0304 cam is listed as the stock head race cam.

The TBW0533 is the YX style cam that has more lift and duration than the above stock head cam.

For the V2 Head you can try the V2-2 (S35) cam.

Cams are immediate delivery.

Cheers

Jaimie

 

[tormentandglory]

Hi All

The TBW0304 cam is listed as the stock head race cam.

The TBW0533 is the YX style cam that has more lift and duration than the above stock head cam.

I wish I'd known that before buying anything! Its so hard to find any useful data on performance parts. Does anyone have the spec for the TB #0533 cam? Or does anyone have one lying around so I can measure it?

 

[tormentandglory]

that is very strange that the TB cam has a larger lobe separation...
its a pretty well know fact among engine tuners that these engines like around 110deg lobe sep..

also i have a dirtmax 160 here and i just measured the standard cam..
it only has 7.00mm(closest lobe to cam flange) and 6.45mm lift on at the cam lobes...
also it has YX2106 as a part # stamped on it.

i also got a V2 roller cam here which i was told was s25 profile(no markings on it)
it has 6.32mm(closest to cam flange) and 6.25mm lift..
whats the rocker ratio in a V2 head?

T & G can you please measure the lift at the lobe to confirm rocker ratio..

Lobe lift on my stock yx cam is 6.5mm. I had data written down somewhere for the V2 head but I've lost it The rocker shafts are much closer to the cam, clearly a higher ratio design.

I set the cams in my 4valver at 108 centres, and the cams I've been using in my lifan style engines are something like that to. Very surprising to see the large centres on these yx things...

 

[sean01]

lol i think there trying to get us to do something like this with all these profiles.

 

[dafunk]

great info tmg

 

[tormentandglory]

A bit more useful info guys. I'm final assembling my engine today. I decided to use the stock dirtmax camshaft. I carefully measured the installed heights, spring solid length, valve travel, etc. It seems that the stock cam is far to big and can't be safely run in the engine. The spring retainers will interfere with the valve seals by about 0.75mm! That means every dirtmax 150 engine out there is punching the spring retainers into the tops of the seals. Thats pretty poor engineering on dirtmax's behalf. I thought about leaving the seals off but I've done that on an atomik 150 (by accident, I forgot them :s ) and it makes for a smoky engine. Not very cool. So the next option is to use the TB #0304 cam. After assembling the head and rotating the cam its very obvious that the wide lobe separation is gonna make a slow engine. Theres barely any visible valve overlap at all. Lame... Who designs these shi**y cam profiles anyway??? I'm gonna send the dirtmax cam out and get it re-ground to something useable.

I'd be very interested in borrowing someones TB #0533 cam so I can measure it if anyone has one kicking around I'm a trustworth chap, you'll get it back!

 

[Artsi_L]

More on camshafts. In search of tuning cam specs, the Google took me to a Philippino minibike site.

Pls. see Thailand sourced tuning cam data:
Affordable Racing cams for Honda bikes

Quote:
"specs: Stage 2 of NANO racing products, 280deg - 9mm lobe lift and 102 lobe angle separation."




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