Pods and Four into Ones

[hen]

I will stay tuned

[AussiXS11G]

hey
I have the opportunity to obtain a set of Web cams with .395" lift (at 50thou")
I will talk to my tuning guy before to be re-assured that I don't need any more porting to get the
most from them.
I will need to ease the head so the lobes have clearance, that's ok, but still wont need to use underbucket shims....good thing I reckon
Evidently, lift is the way forward , not more duration.

[pgnz]

the xs11 cams with a flowed head the cam outfit/head-flow oufit here reckoned you'd lift them to .400 max, said likely bordering on out-of-control after that it's all hard-out racing and hot-rod stuff

[AussiXS11G]

my take on all this...
I was initially running a set of Ivan Tyghe cams and then later stock '78 cams (pre-emissions grind here in Aus) dialled to 105 lobe centres (at 50thou" lift) - I was trying for 110 as suggested by the chap who ported and flowed my head but the slots in the cam sprockets were too short - subject to change atm.

I also was (and will continue) running basically a gutted air box (sans the plumbing for the engine breather (no hot air going into the airbox))
I run a 4-1 '80's vintage Jardine exhaust system (thx again Xtian)
All this to very good effect - the machine was easy to ride at all speeds and made plenty of power evenly across the rev range.

When I first modded the bike in 2003 I toyed with the idea of Mikuni flat slides and pods but was dissuaded by my then (and now) tuning gurus -
the argument was that the pods (or open venturi) are fine on the dyno but when moving they need to draw still (dry) air to be most efficient - so really need to be within the surrounds
of an airbox type protection. Clearly this matters little to drag machines at full noise.

The flatslides, they said would be ideal if MOST of your running is done at 3/4 or full throttle - mine is not - unfortunately 

Shame really, because all that looks soooo cool......
Anyhoo, let's see how it turns out with this current evolution.

This with the (then very worn) Tighe cams and that 4-2-1 exhaust




the red line on these graphs is the run prior to swapping to 160 mains in the BS36 carbs
I forgot to add - i can get 300km (on a run) before I go to reserve......

[pgnz]

dialing in cams means moving the power band
up or down, gain low end grunt and the higher revs
go flat.  xs11 stock 80' cams are perfect as is, 78' cams way more soggy down low . 

and 4-1 pipes down to how expert  the designer is as to how broad the power spread.

 for lo/mid grunt an airbox with the stock xs long rubber carb inlets are best for sure and carbs make big difference with it. beefed out to 1196cc's gives an extra stomp.  pods suck on streetbikes

[hen]

You hit the nail Fuel economy it depends on what you want and like me what sound you like.
I like the best fuel economy I can get depending on my throttle position 
I personally hate that sucking sound of Pods.
I have Tranzac  4 into ones  with a formula one Muffler have replaced the baffle material I love the sound of the engine  roaring but I would like a set of black chrome 4 into 1 without that muffler look
I do believe we should dial in our cams which I have not done

[excess.11]

Pods and four into ones ...........Hey guys what experiences regarding performance / general rideability issues have you had with this set up ....using the standard carbs ?
We KNOW these bikes have unquestionably the best low to mid range power and torque with the oem 4 into 2 and standard air filter system ....a fantastic top end as well.
As far as a 4 into 1 goes........my own experience has been with standard carbs ...........increase main jet one size........no low down torque with power band coming on around 3500 to 4000 rpm.
Plug color seemed to be fine.
As the baffle material wears out it gets worse.
I t s was a pain in the ass around town ......light and fluffy....then......snap.
It seems to me the 4 into 1 and pod setup would be more useful on a raceday where you are mostly using the top end revs and need the engine to breathe more ....obviously fuel consumption suffers as well.
The correctly tuned back pressure the oem exhaust offers combined with standard carbs and air filter seems to be the bees knees for these bikes.