[Adrian II]

Taurim's combustion chamber is actually heading towards the heart/kidney shape, maybe unintentionally, but there might be an unexpected bonus in that as well as un-shrouding the inlet valve.

A.

[StreetKleaver]

Taurim's combustion chamber is actually heading towards the heart/kidney shape, maybe unintentionally, but there might be an unexpected bonus in that as well as un-shrouding the inlet valve.

A.

Older chap next town from me is one of the original Aussie "Ton Up" boys of the era. I've been getting some advice and mentoring along the way. His English 350 Bullets were very short short stroked, high compression, very long duration and high lift cams with with combustion chambers to suit what fuel they were to run on. Mainly methanol. These little machines were 100mph racers. Even with alloy rods and floating bushes! One story was a rod broke a top rpm once and it basically sawed the cases in half!

Generally the heads would get welded up to a "D", "Heart Shape" or "Kidney shape". Didn't go into depth what heads were used to what fuel.

The head on mine is tidied up and unshrouded the most proportional and blended way I could get it without removing too much material from the flat section of the "D". Which was also his advice for pump fuel.

So far I've put 200km on the engine and its pulling harder and harder. I haven't lost any power anywhere. It pulls like a train at 3500rpm.
Stainless materials to build longer velocity stacks are ordered (304 Donut). Also I'm going to see if I can change how the stack is mounted instead of just shoved down the intake boot, with a separate throttle body boot and airbox boot.. See how I go. They should turn up next week.

[StreetKleaver]

Materials arrived to make velocity stacks.
Once again like my Bullet airbox. The stack is made out of a 304 stainless steel donut. So the radius of the bellmouth is the radius of the 1 3/4 pipe.
I've been tacking them together to trial different lengths. Then once happy I'll fully weld one and dress it up.





First test was with the existing Velocity stack. But modified so its a 2 piece setup with a carburetor boot joining the two. For easier changes. This measure 100mm from the airbox wall.





On the test ride it did everything that Taurim had reported with his with the longer stack. Smoothed out the transition up to 3500rpm when these cams come on song. Instead of a abrupt hit. Felt like it gained a little bottom end.

Although the standard boot from the airbox to the throttle body isn't quite straight and has a bit of a off center bend to it.
You can see in the next image what I'm talking about with the exposed edge of the throttle body. So I decided to improve this.



A rough diagram showing how I aim to improve the boot from the airbox to the throttle body and also how to mount the velocity stack. A 3 clamp setup. One on the throttle body, one on the airbox and one securing the pipe for the velocity stack.



Can see the end result here. Its just a silicone hose reducer. 51mmx44.5mm or 2" x 1-3/4". Worked a treat. Secures the first section of the stack and the tract is aligned the best it can be. The Carburetor boot in the foreground for the 2 piece velocity stack setup.





Pictured above is a stack length 90mm from the airbox wall. 10mm shorter from the longest length. Which brought back the known 3500rpm hit these cams do. Which feels no different to the original 70mm stack length I had in there.
Next I'll try 95mm. See if that gets it a happy medium.

I've been making phone calls on various different Dyno tuners. All are over a 4hr drive away for me so I decided to order a Power Commander Auto Tuner and tackle the task myself.
My local dyno tuner who is semi retired and is no longer running his Dyno due to health issues swears by these devices and recommends it for a DIY guy like myself.
Also he'll give me the run down and tips and tricks on how to get the best out of it since he's not running the Dyno.
I have the gist of it, but always open to learn more. Should arrive in a week or so then I can really start testing different stack lengths.

But for now I just wanted to get the mounting of it all a better, sturdier setup.

Cheers

Ben

[Adrian II]

This makes things a bit easier for us, Ben. 

A.

[Taurim]

 

My "next gen" intake with the 36mm injection TB with a Weber 36 carburetor butterfly valve, a Ring with a hole for the Euro 4 air temperature sensor and everything adjusted to have almost no step from one section to another :





I have yet to make some progress for the final assembly 

[Adrian II]

This long stack thing is gaining traction elsewhere too.

A.



Photo: eBay

[Arschloch]

This long stack thing is gaining traction elsewhere too.

A.



Photo: eBay

A short stack won't do much else than to improve optics maybe on this motor.

[StreetKleaver]

Tried a 95mm long stack today and that felt like it was on the money.
Where as to compared the 100mm stack felt a little boggy off the bottom but smoothed the 3500rpm hit out.

95mm felt stronger off the bottom, with a smooth but meaty transition onto 3500rpm, Best  of both worlds. This one so far has felt the best. So I'll leave it at this one for now.

AutoTuner arrives hopefully this week then we can really get things tweaked.

My "next gen" intake with the 36mm injection TB with a Weber 36 carburetor butterfly valve, a Ring with a hole for the Euro 4 air temperature sensor and everything adjusted to have almost no step from one section to another :

Keen to see how the larger TB goes.
I don't think I'll take mine any further than where its at after I get the tune dialed in. I've poured enough time and money into my bikes lately!
Next will be suspension tuning on both my bikes.

[Taurim]

The 36mm mod is a cheap one one you have the PC V and the Auto Tune 

(but I don't know yet if it will work smoothly !)

[StreetKleaver]

The 36mm mod is a cheap one one you have the PC V and the Auto Tune 

(but I don't know yet if it will work smoothly !)

I'm assuming it will definitely help the top end feeding it fuel.

[StreetKleaver]

RDO today so I did some odd jobs that have been waiting to be done.
I had a 2nd set of Clubman bars. The set on the bike are a little too far forward.
So this set I cut them up and re-set them a bar width higher and closer to me. Also a little more pull back to get my hands in a nicer position. Tailored to where I exactly want them.
All tig welded up and I'll post them off to be re-chromed.





Also fully welded the new 95mm long velocity stack I made and polished it up.
Auto-tuner might hopefully arrive by Friday.

[StreetKleaver]

Finally the Auto Tuner arrived.
Wiring it up was a little tricky. Since this bike doesn't have auto lights on. I wired it into a switched power coming from one of the relays. The side stand relay with the orange wire. Which the relay is redundant now since I've removed the side stand switch. Which was actually faulty! I had re-routed some cables and it wouldn't start. So off that came, even the Allen socket cap screws were loose! The Autotune module is mounted on top of the airbox. One of the seat hook ribs needed a little shaving but everything is a neat fit.

O2 sensor is tucked in a good spot out of the way of the brake pedal (Pictures make it look like it's not) But rest assured it is. Which I also have new plans for the brake pedal. I don't like the rubber pad on it. Takes away feel, it's also not inline with the foot peg. It feels I have to somewhat do a Pidgeon toed action inward towards the engine to apply the rear brake. So that will be dealt with this week.

Welded a little loom bar tab to the frame for the cable to be zip tied out of harms way.  Also Fabbed up a little bracket that bolts to the front airbox mount so the 02 sensor plug mounts via the "X-mas tree" clip.





One of my pet hates on these bikes is how messy the looms are. They tend to just shove it anywhere. Mush it all together and throw a lid on it. This is 10x better than what it was.



Another requirement was since the exhaust system is a lot lighter (1.6mm wall thickness stainless steel) even with the mid mounting point still used. The silencer would get a fair old harmonic wobble up at certain rpms. So I made up another little "Z" stay out of angle. So its like as we call in ship building a "bulb bar" steel section. Keeps its strength since the top edge is a "Bulb" compared to a piece of flat bar. Everything feels nice and secure now.



So far today I've replace the spark plug from a NGK BPR6ES to a colder NGK BPR7ES. Since the compression ratio is improved and now we're onto getting it tuned correctly. 
With the laptop plugged in I've just had it idling, setting parameters in the auto tune Target AFR. So far it's cleaned up the idle which was very rich and it's idling a lot smoother with better throttle response.
Taking it for a spin this afternoon to see what the Autotune does. I have a feeling it's going to be rich across the board since the plug that came out of it was black.

[StreetKleaver]

Morning Serg. (It's 6am here) Haha.

So you were right about the autotune. What a difference it's made!

The first run I set the target ARF to 13 in all cells except in the 80-100 throttle percentage to 4750rpm to 6500 gradually richening up to 12.8. Like what you've done. Checked the BPR7ES plug, 13 seems a little rich. Rim is still a little dark. So I've set the lower end target to 13.2. But that plug looks to be the right heat range. The Max lean/rich adjustment to 20%.

Pictured is the old plug top vs the 13afr target plug.

I watched tutorials from Dyno jet not to have the 0 and 2% throttle columns with a target afr. But I still set it to 13 so it would richen up the over-run and lean popping. It tidied the idle up and I actually had to dial back the idle screw on the throttle body. Which now I've left those columns for the 13.2 target.

The attached photo with lots of blue is the auto tuned map. It mainly richened up the bottom and mid range. The high end rev range and throttle positions didn't change too much. Since then I've tidied the random cells with big jumps in values.

Now has a very linear pull all the way through and keeps pull past 5000rpm. I spun it up to 150km/hr easily a few times which is around 5250-5500. It will get the ton easy. I was smiling and giggling. Haha. Stock it barely got past 135km/hr. 140 with a tail wind. Haha

Just wanting for the map to clean itself up and just needs a few more kms to be safe on the new rebuild and a oil change/service to make sure everything is OK (cam lash, primary chain tension etc)

Thanks for your help again mate. I feel the auto tune was a good investment.

[Arschloch]

Overall I was at the Dyno 3 times to verify every change which landed up costing about as much as an autotune device. The only disadvantage to an autotune device as I see it is that it won't tell you the ~rwhp. However if the machine does the ton it's save to claim that some 35ish hp at the wheel are there.

[gizzo]

Overall I was at the Dyno 3 times to verify every change which landed up costing about as much as an autotune device.

Yep, that'd about cover the cost.
I'm OK with not having to interact with the dyno tuners anyway, if I can avoid it. RWHP figures, I DGAF.