Perfect header length

[lazylightning@mail.r]

The header has a number of leaks in it. I tacked it together without a mask, so I had to cover the welding with my hand and not look at what I was doing. So all those bad welds were not good for the welder that finished it for me. They smoke all the time at the Rasta bike shop and the welder that welded it for me just plain missed a few spots ;-) Maybe they will clog up and oil will stop leaking through, or maybe I will bring it back ancd we will try to get it perfect. Grinding and sanding and polishing helps the appearance afte welding. I'm afraid it will rust though. It's not stainless steel. So maybe I should spray some oil all over it when it's hot to give it a more even appearance and save it from rusting %-)

 

[lazylightning@mail.r]

Thanks for the tip on adjusting the pad pressure regulator. It really helped. I turned the gear 1.5 times. I need to make it just a little tighter now, it still slips sometimes. All in all it's great now. I love running it without the muffler, just the stinger. It's got a really wicked sound when it starts getting down and nasty ;-)

The screwdriver needs to go in at an angle down under the lip of the hole towards the clutch plate area to find the slots.

 

[lazylightning@mail.r]

Here it is with the stinger on: http://www.youtube.com/watch?v=tD0ApMUGgWY

And a photo:

 

[lazylightning@mail.r]

Of course now it doesn't want to idle and races wildly again, ever since I put the torque pipe on. I wonder what effect the pipe has to make it race under no load?

 

[Deleted member 12676]

assuming there is no intake or crankcase air leak all we can deduct is that the pipe has changed the jetting need at idle to be richer. Looking it up on the internet just now I see that reducing the exhaust back pressure causes the engine to run leaner. Your new pipe has a wider header pipe, right? What is the inner diameter of your stinger and what is its length? Are you going to make a silencer for it?

 

[lazylightning@mail.r]

assuming there is no intake or crankcase air leak all we can deduct is that the pipe has changed the jetting need at idle to be richer. Looking it up on the internet just now I see that reducing the exhaust back pressure causes the engine to run leaner. Your new pipe has a wider header pipe, right? What is the inner diameter of your stinger and what is its length? Are you going to make a silencer for it?

My header now has an inner diameter of 25mm and my stinger has an inner diameter of 12mm and is 17 inches long. I cut off an inch from the 18 inch stinger to mount the muffler. I just happened to have some stainless steel tube the right diameter. I took the muffler off for now because it is too quiet. A bit quieter than stock with it on. It can't be any quieter because the motor emanates noise through the cylinder and head. I like to raise hell everywhere and make everybody turn their heads in shock. It sounds really wicked with no muffler. It's on the pipe the whole time. Now I don't like to drive real fast always and just cruise around and start accelerating now and then because it sounds so nice.
The problem is that I checked the spark plug and it is very black and oily. It doesn't look lean. But maybe I need to widen that idling hole on or under the atomizer column of my Dellorto SHA.
I've got a piece of industrial teflon as a coupling channel between the pipe and stinger. Great material can work in temperatures of 400+ C and is radiation resistant! ;-)
To tighten the clutch pad pressure mechanism I just rolled the bike backwards a little bit when the screwdriver was wedged into the slot through the adjustment hole. I made the gear turn 1.5 turns clockwise. It's holding much better now under acceleration but it still slips a bit and needs to be tightened some more.

 

[Deleted member 12676]

The plug shows how the fuel mixture is at the rpm most used. Since you don't ride around at idle speed you can't go by the plug to determine if your ratio of gasoline to air is correct.
A 69cc reving to 6000rpm needs an 18 inch stinger between 10mm and 12mm. Since you are using 12mm you have less backpressure. I think you should use the silencer for more backpressure (which often gives more power) and then see how it idles.

 

[HeadSmess]

does look quite nice.

after extensive stuffing around 22mm is the closest match the the HT exhaust port. approx 380 mm^2 25 gets a bit too big.


a flexible join right at the cylinder (springs and socketing tubes) prevents any cracking of pipe, cylinder or anything else.


dont worry about stainless versions. unless its welded properly, which costs money, they really tend to crack badly. you need the right grade of stainless, its harder to work with, and with the majority coming from china these days, it isnt even stainless after 5 minutes at 100 degrees...

otherwise, im quite impressed

use any actual software/design or just wing it?

 

[lazylightning@mail.r]

does look quite nice.

after extensive stuffing around 22mm is the closest match the the HT exhaust port. approx 380 mm^2 25 gets a bit too big.


a flexible join right at the cylinder (springs and socketing tubes) prevents any cracking of pipe, cylinder or anything else.


dont worry about stainless versions. unless its welded properly, which costs money, they really tend to crack badly. you need the right grade of stainless, its harder to work with, and with the majority coming from china these days, it isnt even stainless after 5 minutes at 100 degrees...

otherwise, im quite impressed

use any actual software/design or just wing it?

Hi!

I used Jaguar's calculator. The header length and width and stinger length and width were also calculated this way. The header and pipe should be good for up to about 9000 rpm's by the calculations made (after I bore my Delorto from a 16mm to an 18mm). The 12mm stinger may keep my rpm's down under 7500 rpm's, so I may try something wider later. But it is nice have low down rpm torque and I really need to repress that crank with normal bearings on the conrod ends. I will use some special ceramic-metal coatings used for racing and by NASA for super surfaces that just don't wear. That will be later on though.
Here in Russia we don't usually store metal that we find laying around unless it's something nice like stainless or titanium and so on. So it's harder to find cheap metal here because you have to buy it new and in pieces no less than 6 m long(tubing/pipes). I had alot of stainless I had garbage picked over the years. You can just visit a metal recycling intake where people sell aluminum cans and other metal for money - they always have good metals on hand in small portions for a couple of dollars. The torque pipe was made from some .9 mm thick stainless chemical tank that I had dragged home from the garbage(made in the USSR). The torque pipe was welded together using standard coated steel electrodes and typical welding. It would have never worked if the welder had not been a wizardess. A nice granny with about 40 years of welding experience - started with ship building as a girl. The header is just plain steel with a 1.5 mm thickness, it won't break from the stress. They use it to make frames for big heavy Rasta choppers and electric bikes here. They welded it good. I brought it in yesterday and we got almost all of the holes in it sealed up. I've got the pipe clamped onto the frame and at the end of the stinger too. Nice not to have oil blowing everywhere.
I managed to widen my exhaust opening in the block/cylinder to 25mm (round hole) at the place where header connects to the block. Of course the exhaust port inside the cylinder at the wall is shorter, but wider at 31mm wide. They taper together okay for good flow. My transfers were mega deepened and widened forward. Head was milled down to the fins, but I should milled down the cylinder too so as to increase compression more after I get those new bearings in. Piston has been modified for better flow. Geeze, if I will actually go ahead and make a lightened stuffy stroker crank with like 7mm more distance from center it will be amazing but then the torque pipe will need to be made again.
It rides amazingly well. Just alot of power. If I'm at cruising speed and hit the gas, I'm at top speed in a couple of seconds. Blowing lot's of cars away in city traffic here. The sound is lovely! %-D I cut power ahead of time to coast to stops when possible, trying to save my cantilever brake pads somewhat.... Looking out real careful like for fools on the road. Assuming the worst possible action from every car I see anywhere and waiting for pedestrians and bicyclists to crawl out of nowhere. I've even been dressing up with riding goggles and bright bandana on my head to be seen better. It's much safer with no muffler though. Everybody notices me now ;-)

 

[lazylightning@mail.r]

The plug shows how the fuel mixture is at the rpm most used. Since you don't ride around at idle speed you can't go by the plug to determine if your ratio of gasoline to air is correct.
A 69cc reving to 6000rpm needs an 18 inch stinger between 10mm and 12mm. Since you are using 12mm you have less backpressure. I think you should use the silencer for more backpressure (which often gives more power) and then see how it idles.

My muffler gives no back pressure whatsoever. Remember? It's quite quiet. But I like it much better loud for the time being. Before I removed the stinger to silicone seal the mating surfaces, I must have previously mounted it incorrectly because I noticed from the stain that more than half of the 14mm hole from the pipe to stinger coupling had been closed because of misalignment. It had an even more bumble bee roaring sound then, but there was still an idling problem as I remember. Maybe it's just lean at idling now and I need to give it more gas through the little hole under the column? I did not widen that hole yet, I had made another hole about midway up to the lower column hole to fix the problem before. Maybe it needs to draw from down lower? I don't want to limit my rpm's to 6000 with a smaller stinger, though it might be possible to have a cable actuated partial-plug that would be on a spring and limit the flow at lower rpm's. Then just flick the lever and it opens up. Maybe later I can put a second stinger on too that would be sealed off and open up for much higher rpm's like 9000. It could be electronically controlled and actuated %-D