ESE's works engine tuner

[katinas]

Squish?? err nope チャンバ means chamber, that #1 to#4 is the weight of the bare expansion chambers per cyl number
The two rows above are サイレンサ means sliencer, so material and weight of the silencers.

Yes, of course, thanks

[jonny quest]

Frits, Honda CRF250 and CRF450 2017-18. OEM titanium stamped gas tanks. They're pretty!

[Norman]

Just use epoxy. Prep it well. I use a green marine epoxy.
I cure cylinder in oven at 150. Never has come out. Grind A angle any thing you want after cured. Keep epoxy away from piston about. .15mm .i use very fine grinding wheels here.
Only time it has come out ,is when the cylinder needs a plate after lots of hrs,and the platers grind it out.

You prep it right.
It will stay . It helped my curve every where. Bottom to top.

Thank's for the tip. I will first do the welding I can on the cylinders. Have I understood it right that you actually tested to put something like an extra divider?

[lodgernz]

I need some advice please. Below are photos of my 50's exhaust port as stock. The narrow point at 13 to 15 mm from window centre is only 75% of the window area after downdraft correction.
Should I expand this by raising the roof and/or lowering the floor, or is it serving a useful purpose by accelerating the exhaust stream? The downdraft angle is 25º at the top of the port, 4º at the bottom.
I can increase the window area some, which will make this restriction worse relative to the window area.

[wobbly]

The best duct geometry for a low bmep single port is to have around 90% area at the face of the cylinder exit.
Then a transition in the spigot out to 100% that is then the header area.
For high bmep 3 port setups the exit area drops to 75% , I demonstrated the effectiveness of this not long ago with a dyno sheet on here , with the biggest power increase I have seen
in all my hundreds of dyno runs of the 125 kart engines.

[lodgernz]

The best duct geometry for a low bmep single port is to have around 90% area at the face of the cylinder exit.
Then a transition in the spigot out to 100% that is then the header area.

Thanks Wobbly. I plan to fit an insert to achieve that 90% at 1.5 x bore, and the expansion back out to 100% at 2 x bore, as you have advised.
My question was more about the effect of the 75% restriction that occurs quite close to the port window. I would have thought that a consistent steady reduction from port to 90% is ideal, rather than a wildly varying CSA.
I can probably achieve that, but I'm just wondering if raising the roof and lowering the floor at the tight point is going to have a negative effect. You have written many times about the "ski slope" and it's beneficial effects.

[wobbly]

Yes, the combination of a 25* downslope roof and a ski jump floor that has a gradual area reduction is for sure the go.
But this is mainly directed at reducing the CSA of the duct where the Aux ports blend into it .
Here is a cross section of the cylinder I modified to incorporate the side duct ears and the 75% area at the exit.
The roof starts at 25* then flattens out , and the floor slopes away more past the side duct entry area.

[lodgernz]

Yes, the combination of a 25* downslope roof and a ski jump floor that has a gradual area reduction is for sure the go.
But this is mainly directed at reducing the CSA of the duct where the Aux ports blend into it .
Here is a cross section of the cylinder I modified to incorporate the side duct ears and the 75% area at the exit.
The roof starts at 25* then flattens out , and the floor slopes away more past the side duct entry area.

Thanks again Wobbly. The roof will be raised and the sides of the port will get "ears". Can't go any wider as it's already 72% of bore.

[jonny quest]

I used to do 82% on single exhaust ports. Basically a mild bridge port shape. Works well and doesn't ear rings. But bottom of port needs to be around 68%.

[lodgernz]

I used to do 82% on single exhaust ports. Basically a mild bridge port shape. Works well and doesn't ear rings. But bottom of port needs to be around 68%.

Interesting. Might be able to get it out to 75% before I break through the water jacket.

[F5 Dave]

I always used 75 on the RG50, just be careful chamfering.

[dutchpower]

Wobb can you tell me more about this situation

Thanks

[husaberg]

Early HRC


BSL500 in Cycleworld


Kawa X09 at Daytona (i added the pics to fill in space although the cut off one i think is Aaron Slight judging by the leathers Team Moving)

The deisgn never made decent power with it breating through the bottom of the cases
http://1.bp.blogspot.com/-rYf6KffxOG...0/001-Copy.jpg

[ken seeber]

another step. Machining the cylinder to take the injectors now also. Don't seem to get much workshop time these days.
https://youtu.be/bhKrRlZxomc

Fletto, congratulations on the near completion of your creation of the symmetrical circumcision device. Well done, although a question:

Can you, without the introduction of a second servo or a manual belt shift, vary the opening gap to be advanced ar retarded from the shown mid position?

DANGER WARNING: you kiwis should be very aware of such a gizmo cos it does get so cold over there…

[Flettner]

it may not be readily apparent but the tooth belt drive has different numbers of teeth for each Gib. So opening gib moves less than the trailing gib.
This linked belt is just to get the project up and running, ulitamtely both ( or at least one) Gib will be servo driven.
Gib opening will be throttle, Gib positioning will be decided by ECU for best timing for given rpm and other inputs.