ESE's works engine tuner

[F5 Dave]

Glad its not just me Rob, but I feel your pain. Dynos suck when they show up what must work as doesn't.

[TZ350]

Glad its not just me Rob, but I feel your pain.

Getting used to the pain because things always seem to go backwards before getting it right. ...

But it does leave me I a bit concerned about the dry sump gear box idea and extra large crankcase volume ....

but your dam went all the way to the transfer tops or no ? that is what it appears from the photo. how tall was dam at blue line ?

Blue = no dam. Red = exhaust dam level with the transfer tops.

I think the Aprilia had a CNC machined exhaust port. They started low and progressively raised it finding more power with each step but they ran out of time before getting level with the transfer tops.

For practical reasons Chambers had to start high and now can progressively work down.

Lets see what tomorrow brings. ...

[husaberg]

Blue = no dam. Red = exhaust dam level with the transfer tops.

I think the Aprilia had a CNC machined exhaust port. They started low and progressively raised it finding more power with each step but they ran out of time before getting level with the transfer tops.

For practical reasons Chambers had to start high and now can progressively work down.

Lets see what tomorrow brings. ...

I know its Daves job but I couldn't resist.
I predict tomorrow will bring

one of the pics I seen of the RSA duct seemed to have cuts overlapping for antibackflow but it might have been the angle or a quirk on the machining pattern.
Maybe Frits could confirm or deny the existence of this sort of datail?

[wobbly]

Keep in mind that my take on this is that the major effect is upon the A port short circuiting factor.
If you look at ducts that have had the floor lifted alot the bulk flow goes sonic quite severely, and this I feel can override the positive effect of the A port trapping efficiency.
Try lowering the floor but leave as much infill in the bottom corners as you can.
And at some stage try the big radius on the floor port corner only, as this will increase the outflow Cd but wont influence the trapping efficiency of the corners on the bad A port flow turning.

The Aprilia ducts were CNC cut, and what you are seeing is called steppover, ie the amount the cutter is advanced into the port for each successive tool path.

Another issue is that the added in dam has a crap heat transfer coefficient, and thus will be overheating the retained charge in the duct.

[TZ350]

If you look at ducts that have had the floor lifted a lot the bulk flow goes sonic quite severely, and this I feel can override the positive effect of the A port trapping efficiency.

Try lowering the floor but leave as much infill in the bottom corners as you can.

Thanks, yes instead of lowering it evenly across the port like we were going to, I will suggest to Chambers we take it down in more of a V shape.

[Frits Overmars]

one of the pics I seen of the RSA duct seemed to have cuts overlapping for antibackflow but it might have been the angle or a quirk on the machining pattern. Maybe Frits could confirm or deny the existence of this sort of datail?

That's new to me, Husa. But I'll show you some pictures of the RSA exhaust duct if you show me yours.

[peewee]

hey wob a few questions on the yami twin. i got the straight cut primaries and it uses what appears to be a brass bushing between the basket and trans shaft. every other engine ive seen uses a double roller needle bearing. i may be able to swap the small gear in the center of the basket so i can then use a double needle bearing. would that be a good idea or just leave the brass bushing ?

on the oem ignition lighting coil. does it have enough power to run a small rad fan like whats used on the ktm dirtbikes ? service manual doesnt say anything about how many amps it is. just wondering if it would take more power to run the fan than i would see from a possible gain in lower water temp if that makes sense. if it takes 2hp to run the fan and ill only recover 1hp from the lower water temp is what im getting at

[AndreasL]

Thanks wobbly.

I have used the "75/90%"-rule so far. This was an attempt to try to make it a bit more scientific.
Guess trying some runs at those %, plus minus some, to optimize the duct/power curve is the way to go.

[husaberg]

That's new to me, Husa. But I'll show you some pictures of the RSA exhaust duct if you show me yours.

yours

From memory I tidied the pic up and made it super large as its very low resolution.
This is the low res version.

Likely a trick of light or as Wob said overlapping cuts producing a pattern (much like engine turning)
I think the pic shows a progression in the raised corners at the lower ex duct it also shows the compromise made to the transfers to accommodate the ex and vice versa

[wobbly]

Hey TeeZee, as a favour can you try a radius on the leading edge of floor dam, before you do anything else.
Be interesting to see if that helps the outflow Cd sufficiently to increase power, and wont affect the A port short circuiting efficiency at all.

Re the Yam twin, several models used the bronze bush with oil dimples in the loaded surface.
This works fine as its only actually being used as a bearing when the clutch is pulled in - the rest of the time its just a spacer bush.
The ignition lighting coil should have plenty of power for a fan, as its designed for powering a head and tail light etc

[TZ350]

Hey TeeZee, as a favor can you try a radius on the leading edge of floor dam, before you do anything else.

Be interesting to see if that helps the outflow Cd sufficiently to increase power, and wont affect the A port short circuiting efficiency at all.

Sure, Chambers thinks it looks like a good idea .... probably get to test it next Wednesday.

[J.A.W.]

The fuel is 100 Avgas,its higher octane than what is sold in OZ that is LL100.
The ATAC does not need to "direct " the flow, as I have always used the butterfly so that when its open its in line with the header axis.

It has been most interesting to see what you've achieved in successfully updating the TZ twin for classic racing, Wobbly.

I note that a decent sized contingent of US TZ riding classic racers are taking their 4 cyl jobs to Phillip.Is. next month..

http://www.cycleworld.com/2015/12/15...-vintage-race/

Are any of them applying your TZ development lessons - to give those huge Suzuki 4Ts - a run for their money?

[wobbly]

I met all the USA guys at the Island last year, a great bunch of really enthusiastic racers and tuners.
The TZ400 we took was easily fastest in practice, but the brand new Nova special ratio set shat 3rd gear in the morning warmup and threw Discombe down the road on his head.
He had concussion so wasnt allowed back on the bike.
Dennis Charlett is racing the Nationals at Timaru the weekend of the Island this year,so we will have to wait.
He is entered on the TZ for the last round at Hampton in early March,in the support Post Classic class, hope the new track is all done for that.
We wanted to run the Pre 82 in Superlight,as with a speedshifter working and stickys the TZ would easily cut lap times to be at the front, but the classes are too close together
for the Grandfather to be comfortable racing the SV650 as well.
Master plan is to build another Frepin with a 4 cylinder version of the TZ400, as Paul Mclachlan rode one configured like that at Puke with a std TZ500 back in the day.
If I put the same attention to detail into that bike it will for sure easily smoke the usual 750s as well as the big 4T pigs at the Island, we will see.

Here is another small item in the TZ400 - a double sized CNC waterpump impeller,it sits on 50*C all day.

[richban]

HI All.


I / We are in the market for some single ring pistons for our NSR300's. There is nothing out there so we are thinking of designing our own and have them forged for us.

Can anyone recommend a very good manufacture to contact. It would not be a massive order maybe 32 pistons.

I will be emailing Wiseco Wossner etc. But if someone has direct contact that would be of help.


Much Thanks Rich.

[husaberg]

HI All.


I / We are in the market for some single ring pistons for our NSR300's. There is nothing out there so we are thinking of designing our own and have them forged for us.

Can anyone recommend a very good manufacture to contact. It would not be a massive order maybe 32 pistons.

I will be emailing Wiseco Wossner etc. But if someone has direct contact that would be of help.


Much Thanks Rich.

You Don't need to go forged.............modern cast is more than man enough.
(Unless its turbo or supercharged or burning exotic fuels)
Vertex as well

seen these
https://id3528.securedata.net/test.b...roducts_id=483
whoops 14mm pins