ESE's works engine tuner

[F5 Dave]

Bluur. Eaten too much. Had a quick kip. Kids playing with hot wheels track. Still sober enough for wielding rifflers (wouldn't trust myself with grinder) might have a quick fettle of transfers till next guests arrive. And pack for going to see cmtry cct racing at Wanganui tomorrow.

[TZ350]

Started making myself a twin injector manifold for the Inlet.

Quiet start to the day, Mass, casual lunch, watched the Queens Xmas speech on telly and the film "Red Dog", worked on the bike in the evening, grand kids tomorrow, perfect Christmas. http://www.dailymail.co.uk/news/arti...s-service.html

[peewee]

hi frits it seems your familiar with modena 125cc version. it says max power is 15000rpm . that seems like quit an accomplishment. but what i dont understand is the port arrangment, mostly the transfers. exh opens at 195*, presumably for the main and the flanking ports probly a couple degrees later im guessing. A 130.5*, B 126.5*, C 128.5*. the transfers seem unconventionally staggered compared to what im used to reading about. can you give some thoughts on the theory behind this approach ?

i almost forgot something else. why only a 106mm rod ?

[Frits Overmars]

hi frits it seems your familiar with modena 125cc version. it says max power is 15000rpm . that seems like quit an accomplishment. but what i dont understand is the port arrangment, mostly the transfers. exh opens at 195*, presumably for the main and the flanking ports probly a couple degrees later im guessing. A 130.5*, B 126.5*, C 128.5*. the transfers seem unconventionally staggered compared to what im used to reading about. can you give some thoughts on the theory behind this approach ? i almost forgot something else. why only a 106mm rod ?

I don't know where you read it, Peewee, but maximum power is produced much earlier than 15000 rpm, so you'd better not believe everything you see in writing.
Other than that I am not going to comment on anything related to Modena for the above-mentioned reason; I can't afford to be quoted at the moment.

[peewee]

yes maybe i got some bad information. but thats what it says on their site. read for yourself . click on engine information http://www.modena-engines.it/eng/index.php

[jasonu]

yes maybe i got some bad information. but thats what it says on their site. read for yourself . click on engine information http://www.modena-engines.it/eng/index.php

It says max RPM is 15000. It quotes a max power figure of 44cv (what ever a cv is) but not at what RPM it is made.

[peewee]

my bad. i didnt read it correctly. still it lists a strange stagger pattern on the transfers. although the drawing doesnt seem to match as the C appears to be same height as B. im sure frits will clarify it when the time is right

[husaberg]

yes maybe i got some bad information. but thats what it says on their site. read for yourself . click on engine information http://www.modena-engines.it/eng/index.php

my bad. i didnt read it correctly. still it lists a strange stagger pattern on the transfers. although the drawing doesnt seem to match as the C appears to be same height as B. im sure frits will clarify it when the time is right

so you'd better not believe everything you see in writing.
I am not going to comment on anything related to Modena for the above-mentioned reason; I can't afford to be quoted at the moment.

[Flettner]

so you'd better not believe everything you see in writing.
I am not going to comment on anything related to Modena for the above-mentioned reason; I can't afford to be quoted at the moment.

Yes, this is getting exciting.

[wobbly]

Everyone that works within such small niche technical markets like race engine manufacturing always has to sign a NDA.
Ive been doing this for years and if you dont abide by the agreement terms, you dont get the work - simple.

[twotempi]

44cv

CV = chevaux - horsepower

Citroen 2CV ( Deux Chevaux ) = 2 horse power but having driven one I doubt it was that much !!

[peewee]

hey wob i figured the case ratio to be 1.43 on this yam. im not sure yet if ill dive in and do any welding to correct the transfers, keeping that in mind do you see any harm if i lifted the cylinders a few mm or would it do better leaving the case volume small ?

[Frits Overmars]

so you'd better not believe everything you see in writing.
I am not going to comment on anything related to Modena for the above-mentioned reason; I can't afford to be quoted at the moment.

Yes, this is getting exciting.

My own impression: it sounds rather pompous . But like Wob says: you gotta do it this way or not at all.

[Martin1981]

Hello,

can someone please tell me the compression height of the aprilia rsa piston? i heard of 24mm but i do not know if this is right. are there 54mm pistons available with even less com height?

i have another question regarding carb area and its relation to the cylinder intakeport area. should the intakeport have the same area as the carb (i think so) or should it be bigger or smaller for some reason? thanks

[Drew]

Hey TZ. Is there a chance that the ball valve you're using with the bike injected, is screwing with the air flow at part throttle and causing the detonation?

I see the two sharp edges creating a wicked flow disruption when I picture the valve partially open, and I recall Malcolm (koba) once showing me a simulation of air going through different shaped carbs and trying to explain the pros and cons of each scenario.