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VFR 400 Questions regarding tuning!
Posted: Sun Oct 09, 2011 6:57 pm
by stuartballinger
i have been asked this question i understand the big bang and screamer engines and have a rough idea about the twin pulse! i was wondering if anyone could me with the rest of this question? "The v4 engine can be a ‘droner’, ‘sreamer’, ‘twin pulse’, big bang, 360 crank, 180 crank etc? what are these and how does it affect the engine and the power delivery"
Re: VFR 400 Questions regarding tuning!
Posted: Sun Oct 09, 2011 7:09 pm
by CMSMJ1
Welcome.
On a 400 it makes no difference at all.
see the piccie..gives a good idea of how it works.

Re: VFR 400 Questions regarding tuning!
Posted: Sun Oct 09, 2011 7:41 pm
by VFR400+
Hey guess you Harrys bro. Seems strange you have to answer these questions to get involved with the 400s! Surely the whole point of doing it is to learn from it, if you knew it all there would be little point other than a good crack!
From what I understand.
360 degree crankshaft means the pistons on the same side of the V4 rise and fall at the same time each on different strokes. One piston is rising on the compression stroke, one is rising on the exhaust stroke. This will gives a power stroke every revolution of the crank. Giving a smoother power delivery.
With the 180 degee crank, one piston is rising while the other is falling. Guessing this may be better from a counterbalance view although Im not sure on that.
As I understand it big bang are when 2 cylinders fire within less than 90deg of each other. Can cause larger stresses on engine and possibly led to premature failure. Screamer is when there is an even firing order.
Although ‘droner’, ‘sreamer’, ‘twin pulse’, and big bang all sound like sex toys if you ask me!
This page might help abit
http://www.vfrdiscussion.com/forum/inde ... ng-engine/
Re: VFR 400 Questions regarding tuning!
Posted: Sun Oct 09, 2011 10:09 pm
by stuartballinger
yeah i'm Harrys bro... yeah it is just because there are 2 bikes and alot of students that want to get involved on the same project, i presume they just want to see who is taking the project seriously and will do the leg work!
Thanks for that it will help expand upon the answer i have written already! i'll check out that link now and let you know how i get on!
do you have the vfr your doing up? i think harry showed me some pics.... looks good!
Re: VFR 400 Questions regarding tuning!
Posted: Sun Oct 09, 2011 10:15 pm
by VFR400+
Yer guess they have to sort out the clueless from the clued up.
Thats me just finished rebuilding it then went out on the piss with Harry and woke up with a broken wrist so its not doing much now! lol