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Post by terrencelp on Oct 14, 2011 16:38:22 GMT
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Post by JohnRogerOhanlon on Oct 14, 2011 20:16:06 GMT
sorry can you do the link again as it leads nowhere
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Post by terrencelp on Oct 16, 2011 17:00:51 GMT
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Post by Graham on Oct 16, 2011 21:38:02 GMT
works for me?
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Post by jukkax on Aug 14, 2012 21:14:10 GMT
Opened to me too. I also got the answer to the question I was gonna ask..: so the 122,5's really r OK with a 4-1 exhaust (Sebring + Leo Vince (of a cbr900) and up to 130 is OK too! I just tonight replaced the 117,5's with the 122,5's, and it felt better -> the 'dead' zone at the end of the gas grips' movement had maybe become narrower. So I can move to bigger jets with courage or smth, I think I have 125's and 130's in the shelf. I of course want to get rid of that 'dead' zone completely. The dead zone from 3k to 4k can wait..
Oh yea, mine is a '85 1FN and it has a K&N in original airbox and iridium sparks!! ;-)
I haven't yet played with the air screws at all, and have 'synchronized' the butterflies with naked eye only. That lenghtening and baking those springs sounds compelling..
I already found out that raising the needles one step (from the middle) isn't good; the bike became a horrid to ride.
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Post by Graham on Aug 15, 2012 17:41:28 GMT
jukkax I think your dead zone between 3-4K will be due to your exhaust system. FZ doesn't like primaries/down tubes that are too big. Causes the flat spot you describe.
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Post by jukkax on Aug 17, 2012 8:12:12 GMT
Yes Graham, I know it's due to the 'race' exhaust giving not enough back pressure, some valve over lapping there or smth.. These engines r build for racing/powerful top end, had to be tuned down with a cramped exhaust to make it drivable in civil use :-D Wish Yamaha had put EXUP in these already.. :-)
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Post by onewicked750 on Aug 21, 2012 7:08:50 GMT
Looks like I need to step my jets up! I'm running 107.5 across with stock exhaust and pod filters. Runs great as far as I can tell, but who knows maybe there's more power in there?
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Post by jukkax on Aug 21, 2012 8:24:04 GMT
Yea, I'm sure there there is! :-D I had 117,5's with stock exhaust + K&N in airbox from the last summer and it HAD more power than with original 105's, amen. I'm going at 125's now with my 'race pipe', but still it doesn't work best with full gas. I'll next try the 130's and if it's to no use, I'll go back to 110's.. ..or 117,5's.. I don't have jets in between. Yet. BUT ISN'T IT SO, that throttle full open only main jets r in use? Pilot jets, needles, air screws mean nthn then. But what about the benzin level in carb bowls, isn't the original hight OK?? :-D
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Post by fz750horse on Aug 21, 2012 13:01:03 GMT
I think that what we need to remember here is that what works for racing - maximum top end power, race pipes, open velocity stacks, individual filters etc. - is completely unsuitable for road use. Kenny, myself, and just about everyone else who has raced FZs all ended up using Mikuni mains of 137.5 or 140 (for 34mm carbs) with a properly designed race pipe and free flowing intake (remember DYNOJET NUMBERS ARE DIFFERENT - 137.5 Mikuni equates to about 144 Dynojet). This gives a little over 100bhp at the rear wheel - up from about 90 bhp for a stock 2mg, assuming a newly refreshed engine. The downside of all this is that the bike only fuels properly above 8000rpm and is barely useable under 7000rpm. This is no problem if you're racing but would be a royal pain in the arse if you were in traffic. Factory Pro's kit is said to be the best for road use - I've got one somewhere but never fitted it - and I think it uses 122 mains with a free flowing version of the OE filter in the stock airbox. Received wisdom is that the airbox and smallish headers are essential for mid range driveability which, on the road, is a lot more useful than an extra 10 bhp at 11000rpm
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Post by Graham on Aug 21, 2012 17:59:08 GMT
Wise words Mr horse. torque beats bhp in the real world every time for me. I would be very interested in buying your factory pro jet kit if you have no use for it?
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Post by fz750horse on Aug 21, 2012 18:45:16 GMT
I'll give you first refusal if I decide to sell it but I'm meaning to try the needles to see if they'll improve the fuelling lower down. I may never get round to it because I've just followed Alison to the dark side and bought an FZR1000 frame I have vague plans to put all the bits off my FZ onto it and make a sort of poor man's OW01 while I sort out some damage to the FZ frame that I did when I fell off... One other thing I should have mentioned above - by far the biggest difference between my race bike and my old road FZ is the near 50kgs weight i got off it; quoted kerb weight for an FZ was about 230kg, mine weighs 181kg with 2 litres of fuel . The 10bhp power increase is insignificant in comparison
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Post by onewicked750 on Aug 21, 2012 19:02:49 GMT
hmmm... 122s...yes, I think I will. Also, I second the power to weight above all else school of thought.
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Post by jukkax on Aug 22, 2012 8:49:01 GMT
Yes, okay, yesyes. Anyway, I'll first wanna get it working @ 100% in full gas before the winter comes damn it. I've cut about 500 gram off the frame too and it didn't even collapse.
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Post by jukkax on Aug 22, 2012 9:09:10 GMT
@ Onewicked750: Those 122,5's r with 'race' pipe, probably too big with stock exhaust. But u never know..
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