F1 Cams

While no expert, and probably going to get shot with my head above the parapit, I seem to remember that the CV carb has an effective size of 10% less than it's physical size.
This is down to the butterfly in the carb outlet.
If correct then the 38CV's you are running are closer to a 34mm flat slide.
While they were working well prior to the cam change, it sounds like you need bigger main jets, or a set of 40mm CV's
Performance improvements on the Lav's are to a 36mm flat slide (bigger in Lothars case), this would support the change up to 40mm CV's.

Had 38CV's on the RGS until the needles & emulsion tubes needed replacing and it was cheaper to change to 36's.

Watching this thread with interest as it would be good to see how others are going.........
 
Heh Vince
Its good to see you getting to grips with your tuning..  Im not being even slightly critical here, simply defensive of C4 cams...Ive yet to see a dyno graph running F1 cams. Its not a pissing contest, just a fair comparism, I get storming results outs of C4 cams with a graph to prove and it would be good to be able to compare real torques curve (the outright figure is less so)..Would probably promote them the F1's more so, certainly food for thought !



Cheers Rob
 
Thats the plan Rob,I was keen to do the same with a set of Axtels but that didnt happen.Yes I have head the same re 10% loss of throught put.I am not chacing ultimate power,so the carbs are staying as is.
 
"but from what I hear the C4 has top-end but lacks a bit in the middle and the Axtals have the middle but lack top-end"

yep, that's pretty much the way it is. changing lobe centers on the 4C really helps the mid range without loosing anything on top but the F1 is a good all around profile. i would pick it over the Axtell profile and not blink an eye. the axtell is an older design meant for the american market where most riders wanted more mid range and the 4C makes power farther up the band where few could use it
 
My Motodd has an Axtel cam. When I first fitted it I really noticed the improved mid range at the cost of the top end.
At the time I was racing hooning on the Old Road nth of Sydney most w/ends, lots of posted low speed corners so the mid range was fun. The older I get the less interest I have for the top end.
 
When you get even older you will lose interest in the bottom end as well, but they tell me Viagra helps  :D
 
Whilst on the subject, i had the cover off the Seth African today and it just so happened both sprockets were lined up so i could see the stampings

F1s
Inlet sprocket is marked A12

Exhaust is Marked A11

is this right?
 

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Hey Cosi

I'm not an expert but my RGS F1's have both sprockets stamped F1, my 4C's had 4C stamped on both sprockets.

                                Cheers
                                        Matt             
 
As far as I am aware, it doesn't matter what the sprockets are - as long as they have been indexed correctly for the cams.
 
Hmmm, interesting.....
From what I can see, in the top picture definitely shows the left side and the right can be clearly seen in the second picture.
However, if you go to the other side of the bike then for some strange reason, these are reversed.
Is this right?, all depends on which side of the bike you are on.

Now back to the bottles of red, I have a new toy to aid wine drinking and giving it a bit of a hammer. Just pour the wine through it and it gives artificial respiration to the wine, saves time letting it breath
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So I did a dyno run on Friday.Just by chance I rang them and hear there Dyno is being replaced,old one out this Saturday and new one due in a month.To late for me to have a run before the big club trip to the Snowy Mountains.Bike runs much stronger by feel and was expecting good news.To cut to the chase not so good.It had 84hp and now has 73hp.That's completely differant to how it feels.So its now considerably lean in the topend,its running 172 mains in the Kehan CV carbs and Harley,yep that's his name recons it needs at least 185s.Last time going from 145s to 168s picked up 12 hp.Its also rich on the needles and upping the mains will exacerbate this even more.I bought a Dyno jet kit a couple of years back and will measure up and compare the needles that came with the kit to see if I can lean out the midrange.Today I pulled the Unifuilter element out and went for a ride.It defiantly helped clean up the midrange,more air flow so yep its a bit restricted with the filter so I am making a new one out of AC medium.This is not a stock airbox but it shouldn't be to hard to do.On occasion we find ourselves on dirt roads so its worth running at least a finer less restrictive filter.So I will do another run after doing these changes and there new Dyno arrives.I do like the effect of these cams and hope after the jetting is better the numbers go a bit higher.
 
Are you sure the first dyno run was measured correctly? 84 RWHP with A11 cams seems a bit high. I'd have expected something closer to 70.
Were both runs done on the same dyno with the same operator?

Cheers,
Cam
 
Yes both were done at R and B Imports and the operator is Harley,knows his stuff.That's on a 3C with a big bore exhaust,10/1 Pistons,ported up the wazoo,38mm CV carbs,40mm inlet valves and 34mm exhaust,
a much bigger airbox than standard,valve timing indexed,and generally put together right motor.What I defiantly find odd is how strong the bike feels now and how the numbers are less than before.The next time I use them it will be a differant Dyno,old one is a typical Dinojet,the new one is the latest Dynojet with a load cell and some other gadget that make working on FI bikes much quicker and easier.It holds the motor at predetermined fixed revs and load I think
 
Hi Vince

I'll understand if you dont want to, but if you can persuade the operator to release the files, via email  (they're DRF) I'll pick the bones out of the results and put them together for you alone (what you do with them after that is up to you)..

You're talking top end figure which is a small feature of the overall power curve, although I agree it doesnt sound right.
Correction factor the same, wheel size and tyre wear the same, same motor, same gear runs ?

The files are very useful for analysing the data, compared to a print off, there is no comparism...

Cheers Rob
 
Hi Vince,
My thoughts are that your new setup is producing alot more torque then the old set up,and thats why it feels better.Was your Dyno man able to record torque figures for before and after?


Andy
 
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