That bleedin\' 675 motor :(
 

Well, we've tried our best, but no amount of jiggery-pokery, carb black magic, or hitting it with a hammer will extract any more bleedin' power.

Spent another few hours on Mark Hill's dyno last night without managing to get anywhere, so it's off with the flatslides and back on with the CVs this weekend.

So a word of warning to anyone looking to tweak a 675 for next year, be prepared for a very long, expensive process that may well yield no results. :(

On the positive side I will be shifting the FCRs to the 900 tomorrow and dropping a tooth on the front, so Brands should be a hoot on Monday! :D

Cheers,

Ali

So not worth putting FCRs on it then?

I've got a set of FCR39s here which are ready to go on ... as this is supposed to plug the 20% gap in horsepower between the 674 and the 618s ...

:puzzled:

wont do anything about the 20% gap in skill though. :o

Heh. I'll remind sir of my highest results, compared to his own. :P

Antony - best you come & have a look at the 600 heads & the (albeit knackered) 620 ones that AK has.

Ali was a bit amazed when he saw then last night too!
When they are side by side, you can see the big difference on the inlet & outlet:o

Porting (Alan thinks) is the only thing that will make them come up to the same performance level - and we arent allowed to do that

C, rapidly becoming an expert in this field.....:o:rolleye:

Yes, I know the issue is with the ports, but as you say we're not allowed to touch those.

First it was the big-bore. Then it was the carbs. What now?

The Tweak next year for the 675's will be head work i imagine...which is alot cheaper and more effective than FCR's..

and YOU dont need anymore power ....:puzzled:..you are already the lad to beat...........:P

Phil

620 injection................:devil:

Well yes, but that just means I won't be entering next year as I can't afford to buy a 620, and who is going to buy the 674 now?

Money down the drain :(

?riders?:puzzled:

sorry, poor show

coat, off.............................

"Money down the drain "
Patience Grasshopper, patience-it has been written that all comes to he who waits, and the rules for 2006 will not be decided until after Brands....................I wouldn't be selling off those carbs cheap yet if I was you....;)

John

[Edited on 1-7-2005 by Monty]

Next year...nothing has been decided yet... but head work may be allowed so that a 675 will be competative in terms of power with a 620injection...that way you can keep the 675 and race next year............... :D.....

All is not lost yet Bro.................................

Phil

Thanks.

Might as well give up now then!

Wise words from Phil!

Patience Ant ... if nothing else you'll have a lovely ornament for the lounge room.

Read Chris' post above, looks positive for you antique owners.

It's not over until the slightly-overweight rider #68 sings.....

I'm convinced that there is more usable power to come from my 674 for Donington, without resorting to headwork or anything illegal. Things like manifold matching and a change of exhaust should help both bottom end response and top end power.

Ali, IMHO your FCR41s are way too big - even my 39s are excessive given the current valve sizes (but may be useful on a 620 motor...)

Also ignition and cam timing can make a difference, but now I'm giving too much away;)

Ah yes, but the cams are different in their lift and duration.

41s are definitely too big, as we've discussed before, but I also tried the DP transducers with a different ignition curve. No noticeable difference....

Your 39s are also too big, but not by much. The real issue is the lack of a base setup to work from.

Ali

Im sure there is Paul but i shudder at the cost of the FCR's the dyno'ing the engine work the bespoke zorst set up etc etc.....just for a few bhp is it worth it when for next head work may be allowed or a split class...............:puzzled:....

Phil

[Edited on 1-7-2005 by fil2]

To right 41s are to big, basically a good smoothbore carb will flow 20% more than a CV carb, so to match the flow of the 38mm CVs you will probably find a set of 35mm flatsides is the max you will need. Also bear in mind how much power the 900SS makes with the same 38mm carbs and airbox setup.
Its the head and inlet tracts that are the restriction and as mentioned some good flowbench work should deliver good results.
Just let me at Senna3's 675 with my air grinder or maybe we can get the experts have a go over the winter.

being that I am pretty simple in techy terms, but is it not easier and cheaper to source a 620 lump and injector system etc and chuck them in the 600ss/monster frame?

No! No! No! Kev's bike is too fast as it is :sniff:

very rare to find them 2nd hand at all Bradders. (rocking horse****)

can find 750's (carbed & ie) which have a few differences (not at the bottom tho) but cant use them - even the bottom end, so we have been told.

C

ps: Antony - that want personal mate, but poor taste 'joke':(

Totally agree with you - as should be fairly obvious from your performances all season the FCRs do not guarantee as much an advantage as a good rider (no sour grapes, just a statement of fact!)

I'm about to contradict my vow from last Saturday to stay out of it, but IMHO the best results are being gained by the best riders and the differential between a 620 and a 675 is negligable.
Tin hat on. :flame:

dare i say i agree......

on the flip side my bike is probably one of the best out there in terms of power and reliablility. but my (lack of) skill means i'm not fully exploiting it.

the bikes dont ride themselves.

i personally dont think a few bhp here or there makes any difference

shall we not go into this AGAIN .............



Phil

no its not the engine issues. i agree it would be ideal to have all the engine configs chucking out the same. but i honestly dont think 5-10 bhp makes that much difference. ridaer ability is much more important. take 5 bhp from you and add it to me would it make much difference. i dont think so. your better ability will come through.

Well if you don't want it can I have it :P

you recon you'd beat me with 10bhp more???

this is not a derogatory question, just wondering?

ok then let me suggest this..as you improve as a rider gain more experience, the mental attitude to racing changes and you start to bridge that abilty gap which will happen as none of us are gifted Rossi's then the BHP difference will become more evident........the 675's are at there limit being ridden on abilty if you like..you have huge potential on the bike you have and have barely scratched its potential.........

Phil

YES !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

How about you and dickie swap bikes for donny and then you taste life on a different bike.?

could be fun

Phil

No disrespect to anyone.
 

But I reckon I'd be way up the field with a few more ponies between my knees Dickie, yes mate.
I agree with you about it having a lot to do with ability, but it's not the be all and end all, neither is power, but it's the combination of the two. I've lived and breathed bikes for 27 years but this is my first go at racing and it really has got a grip on me. If I could afford the mods to get there I'd go for it, either that or swap my 583 for a 620ie so I could dice on more level footing with you. As I get more race experience I will improve but my limiting factors are gonna be health related and power. I was much closer at Snett than CC to the 620's and I can only see that getting closer with time until my ability improvements plateau ;)

Two riders of equal ability - one has 10hp less.

Which one is going to win?

Don't see how you can argue that it doesn't make any difference...

phil, i do agree to a certain extent as the skill level rises your ability to get the maximum out of the bike obviously increases. you are alot nearer to it than i am but not at its maximum.

for me there is nothing i need to do to the bike. im at, for arguments sake, 80% of its potential maybe you are at 95% of yours.

but everyone out there can cut their times still considerably i would say even someone like you. if you spent a day at snett really sorting your technique out what would you drop. 1 maybe 2 seconds? not saying there is anything wrong with your riding but you know what i mean.

its funny at the start of the season everyone was saying "no the best rider will win no matter what bike they are on" now we are out there it seems to be a different story.

what would be really good would be to get some dyno charts and compare them. i've no idea what mine is chucking out. could be 70 bhp for all i know!

hope not......means im even worse than i thought!

its an interesting debate and one that wil lnever be drawn to a satisfactoy conclusion for all but its good that we can discuss it with good intentions...
I agree with you that a day at snetterton or any track will greatly improve lap times for any1 and that i have alot more to learn and if a better rider rode my bike he would lap in a time way better than mine but i dont believe as good as if he was on a bike producing 11bhp more.

Phil

"but IMHO the best results are being gained by the best riders and the differential between a 620 and a 675 is negligable"

paul payne


"personally dont think a few bhp here or there makes any difference"

dickie


if we are talking 10bhp, well thats quite a bit. and clearly the same rider will be quicker on the more powerful bike but by how much?

ant, take the lap times you did on your 748 at snett compared to the times on you DD racer. what does that equate to: bhp per second............

40bhp more = 4 seconds????

im only guessing, but its not much time per bhp.

i would think most people could match that with better suspension set up/better riding

OK, here's my 2 penneth...

We have 52 bhp at the moment, and I managed a couple of 1m 23's (high 1.23's mind you).

I think I could find 2 seconds pretty easy, with another 10bhp. Then I'd be getting very close indeed to Geoff.

Geoff passed me into the Esses at Snett in practice or qualifying (can't remember which) and whilst he was very fast, we were surprisingly even on corner speed. It didn't take long before he disappeared though.

I'm 99.9% sure that when Louigi finds the missing bhp (legally) we will be up the front with Geoff & Clint.

Time will tell, but hopefully I can show the diff between 40bhp/52bhp and 62bhp(?)

Also I think Geoff or Clint would only be marginally quicker than Phil & Ali on their bikes, purely on experience and a little bit of ability perhaps.

Phil & Ali and Mark & Andy on #36 are showing what is possible with 51bhp.

Geoff & Clint are leading the way on 620's.

Everyone has a marker of what is possible, just need to shut your eyes more and stretch the throttle cables!!

:D

[Edited on 1-7-2005 by domskidue]

I've never ridden the 748 under race conditions, so I cannot compare the two, but I certainly know that I was lapping Snetterton last year on a trackday in 1:29s according to Jamie's stopwatch - so not that far from the 1:27.40 I did on the DD bike.

Now that might not seem like much, but given how I ride now in a race compared to how I was riding on the trackday, I'm sure I could easily knock 4 seconds off that time.

I like your idea of the dyno session to compare everyones bikes, but all it's going to achieve is showing that some bike have more power than others, and that some riders have far more talent.

I wouldn't be moaning if I was out there on a 620, but I want every advantage that I can get (legally, Dominic ;) ) to improve my results, and at the moment my bike just isn't on par with the majority of the pack.

All you need is 51bhp to get top 5.

Phil's bike is mega basic, all it has is an old 900SS standard shock and a big bore - and that's it!!

True, but my ability obviously isn't stretching that far, so I need the HP to make up the difference!