Dyno Runs and set-ups with 28mm carbs

[Kingy62]

has anyone actually seen over 60bhp on the dyno using the stock 28mm carbs?
i've never modded my reed stops btw,
Warwick,have you got a copy of my last dyno run,so we can compare to this one?

[Warwick]

Hope you don't mind, but I've shuffled this one into a new topic Ian. Primarily to avoid confusion as the other thread was discussing a set-up with 36s, but I think it warrants its own thread in any case.

The set-up I used to run with the 28s, Martin's SP port job and pipes and an -80 sugo box gave a little over 60:



Mains were 250 lower and 210 upper, but otherwise the carbs were as stock for a 91 R - all the variable air jet gubbins still in place even - and stock needles and all other jets, slides etc.

I never had the raw data for yours, Ian, so it's not easy to plot a direct comparison. Didn't Martin do a drawn mock-up in another thread though? If you have the run file data, flick it over and I'll feed it into the software to bring up the comparison. Running the stock global timing -00 boxes seem to be stronger up to about 9k, but then drop off a bit compared to the Sugo boxes. Andy Bush's recent experiments with some global advance looked to perk it up very nicely higher up the range though, and I do wonder if using a fully adjustable ignition and PV unit it would be possible to improve on the Sugo stuff? Be an interesting project for someone...

Anyway, this could be a really informative thread in itself - a kind of 'home' thread to post up set-up info and charts for bikes running the R/RS 28mm carbs specifically.  What do you think, fellas? It's spring! Time to get to work on pepping the old birds up a bit! This will be an ideal place to post up your results and set-up info.

First to beat mine above with stock R/RS type 28s wins one of my old melted pistons  . It should be pretty easy really as that was the first attempt at setting it up with the 28s. Definitely room for improvement betweeen 10 and 11 there, which might have lifted the final figure a bit. I went over to the TZ carbs not long after though so never dyno-tested any of the little mods I tried with the 28s after that run that I though might improve it a bit up there. It was bloody quick and very flexible though. That set-up would make a great, relatively cheap and easy to do full fat road R/RS - using all R/RS parts - 'cept the sugo box of course, but I reckon 60 (on a dynojet) is do-able with the -00 box and some careful optimisation and set-up in any case. Go to it! 

   

[Martin77]

Here's your run Ian;



The best I've seen using the 00 cdi in fact, some fine tuning on the dyno could easily see you crack 60hp...

[Kingy62]

thanx for that guys,since that run i've modded the ignition pick ups to give as much advance as poss,(which hopefully should make a little difference),re-modded the pv spools so not only do they clear the sub-exhaust ports at WOT,but also improved the profile a little too.currently running 240 upper/270 lower.and a set of martins pipes/nikkon silencers
only got martins halfway porting for now,so maybe the full works would release even more ponies? 
( i would also like to think that my personally modded airboxes have helped too!!)(pics in the gallery somewhere)
(and yes it's still in bits since my 2 warm up laps at the Cadwell 2-stroke trackday....)

[Martin77]

I don't think the full SP spec porting would gain you much peak power, but possibly lose some from the midrange. It's only when you have the sugo ignition that the bigger ports show their benefit...

And loking at your graph, the powers still climbing at 11,000 when the speed limiter kicks in, so you may have cracked 60hp already...just not when it was on the dyno....

good luck with the rebuild though

[wullie3XV9]

Well Gents, I'm just back from getting my Martin77 tuned, but otherwise ( nearly ) stock '93 RS dyno'd at Grant Racing across at Knockhill Circuit
this after'.

I'm chuffed ( & relieved ! ) to report a peak rear wheel HP figure of a gnats tadger short of 50 hp !  49.88 to be exact @ 11,100 - 11,200 true rpm.      
Unfortunately, my -40 CDI's rev limiter decided to kick in then !     ( my tacho reads 12,000 rpm at a true 11,200 rpm ).
Warwick, your prize of a melted piston is safe. ( for now  ).

Peak torque was a paltry 24.3 ft-lbs from 8,600 rpm right through to 11,000 ish rpm ! !
I asked how the fueling was through the rev range & was told it seems about right, as Bob ( Grant ) the dyno operator cracked the choke open
at one point & it lost a bit of power all the way through, i.e. , too rich.

I bit the bullet during the winter & removed ALL of the restrictor tab on the speedo unit, to see if it allowed the engine to rev out when stationary.

EDITED 24 MAY 2010 :-  DO NOT REMOVE THE TAB THAT SITS BETWEEN THE TAB SENSORS WHEN SPEEDO READS 0 KmH .
ENGINE WILL NOT REV. PAST AN INDICATED 12,000 RPM ( 11,200 - 11,300 true rpm ), IN ANY GEAR AS A RESULT OF CDI NOT RECEIVING REV. LIMITER DEACTIVATION SIGNAL FROM SPEED SENSOR UNIT INSIDE THE SPEEDOMETER ! ! 
I'VE HAD TO MAKE & FIT A REPLACEMENT TAB, WHICH ON TESTING AFTERWARDS, NOW ALLOWS THE ENGINE TO REV. UP TO AN INDICATED 13,000 RPM
IN ALL GEARS ! !           

I discovered this during test runs last week & today AFTER fitting my set of MARTIN77 expansion chambers.
( Final gearing for above test runs was my trackday 15 / 39 gearing & also with a home made +2 degree timing advance woodruff key fitted ).
I thought the stock pipes were causing the problem, but it was of my own doing ! !  Mucho embarrasssment !    
 
 
I scanned the paper print-out into my pooter & uploaded into "Photobucket" as I don't have the run file yet.
( Didn't know I would need to take a memory stick with me !  )

Any usefull comments / advice gratefully received.



Spec of bike is :-  Martin77 "not quite SP" ported -00 cylinders, ( should be -30's for 3XV9 ), with auxilliary exhaust port part of P.V. spool modified to
                            match enlarged aux. exhaust ports in cylinders.   -01 cylinder heads skimmed ( stock are -50's ) & 0.5 mm TZ 4DP base gaskets     
                            fitted to give a squish of 0.95 mm's.  ( Stock 3XV base gaskets are 0.6 mm thick ).
                            Both combustion chamber volumes at TDC = 10.5 cc's.
                            Compression ratios both work out to be 7.4 to 1 corrected.  ( stock is 7.5 to 1 ).
                           
                            Virtually stock airboxes & filters. ( L/H upper airbox intake has had taper removed ).
                            Stock reed valve petals with stops adjusted to give 11 mm of reed tip lift.  ( Stock lift 9 mm ).
                           
                            R/H 28 mm carb is on stock '93 RS internals, except for the emulsion tube, which is a P8, ( stock is P6 ).
                            As a result, the stock 5FN117 needle is on it's lowest setting. ( stock is 2nd lowest with P6 emulsion tube ).  Main jet is stock 270.
                           
                            L/H carb is also on a P8 emulsion tube, ( again, should be a P6 ), with the stock 5FN117 needle on the middle clip position,
                           ( stock is 2nd lowest with stock P6 emulsion tube fitted ).  Main jet is a 230 as a result of enlarged L/H airbox intake.  ( Stock is 190 ).
                           
                            Pilot jets in both carbs are stock 12.5's.

                            TPS & variable air jet system still connected & functioning.

                            CDI unit fitted is a -40.  ( should be a -60 for '93 R / RS's ). Stock BR9ECM spark plugs.  Stock ignition timing, i.e. , no advance. 

                            Early R model 2T oil injector pump system retained.  ( Previous owner ditched the complicated looking electronically metered 2T system )
                           
                            Stock exhausts & mufflers still fitted.  ( I double de-coked the mufflers a while back ).
                            They do indeed do a good job of capping the torque ( & hp    ).

                            Final gearing during dyno run was 15 / 38.
                           
I spent yesterday morning doing plug chop runs at every thousand rpm, from 5,000 up to 12,000 rpm, to check both spark plugs were matching in colour
all the way through the rev range, which they were thankfully.   Each plug never varied in colour at each check from 5,000 rpm up through to 12,000 rpm.
I also made sure both carb slides & the oil pump were all synchronised for optimum performance.
 
                            Stage 1 of my RS's "un-corking" succesfully completed ( at last ! )  Roll on Stage 2.  ( a set of Martin77's pipes )    

[Martin77]

That's a very flat torque curve Wullie, I bet it's very smooth to ride and very flexible...

I'm not so sure if the -40 cdi is what stops it past 11200, more likely the standard pipes stop working properly. It'll be more interesting to see how it goes once you have some pipes on to match the porting though (eventually).

Is that with any advance on the flywheel or pick ups? that may gain you a couple of hp as it is.




I've just compared Wullie's run with that of Kingy's earlier run with the same tune running Nikons, and they're pretty much identical apart from Wullie's is slightly better through the midrange. Thus proving that Nikons are nothign more than lightweight copies of the stock pipes, and that fact there's plenty more to come

[wullie3XV9]

That's a very flat torque curve Wullie, I bet it's very smooth to ride and very flexible...

I'm not so sure if the -40 cdi is what stops it past 11200, more likely the standard pipes stop working properly. It'll be more interesting to see how it goes once you have some pipes on to match the porting though ( eventually ).

Is that with any advance on the flywheel or pick ups? that may gain you a couple of hp as it is.

Yep, even on 15 / 38 final gearing she'll potter around in ( & accelerate from ! ), 4th, 5th AND 6th gear from as low as 2,500 - 3,000 rpm no problem.
No flat spots felt anywhere !     The power just builds & builds in a smooth, steady rush all the way to the redline.     ;
For anyone who wants a more powerful, but still flexible, state of tune for the road / street without sacrificing much reliability, ( hopefully ! ), it's definitely recommended.
Ignition timing was still on stock setting, by the way.    I've bottled out of trying 4 degrees of advance for now.    ( coward    ).

[wullie3XV9]

I've just compared Wullie's run with that of Kingy's earlier run with the same tune running Nikons, and they're pretty much identical apart from Wullie's is slightly better through the midrange.
Thus proving that Nikons are nothing more than lightweight copies of the stock pipes, and the fact that there's plenty more to come.

The Nikons only real advantage is that they're half the weight of a set of stock pipes !  

[Warwick]

Looks good, Wullie - very strong up to about 8.6 or so. With a stock CDI I expect that you'd lose a bit of it's overall flexibility (below 10k) when you get some good pipes on it though. Andy Bush's experiments recently suggested that a bit of global advance might help fill in the slightly concave power curve you tend to get with porting and pipes but the stock CDi, so that might be worth looking at once you have some pipes fitted and tested?  I'd expect you to still see good gains above 10k of course, but it'll probably feel peakier to ride than it does now. If the global advance trick doesn't do it for you you'd probably need to consider either a Sugo ignition or a zeeltronic gizmo to win back some midrange - or just rev it harder...   

[wullie3XV9]

Thanks Warwick.  I didn't want to gamble trying the 4 degrees global advance 'till after I'd checked the mixture strength was rich enough all the way through the rev range on both carbs / cylinders, hence why I spent yesterday morning doing all those plug chop runs to compare spark plug colouration !  
Once I've saved up a few more quid, I'll advance the timing 4 degrees, ( I've already made my own 0.6 mm offset woodruff key ), & take it back in for another session on the dyno & see what happens.  Watch this space .....  

[wullie3XV9]

Well lads & lassies, I've finally extracted the proverbial finger & got my Martin77 "not quite SP" ported & piped RS back on a dyno to see what power it's producing now.  
5 runs were done with the stock flywheel / timing rotor woodruff key fitted & another 5 were done with my home-made +4 degree advance key fitted.  
The idea being to back up Andy Bush's +4 degree ignition advance key experiment early last year.  ( See in 3XV tech. sect., page 8, "Bush's 2010 st3 engine" ).
( By the way, the runs were done at Bob Scott M/cycles, Glenrothes on a dynojet 250i, not at Grants M/cycles, Knockhill ! ).

I was a bit disappointed with the rear wheel figures, but with the advance key fitted, the lines are fairly smooth & straighter now & show that some "global" ignition advance is definitely a worthwhile exercise on a road / street 3XV sticking with stock -00 / -40 CDi's, but with ported cylinders & different exhausts fitted.
It looks like the -40 CDI over retards the ignition from approx 8,500 rpm onwards.  The 4 degrees of ignition advance seems to have negated most of the effect.
Oh !, & we managed to defeat the 0 kph / rev limiter system by driving the speedo cable with a cordless drill turning anti-clockwise & keeping the needle above 20 kph.    

The blue line is the best run with the stock rotor woodruff key.
The red line was the best run with the +4 degree advance key fitted.
The green line was the last of the 5 advance runs done, with the engine at normal working temp. ( 65-70 deg. C ). Note how it's straightened out compared to the 2 earlier runs.
On the 5 advance key runs, the hp output results were all within 0.75 hp of each other so were pretty consistant.  ( i.e., no major losses due to "power fade" ).



Changes to my bike set-up wise, since the first run last April, include a set of Martin77's pipes, the non-standard P8 needle jets / emulsion tubes in each carb replaced with correct ( for a 3XV9 ) smaller bore P6's & both carbs stock 5FN117 needle clips placed in the ( stock 3XV9 ) 2nd from top slot.  
Main jets are now 220 left / upper carb & 260 right / lower carb.  Fuel was normal 95 octane un-leaded.
The runs were done with a fresh pair of BR9ECM plugs fitted & the top-end has done just over 6,000 kms.  ( 3,750 miles ).

Any constructive hints & tips on improving the output further, in it's current state of tune, gratefully recieved.

I'm toying with the idea of re-fitting the stock exhausts sometime to see if a couple of degrees ignition advance works with them fitted.  

[louis]

Hello Wullie,

Looking very good

Its a nice differends with a +4 degree advance key,

Do you know how the ignitioncurves looks from a 40cdi?
How much advance do you have at 11.750rpm?

Does it look like these?

[wullie3XV9]

Hello Wullie, looking very good.  Its a nice difference with a +4 degree advance key.

Do you know how the ignition curve looks from a -40 cdi?  How much advance do you have at 11.750rpm?  Does it look like this?

Thanks Louis.  I haven't got the foggiest idea what the ignition curve is in -40 CDI's, but it looks like they over retard above 8,500 rpm, which was where stock 45 hp motors made the brochure peak torque figure.  If you look at last years run above with the same CDI & stock exhausts, the torque peaks at 24 lbs ft at 8,500 rpm & produces that figure right up to around 10,750 rpm !  Not a torque curve, but a torque plateau !  
It could be that -40 CDI's are even more retarded above 8,500 than -00 CDI's !  

I could do with borrowing a -00, to experiment back to back with my -40, to see if there's any improvement to be had that way.  I could also make a +5 key & see if there's any improvement with that.  The problem is, that with the +4 fitted, it looks as if the power & torque is beginning to suffer because of the extra advance below 8,500 rpm !  
I might also be able to come down a size on each main jet which could net me another hp.
But it does look like the main hinderance at the moment IS the CDI, as everything else is set up as it should be.

[EEKNOWS]

That's about 10HP and 5 ftlbs torque down on what a NSR/RGV/KR-1 makes with similar modification.
 Ignitech or Zeeltronic would be the best money you ever spend. Problem with advancing the stator or pick ups is you shift the whole curve,  your power valve curve might need a tweek also.
You look to have peak at the right peak rpm but you have a mismatch somewhere between carb/reed/ignition/compression