Alky or race gas on Sabertooth 250R Saber CPI

[Mickkey82984]

Hey Guys,

Im buying a 569 saber built and drag ported, set up for Alky by pete, I never ran alky, Is it hard to tune? Would it be better to have pete cut race gas dome for me? I'm also going to need to buy a carb, Anyone have any ideas on how big of carb I will need? I was thinking one of the packard 48mm lectron's.

Thanks,
mike

[Jerry Hall]

Packard measures their Lectrons differently than other carburetor companies measure their carburetors.  All of the 48 Lectrons I have measured, measure 43mm using conventional carburetor measuring procedures.  Conventional measuring procedures consider the smallest diameter through the carb to be the carb size.

[Mickkey82984]

Packard measures their Lectrons differently than other carburetor companies measure their carburetors. All of the 48 Lectrons I have measured, measure 43mm using conventional carburetor measuring procedures. Conventional measuring procedures consider the smallest diameter through the carb to be the carb size.

What do run on your drag lt 500 builds Jerry? Do you think alky will be hard to tune up here at 7000 feet?

[rsss396]

I have had a few lectrons over the years and typically they run 2mm smaller at the slide compared to the outlet

44mm = 42mm at the slide
48mm = 46mm at the slide
50mm = 46.5mm at the slide - this is as large as you can go without a wider slide, this also includes a billet outlet because the factory body is to thin to support the carb.
52mm = 49mm at the slide - this includes a custom slide, billet inlet and outlet along with custom billet cap on top for the carb cable because the screws are moved out to make room for the wider slide. This is the same body as the 48 lectron just taken to its extremes

there is a HV version of lectrons and tyically they have a 4mm differance from the slide ID to the OD, I do not have any experience with these


And to answer your question, I do not believe alcohol is hard to tune, and IMO more forgiving than race gas, but you MUST purge the carb and engine at the end of every day or you will have issues with fuel gumming up and possiable corrosion in the engine from the alcohol absorbing moisture.

[Jerry Hall]

..............There is a HV version of lectrons and tyically they have a 4mm differance from the slide ID to the OD, I do not have any experience with these


.

This must be the ones that customers have sent me.  They had a venturi down stream of the slide where the minimum diameter in the venturi was about 43 to 44 mm.  Something like that is not going to flow like a straight bore 46 to 48 mm carb.

[Jerry Hall]

I usually use the old round slide VM 44 Mikuni.  Sometimes we will bore them to 46mm.

Alky is never hard to tune if you have all the tuning parts you need for the application and you have the rest of the fuel system setup so there is adequate flow and pressure to the carb to keep the float bowl full.  

 Extra Large float bowls are a sign that the tuner has not figured out a way to keep the fuel level constant inside the float bowl at all throttle positions and RPMs. A carburetor has to maintain a constant fuel level to be able to tune it.  As the fuel level in the float bowl goes down the air fuel ratio becomes leaner.   A carburetor that cannot accept fuel into the float bowl at the same rate as fuel is being consumed, will run leaner and leaner as the fuel level in the float bowl drops.  If the throttle is held wide open long enough the float bowl will eventually run dry if the piston does not burn up first.

Tuning at 7000 ft. elevation is not any different than tuning at sea level.  It just takes different jet, needles, etc.

[rsss396]

the old no longer made CPC carbs are nice,  especially if someone has already got them dialed in close for alcohol.
They use all Mikuni tuning pieces and floats

They had oval and round versions and the best place to find them is on the snowmobile forums.
I had a set of 48 rounds that worked real well on gas the ovals I think came in a couple sizes 48x52 and something like 52x56






I do not know of any shops that know exactly what needle and jets to run to make them work but Mat Shearer or Nate McCoy would more than likely be your best shot


I run a 56 round crankshop carb on my Liger and it also uses all mikuni tuning and float pieces plus crankshop also has custom needles and jets
But they offer no alcohol tuning advice and you basicly go out and fiquire it out, it was not really all that hard and I got it pretty much exactly were I want with only buying a few differant needle jets and adding 3 power jets to it.
There are a few guys that have been tuning the 52 crankshop also that maybe able to help you

[Duner]

Hey Guys,

Im buying a 569 saber built and drag ported, set up for Alky by pete, I never ran alky, Is it hard to tune? Would it be better to have pete cut race gas dome for me? I'm also going to need to buy a carb, Anyone have any ideas on how big of carb I will need? I was thinking one of the packard 48mm lectron's.

Thanks,
mike

Pete has only built 1 Saber that big, guessing this used to be Rogers old motor.

48mm is too small for that motor. 50mm at the least but 54mm would be ideal. Alky is only way to go

[udontknowme]

been using a 48hv and have no complaints with the carb itself but i wonder if i have the wrong needle so im gonna talk with packard about it

if you have all the right pieces like compression, plug, carb, needle, timing etc then you shouldnt have much problem tuning. but if you have a few things out of wack then more than likely youll be scratching your head alittle bit. i had a hard time getting mine to run good because i think the head dome was wrong and possibly wrong needle also

[rsss396]

Alcohol bikes are drove differently than gas bikes, they load up easy and must be cleaned out, I see newbies driving around at low rpms loading the pipe up with fuel, then pull up to the line and rap the throttle a couple times and try to launch the bike only to fall on its face.
First before pulling up to the line, you need the pipe clean of excess fuel from putting around or extended idling. You then have to learn to tune your carb to your style of launch, I have this issue between me and my Jockey we do launch the bike differently
He likes to set at the line and rap the throttle which requires a leaner needle setting than the way I launch, I hold the motor rpms/throttle position at a constant right before launch, this requires the needle setting to be richer.

[Mickkey82984]

Pete has only built 1 Saber that big, guessing this used to be Rogers old motor.

48mm is too small for that motor. 50mm at the least but 54mm would be ideal. Alky is only way to go

Is there a reason he has not built many this big, I know almost all the ones I see are 496's. Is there a big difference between the two?

[rsss396]

IMO the 569 saber will more than likely run better with its longer stroke than the 496, My guess is out of the small amount still being built lately very few are 70mm stroke 496cc motors

[traxman]

Is there a reason he has not built many this big, I know almost all the ones I see are 496's. Is there a big difference between the two?

There's hand full of these motors out there. Honestly you gotta have a customer willing and wanting to build one in order to do so. Your cylinder was one of the first to be cast with a 4mm stroker in mind otherwise mine would of been built to those specs too. My cylinder is like #4 or 9 cant remember and it was one of the first 510's out there cause everyone was building the 496's. That motor's a beast I had it in my chassis for it's first outing and @ Dunefest. The rotating mass is the major factor between the two. The 496 internals are massively heavy compaired the stock stroke and stroker set-ups. I noticed quite a difference in torque from my 510 to that 569, I can only imagine that the 496 would of been less that my 510.

[Mickkey82984]

The coc PM'ed on the other site trying to me tell that the saber I'm going to buy is a old casting that can't be tuned right, only the new *** casting can be tuned to run right and that a full drag port on a single wont run right at 7000 feet. Yet I have a couple of friend with lt 500's drag ported, drag pipe on race gas that run flawless up here.

[JesseA420]

dang he sure is trying hard to push that lot of sabers onto someone!