zxrmick

hi,
what base jeting spes for my twin 44s mikuni
and timing on msd total loss ??

mono carb 46 sbn is light for this engine ...

engine:

pjs 800 super cylinder
stroker crank 77 mm
head 140 psi
squish 1.6
factory pipe exhaust with rpm chamber
Msd water injection
Msd total loss
twin 44 mikuni
boyesen reed

impeler :solas dynafly 14/23



thanks

Mick

mcn6

With the Factory pipe:
Dual black 44's = 130 main, 125 pilot, 14-16psi popoff
Dual silver 44's = 145 main, 125 pilot, 12-14psi popoff
The above should be a good starting point with your setup.
Timing... 28*-30* initial, start ramping down at 4500-5000rpm, 14*-15* at 7400rpm with pump fuel.
I don't see any problems with a single 46mm SBN and your set-up???
No comment on the sorryass... Errr, I mean Solas impeller...

rowdy925

You should sell me your PJS super cylinder: )

zxrmick

thank you

it is black mikuni carb
i try this the next week

i have find one
i keep !!
old supercylinder pjs rules

stock kawa ported cylinder crack ...

i have run on it only 5 min for first test with this ski !!

the mono carb 46 jeting is bad

i have

110 main jet
155 pilote jet
2.0

i test this week ??

130
155
2.0

there is a big difference with a factory dry pipe vs b pipe with this chamber ?
looking to trade for a factory dry pipe ?

i have wet chamber too ... for this pipe

mcn6

If thats the new 46mm jetting, sounds good. popoff is still a little high though... Any one of those pipes is good IMHO. Beyond your jetting issues, you should probably be more concerned about the compression vs. whatever octane fuel is available in France than which tuned exhaust to run. 140psi seems kind of low even for European octane numbers... Again JMHO.

zxrmick

what is the good head pressure for rec ride... ?

i search 1 head for my supercylinder
this head is cut for low compression ...

in france i have 98 octane fuel for 1,4..€
and e85 ethanol octane fuel for 0.8€ 105 octane fuel

Anyone has already tested with good result the e 85 in a ski ?

Timing... 28*-30* initial, start ramping down at 4500-5000rpm, 14*-15* at 7400rpm with pump fuel.

what is your pump fuel octane in usa ?.

my exhaust timing is +-198 °
+- 2 mm base join cylinder

my wiseco piston is 80 mm bore
max bore is 84 mm or 83.5 ...

mcn6

I use corrected compression ratios to estimate fuel octane requirements, unless you can provide me with an accurate trapped volume I won't be much help. I just noticed the low psi reading and commented on it... However, the compression gage gurus around here seems to be of the opinion that 170-175psi is acceptable for 92-93 octane fuel (our 93 octane is roughly equivalent to your 98 octane) You should do a search to yourself to verify 170-175psi.
Do not run e85. That stuff is 85% ethanol... Not what you want at all IMO!
Yeah, your using a 2mm base gasket as a spacer plate for the stroker crank... Which explaines the 1.6mm squish clearance. Even with the added 3mm stroke 198* is an aggressive exhaust duration... Depending on the rest of the porting package and impeller your boat should be making peak hp at a fairly high rpm, increasing the compression should help with the low rpm torque issues.
Whoever put tour motor together sounds to me like they know what they are doing. How come your on here asking questions instead of asking your builder?

zxrmick

the ski run great in botom end
with water injection i have very much more power and torque ... the ski pull hard

the b pipe sucks in hight rpm

looks for a dry pipe ...

i trade my b pipe...

next week
tuning my twin 44 for more hight rpm
and look for new pjs head i have 130 psi ...

zxrmick

i buy hs engine\supercylinder head



rebuild head ---) 27,5 cc








i have 3 set dome: 30 ,27.5 ,25 cc

1,3 mm de squish 25 cc big squish band

1,8 mm squish 27,5 cc smal squish band

run great with 25 cc and my spark plug ngk br10 explosed

zxrmick

i have remplaced my spark plug BR9es for 2 new ngk br10

3 min later the ski run on one cylinder
I substitute for my hold br9es
2 min the next ngk b10 explosed !!!
exhaust leak on the spark plug !!
ceramic dust everywhere !


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