Marks exhaust tuning

[warp1]

Read through a lot of the tuning threads on here, just seeing if this sounds reasonable.

98 V max, stock. Installed the Mark's 4 into 2, shorter cans, 2 inch. My initial jets were 152.5 and upped to 155's, my air screws are all 2.5 turns out.

What I've read recommended original jets, shimming needles and 3 turns out?

Should I not have upped the jets?

Heard there is a decent dyno in town, I suppose I should just run it on there and look for any flat spots in the HP curve and adjust from there?

Hope the jets can stay, don't want to pull the carb rack again And no, haven't pulled my plugs yet to check color etc. It idles well and seems to pull pretty well (not sure what is normal). Kind of funny...tried every plug socket in my garage to get the plugs out...none worked. Friend told me to use the one in the tool kit....duh ...

 

[sdt354]

Read through a lot of the tuning threads on here, just seeing if this sounds reasonable.

98 V max, stock. Installed the Mark's 4 into 2, shorter cans, 2 inch. My initial jets were 152.5 and upped to 155's, my air screws are all 2.5 turns out.

What I've read recommended original jets, shimming needles and 3 turns out?

Should I not have upped the jets?

Heard there is a decent dyno in town, I suppose I should just run it on there and look for any flat spots in the HP curve and adjust from there?

Hope the jets can stay, don't want to pull the carb rack again And no, haven't pulled my plugs yet to check color etc. It idles well and seems to pull pretty well (not sure what is normal). Kind of funny...tried every plug socket in my garage to get the plugs out...none worked. Friend told me to use the one in the tool kit....duh ...

condition

I'd be very interested in the plug condition. I was going to step the same setup down to 150's. I ditched the neddle shims, was rich. a/f about 2 3/4.Keep me informed k?
Steve-o

 

[Rand-5107]

Mine was running 12to1 air fuel ratio with Mark's 4into1 and 152.5's

 

[Rand-5107]

That was from 6000-10,000 rpm. So on the main jets.

 

[Rusty McNeil]

Your fine the way you are, no harm no foul I think.

The a/f screw is kinda subjective, whatever idles best and gives best off-idle throttle repsonse is probably right.

But if it was me I'd step those mains down to 150's at least, maybe 147.5's, you'll be surpised at the difference if all else is right. I think most Maxes are rich to begin with. I stepped my UFO' all the way down to 147.5 at sea level and it runs fantastic and is about 13:1, 13.5 when "on the mains". Maybe a little lean in some peoples opinon but no signs of Det. in my case. The load on a m/c is minimal any way, so tendency for det. is gonna be less.

What elevation are you at?

 

[SpecOps13]

This is the set up for my 1994


Altitude 0-42 Feet
Exhaust Marks 4-2, 2" cores, 14" cans
Stock carbs
Stock needles shimmed 0.028
152.5 Mikuni Mains
Stock PAJ 1 & 2 (Mikuni 90 & 170)
Air / Fuel Screws 3.0 turns
K&N, Stock Box
Dyna 3000 set on curve 1
Stock Vboost
Nearly flat 14 to 1 Air Fuel on Dyno

Sean Morley says the HP would be up with more fuel. So 155's might be the ticket...

 

[ninjaneer]

...Altitude 0-42 Feet...

where the eff is there 42 feet of elevation in tampa? scratch that where in florida? and landfills don't count :rofl_200: ...neither do the multi-level parking lots. i wonder if anyone has a setup for negative elevation...hmmmmm

 

[Rusty McNeil]

where the eff is there 42 feet of elevation in tampa? scratch that where in florida? and landfills don't count :rofl_200: ...neither do the multi-level parking lots. i wonder if anyone has a setup for negative elevation...hmmmmm

Florida High Elev. 345 Ft

Low is sea level.

Mean Elev. is 100 feet

 

[SpecOps13]

I live on Diston Ridge.. 42" Elevation....:rofl_200:

 

[warp1]

Elevation about 700ft

Forgot to mention the K&N in a stock air box. I'll see what the dyno says I guess. She runs pretty good...rich if anything but still crisp

 

[ninjaneer]

I live on Diston Ridge.. 42" Elevation....:rofl_200:

:rofl_200:43 for me