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Discussion Starter #1
Doing a winter build bproject out the Marauder, including some maintanence upgrades, paint motor work and performance enhancers. Some of the parts are here and others are beginning to flow in, others have yet to be ordered, but it's early in the season and I probably won't get started on it until late February so lots of time to get exactly what I want.

Parts on hand:
Corbin Solo Seat
Michelin Pilot 3 Tires in 120/70 front and 190/55 rear
New three fin Cone breather
Thunder 6 Spring clutch adapter

Parts on order:
Barnet Clutch plates

Part s to be ordered:
4.065 Forged Pistons and rings
Dynatek wide band O2 sensor
PCIII Fuel Processor
DynoTune Dry NOS
Top end Gasket set

Machine Shop:
Cam Grind
Cylinder Honing
Polish exhaust Ports and Combustion chambers

Not complete but that's off the top of my head.
 

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Discussion Starter #3
Lets hope so, the NOS is bonus power so that will be the last thing to be done this go around. I wanted to run twin 20oz bottles, but they're to big for the application so I'll go with twin 12's.
 

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Pics as you go!
 

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You're not done yet?
 

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Put some work into a bowl blend then a 5 angle valve job. There is a lot of room for improvement there along with cutting down the valve guide since it also obstructs flow.
 

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Discussion Starter #7
I'll look at the bowl blend and assess it, but don't intend to make any mods to the intake side. Increasing the flow of the intake side reduces velocity and negativwly impacts mix. That effect has a negative impact on mid range torque. Sinc our bikes run at low rpm rev limits this is a big issue. Maintaining velocity on the intake side while maximizing flow on the exhaust side will maximize benefit on both ends, maintaining or improving mid range torque whil minimizing crank resistance from exhaust cycle.

I'm not going super high compression as Colin did. My intent is about 11:1 compression with onboard instant power. I want the power when needed with a little more ban for my buck on pump fuel.
 

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You aught to buy one of David Wizard's books on porting heads, it will open your eyes to more than what you come up with on a simple google search. The main restriction in any head is/are the bowls, which will increase velocity as any bad angles will cause reversion and thus slowing your intake velocity. Also you need to know the rpm band you are working with for whether to put your attention to the top or bottom.
 

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Discussion Starter #9
I'll check it out.
 

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Maintaining velocity on the intake side while maximizing flow on the exhaust side will maximize benefit on both ends, maintaining or improving mid range torque whil minimizing crank resistance from exhaust cycle.
Overly large exhausts hurt your power band just like overly large intake ports do. Normal "rule of thumb" on the flow bench is that the exhaust should flow 80% of intake. More on a nitrous motor if you're tuning for power on nitrous and willing to accept some loss when the nitrous isn't on.
 

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Discussion Starter #11 (Edited)
I've researching aero and Hydro dynamics the last couple days based on wing surface and smooth vs textured surfaces. more research to be done, but I'm considering a very specialized surfacing technique in the combustion chamber bowls. My goal is to increase flow and turbulence. the problem as I understand it is increasing flow at the expense of lost velocity negatively impacting mix turbulence. I still plan to polish the exhaust ports. I agree the 5 angle valve work is a very possible mod for this project.Well see this whole thing is developing.
 

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Discussion Starter #13

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Discussion Starter #14
I think I've located my pistons Forged flat top 4.04 dia. with 1.26 compresssion height. Not ideal, but the closest I've been able to locate. I wanted 1.20 compression height but can make this work with an adjustment to the bottom gasket, or a simple grind of about .03-.05". Still need to confirm the weight of the pistons and run some compression numbers, they should be a good fit to put me between 10.5 and 11.5:1 compression. Basically, with a OEM deck height of 1.1875 and the piston .045-.05 in the hole I'll be increasing piston surface lift .0275 out of the hole using OEM Gaskets on both ends, adding another .03 in compressed gasket materail on the bottomwill give me exactly what I'm looking for.

I got the new air breather out tonight and checked it out. It's Sweet, but I need to Mod it to accept the temp sensor.

I've reading a lot about adding NOS as it relates to compression. seems the rule of thumb is run low compression and compensate for the loss in natural HP with extra NOS. The proper set up however is managed in tuning on a motor with compression between 10:1 and 12.5:1. I personally dont believe in sacrificing natural power daily to make it up in 15 second bursts rarely so I'm going to run it right and tune it. Probably need to retard my timing about 4-8 degrees and run cooler plugs but it's worth it.
 

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Discussion Starter #15 (Edited)
Pistons ordered, I ended up going with the the 4.03 bore pistons in a 1.26 compression height, piston weight is 435 grams plus rings and and hardware. Decided a more conservative bore, even by .01" is a better option considering the increased pressures of NOS. Barnett Friction plates on the way, I'll order steels if I need them when I pull it apart. Intended to replace the friction plates either way.

Can't wait until everything arrives, I'll be ready to get r done, and replace any necessities I find along the way. Being the Nitrous is bolt on for the most part I'll get everything built set up and tuned beforehand, and Add it last to the prepped system. Still need to acquire the wide band O2 sensor, but thats about it right now.

Edit:
Parts now on hand or in the pipeline-
Corbin Solo Seat
Michelin Pilot 3 120/70 and 190/55 tires
Balancing Beads
Intake breather
Barnett Friction Plates
.03125 compressed gasket material
4.03 SBR Flat top Chevy Small block pistons
6 Spring Clutch adapter

Left to order-
Dynotune NOS
Dynotune O2 sensor
Top end Gasket set
Cooler plugs (8's or 9's)
 

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Wait. Winters pretty much over here except for 66 here on Sunday then 30s and snow on Tuesday. So if this is a winter build you need to hurry so I can decide what I want to do
 

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Discussion Starter #17
Oh, sorry ha to hold off a couple days. It's gonna be 60 here today and I needed to get on las ride in before I tear into it.
 

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I think I've located my pistons Forged flat top 4.04 dia. with 1.26 compresssion height. Not ideal, but the closest I've been able to locate. I wanted 1.20 compression height but can make this work with an adjustment to the bottom gasket, or a simple grind of about .03-.05". Still need to confirm the weight of the pistons and run some compression numbers, they should be a good fit to put me between 10.5 and 11.5:1 compression. Basically, with a OEM deck height of 1.1875 and the piston .045-.05 in the hole I'll be increasing piston surface lift .0275 out of the hole using OEM Gaskets on both ends, adding another .03 in compressed gasket materail on the bottomwill give me exactly what I'm looking for.

I got the new air breather out tonight and checked it out. It's Sweet, but I need to Mod it to accept the temp sensor.

I've reading a lot about adding NOS as it relates to compression. seems the rule of thumb is run low compression and compensate for the loss in natural HP with extra NOS. The proper set up however is managed in tuning on a motor with compression between 10:1 and 12.5:1. I personally dont believe in sacrificing natural power daily to make it up in 15 second bursts rarely so I'm going to run it right and tune it. Probably need to retard my timing about 4-8 degrees and run cooler plugs but it's worth it.
What mfg and part #s are you going with on pistons? This has got me thinking about my own bikes engine next winter.
 

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Discussion Starter #19
Hey bro, I ordered my Pistons from Jegs, part #867-138085-1 (SBR 4.03"/ 1.26 Comp Ht.).

Here's a shot of the new intake, I threw it on last night so I could ride the bike today, it's preported for dry Nitrous to the intakes. I've not gone this route previously because it seems everyone with a Vtwin uses this style. but this one was different enough I caved in. I need to clean up the internals to get max flow though.
 

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Hey bro, I ordered my Pistons from Jegs, part #867-138085-1 (SBR 4.03"/ 1.26 Comp Ht.).

Here's a shot of the new intake, I threw it on last night so I could ride the bike today, it's preported for dry Nitrous to the intakes. I've not gone this route previously because it seems everyone with a Vtwin uses this style. but this one was different enough I caved in. I need to clean up the internals to get max flow though.
Nice intake, looks good. Another question about the pistons, what are you planning on doing about the wrist pin? The wrist pin in our bikes is bigger around and longer than the one those pistons use. I'm just curious as I like to see what others are doing for their builds and yours has my interest.
 
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