MS'ing 45 degree V-Twin

Cyco · Post by **Cyco** » Sun Nov 12, 2006 3:13 pm

Curious, has anyone Mega-Squired one of these? I have a '98 Honda VT1100C2 ACE that I am considering doing this to. It is a stock engine with dual Keihin 36mm CV carbs. I have considered a small TB (calculated to 52mm bore by calculating the area of 36mm X 2 and figuring the dia. to double the area to feed both cylinders) but found a formula that says 32.5mm is the size to power a 60hp engine. With pretty extreme space restrictions, I am considering plugging the fuel inlets, the overflow or vents, removing the floats, capping the main and idle circuit wells, pull the CV diaphrams/slides and turning some aluminum inserts to replace these, to hold the injectors at a height to spray the bottom 1/3 of the venturi bore. Injectors need to be ~200cc/min by my calculations.

Right now I would not worry about IAC for warm-up, just lock the throttle off idle, cracked slightly with a temp sensor reading for enrichment.

Experience, thoughts, comment welcome.

Cyco....maybe.

newtyres1 · Post by **newtyres1** » Sun Nov 12, 2006 10:54 pm

It should be possible, quite a few odd-fire engines have MS for fuel control only. The MicroSquirt has odd-fire ignition capability as well, so if you can give it the correct inputs from the crank or cam sensor then there should be no problem. Either way it's probably easiest to do fuel first and then add ignition control later if you want it. I have a fuel-only setup on my '03 1200cc Buell and it runs better/smoother than stock.

Ian.

Dr.Hess · Post by **Dr.Hess** » Mon Nov 13, 2006 6:21 am

Ian,
I'm working (well, thinking about and collecting parts) on a 883 conversion with Buell parts. I plan on triggering off the negative coil lead using the OEM ignition. I have a Buell fuel pump, manifold and TB. Care to share your MSQ or provide some other hints? Thanks.

newtyres1 · Post by **newtyres1** » Tue Nov 14, 2006 12:47 am

Dr Hess. no problems sharing any info, PM me and give me your email address for msq etc (files cannot be pm'ed back to you). Only thing is I'm running MS1/Extra which has the odd-fire averaging of the coil pulses to make it all work, which MS2/MicroSquirt doesn't do yet, but that feature *may* become an option in the future in the MS2/Extra code if enough people ask for it. The MS2/MicroSquirt code can handle odd-fire engines if you give it the right inputs for tacho, I am working on a way to do this for Buell/Sportster but it will take me a few months at least.

So as far as I can see your immediate make-it-run-now option is MS1 on a V2.2/V3.0 PCB running MSnS-E fuel only, that is what I'm doing and it runs great. If you want to use the MicroSquirt you will have to either make up your own tach interface for it, or wait till someone else does it, or wait till MS2/Extra code does odd-fire averaging of the irregular coil pulses of the Sporty so you can run a fuel-only setup. Right now the coil pulses from the Sporty will not run MicroSquirt, it needs even pulses. I've followed your posts with interest and get the impression that you are not in a screaming hurry, so probably best to use time to your advantage. I also owned an 883/1200 for about 70,000 km, loved it!

Ian.

Dr.Hess · Post by **Dr.Hess** » Tue Nov 14, 2006 6:57 am

PM on the way. Thanks.

Yeah, the need is not that pressing right now, as I have to finish the Truck first. I'm at the wiring stage on it now, and it just seems like everything is taking about 6x as long as it should. That's life, I guess. Anyway, as the uS isn't out yet, I'm still waiting for that. And I know Ken is working on the extra code for uS, so I hope that should be out by the time I am ready to start on the bike. Also, a friend of mine in Texas is seriously considering doing his Twin Cam too, so after I finish Dr.Linda's Sporty, I think that one is probably next.

My wife has about 46K miles on her bike, and she put all but about 100 of those on there.

FIntruder · Post by **FIntruder** » Sat Dec 09, 2006 8:15 am

Cyco, you may wanna track down a Buell TB, it is the right size, uses one TB and has the injectors included. I think it is in the 45mm area and should provide more flow if yer bike can use it. I'm plannin' on using one on an Intruder 1400. One TB, two injectors(one per cylinder), small and usually very affordable on Ebay. Remember, the dual carb setup on yer bike is only one 36mm per cylinder, they don't share.
Yer biggest obstacle will be the fuel pump. Most fuel injected motorcycles use an "intank" style and are the wrong shape for yer tank. The inline pumps that are available draw and flow way more than you need or yer electrical system is gonna easily power. I have an MSD pump that is supposed to draw around 5 amps and support 500hp. My Intruder makes close to that hp

but 5 amps really is too much and the extra fuel that is circulated can cause unnecessary fuel heating. I don't know if I could use a resistor to slow down the pump, my gut says yes but most replies here have said no but gave no reason that made sense to me. No offence to those who replied, I do appreciate yer input.
I recently purchased a fuel pump for a 2005 GSXR750 and if it draws in the 2 amp range I may try to construct a secondary tank that the main fuel tank will keep full and this pump will pump from. Space and visualness is always important on a cruiser. Use Ebay for reference and pricing. Rediculous how cheap some stuff is.

FIntruder · Post by **FIntruder** » Sat Dec 09, 2006 8:23 am

Another pump possibility is the VW style intank setup. Basically it looks like a points style ignition coil and sits in the tank. Securing it somehow would be a good idea but the wires and hose just attach to it right inside the tank and the intake side uses a sock style filter. My 1985 BMW K100RS used this set up. I don't know what kinda amperage it draws but since it only needed to support around 100hp it should be less than 5 amps.

Dr.Hess · Post by **Dr.Hess** » Sat Dec 09, 2006 2:22 pm

The Buell fuel pump is external/inline and made for a bike. Dunno about the HP, but should be plenty for about any bike motor. I got one with the TB/Intake.

I think a resistor inline with a regular fuel pump wouldn't hurt. Toyota does that with their high HP 3SGTE motors as in the MR2 Turbo. Then they have a relay that bypasses the resistor when in boost, or high boost, I forget the exact logic. If I recall, Toyota drops the voltage at the pump to around 8V or so with the resistor. The important thing is to get the resistor big enough to handle the heat. Toyota uses a big sucker. May take some experimenting.

FIntruder · Post by **FIntruder** » Sun Dec 10, 2006 5:23 pm

This may be the answer we have all been waiting for. 'Bout time you spoke up! Do you have any idea how many amps it draws? I'm sure it will provide more than enough pressure and volume for my needs. Gotta run and check Ebay.
I used a 50watt resistor on the ground wire in a stereo system to make the speakers show 4ohms so the amp would not cook. At least 5 different sources insisted it would not work but it does like a charm. I'm figurin' it would work fine with the pump too.

Skiericski · Post by **Skiericski** » Sun Dec 10, 2006 8:59 pm

Dr.Hess wrote:The Buell fuel pump is external/inline and made for a bike. Dunno about the HP, but should be plenty for about any bike motor. I got one with the TB/Intake.

What Buell did yours come from? The two currently on eBay are both internal pumps.