Multipoint injection on 3 cyl two stroke.

[tanshi]

I have a 500cc 3 cyl 2 stroke motor that im putting together a parts list for injecting. I have a set of triple injected throttle bodies that im fabbing a mainfold for.
my question is:
How do i run the three seperate injectors using a MS as i understand that the MS 2 only has two seperate channels for injectors. Is there an upgrade or modification for this?

I guess i could run all three injectors at once and allow the reed valves to control the inlet of fuel,

Am i missing something.???

[DonTZ125]

Hi, Tanshi.

Is this a skidoo engine? I can't think of any recent 500 triple bikes... or... OMG - are you squirting an H1?!

The latest 'extra' code for MS2 has 4 channels (with certain mods to the card and board) and sequential injection.

[tanshi]

its not a recent motor at all, Its actually from a suzuki 4x4 car from 1974 an LJ50 is the model. Triple throats from a triumph 700 cc motor cycle

Im not real good with the solder etc, is there any one around the place that does good work and could put the MS together for me including the mods i need?

[DonTZ125]

Where are you? This IS a fairly global site. There are people who build and sell these, including a few who do custom work, but shipping will be easier if you aren't dealing with someone from the other side of the planet...

[tanshi]

Im located in Brisbane, Australia.

Custom work sounds good.

[Stag76]

If you contact Kendall Shore @ Shore Electronics (07 4632 2533) in Toowoomba he may be able to help
There is a small MS community around this area, and most would be willing to help.

[drmiller100]

run all 3 on one bank all firing at the same time for the same duration.

by the time everything gets mixed in the crankcase, it won't matter a bit.

are these reed motors, or piston port? Doesn't really matter, just curious.

[tanshi]

It is a reed valve motor. Im looking at bigger reed valves from a suzuki outboard Motor which bolt straight on.

If i was to run them in one bank, i would have them only fire once per full engine revolution? When in the cycle would be best to firethem?

i would have thought that while one bank would work. three seperate injections would be more effective.

I have contacted Kendall, I just need to find some time to call him. Is there any one else around the area who would like to make a few bucks?

[drmiller100]

it does not matter where in the cycle.

By the time the air goes past the reeds, into the crankcase, churned by the crankshaft, up through the transfers, and into the cylinder, it is well mixed.

There have been some games played with semi-direct, where the injectors are firing through the transfers, and trying to squirt into the cylinder to reduce emissions, and those obviously must be timed correctly.

Some injector setups also inject directly into the crankcase. makes little difference there, but you can get more horsepower at WOT with crankcase injection then transfer injection because you can cool the piston.

Bigger reeds often do not translate into more horsepower. And outboards are notoriously low performance 2 strokes. and, outboards need very reliable reeds. I would consider something off of a snowmobile or motorcycle if you are serious about wanting more power.
Do you have a "pipe"?

[tanshi]

im trying to get more power, while keeping it relyable. reliability its the most important thing.

reeds from a snow mobile might be hard to come by as im from some where that is thousands of miles from anywhere with snow.

[tanshi]

oh and by a pipe do you me a tuned expansion chamber?
if so,
then no i only have the factory one at this stage. i am hoping to find some one who knows about improving performance on the two stroke at some point.

[drmiller100]

yeah, pipe is "tuned expansion chamber."

how many horsepower is it now, and how many do you want? what rpm now, and what rpm will you be willing to rev it to?

[tanshi]

from stock they had 26 horse power, lol
50 hp would be nice but probably unrealistic.

as for revs, just before it goes bang would probably be the limit

[tanshi]

from stock they had 26 horse power, lol
50 hp would be nice but probably unrealistic.

as for revs, just before it goes bang would probably be the limit

opps i meant 26 kilowatts

its about 35 HP and would like to push it up to 50-60 if possible

[DonTZ125]

35hp out of a 500 triple?? And this was in a CAR?! Yeesh - lots of room for improvement there...

[drmiller100]

need some idea of rpm to build a pipe.

4000 rpm? 6000 rpm? I would guess somewhere in there.

The higher the RPM, the shorter the pipe. a 4000 rpm pipe is probably 4 or 5 feet long or more, as a guess. Have to do some math to know for sure.

also, a triple REALLY likes triple pipes. one single pipe with a 3 cylinder does not work very well.

drop me a line when you start working on the pipe design. my email is the same user name at hotmail.

[tanshi]

is it possible to setup the pipe to not be quite as powerful but to work over a wider power band?

yeah they werent the most powerful things out there.

the 4 cyl four strokes in the newer ones were only about 45hp

[drmiller100]

absolutely you can have a wide powerband. but you still have to have SOME idea of what RPM you are after.

For instance, a WIDE powerband is 3000 rpm to 5500 rpm. Or 2200 rpm to 4000 rpm. When you buld the pipe, you try to get as much bottom end as possible, but the top Rpm is the absolute upper limit. it almost won't free rev past that rpm, and for sure makes no power.

[DonTZ125]

There are games to be played to spread your power band. Power valves are rather difficult to retro-fit, and slippy pipes might be hard to control. You can however use water injection to significantly improve your bottom end and mid-range; retarding your ignition timing improves the over-run (past the top of the pipe's design speed).

[tanshi]

i wouldnt even know where to start with water injection. so that might be pushing it.

the top revs would be about 6500 i would think. I have heard of these motors test bedded by suzuki run for days straight at revs over 10k but 6500 would be as far as i would be likely to push it.

being a 4x4 the low down torque would be the most important thing. top end power not as much.