Bmw r75/5 microsquirt project for a newbie

[fefenin]

Yes I got it thanks. Ordered some graduated mesure . The hard part will be rewiring

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[fefenin]

Ok got the two injector bodies moded. Will order some low flow injector in China . Still need to find a way to close the holes of the electronic controlled butterfly I removed.

Waiting for the right moment to test the flow . And I have to get the engine parts for the rebuild. But looks like I am back

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[LAV1000]

Tap a m5 or m6 screw thread en it and use a screw whit O-ring to seal it.

[fefenin]

Do I have to have the inner diameter of the body smooth? Or is it just ok to seal it outside?

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[LAV1000]

Of course it would be nice to keep the bore smooth, but on the other hand I don't expect much gain in it.
Just make sure it seals the outside.

Make something that can't be sucked into the engine !!
Especially since you got a fresh build engine.

[fefenin]

Yes that make perfect sense. No part flying around in my nice expensive engine.

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[fefenin]

Got new engine block cam shaft and crankshaft. Ready for rebuild. Yeah

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[LAV1000]

Did you see this one about injector size ?
http://www.msextra.com/forums/viewtopic ... 34&t=66558

[fefenin]

Did you see this one about injector size ?
http://www.msextra.com/forums/viewtopic ... 34&t=66558

Thank you I did not see that before...I don't know if I have the datas to put in. Will have a closer look.

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[fefenin]

Just to have some clues ...here are some pics

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[fefenin]

Ok for the test of the flow rate it is going good but my old wiring is making the voltage drop to a constant 10.5 volts. Is that ok to make microsquirt and everything run this low? Will that change a lot the injectors flow rate if I do the test with 12.8volts?

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[fefenin]

Ok 3bars 11 volts 184 grams of gasoline in one minute full open looks like it is about 250cc per minute.... busted need to get lower rate fuel injectors as you said . But how do I know for sure what to get ?

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[R100RT]

Couple of things:
In order to test injector flow rate/ dead time correctly, you need to really apply the same conditions as during runing. Hence, exactly the same pressure and fuel pump and running voltage. If you are testing with a static battery, it will be lower voltage than with the engine running.
Best thing if setting up a test lab with your graduated glass containers etc would be to use a pretty well charged battery, and then have a charger on it to replicate the actual running voltage. You can get clever with a headling or two wired up to load that back down if the charger makes the voltage too high. Basically, cheat up or down till its the same, when running the test.
If I remember correctly, didn't you have an alternator upgrade for higher amperage output? If not, the MS extra components will overtax the stock Bosch charging system on our bikes. If its just slightly low when running, then it can be managed but involves plugging the bike into a charger everynight after riding. However if you're seeing drops like that already I suspect some rewiring will be in order.
Can you clarify if you have a different set of throttle bodies containing smaller injectors? What is the size of the injectors you were testing? Do you have a part number (may be able to help identify something over on this side of the pond if you don't have options over there.
Your engine parts are looking quite nice. Make sure to take you time and review several R75 assembly threads and U Tubes before & during the assembly.

[racingmini_mtl]

... to use a pretty well charged battery, and then have a charger on it ...

That's usually not a recommended thing as many (most?) chargers are extremely noisy. That can bring a whole host of issues.

Having said that, I agree with the idea behind this of having a test setup as close as possible to the real setup. You just have to make sure you don't introduce unwanted things in the process.

Jean

[LAV1000]

As for flowtesting run the fuelpump from a different powersource, because this the biggest power drain.
Par example run it from a car battery whit some jumper cables.

This way you only need to power the microsquirt and injectors from an other battery ( motorcycle or other spare battery)
Also disconnect sensors and ignition, saves on the power.
And use a well charged battery !!

Injector size:
Use the link I provided earlier.
You only need to fill in max rpm and hp, or post those figures and I run the calculation.

@R100RT
Did you mean headlight instead of headling?

[R100RT]

LAV1000, I meant "headling", it's an obscure and rare type of electrical animal that takes up residence in workshops.
Actually, I jest - not only is my spelling poor, but my spell check has it in for me.
It wouldn't even let me write it again without becoming something else.
May be the interference from overuse of my battery charger - sorry Jean!

[LAV1000]

Also related to Lucas "the" King of darkness

[R100RT]

I heard King Lucas carried a sceptre laced with emf's, a failed attempt to eradicate the darkness around him
(bet his dead times were way off the map)
Way off topic for current consideration, I was wondering what size of injectors Fefenin was now testing?

[LAV1000]

Ok 3bars 11 volts 184 grams of gasoline in one minute full open looks like it is about 250cc per minute.... busted need to get lower rate fuel injectors as you said . But how do I know for sure what to get ?

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So I gues 250's

[fefenin]

Hello I had a charger running parralel with the battery plus a car batteries but voltage was still 10.5 the wiring is old and bad. I have the heptik charging system it is way better than the stock device.for the injectors I have no info except the part number 25002zm

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