Start in neutral

[Tcapling]

Hey folks.
Have s 90 k100rs
It's very not stock.
But my question is are they supposed to start in neutral with out pulling the clutch? Because all I get is a N light going off when I push the button unless I pull in the clutch.

Thanks

[Laitch]

Yes. A Brick should start in Neutral without the clutch hand lever being squeezed, and the neutral light should remain On. It seems than many aftermarket instruments will not provide that function unless modifications are made.
What are the modifications, especially the speedo/tacho array?

[Tcapling]

Speedo unit and wiring is all factory at this time.
Engine is the modified bit - but all of nits wiring has been integrated to the bmw harness.
When I use the button to start it it turns over slower than it does if I jump the solenoid trigger wire direct. (With clutch pulled) I found damaged wiring it the clutch portion that has solved the slow turning. But it still won't turn with just the button. I'll investigate the  neutral light to button side of the wiring next I guess.

Thanks
 

[rbm]

The neutral detect / start enable circuit in the instrument cluster may be defective.  What I'm thinking is that the transistor switching the neutral light is strong enough to supply current for the light but too weak to supply current for the start relay.  Need to repair or replace that circuit.

[K1300S]

Is the sidestand down when you are trying to start it?

[Tcapling]

No. Side stand is up. Fuel pump p doesn't run with the stand down.
If I bypass the speedo. It seems to function normal. So likely an internal speedo issue

[rbm]

When you say speedo, do you mean speedo or do you mean the entire gauge cluster?  How do you just bypass the speedo?

[Tcapling]

I mean the entire cluster.
And by bypass I am specifically referring to jumping the green with black tracer to the black with green tracer wire in the connector for the cluster. Effectively removing the clusters internal neutral light circuitry.

[frankenduck]

I mean the entire cluster.
And by bypass I am specifically referring to jumping the green with black tracer to the black with green tracer wire in the connector for the cluster. Effectively removing the clusters internal neutral light circuitry.

If you do that jump then the starter will work when the bike is in gear - not advisable. I'd just pull in the clutch instead to start so that bike will not start unless the drive train is at least disengaged at the clutch.

[Tcapling]

If you do that jump then the starter will work when the bike is in gear - not advisable. I'd just pull in the clutch instead to start.

This was done just for diagnostic purposes. From what I've found the neutral light circuit just can't flow enough power to trigger my solenoid.
This bike is not using a factory starter. Or starter relay,  current demands are much higher from what I can determine. I'll likely just have to put a relay on the trigger side of the solenoid. Like the big rigs run. I hate adding complexity to a circuit but there's not always a choice.

[The Mighty Gryphon]

This bike is not using a factory starter. Or starter relay,  current demands are much higher from what I can determine. I'll likely just have to put a relay on the trigger side of the solenoid. Like the big rigs run. I hate adding complexity to a circuit but there's not always a choice.

The people trying to help you are basing their suggestions on a stock system which is what almost all the bikes are equipped with and everyone's experience is with.

You could really help us help you by providing a circuit diagram and details on the non standard parts you are using.

[frankenduck]

What non-factory starter are you using? And why?

[Tcapling]

What non-factory starter are you using? And why?

The bike is now home to a Mercedes Benz om660 engine. 800cc turbo 3 cylinder.

The entire factory harness is being used with the exception of the motronic section. An aftermarket standalone ecu is being used and has been wired in.

I had assumed that the starter should engage while in neutral without pulling the clutch. But since it's been 8 months since I pulled the k100 lump I couldn't remember.

I find that the engine turns slower when using the start button than it does when I trip the solenoid direct for the battery. Hence the thought to use a relay so it will start in n and will turn faster.

[Tcapling]

[frankenduck]

Does the headlight go out when you start with the clutch pulled in?

Does the headlight go out when you start from the N light circuit?

I have no idea how you've rewired things but if, for some reason, the load shed relay isn't turning off the headlight (and a few other  things)when you start from the N light then that would cause the bike to start slower.

[Tcapling]

Load shed relay is hooked up however that is a good point. I will have to check and see if it is infact functioning as it should.

[Past-my-Prime]

Yes, I'd consider non-brick brick VERY non-oem. I imagine this is from a Smart Car.
And diesel. With a very high compression ratio - may need a bigger battery - not sure how much it takes to turn this engine over. .  .
Was this a fun project or is there actual utility for the conversion?

[The Mighty Gryphon]

The starter relay in the stock configuration gets power from either the gear position circuit in the cluster or from the clutch switch on the left handlebar.  The gear position circuit is not a high current source. 

Because of this, the relay coil for the starter relay is a low current device so as to not overload the gear position circuit.  I am not familiar with the starter on the Smart Car engine, but if it has a Bendix gear combined with the starter solenoid, the current draw to pull it in will be a lot higher than the K bike starter and require a higher current starter relay that may need a higher coil current that the gear position circuit can't supply. 

Have you replaced the Start Relay on your bike?  If so, what is the coil current spec for the new relay?  That could explain your problem. 

[frankenduck]

According to my advanced Internet research ( ) a typical 12V relay needs roughly 150-200 mA to activate the switching coil so I ASSUME that that is the approximate current that the factory GPI circuit board can put out.

As to it starting "slower" that seems odd as a relay either makes a successful pin 30 to pin 87 connection or it doesn't.

However, as  I pointed out in my previous post, if the load shed relay isn't cutting the power to other circuits then that would account for less power to the starter vs. a  direct short circuit to the starter motor.

On top of that there is the weirdness of how the starter grounds things on a K. You need RBM's input on this as he is a much better electron chaser than the rest of us.

[Tcapling]

Yes, I'd consider non-brick brick VERY non-oem. I imagine this is from a Smart Car.
And diesel. With a very high compression ratio - may need a bigger battery - not sure how much it takes to turn this engine over. .  .
Was this a fun project or is there actual utility for the conversion?

Good eye. It isnindeed a smart car .8l common rail turbo diesel.
Factory battery turns it over quite well surprisingly. But  only so many times.

I will swap it for a yix 30 or an odessy at some point.

It was mostly a because I can project. Though there is a small endurance event in June that I'll be taking it to, and it'll be the first diesel ever in it.

[Tcapling]

The starter relay in the stock configuration gets power from either the gear position circuit in the cluster or from the clutch switch on the left handlebar.  The gear position circuit is not a high current source. 

Because of this, the relay coil for the starter relay is a low current device so as to not overload the gear position circuit.  I am not familiar with the starter on the Smart Car engine, but if it has a Bendix gear combined with the starter solenoid, the current draw to pull it in will be a lot higher than the K bike starter and require a higher current starter relay that may need a higher coil current that the gear position circuit can't supply. 

Have you replaced the Start Relay on your bike?  If so, what is the coil current spec for the new relay?  That could explain your problem.

The problem is likely that I eliminated the factory start relay, and am wired direct to the solenoid/bendix actuator. It would make sense that there justbisnt sufficient current capacity through the stock cluster on the n wire. After much fiddling about with chasing the circuit etc, I stabbed a std bosch 3amp relay in and the starter spins at the faster speed. Now I just need to figure why I have no N light anymore. (had the cluster open to see if there were any burnt traces etc. And eveer thing worked as it should. But once I screwed it back to gether. No more n light. I assume the one wire has ousted out of the connector.)

[Tcapling]

According to my advanced Internet research ( ) a typical 12V relay needs roughly 150-200 mA to activate the switching coil so I ASSUME that that is the approximate current that the factory GPI circuit board can put out.

As to it starting "slower" that seems odd as a relay either makes a successful pin 30 to pin 87 connection or it doesn't.

However, as  I pointed out in my previous post, if the load shed relay isn't cutting the power to other circuits then that would account for less power to the starter vs. a  direct short circuit to the starter motor.

On top of that there is the weirdness of how the starter grounds things on a K. You need RBM's input on this as he is a much better electron chaser than the rest of us.

I do find it weird that it turns slower as I agree, once a realy is closed, it's closed.
Load shed relay works as intended. Checked it specifically today after your last post.
Wiring a relay between the button and the solenoid makes it spin at proper speed. So i guess that's the route to take. Now to fix my n light so I can test that it functions in n the same.


I can freely admit, 33 year bmw wiring is bonkers. F'n side stand fuel pump cut out has caught me more than once changing a circuit that has nothing wrong with it. Things to get used to I guess.

[Laitch]

I do find it weird that it turns slower as I agree, once a realy is closed, it's closed.  Things to get used to I guess.

An 18:1 compression diesel needs more cranking power than a Brick's factory battery can provide—probably twice as much.

[Tcapling]

An 18:1 compression diesel needs more cranking power than a Brick's factory battery can provide—probably twice as much.

While this is true, the cranking speed difference come when using the factory wiring to trigger the starter circuit. If I use an 18g jumper wire from the Trigger terminal on the starter direct to the battery + it cranks faster.
Same solenoid, triggered by the same battery,  the only difference being the factory bmw wiring...

[Laitch]