ST1300 Engine into ST1300PA motor Swap

TallPaul

Joined
Nov 20, 2023
Messages
6
Age
33
Location
Florida
I am interested to know if the motor from a 2008 ST1300 (civilian) model would fit and run in a 2009 ST1300PA (police) model.

The motor on my ST1300PA seized up and I am trying to source a replacement. The only ones I see are civilian model motors.
 
I know that the ECU changed between 2006 and 2008, but I have been unable to note any difference between the 2008 and 2009 models.

You could compare part numbers on the microfiches. I did this once with the CTX1300 bagger and the ST1300 - I wondered if the the increase in low down power between the 06 and 09 had anything to do with the 'CTX1300 experiment'. It turned out that they had a different ECU but also, the crank shaft was different. I think that the con rods were also different (may be mistaken).

Even if there is difference in the engine management / tuning components - if the engine is the same ....then they should switch.
 
Are you only transferring the motor or motor and ecu? @aniwack would probably know the answer to this one. If the '08 civilian ECU is the same part number as the '09 P ECU, then I would guess both engines are the same. But, I have guessed wrong before.
 
I am only transferring the motor from a civilan ST1300 to my PA model, but I can source an ECU as well if that would be necessary.
 
Question 1: Is the motor the same on the 1300 non-ABS, ABS, and PA? YES!
Question 2: Is the ECU interchangeable? NO!!

Let's get into the nuts and bolts of your question. Dropping this engine is no easy task. For me I can do it in 3 days. For your very first time it will take 60+ labor hours to complete. But let's go back to question zero: Why are you swapping the motor?? These things are overengineered. If your engine is truly toast [ie ran 10k miles on no oil] then you will need to start shopping the auto auctions.
STUDY. THE. MANUAL.
Let's get into the harness question. I restored a bike recently the owner wanted to convert it into an escort bike. He paid the man to change it over and [insert shock] IT DIDN'T WORK!! He took it to a catch all motorcycle deal that charged him a couple grand to not solve the problem. The harness was butchered by whoever removed it from the salvage bike and it was obnoxious to fix. Let's get into the ECU: THE L01 AND R21 ARE NOT INTERCHANGABLE!! What is on your bike is what you've got. The police bikes run different alternators with higher amp loads that the civies don't have. [130 vs 145 amps]
VERY IMPORTANT: Honda has published that the 31100-MCS-003 civilian alternator CAN BE REPLACED with the 31100-MCS-013 PA Alternator without any mods to the wiring harness!!!
When you're done with the swap, do not dispose of the engine. It can be torn down and repaired. KEEP IT. These blocks are getting harder to source. Fixing it for a couple hundred is cheaper than sourcing an unknown engine.
 
aniwack said:
Question 1: Is the motor the same on the 1300 non-ABS, ABS, and PA? YES!
Question 2: Is the ECU interchangeable? NO!!

Let's get into the nuts and bolts of your question. Dropping this engine is no easy task. For me I can do it in 3 days. For your very first time it will take 60+ labor hours to complete. But let's go back to question zero: Why are you swapping the motor?? These things are overengineered. If your engine is truly toast [ie ran 10k miles on no oil] then you will need to start shopping the auto auctions.
STUDY. THE. MANUAL.
Let's get into the harness question. I restored a bike recently the owner wanted to convert it into an escort bike. He paid the man to change it over and [insert shock] IT DIDN'T WORK!! He took it to a catch all motorcycle deal that charged him a couple grand to not solve the problem. The harness was butchered by whoever removed it from the salvage bike and it was obnoxious to fix. Let's get into the ECU: THE L01 AND R21 ARE NOT INTERCHANGABLE!! What is on your bike is what you've got. The police bikes run different alternators with higher amp loads that the civies don't have. [130 vs 145 amps]
VERY IMPORTANT: Honda has published that the 31100-MCS-003 civilian alternator CAN BE REPLACED with the 31100-MCS-013 PA Alternator without any mods to the wiring harness!!!
When you're done with the swap, do not dispose of the engine. It can be torn down and repaired. KEEP IT. These blocks are getting harder to source. Fixing it for a couple hundred is cheaper than sourcing an unknown engine.
Click to expand...
 
Thank you for the detailed reply.

Unfortunately the PA motor I had got bad gas and sat for a month or so while I saved money for repairs. By the time I realized what had happened, everything got rusty and corroded and the motor won't turn over (seized up). I can look down the intakes and see corrosion built up along the valves and can't get the darn thing to budge no matter how much marvel mystery oil I soak the cylinders with.

So I took to researching engine replacements and can only find ST1300 (civilian model) replacements, at least at a lower mileage.

I have the bike torn down to the alternator already and have just the exhaust and a few other connectors to remove before I can get the motor dropped.

I have the alternator off of my 1300PA and it seems to be in great shape. Spins freely and will likely get it tested before putting everything together. If I am understanding correctly, you can use the PA alternator on a civilian motor then? You just can't swap the ECU from one model to the other.

Anything else I should be on the lookout for as I do this project?
 
The police bikes run different alternators with higher amp loads that the civies don't have. [130 vs 145 amps]
Click to expand...
If no wiring mods are needed the wiring harness must be the same. If so, it shouldn't matter whether a 130 or a 145 amp alternator is installed. Or does it?
 
They don't have 130 amp alternators at all.
According to the service manual;
2003 to 2007 model years have a 0.742 KW alternator.
Post 2007 model years have a 0.675 KW alternator.
 
So, it sounds like the answer to the original question, "Can a 2008 civilian motor replace a 2009 Police motor in the '09 bike?" is YES!

The alternator used may be either the P bike's or the Civil bike's, using the original P ECU. That ecu has a speed limiter, but the OP has lived with it for a while. Oh, and the swap is labor intensive (but we all knew or suspected that).
 
Thank you all so much for the guidance with this. I will keep everyone posted on my progress and share any tidbits I might discover along the way.
 
aniwack said:
The police bikes run different alternators with higher amp loads that the civies don't have. [130 vs 145 amps]
Click to expand...

Andrew Shadow said:
They don't have 130 amp alternators at all.
According to the service manual;
2003 to 2007 model years have a 0.742 KW alternator.
Post 2007 model years have a 0.675 KW alternator.
Click to expand...

Larry Fine said:
So, around 60 and 55 amps, respectively.
Click to expand...
Dang, I thought I was going to be able to get a microwave.
 
Larry Fine said:
The bottom line is to keep the ECU with its engine.
Click to expand...
I'm not sure but I think that Aniwack has posted in the past that the connectors are different between the civilian and P model ECM's. I wonder if everything else is the same, such as all the sensors. I wonder if swapping the harness to maintain connector compatibility would allow either ECM to be used.
 
TallPaul said:
I have the alternator off of my 1300PA and it seems to be in great shape. Spins freely and will likely get it tested before putting everything together. If I am understanding correctly, you can use the PA alternator on a civilian motor then? You just can't swap the ECU from one model to the other.
Click to expand...
Use your PA alternator. Be sure to not crush the o-ring while inserting or you will have 'mystery' oil leaks. And replace the o-ring. The og ring can't be resused.
 
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