Looking for some insight

[Kruger24v]

Hi all, new here. I’m buying an 81 (I think) xs650 engine for use in a racing tractor. It needs carburetors but seems otherwise intact. Is there anything I need to know with wiring harness if it has one that I’ll need and any issues to look for beforehand? Any information would be greatly appreciated

 

[DogBunny]

If it is really an 81, then it came with a TCI (electronic) ignition. You will need a working TCI box (similar to an ECU), or you will have to buy an aftermarket ignition system.

 

[nj1639]

That's a can of worms to open for a newb on these engines.
Carbs, ignition, wiring.....it'd be grand to have a running bike to transfer what you would need or to have known one to know.
Tech section of this forum has some minimal wiring schematics, look under the heading "electrical" and "some wiring diagrams".
'81 should have the TCI ignition system. The brain is located under the battery box on the bike. I'd be trying to get that too.
A pic of the engine for us - and keeping the sellers contact info for you might be a good thing.

 

[Kevin Werner]

The ignition unit from a Suzuki GN250 works on that motor. Look up Gonzo ignition for the simple wiring. The Gonzo costs $15-$20 online.

 

[Kruger24v]

If it is really an 81, then it came with a TCI (electronic) ignition. You will need a working TCI box (similar to an ECU), or you will have to buy an aftermarket ignition system.

I was told it’s an 81 but I think it’s not. It has a kick starter

 

[Jim]

I was told it’s an 81 but I think it’s not. It has a kick starter

ALL years of the XS came with a kick starter.

 

[Kruger24v]

That's a can of worms to open for a newb on these engines.
Carbs, ignition, wiring.....it'd be grand to have a running bike to transfer what you would need or to have known one to know.
Tech section of this forum has some minimal wiring schematics, look under the heading "electrical" and "some wiring diagrams".
'81 should have the TCI ignition system. The brain is located under the battery box on the bike. I'd be trying to get that too.
A pic of the engine for us - and keeping the sellers contact info for you might be a good thing.

I’m not getting a bike. Just the engine itself for 150 dollars

 

[mike in idaho]

If it was Mine I would find some parts to convert it over to points, it would greatly simplify the wiring. If you charge the battery between races you could run a total loss type ignition, no alternator, with literally one wire in the harness from the battery to the coils.

 

[Kruger24v]

If it was Mine I would find some parts to convert it over to points, it would greatly simplify the wiring. If you charge the battery between races you could run a total loss type ignition, no alternator, with literally one wire in the harness from the battery to the coils.

If I can keep the alternator that would be preferred because then I can hook up headlights and the fuel pump for it since I need a pump for what I’m doing

 

[gggGary]

You need this.

Getting the carbs for $150? Does it kick with compression?

 

[Kruger24v]

You need this.
View attachment 258196
Getting the carbs for $150? Does it kick with compression?

I am going to go look at it soon. It doesn’t come with carbs but I found a clean used set for 120 on eBay

 

[Kruger24v]

You need this.
View attachment 258196
Getting the carbs for $150? Does it kick with compression?

I will also see exactly what it comes with when I look at it

 

[YamadudeXS650C]

At some point we are going to insist that you post pictures of this racing machine !



.

 

[Kruger24v]

That's a can of worms to open for a newb on these engines.
Carbs, ignition, wiring.....it'd be grand to have a running bike to transfer what you would need or to have known one to know.
Tech section of this forum has some minimal wiring schematics, look under the heading "electrical" and "some wiring diagrams".
'81 should have the TCI ignition system. The brain is located under the battery box on the bike. I'd be trying to get that too.
A pic of the engine for us - and keeping the sellers contact info for you might be a good thing.

 

[650Skull]

An 81 came with a sight glass in the side over from the factory. They are interchangeable with years 74 - 83 so it could b that or it could b that it is not an 81.

Also an 81 came from the factory with a black rocker cover and black barrels. Check the vin no against a chart in this link.

https://www.xs650.com/threads/xs650...workshop-manuals-and-other-information.30569/

 

[Jim]

Elec starter motor is missing.

 

[gggGary]

I wouldn't spend money on an XS motor unless I could kick it through and it had (some) compression.
cuz "there's other fish in the sea"

 

[Kruger24v]

Found a guy with a 79 motor that has the starter and electrical stuff and has compression. Going with that one instead. Will need to buy carbs for it. How do they have them synced on the bikes?

 

[nj1639]

Found a guy with a 79 motor that has the starter and electrical stuff and has compression. Going with that one instead. Will need to buy carbs for it. How do they have them synced on the bikes?

You could run a single carb with equal length intakes and be done with syncing.
The down tube on these xs frames makes running a single carb......ugly? Without a down tube - which runs between the two carbs - one and done could be an option.
Early xs650 carbs came separated and had dual throttle cables, one for each carb. Newer carbs came mounted on a length of angle iron, were then linked carb to carb and had a single throttle cable. Syncing is getting both carbs throttle plates opening the same amount at the same time.

 

[gggGary]

Will depend on the carbs you buy. Late BS38s 1978 1979 are a good choice. Depending on how you plan to run the motor. Usually syncing visually before install will get you at least 95% there.