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XR600 Engine question

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Just purchased a XR600R engine that was built by Thumper Racing. Apparently it has the 660 kit in it. My question is about the carbs I have currently which are off my '86 XL600. Anyone know if these will work and if so, any idea on jetting specs? I'm from the midwest so I'm roughly 1000' above sea level. Thanks for your time.

 

Kyle

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What year is the 600 motor? It looks black in your pic so maybe it's an older dual carb motor, but hard to see. I personally would hope it's a single carb motor so you can throw an FCR on there for some real performance (and much more straight forward tuning). If you stick with the duals, they can be quite a pain to set up but can run real well if you do get them set up right. I am not sure if the XL carbs were the same as the XR carbs back when they were duals though.

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XR and XL used different sized duals..they both fit the bike ok but the tuning may be a bit of a mission..Have a search around the net on the size difference,,it's not a lot but they are slightly different in a few respects besides just the intake size..Couldn't really say what would be the right jetting..couple of 122 mains and I dunno..45s the stock pilot in an XR,,maybe a 52 or something around there..What's wrong with the XR carbs???

Edited by Horri

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Xr/xl dual carbs range from 27-30mm. The bigger 30mm carbs are only in 83 and 84 xl600's. Your carbs should work fine in your bike. The only install issue is that the xl uses a remote choke control and the xr is on the carb but depending on the exact model of carbs some can be interchanged.

For jetting i pretty much agree with what horri said, you will probably end up with about a 50 -55 pilot and 122-128 mains but you will have to play with it a bit. Assuming you have an aftermarket exhaust on the bike, I would start with 52 pilot, 125 primary main and 122 secondary main.

Dont be scared of dual carbs, they arent that hard to deal with and can offer great throttle response and good fuel economy.

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I am running 122/115 on a similar sized engine in an XL with XR carbs.  Pilot jet 42, which is similar to XL 62.  The carbs are nearly alike except the pilot jet size and needles.  XR carbs are my favorite because of the easy main jet change. (screw off cover)

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Does anyone have a 85-87 XR600 manual. Im chasing the info on the fuel system/carb setup. i only have the set up for the XL dual carbs which is slightly different apparently.

Ive purchased a digital manual that claimed it was from 85 onwards however it doesn't have the dual carbs thus its really only 88 onwards. I don't want to go by another that says its a 85 on wards and find its the same thing.

if anyone has XR600 dual carb info that would be amazing

Edited by mrlablack

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Does anyone have a 85-87 XR600 manual. Im chasing the info on the fuel system/carb setup. i only have the set up for the XL dual carbs which is slightly different apparently.

Ive purchased a digital manual that claimed it was from 85 onwards however it doesn't have the dual carbs thus its really only 88 onwards. I don't want to go by another that says its a 85 on wards and find its the same thing.

if anyone has XR600 dual carb info that would be amazing

What info are you looking for? I may be able to take a pic of the manual page and post it.

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What info are you looking for? I may be able to take a pic of the manual page and post it.

Im new to working on carbs, and building a 85XR600 back up after being apart for 13 years. I've pulled the carbs apart and cleaned them and put back together but i dint really know what I'm doing so i just did them one at a time and assembled back the same way i pulled them apart. Im just pretty sure the thing might not run right up so have been hoping to see what the manual says for assembly, settings and troubleshooting etc for when the time comes. My dad said it was running sweet when he rode it last that the carbs were great. but they open at the exact same time which I've heard the xr's aren't meant to.

 

putting new valve stem seals in tonight. and if time will get the new piston and rings in tomoz, she's getting closer to kicking

 

 

Thanks heaps  for replying 

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