Comments, advices, opinions XR650L re-build.


5 replies to this topic
  • ghoti

Posted September 20, 2006 - 09:04 AM

#1

It's getting to be time to freshen up the L. It's an 04, 21,000 miles, E series can with stock head pipe, Uni, de-smogged, de-snorkled, carb mods. I am happy with how it runs and the gas mileage so I would like to keep those in mind during the re-build. As a minimum I'm thinking rings, cleaning up the ports, maybe a polish on the exhaust side, thinner base gasket and of course a thorough inspection. Opinions on a hotcam or high compression piston upgrade. Do you need a bigger head pipe and carb to realize a difference? Would you have rathered done something less radical? Gas mileage? Anyone know of a 9:1 or so piston for the L?

  • mgs781

Posted September 20, 2006 - 09:14 AM

#2

You can't do a thinner base gasket on the L, it throws off the timing.

A high comp piston is the way to go. Easy to do and worth it.

Hotcam changes the engine completely. Wants to rev much more than stock.

If you do both these mods the stock carb is crap, vacuum slide is slow to react and not a good match for the engine. I could not jet mine to work well after the mods. At a minimum, you will need a flat slide, best to get a pumper, Edelbrock or FCR.

Exhaust header is probably not needed unless you want every last bit of topend.

Stock comp ratio is 8.3:1, Wiesco is 10.25:1, JE is 10.5:1. I have heard Thumper Racing make a 10:1.

My mileage is roughly 45mpg. My temp dipstick doesn't get over 225F even at 90 mph on the highway.

MGS

  • ghoti

Posted September 20, 2006 - 12:30 PM

#3

You can't do a thinner base gasket on the L, it throws off the timing.

A high comp piston is the way to go. Easy to do and worth it.

Hotcam changes the engine completely. Wants to rev much more than stock.

If you do both these mods the stock carb is crap, vacuum slide is slow to react and not a good match for the engine. I could not jet mine to work well after the mods. At a minimum, you will need a flat slide, best to get a pumper, Edelbrock or FCR.

Exhaust header is probably not needed unless you want every last bit of topend.

Stock comp ratio is 8.3:1, Wiesco is 10.25:1, JE is 10.5:1. I have heard Thumper Racing make a 10:1.

My mileage is roughly 45mpg. My temp dipstick doesn't get over 225F even at 90 mph on the highway.

MGS

They sell high compression gasket sets??? What timing is thrown off, cam? Can you explain how.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Wheels up

Posted September 20, 2006 - 02:18 PM

#4

Carb, cam, piston, filter, open box, cut junk off, big tank, exhaust and you will have a beast.

  • mgs781

Posted September 21, 2006 - 02:42 AM

#5

As a minimum I'm thinking rings, cleaning up the ports, maybe a polish on the exhaust side, thinner base gasket and of course a thorough inspection.


Your original post stated you were looking at a thinner base gasket. They don't make this nor can you do it without slotting the cam sproket.

When a thinner gasket is installed (or the head is decked) the distance between the crank and cam changed. The timing chain is a fixed length, so by reducing the crank to head distance, you throw the timing off by a few degrees. To get the engine timed correctly, you need to slot the holes in the cam sproket, XRs Only offers this service.

A high compression piston, hotcam, pumper carb, and exhaust is the way to go. I have 5000 miles on mine.

MGS

  • crmc33

Posted October 12, 2007 - 03:33 AM

#6

Yes, this is right, if you lower the head relative to the crank then this retards the cam timing. It can be easily dialled out by slotting the cam sprocket (I did mine myself with a drill + rotary burr) You need to be careful setting the timing cam afterwards of course





Related Content

Forums
Photo

93 xr650l Restoration Project by Zigster


Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 17 replies
Reviews

Honda XR650L 2017 by Chris.GVS


Honda XR650L 2017
  • - - - - -
  • 0 reviews
Forums
Photo

ignitech programmable XR650L CDI by brianhare


Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  60 replies
Forums
Photo

Wiseco 101MM Spark Knock Low Engine Temps by imandrewparks


Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 7 replies
Forums
Photo

Post Apocalypse, ThumperTalk style! by Justin Pearson


Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  35 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.