Building A XR650l Engine

Discussion in 'Thumpers' started by mcma111, Aug 6, 2011.

  1. JD_Mckoy

    JD_Mckoy Adventurer

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    Does the XL600R headers flow more than XR650l true or false?
    Can anyone comment on this, I have also read that it out perform FMF power bom, is it a direct Bolton on the XR650L?
  2. cms81586

    cms81586 Been here awhile

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    Two quick questions... My XRL has about 22k miles on it now. So far been pretty trouble free. I have noticed two things though.

    1) I'm getting some slight surging in the mid range RPM's in lower gears...say in a 45MPH zone in 3rd gear for a few minutes. "Seems" like a carb issue to me. Daves carb/airbox mods were done at about 10k miles and this just popped up. Any suggestions?...and where to look for a carb rebuild kit (diaphragm and spring mainly)?


    2) Upon start up every now and then (not consistent or repeatable) I'll get a bit of white smoke for about 5-10 seconds. Thinking maybe valve seals?
    Thanks!

    CMS
  3. mcma111

    mcma111 Long timer

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    cms81586,

    First thing, when was the last time you checked the valve adjustment? It could be as simple as adjusting the valves.

    Why rebuild the carb? If the diaphragm is bad you would know it. If you really want to replace it buy OE. The spring doesn't go bad.
  4. mcma111

    mcma111 Long timer

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    Wow, 70,000 views. Who would have thought it?
  5. award900

    award900 Been here awhile

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    Great Thread, mcma! Thanks for posting!
  6. thebigman

    thebigman bout a dollar 3.98

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    Congrats ,

    I know I myself have been here a few hundred or more of the 70k .

    Learn and catch something new every visit .

    Thanks again for doing this :clap:freaky
  7. mcma111

    mcma111 Long timer

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    This gives me an idea. Since my son recently blew up his XRL and is at my place right now (I'm at work) prepping the bike for the motor removal I'll email him this thread for him to read. There will be a test!! :deal
  8. 1Bonehead

    1Bonehead Fearless of Falling

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    Yeah, he will just test Dads patience, Lol.

    Steve, you have always been a great source for those willing to listen.
  9. cms81586

    cms81586 Been here awhile

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    Valves adjusted every other oil change. Carb rebuild is my guess at what's causing the surging issue. It's not a major problem....just an annoyance.

    CMS
  10. RFVC600R

    RFVC600R GOT SAND? NO!

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    I was weary of going into the topend of my XL, until I found this thread.:deal Now if I could just stop breaking bolts....

    70,000 views, this thread still has a lot more coming.
  11. cms81586

    cms81586 Been here awhile

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    What are you charging for a rebuild these days? I posted up a while back about the countershaft splines on my bike being shot. I'm considering just sending it your way for a NX 2nd gear, new countershaft, cam chain (if needed), and a top end job. It began smoking like a locomotive upon startup about 6 months ago and it's getting worse. From maybe 3-4 seconds of smoke to a good 30 seconds or so until it stops. At that rate I imagine it's burning a decent amount of oil during startup (no smoke once running) and so at this point I'm being extra vigilant with oil levels until it's fixed.

    The bike is an 04 with 21k hard desert miles on the clock. I tossed on a R countershaft sprocket about 8k ago to hold off any more accelerated wear on the countershaft but want to get it taken care of. I got the bike for a steal with 6k miles on it for $2000 a few years ago and have gotten a lot of enjoyment out of it. I'm at a point where I need to either put some money into it now or face a big bill later on. Was initially planning on tearing the motor apart myself but I have a kid due next week and my time is short right now. Any help is appreciated, and if you provide part numbers for the minimum you know I'll need I can purchase them all and have them shipped to you as well.
  12. mcma111

    mcma111 Long timer

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    PM sent
  13. brayjay

    brayjay Been here awhile

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    Very informative thread sir, I am just about ready to install my new piston and rings and was wondering if you install the piston and rings dry or with oil. Also what kind of assembly lube do you recommend for the con rod small end and piston pin. Thanks in advance.
  14. FongMan

    FongMan Been here awhile

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    I don't own an BRP, but that was a great read!! Great info to have when I
    Go bike hunting.....
  15. mcma111

    mcma111 Long timer

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    I use a piston assembly oil. I can't remember the name right now. I apply some to the rings (sparingly) and coat the lower part of the cylinder. Once the cylinder is bolted down I rotate the engine and I wipe the excess off of the top of the piston. Again I can't remember what lube I use on the cam. I'll have to go look.
  16. gasit4fun

    gasit4fun Adventurer

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    2007, 23500 miles, fully warmed up
    60 PSI, decompression enabled
    120 PSI, decompression disabled

    Wet compression test
    62 PSI, decompression enabled

    It starts harder than it used to when cold, but it does start and it runs/starts great after warmed up. Sometimes white smoke when cold. Uses more oil than it used to, but I don't know exactly how much.

    I thought maybe my compression tester (new, Taiwanese from Sears) was junk or not installed properly, but it doesn't seem to leak, and I hooked it up to my air compressor and it read the same as the regulator.

    62 is a long way from 92. But it runs good? :dunno
  17. mcma111

    mcma111 Long timer

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    More that likely the rings are going south. At your miles it looks like it's time to pull the top end for a look see. Perhaps a valve job will also be needed.
  18. JD_Mckoy

    JD_Mckoy Adventurer

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    Hi Steve, can you answer me this do I need to re sleeve my cylinder to accomodate a 102.4 piston? is the web cam 450/451 profile ok for every day riding 256 deg duration some 26 deg above stock grind.
    Thanks
  19. mcma111

    mcma111 Long timer

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    If you have a XR650l the 102.4 piston can go right in the stock sleeve. If you have a XR600 then No, you need a bigger sleeve.

    That Web Cam looks fine. You do need a high compression piston and performance valve springs.
  20. JD_Mckoy

    JD_Mckoy Adventurer

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    One more thing since im going to open up the moto I was considering installing the nx gears whats the advantage of the nx second & fift gears?
    Thanks much.