R65 typ 247 1990 engine upgrade issue

Discussion in 'Airheads' started by Rasputin Saint, Sep 23, 2013.

  1. Dmaster

    Dmaster Been here awhile

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    I've done the engine upgrade.
    Went from a R65GS 20KW to the R65LS 37KW.
    Changed the heads, carbs, pistons, camshaft and the top air filter piece (one big one small pipe instead of two small pipes, don't forget that one!)
    BIG difference in power, a bit more low end, end where the 20kw version stops the 37KW keeps going in the high revs.
    I still have the short final drive (31/9) sometimes i think its faster then a R80.
    You will still lose it on te straight above 140km/h but who cares.
    I like the small engine of the R65 more than i like the bit extra power of the R80.

    I do think you need to do the complete swap, all the 20kw to 37kw parts are a big difference, i don't think it will work well if you only do some parts.

    My top speed with short final drive and 17" rear wheel (supermotard :evil) was 168km/h on the gps (over 180km/h on the speedo)

    So against all the NO sayers, i'll tell you, Do it if you can get ALL parts for cheap.
    #41
  2. Rasputin Saint

    Rasputin Saint Adventurer

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    That is exactly what I havein mind, thank you very much, I will have more questions for you. Get ready for it. BTW where exactly in Netherlands you live?
    #42
  3. Rasputin Saint

    Rasputin Saint Adventurer

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    when you are talking of changing carbs as well you are refering to BING 32 or another make like mikuni or something else?
    #43
  4. Dmaster

    Dmaster Been here awhile

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    I had a R65LS as a donor, so i got all the stuff from that bike including carbs. :)
    #44
  5. Rasputin Saint

    Rasputin Saint Adventurer

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    just bought a pair of R65LS cylinderheads with valves and also a 308 deg. camshaft of the same model. Year of production is 1985 and it has about 50k km running life according to the seller.
    Do you have any suggestions about the valve seats? Change them or not?
    Anybody knows the code of the apropriate BING 32 carbs?
    Looking for the rest of the parts...............
    #45
  6. Plaka

    Plaka Brevis illi vita est

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    I'd just run the heads if the valves look good. Keep a good log of your valve adjustments (like measure before you adjust them). if it wants different seats, it will tell you. All you're out is some gaskets.

    The carb model # is not important, esp. if you are changing other engine factors. You just want to know the correct jetting. not knowing where you live, I can't comment.
    #46
  7. AntonLargiader

    AntonLargiader Long timer

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    Seats should be fine but I'd be more concerned about the guides. Pull the exhaust valves and see how loose they are in the guides.
    #47
  8. Rasputin Saint

    Rasputin Saint Adventurer

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    a pair of 32 BING carbs is on its way. Codes are 64/32/353 & 64/32/354. Anyone knows what are the correct jets ?
    #48
  9. Plaka

    Plaka Brevis illi vita est

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    Yes.

    Depends on your zip code.
    #49
  10. Rasputin Saint

    Rasputin Saint Adventurer

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    zip code? What do you mean, where I live? In Corfu Greece if thats what you are asking.
    #50
  11. Plaka

    Plaka Brevis illi vita est

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    Hmmm...Corfu. max elevation 3,000ft. I don't know if there is a road to the top of the hill and I doubt you spend much time up there so altitude correction not needed. gentle Mediterranean (5-31C) climate so temperature correction not needed.

    R65 motor, 32mm Bing CV carbs, hmmmmm...not finding those part numbers in either my Bing manual or my Clymer. Suspect they are from some sort of R80 tho'

    The 1987 R65 used /361 and /362 carbs:

    main jet = 130
    needle jet = 2.66
    needle jet number = 46-251
    Needle cli[p position = 3 (1 is the top position, top notch on needle)
    idle jet = 40

    If you follow the jetting changes in the Clymers for the R65 over the years, you see this leaned out and that richened up. Emmissions stuff. (careful, one change of carb type too) So your ideal setup for power and economy may not be the factory one for the year you are shooting at.

    I didn't go through the r65 page exhaustively. You might want to.
    #51
  12. supershaft

    supershaft because I can

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    3000ft is no reason to re-jet. Especially if you plan on riding to the sea!

    Googler types will have you thinking that earlier 'pre emissions' bikes run better for being jetted way too rich. WRONG! Earlier models are not jetted for best power and economy. The later models are. Too rich sucks hp AND ruins economy. SOME later models might have just a tad too lean needle jets in them but other than that they are jetted MUCH closer to spot on than the earlier models.
    #52
  13. 190e

    190e Long timer

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    I wonder how safe it is to make comparisons in jetting between clam shell filter models and the flat filter models. Jetting did change in this transition and it was generally weaker but some of that may have been down to the tuned resonant intakes.
    #53
  14. supershaft

    supershaft because I can

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    In my experience the airbox makes much more of a difference than exhaust, dispacement, . . . the list could go on.
    #54
  15. Stagehand

    Stagehand Imperfectionist

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    I just heard the same thing this morning.
    #55
  16. Rasputin Saint

    Rasputin Saint Adventurer

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    I appreciate all the research you did for me. Thank you. I was told that as long as the carbs are 32 its ok no matter what the code. The ones I bought come from a R80 indeed. I will jet them as you suggest and see how it goes, I am not very demanding about the economy, as I am to get the best running of the engine. BTW I like the link of Corfu you posted. Here is a foto of the bike and another one of my other BMW in front of the famous mouse island in Corfu .
    Cheers.

    [​IMG]

    [​IMG]
    #56
  17. Plaka

    Plaka Brevis illi vita est

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    Correct. The last three digits are the jetting for a particular application. For example, the 351 and 351 used on the R80 resulted from a mid-model jetting change. Snowbum has the service bulletin on that showing the carb model number change and the jetting change. (he has the owners manual too for the points ignition bikes, BEWARE the tuning procedure, cannot be used with electronic ignition!...)

    If you can find the carb numbers for your bike, stock, that will reveal the jetting.

    I would ask around a bunch, including on the airlist for what people are running. The closer you can get off the bat the lest screwing around you have to do and the less you spend on jets. Adjusting the needls is free, but it's a big change. if you want a setting in between needle clip position, you need to change the needle jet. You also want the correct needle. I don't think they are marked. knowing exactly what model and year the carbs came off of will reveal the needle. The other jets are marked.

    You can tweak the fuel height and the idle mix for free--but those are very small changes.

    Figure the stock jetting was pretty lean for emmissions. So if you have something a bit richer, run it and see...
    #57
  18. supershaft

    supershaft because I can

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    Changing needle jets does not get you 'in between' jet needle settings. The two different jets do almost entirely different things. There is only one needle jet available for specific Bing carb models. That's why they are not marked. There is no need. I don't usually guess about stuff when giving advise but, if I did, I would warn people!

    Don't figure on the stock jetting being lean for emissions. They weren't other than maybe the mixture screw settings and the needle jets.
    #58
  19. Rasputin Saint

    Rasputin Saint Adventurer

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    The process has started.

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    #59
  20. disston

    disston ShadeTreeExpert

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    Those carbs do indeed appear as R80 carbs in my Bing manual. The jets in them should be the same as Plaka suggests except;

    Main 135
    Idle 45

    I'd try them as they are to begin and if a little rich change the idle jet first to 40. Some R65's actual;ly used a larger main jet than those should have.
    #60