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Roller motor Griso, impressions

Discussion in 'Griso-Bella Chat & Tech' started by uzidzit, Mar 10, 2013.

  1. uzidzit

    uzidzit Cruisin' Guzzisti

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    Got out all day yesterday with the only real silver Devil bike 2012 Griso se. The new Roller Motor is a Amazing mill. Yes it is quieter! The fueling is well I almost hate to say it, it is about perfect! unless you make a mod just leave it be. The cam profile is spot on for LINEAR power from idle to the red line!! NO HUMPS OR STUTTERS ANYWHERE! The sacrifice is the 5,500k turbo hit felling of the older flat tappet mill, but this engine is so good who cares. This Motor makes all the right noises it just makes them in a little more hushed tone.

    I always said the New Guzzi is like Ann Margaret in a cocktail dress wearing combat boots...she just traded the hobnails for doc Martins.

    Wish stella was a roller now, but the flat tappet mill Is really a charmer, I have noticed that the ROLLER is a bit smoother feeling running, just a tiny amount but that may just be a motor to motor variation.

    AS TO THE FUELING what I mean is it is perfectly rideable as is, not that a revision to richen up is not a good idea, richening it up is still a good idea in my book to get the engine temps down a bit. BUT the lean surging is not present at small throttle openings at parking lot speeds. like the late flat tappet map. Re-map would still allow the thing to rev a bit quicker and cleaner, and what is great in town now could only be a bit better.
     
  2. uzidzit

    uzidzit Cruisin' Guzzisti

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    ....It does still pop a time or 2 on hard down hill switch backs, I consider full closed throttle engine braking bad riding form anyway, so unless stopped dead you are never at idle anyway.
     
  3. pete roper

    pete roper GT Godfather!

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    There have been no map revisions for the roller tappet machines.

    I still can't get a flat tappet bike to 'Surge' either???

    Pete
     
  4. lucky phil

    lucky phil Cruisin' Guzzisti

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    ?????
    Ciao
     
  5. uzidzit

    uzidzit Cruisin' Guzzisti

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    slamming the throttle shut on corner entrance or even shifting is what I mean (that whole high side thing starts from over use of the brakes in the rear be it engine or caliper) I watched a bike that did not have a front brake at all High side beautifully last year at Deals Gap. , there is really never any time you are moving you are do not have the gas on, (except maybe coasting to a stop) :?: I watched an aspencade on a straight road coming home today, with the pilot and passenger doing the head bump every shift.

    even a very tiny amount of power even during braking, keeps the chassis stable and lets you shift the grip fore and aft as needed.

    Try this go to a parking lot and practice rolling on and off the gas in second gear, you are getting smooth when the chassis stays perfectly level. and there is no noticeable weight shift, when ya got this down, you practice it over and over adding in braking, and increasing the top speed you reach and shortening the distance you do it in. while keeping the chassis movement smooth and even, the weight shifts but there but nothing happens completely out of your control. You can actually control the rate the front end unloads with the throttle. (or doesn't) Using the throttle and brake effictively and quickly at the same time = smooth = rapid

    My comment is meant to be more generally directed at the total lack of finesse, I see every time I go out to ride. I have watched a glide leave short rear end skids from engine braking alone from a chopped throttle, which I am pretty sure was not on purpose.
    Have fun hope this starts to clear up what I meant a little any way.
     
  6. uzidzit

    uzidzit Cruisin' Guzzisti

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    I do not know the map history of the 8V
    Pete I have a question, did you ever ride the big 2 stroke bikes in the 1970s'? ( I am curious specifically about the '74-'76 gt750 suzuki) That bike had a lean surge at small throttle openings, and my ntx really felt similar, as did my neighbors Griso, it is very much better when the valves are spot on, and the sync is perfect. but still does a bit of the uuuuuh, nuuuuh, huuuunha. The guzzi is a 4 stroke but the cond. yields the same result, it is just worse feeling in a a big twin. It can be pretty much mitigated if you are very very good with the throttle and know how to use very very small rear brake inputs.

    I do not know the difference, I know the cam grind has to be different, because it makes power very differently than the '10 Griso my neighbor has, or my '12ntx. The difference with the ntx may be the factory exhaust layout, I do not know. But I do know the roller motor is more linear in power delivery, quieter by a good bit, and is very plesant to ride very slowly(read parking lots and the 5mph crawl when you have to) My Stelvio would not do the 5mph crawl with this ease, and neither does the '10 Griso I rode a good bit before I got this one. It isn't any magic but it so far behaves better than any of the stock carc bikes I have ridden.

    So far all the good qualities of the 8v and none of the quirks some of them have. The valve on the evap system still farts :oops:

    Only mentioned the difference because I have ridden 2 roller bikes, both quieter motors. Both very nice and bit more sorted feeling. (a griso and a norge)

    Ps I did the valves and sync on all the bikes above, the same and very carefully so It should not really come down to state of tune.
     
  7. pete roper

    pete roper GT Godfather!

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    Yes, I rode water buffaloes, horrid things. The thing is comparing the performance, behavior and fueling of a carbureted two stroke and a modern fuel injected engine is so lacking in relevance that I'm struggling to find a 'Golden Thread' that joins the two. Can you expand on the subject and perhaps I'll catch up.......

    Pete
     
  8. lucky phil

    lucky phil Cruisin' Guzzisti

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    So I guess my bang it down 3 gears at a time and let the slipper clutch take care of the rear end (not the Guz)isnt going to impress you much :)
    Anyone that high sides a bike on the "road" going into a corner is truly a muppet and probably should be driving a car.
    Ciao
     
  9. GuzziMoto

    GuzziMoto GT Reference GT Contributor

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    What he said.

    I think you are confusing different aspects of riding.
    You should not normally have the throttle open when you are on the brakes trying to slow down.
    There is an aspect of high performance and dirt bike riding where you lightly drag the front and/or rear brake while you are on the gas. But when you are trying to slow down the throttle should be closed.
    Perhaps there is a language issue here.
    And a two stroke surges at some rpm and throttle positions for fairly complicated reasons having to do with exhaust timing and cylinder filling. It is not just a "lean" thing.
     
  10. Spaceclam

    Spaceclam Cruisin' Guzzisti

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    So question for you-

    What cam revision are you comparing your new roller motor to? There's the a5, a9, and a12.

    I have an a5 and it definately has a turbo-kick. I test rode an a12 a few weeks ago and it was pretty linear. A little more low, a little less top
     
  11. pete roper

    pete roper GT Godfather!

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    They are all the same profile Andrew.

    Its a common misconception that the profile changed. It didn't on any of the flat tappet motors until I *Think* the 1200 Sport 4V. The part numbers changed when the cams started being shimmed for end float with the A8 motor but nothing else changed, the profiles of the cams themselves remained identical, as did the part numbers and figures for all subsequent 8V motors until the 1200S and Norge8V.

    Any early model that still has the GRS8V01-2 map in will have the 'Kick' at 5,500. This was always a poor mapping problem. The #68 and #03 maps have addressed this and if set up correctly the power delivery is perfectly linear with no detectable, (Through the 'Seat of the Pants.) flat spots or midrange dips.

    The only way the valve timing as been changed is that with the A8 and later motors the valve clearances were changed from 4 & 6 to 6 & 8 thou.

    With the adoption of the roller top end there have been no changes to the map so one has to assume that the profile of the roller cam mimics the characteristics of the earlier flat tappet cam.

    Pete
     
  12. Spaceclam

    Spaceclam Cruisin' Guzzisti

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    Well I can't argue with part numbers, but I can tell you that even after the fueling modifications, my a5 8v definitely has a kick to it. It runs super great and has way more torque all across the board, but the kick is still there, although a little less-obvious.

    Perhaps the issue is how each of us defines "linear"?
     
  13. Phang

    Phang Cruisin' Guzzisti GT Contributor

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    Ride like a Honda? ;)
     
  14. uzidzit

    uzidzit Cruisin' Guzzisti

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    the Thread is how they actually behave while riding at very small throttle imputs, the lean surge at a point on ( not every two stroke as has been incorrectly said), manifests itself in the same bucking condition, as some of the new carc bikes they are a fight creeping around town, when you have to...just noticing that of the two roller bikes (griso, norge) I have ridden this has not been the case. But my ntx was a bit more of a challange to ride around town, as is the 2010 griso next door. (bucking)

    really the point of the whole thing was to note that the latest revision of the 1200 seems from a 2 sample study, to behave very well out of the box and better, than the later flat tappet bikes.

    Actually you may be correct my ntx may not have a lean surge, it may have just been the FI system not being able to follow the needs of the motor closely enough for even running. Which would mean some running parameters in the feed back loop are off, I have worked on a lot of closed feedback loop controllers and tweaking running parameters is a bear at times. (I am speaking about the deep logic tree here not mapping or the like, but how the ecu applies its math to the sensor signals)

    Ps why were my insulators snow white, with tiny specs of spherical deposits? at 6k on the ntx.
     
  15. uzidzit

    uzidzit Cruisin' Guzzisti

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    I define linear as the first derivative not changing much on a dyno trace, for as long as possible.
     
  16. uzidzit

    uzidzit Cruisin' Guzzisti

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    must be on the lang. thing maybe,

    If you go to school, (Freddies is gone, too bad it was good years ago) but cali superbike for track, total control (for just street), or Corner Spin for the most fun you can ever have in your life, in the first day you will understand fully what I am saying badly.

    You actually do have it open when braking, it is rolling closed simultaneous, with the brakes being applied in an inverse relationship. You don't slam the throttle shut and then just snatch the brake lever tight, treating these controls like light switches is not a recipe for smooth. actually I think Lee Parks makes it clearer than anyone.

    that surge on a two stroke you speak of is mitigated with correct mixture, and good technique, I know this there is garage full of smokers behind the house. ;)
     
  17. GuzziMoto

    GuzziMoto GT Reference GT Contributor

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    I have a fair bit of experience with race tracks and motorcycles.
    Typically you close the throttle, smoothly but as fast as you can, and apply the brakes, smoothly but building to full braking as fast as you can. You may have a small amount of overlap as you are releasing the throttle but applying the brakes, depending on your technique and how your brake lever is positioned. But the end goal is to shut the throttle to slow down. The idea is not to keep the throttle open while braking, that would result in a longer/slower deceleration. The faster you can smoothly shut the throttle and reach full braking power the less distance it will take you to slow down. That results in faster lap times.
    That is not usually the goal when riding a Guzzi but the idea of being smooth still applies.

    And often, both on a racetrack and on the street and especially when riding a big twin, all that may be needed to reduce speed is closing the throttle and possibly downshifting. There is nothing wrong with engine braking. It can be your friend.

    The issue with some two strokes and surging on low throttle openings and/or rpms is not only a jetting issue. It has to do with other factors and is not the same as surging on a four stroke. Apples to oranges.

    The thing I wonder about with regard to the differences you describe is, other then bike set up, what could cause such differences if the mapping and other aspects of the motor are the same. The switch to a roller tappet alone is not likely to make any difference in the way the motor runs. If the cam was noticeably different then I would think it would require a new map. From what I hear that is not the case.
     
  18. pete roper

    pete roper GT Godfather!

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    My feelings exactly. Hopefully I'll get to ride one soon.

    Pete
     
  19. ferdi

    ferdi Tuned and Synch'ed

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    I can imagine the differences are not caused by flat or roller tappets but by the spreading of serial models itself.
    I personally own a Stelvio EU2011 model and have the surging problem very intense, but other bikes of the same model/year I have driven have it differently, some not so definitive, some not a bit.
    Surging on my Stelvio went away by disabling lambda regulation with DucatiDiag and going all the way thru the mapping and not using closed loop any more.
     

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