Ridemalibu Motorcycle Rentals & Tours – Los Angeles CA
  1. Ciao Guest - You’ve landed at the ultimate Guzzi site. In SoCal? See the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have are already answered on the Forum with FACTS, NOT OPINIONS. PLEASE DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back if you are posting elsewhere on the web. Note there's decades of Guzzi hands-on experienced help on this site, all whom give endless amounts of their time for free; BE COURTEOUS AND RESPECTFUL! There is zero tolerance on personal attacks and off-site links to other Forums or competing products. Also be sure to click on the STORE link also above for our 600+ product inventory, including many of our 100% Made-in-house-USA GTM products and engine kits. We appreciate the consideration, understanding and your business... past and future. And if you haven't seen our MotoCycle (not) art, click on the BUILDS tab above to see our work at our sister business; GT MotoCycles®-- WE ARE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED.

Guzzi cafe racer,LSR racing

Discussion in 'Racing' started by Rough Edge Racing, Oct 1, 2013.

  1. Rough Edge Racing

    Rough Edge Racing Tuned and Synch'ed

    Joined:
    Jun 12, 2013
    Messages:
    38
    Likes Received:
    0
    Location:
    Western NY
    I just finished building this cafe racer from a well used 85 California. Swapped to spoke wheels,eliminated clutter ,home made parts,shortened existing cable,made a wiring harness,battery under chassis,but left the engine stock other than open exhaust. Replaces wheel bearings, swing arm and steering neck bearings and of course the U- joints. Surprising the exhaust is no where as loud as a Harley and the bike runs well through the RPM range.The engine has 106,000 miles but I have no idea if it was ever apart.
    Last weekend was the ECTA one mile standing start finals in Ohio.Very serious cars and bikes at these meets,some exceeding 230 mph.
    Out old Triumph bumped it own record up to 120 MPH in 650cc modified production class putting the competition on trailer.
    My rider made three passes on the Guzzi all nearly identical 116 MPH. All i did was install 135 main jets in the 30 mm PHF's.This speed actually set a new class record in 1000 cc modified production.You might think Sportsters and BMW's would be all over this pushrod class ???
    Modified production is a naked bike class with with no engine restrictions other than it must retain the basic layout . At Bonneville and El Mirage there more interest in thisclass with Guzzi record holders near 160 mph .

    The Guzzi is fun to ride and the reduced weight makes it a bit less bulky at lower speeds.

    [​IMG]
     
  2. falcor

    falcor Tuned and Synch'ed GT Famiglia

    Joined:
    Aug 13, 2009
    Messages:
    19
    Likes Received:
    0
    Location:
    Austin
    Re: Guzzi cafe racer,LSR raing

    looks and sounds like a lot of fun to ride!
     
  3. essexboydave

    essexboydave Tuned and Synch'ed

    Joined:
    Oct 5, 2013
    Messages:
    84
    Likes Received:
    1
    Location:
    London
    Re: Guzzi cafe racer,LSR raing

    That looks smart mate, I like the way you've hidden the battery :) Did it take much messing with the carbs to get it running right? I wouldn't have thought it would run that well on those short pipes and the K&N type air filters but it obviously does if you're racing it-just goes to show that I'm no expert then lol!
     
  4. Rough Edge Racing

    Rough Edge Racing Tuned and Synch'ed

    Joined:
    Jun 12, 2013
    Messages:
    38
    Likes Received:
    0
    Location:
    Western NY
    The bike runs excellent with the 36 inch pipes and the stock cross over. No funny power band just steady increasing power from idle to 7000 rpm. Raised the needles one notch,#135 main jets. Some one in the past had stretched a distributor advance spring ... I left it that way and set the total advance at 32 degrees.
    I was told by others it won't run worth a damn with shorter pipes.This may be true with highly tuned Guzzi engines but on a stock one,not necessarily so. My old Triumph race bike has short pipes,the competition had traditional long pipes. They can't catch me ...
     
  5. GT-Rx®

    GT-Rx® Administrator Staff Member GT di Razza Pura

    Joined:
    Jul 1, 2009
    Messages:
    11,384
    Likes Received:
    3,461
    Location:
    Malibu
    I'd bet there's plenty of power hidden with another type of exhaust system. Did you dyno this set up? Free-flow is good, but a balance pipe and some sort of reversion dampers would be nothing but beneficial I'd bet.

    Thanks for the post though, and words on the speed runs.
     
  6. ghezzi

    ghezzi High Miler GT Contributor

    Joined:
    Jul 7, 2011
    Messages:
    836
    Likes Received:
    14
    Location:
    Brisbane
    Something to consider;
    On the 36 and 40mm carbs, the standard type conical shaped K&N air filters had too little surface area and restricted air flow in the top end. They needed the vertically elongated cones that had the carb attachment point offset to one end.

    Don't know if this translates to your 30mm carbs and your increased VE / CFM mods.
     
  7. Rough Edge Racing

    Rough Edge Racing Tuned and Synch'ed

    Joined:
    Jun 12, 2013
    Messages:
    38
    Likes Received:
    0
    Location:
    Western NY
    The stock crossover is still on the Guzzi... There is no reversion and I know what reversion is because the Triumph has enough for two bikes :D My rider used to 1000 cc crotch rockets was impressed with the Guzzi engine response on the street. Shorter pipes work fine on mild engines and for some LSR racers . LSR is a longer drag race where the only concern is top end power.

    We ran two runs with air cleaners on,one with them off. No real difference. On a higher HP engine for sure better flowing filters....
     
  8. jr1967

    jr1967 Cruisin' Guzzisti

    Joined:
    Oct 29, 2008
    Messages:
    183
    Likes Received:
    36
    Try to take the filters off and replace them with velocity stacks. You need the intake length back that is lost with mounting K&N's. I did a back to back comparison with the larger type off-set K&N's and velocity stacks on 40mm carbs and gained 3-5 hp over the whole rpm range, plus the motor pulled over 8000rpm instead of dropping off at 7300rpm. The engine was a mid size valved 992cc with V7 sport cam shaft with a restrictive exhaust system.
    66rwhp with the large K&N's, 70rwhp with stacks, measured without jet modifications.
    JR
     
  9. Rough Edge Racing

    Rough Edge Racing Tuned and Synch'ed

    Joined:
    Jun 12, 2013
    Messages:
    38
    Likes Received:
    0
    Location:
    Western NY
    There's intake length formulas to tune the peak power RPM. For instance on this photo of my Triumph the total intake length from velocity stack bell mouth to intake valve is 12.5 inches.Generally this will make power peak at 7200 rpm. Some tuners say it's better to have all the length from carb to valve.In this case that would have the carbs interfering with the rider's legs.There's more to with camshaft and other engine characteristics affecting the power peak but it's fairly accurate.There is a down side,increased reversion.....
    I think the 30 mm carbs restrict the airflow enough to make intake tuning less important than say with 36 mm carbs.But I have limited experience Tuning Guzzi's ............
    I shoulda posted this in the racing forum :D

    [​IMG]
     
  10. Strosek Ultra

    Strosek Ultra Just got it firing!

    Joined:
    Jul 13, 2012
    Messages:
    7
    Likes Received:
    0
    Intake tuned length 13" 7250 rpm. Peak power at 8400 rpm, red line at 9250 rpm. Engines making peak power at lower rpm should have extended intake tuned length for best torque and power curve.

    Åke Jonsson Engineering.
     

    Attached Files:

  11. Rough Edge Racing

    Rough Edge Racing Tuned and Synch'ed

    Joined:
    Jun 12, 2013
    Messages:
    38
    Likes Received:
    0
    Location:
    Western NY
    I Had to compromise length due to space limitations.On LSR top speed bikes in the winner circle I see very little consensus on intake and exhaust length. I tune the engine for the track not on a dyno.
    We're going to do some modifications to the 1000 Guzzi engine mainly for street .I see most have a two into one exhaust...
     

Share This Page