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Thread: Finding my lost horsepower and other stuff

  1. #11
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    Re: Finding my lost horsepower and other stuff

    Quote Originally Posted by HogHog View Post
    Very interesting. With pipes like that, I'm guessing your brother or father must run an MOT test centre though.!! :wink:
    Forgot to mention the racebike wasnt road legal, no need for an MOT :439:

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  2. #12
    grbrown Guest

    Re: Finding my lost horsepower and other stuff

    I'm very pleased with the SuperMegs 2-into-1 I have on my S&S 107, but my next system, come the day I change again, will probably be an RBR LSR Black-Hole! Should provide a decent level of muffling with excellent performance.

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  3. #13
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    Re: Finding my lost horsepower and other stuff

    Quote Originally Posted by Ukkid76 View Post
    If your running without any baffles at all then wheres the back pressure? it sounds like you have just richened the mixture to compensate....

    two in to one always works better because of back pressure problems with twin exhaust pipes without silencers i.e straight through....

    Don't forget if you open up any motor for instance bigger/wider air intake free flowing exhausts, bigger pistons valves ect then you'll need to weaken the mixture to compensate not richen it,

    With all that fresh air being sucked in with all the mods you have described it must be running so rich it's no wonder it won't perform,

    Did you have the bike hooked up to a gas analyser or computer when he ran it up on the Dyno??

    Dont want to upset anyone, but I couldnt let this statement go ..''Don't forget if you open up any motor for instance bigger/wider air intake free flowing exhausts, bigger pistons valves ect then you'll need to weaken the mixture to compensate not richen it'' Sorry but thats completely wrong, if you pump more air through an engine, whether via a big bore kit, free flowing exhaust, air filter etc, then you also need to INCREASE the flow of fuel otherwise the engine will run weak. We see it all the time on the Dyno, from Harleys to R1's they all run on the weak side to pass emission regs, then the owner fits a loud can and a K&N and it runs worse than std, because they have taken an engine already running lean and made it worse. The solution is to increase the fuel going into the engine, via a jet kit (carbs) or a Dynojet Power commander (Injection) or similar to overide the ECU and give a new fueling map.

    If that wasnt the case then Dynojet wouldnt be selling all those Power Commanders and my mates workshop wouldnt be busy fitting them!

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  4. #14
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    Re: Finding my lost horsepower and other stuff

    Quote Originally Posted by MisterB View Post
    Dont want to upset anyone, but I couldnt let this statement go ..''Don't forget if you open up any motor for instance bigger/wider air intake free flowing exhausts, bigger pistons valves ect then you'll need to weaken the mixture to compensate not richen it'' Sorry but thats completely wrong, if you pump more air through an engine, whether via a big bore kit, free flowing exhaust, air filter etc, then you also need to INCREASE the flow of fuel otherwise the engine will run weak. We see it all the time on the Dyno, from Harleys to R1's they all run on the weak side to pass emission regs, then the owner fits a loud can and a K&N and it runs worse than std, because they have taken an engine already running lean and made it worse. The solution is to increase the fuel going into the engine, via a jet kit (carbs) or a Dynojet Power commander (Injection) or similar to overide the ECU and give a new fueling map.

    If that wasnt the case then Dynojet wouldnt be selling all those Power Commanders and my mates workshop wouldnt be busy fitting them!
    About 4 or 5 years ago I would have totally agreed with you, not only because it makes sense,

    But bare in mind a power commander is just a piece of kit that can be set up to meet the exact needs of any particular engine, rather than stuck in one mode which is what's fitted to most bikes, so your mate has to fit one or something similar if wants to tune an engine,

    After my first upgrade which was the basic 1550 pistons barrels bigger intake manifold and cams, I already had a Mikuni carb with the standard main jet fitted,

    I used the bike for a few miles and noticed the excessive fuel consumption, so that’s when I decided to go and get it set up on a Dyno,

    Please bear in mind this guy builds and races Suzuki motorcycles and really knows everything about tuning engines,

    I explained to him at the beginning what I did to my motor and told him what happened to the fuel consumption,

    It was then he explained to me about jet sizes and the fact that one would have to decrease the size not increase “as I expected”,

    And true to form we he set it up on his Dyno and had to decrease the main jet three times during that session before he got the mixture absolutely spot on the power increased went from 80 something to 98 ft lbs and the ride home was brilliant, but this engine was a total miss match and never really performed that well,

    So after my inner bearing problems I changed to flat top pistons which decreased the compression from 10.5 to 1 to 10.0 to 1, I remover the standard two into one pipes and my screamin eagle silencers and fitter V & H ovals with their dresser pipes I increased the cams to a much bigger cam, (sorry I can’t remember which ones I got them from Madmax) but much bigger than the screamin eagle 211 and 203 cams, I also had screamin eagle cylinder heads at that point which had big valves (all the more to suck in and blow out)

    I went back to Paul "my dyno man" and we again decreased the main jet, this time to just the next size down, after we fitted the new jet the bhp had increased to over 100 and the mixture ratio was as good as it was ever going to get,

    The only problem with all the above upgrades is my fuel consumption is 7.8 miles to 1ltr of fuel...... which is about 34ish to an imperial gallon

    And I really don't push this bike anymore at all.....

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    Re: Finding my lost horsepower and other stuff

    Quote Originally Posted by MisterB View Post
    For my new system I wanted a 2-1 with a big megaphone style 'silencer' angled up to follow the line of the rear fender. But I couldnt find a cone big enough to make the mega from, so changed to a 2 into 2 system. This may lose me a a little mid range torque but its got plenty enough already, so thats ok. I drew up a rough idea of what I wanted using Paint on my PC, which looked like this...oops seems I've already exeeding my quota of images, so cant show it you..
    ok, better late than never, worked out how to use photobucket...

    First a rough idea of what I wanted the new system to look like


    Next, take a couple of stainless cones and make a pair of billet end caps..






    Machine a couple of stainless 'headers' to bolt to the heads which the downpipes will slide over




    Next get hold of some high quality stainless 45 and 90 degree 2 inch bends

    then the hard work begins.. its not as easy as it looks !
    Last edited by MisterB; 19-02-2018 at 11:38 PM. Reason: remove dead links to photobucket

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    Re: Finding my lost horsepower and other stuff

    After the downpipes were tacked together, they were welded up and the welds linished.. bit rough and ready, but cant complain as I did it lol..

    This is how it all looks now..


    Last edited by MisterB; 19-02-2018 at 11:39 PM.

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    Re: Finding my lost horsepower and other stuff

    The sun was shining, bike's running great, nearly home when I went to pass a line of cars, pull out, open it up, got half way past when I lost all drive, engine was reving its nuts off, clutch felt ok, somehow got to the curb without being run over.. here we go again, the rear drive belt had gone awol, for the third time. Should I push it home or sit and wait for hours the AA? Didnt seem that far, so started pushing.. 2 miles and two hours later I made it home. Should've called the AA .. after a well earned cuppa and a rest, I went back to the scene of the crime, to look for the belt, just to see if it gave any clues as to why it had snapped. I found it no problem, a clean break with no sign of stone damage anywhere, cant cope with all that torque I guess. Now I have to decide if I want to fit another belt and risk it going yet again, or convert to chain ? I think its time for a chain, at least if they fail, I wont have to dismantle half the bike to fit a new one..
    Last edited by MisterB; 19-02-2018 at 11:39 PM.

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  8. #18
    grbrown Guest

    Red face Re: Finding my lost horsepower and other stuff

    The subject of belts with big motors has been discussed on US forums. There are owners with SE120Rs, 124", 131" and even bigger riding with standard Harley belts on full dressers. They are also used with no problems on Harley trikes, so they CAN deal with a lot of torque, unless you have a real monster in that bike!

    The most common cause of broken belts allegedly is over-tightening them.

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  9. #19
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    Re: Finding my lost horsepower and other stuff

    Quote Originally Posted by MisterB View Post
    The sun was shining, bike's running great, nearly home when I went to pass a line of cars, pull out, open it up, got half way past when I lost all drive, engine was reving its nuts off, clutch felt ok, somehow got to the curb without being run over.. here we go again, the rear drive belt had gone awol, for the third time. Should I push it home or sit and wait for hours the AA? Didnt seem that far, so started pushing.. 2 miles and two hours later I made it home. Should've called the AA .. after a well earned cuppa and a rest, I went back to the scene of the crime, to look for the belt, just to see if it gave any clues as to why it had snapped. I found it no problem, looks like this, a clean break with no sign of stone damage anywhere, cant cope with all that torque I guess. Now I have to decide if I want to fit another belt and risk it going yet again, or convert to chain ? I think its time for a chain, at least if they fail, I wont have to dismantle half the bike to fit a new one..

    convert to chain i had the belt brake last year on my played with Dyna
    i lost confidence in the belt the bike runs just as well on a chain with no fear of braking it
    just fitted woods night prowler cam followers to match the woods cams
    they were a little noisy ,
    great post and good to have another tuner on the site with are own simon dyna( worth looking at his threads!!)

    john
    (old iron ass)

    BMW R80GS winter hack
    1978 FLH80 SHOVELHEAD
    1950 EL hydra glide PANHEAD

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  10. #20
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    Re: Finding my lost horsepower and other stuff

    Thanks for the link to the Dyna, just read it all the way through, I can relate to the problems of getting the power down on the drag strip, had similar issue with my Merch 120 race bike. As I read the thread, I was saying to myself, you dont need more HP, you need less weight and more grip... thats the problem with racing... its very addictive

    This is another project... all made in a shed..


    Last edited by MisterB; 19-02-2018 at 11:40 PM.

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