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Pressureangle

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Pressureangle last won the day on November 1 2018

Pressureangle had the most liked content!

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About Pressureangle

  • Rank
    Guzzisti

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  • My bikes
    '85 LM1000 '97 1100 Sport i '89 Mille GT '71 Norton Fastback Commando '74 Aermacchi 350 Sprint
  • Location
    South Florida

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  1. Pressureangle

    Pressureangle

  2. I looked at those, didn't get one...still haven't mounted mine on the stem. What sort of SNAFU is it to get it on the stem? It was obvious as soon as I opened the box it wasn't going to be a standard easy install.
  3. I spoke with Pete about making them here in the U.S. under his name and sending back profit per piece. He hasn't any made, and said next batch he'd send a sample. If anyone actually has a genuine Roper plate they'd like to give up temporarily for a pattern, that would speed things along. I ain't buying one from Guzzibits. Oh hey, Pete. Your post magically appeared after I put this up. Still open for business.
  4. I've been thinking about this for a while before responding. Elevation equals reduced cylinder pressure, no exceptions. So that cannot be the source of your ping. I can say with certainty that the variability in pump gas out west was disconcerting and surprising. My 1100 Sport-i was sensitive to gas stops far more that it was to altitude. I never got pinging, but I did get noticeable weakness and a couple times generally unhappy low-throttle running. I don't believe for a second that either the octane number nor the alcohol listed on the pumps is a reliable indicator of what's going in the tank. Miles per gallon was the most noticeable difference, however. It varied between 45-ish in Georgia to 34-ish in New Mexico, though the performance aspect is not so apparent on those long flat fast stretches. NoCal and Washington State seemed the least consistent. Of course, none of this is scientific, only subjective- but over 10k miles one gets a good feel for what's going on. So I'll suggest that your condition is a symptom of local fuel quality. The worst tank I had by far was somewhere South of Sacramento. Not quite. Pre ignition or ping as well call it here is caused by hot spots in the combustion chamber that cause the fuel in isolated areas to, well pre ignite hence the sound you hear. Detonation is caused by the fuels inability to maintain its chemical stability during the ignition event and the oncoming flame front and then burns in an uncontrollable fashion combined with the spark ignited flame front and the two intersecting a lot more cylinder temp and pressure is created. A much worse scenario than ping. The reasons for both are many and varied. But back to the original issue.Poor fuel can of course cause ping but the altitude can also play a roll if not be the actual cause. When you climb 3000 feet the pressure will drop 3/4 of a psi. (old aircraft engineers figure-1/4 psi per 1000 ft) Chuck may be able to confirm piloting and all. So thats about a 5% drop in atmospheric. The ecu of course leans out the mixture to compensate and of course you get a commensurate drop in power. Problem is your brain and right wrist dont necessarily accommodate this loss of power and unconsciously just apply more throttle to achieve the same performance. So what you end up with is the same load ( speed and resistance to climb the given rise) but with a leaner mixture and more throttle and if the temperature is also high more leaning.Result....increased combustion chamber temperature, hot spots and ping. Your theory about elevation and cylinder pressure also only holds true for WOT or a given throttle position. But in the real world when we all ride the reduced atmospheric pressure is compensated for by opening the throttle more to maintain the performance we seek. Most of us even when we are "going for it" in the twisties are only using maybe 35-50% throttle. You'd be amazed how little time even a race bike spends at WOT. Ciao Throttle position isn't even in the equation here. You need a given amount of cylinder pressure to do a given amount of work, and if you need to open the throttle farther to get that, it's irrelevant unless opening the throttle adds in more ignition timing, which is usually the opposite. So your point about 'my theory' is problematic because you say it 'only holds true for WOT or a given throttle position' WTF even is there other than WOT or a given throttle position? Would you like to add acceleration enrichment to 'my theory' and explain how a richer mixture makes it ping? One might reasonably suggest that his ride at altitude was more aggressive than below, but I surmise that he rides pretty near sea level aggressively as well without the ping, or he wouldn't have bothered with the question eh? The point is that at one altitude higher than another, there is no point at which the cylinder pressure can be higher, at any given throttle opening, than at the lower altitude, so that cannot be the root of the problem. On to the next 'theory'.
  5. After my recent 5,000 mile/ 8.000 km tune-up, my Sport renewed it's undesirable popping and burbling on the over-run (closed throttle decelerating), idle stumble, with popping and hiccups below 3,500 rpm. But, it really ran like the cliché scalded dog 4,000 to redline. I had decided to skip the TPS reset and simply adjusted the valves, new plugs, and throttle body balance. I looked at my notes and see I skipped the TPS last time as well. No good. TPS was 172 mv. I have set it back to 157 mv, but probably will not get to test ride for some time. So, at 172 mv, would this account for why it ran wildly stronger in the upper range and lost its ability to stay stable below 3500? [Amended the Decent Tune-up to retain emphasis on this critical step.] Your fuel map would think you have the throttle open farther, give more fuel and richen the mixture. Perhaps you're a little lean up top normally.
  6. I've been thinking about this for a while before responding. Elevation equals reduced cylinder pressure, no exceptions. So that cannot be the source of your ping. I can say with certainty that the variability in pump gas out west was disconcerting and surprising. My 1100 Sport-i was sensitive to gas stops far more that it was to altitude. I never got pinging, but I did get noticeable weakness and a couple times generally unhappy low-throttle running. I don't believe for a second that either the octane number nor the alcohol listed on the pumps is a reliable indicator of what's going in the tank. Miles per gallon was the most noticeable difference, however. It varied between 45-ish in Georgia to 34-ish in New Mexico, though the performance aspect is not so apparent on those long flat fast stretches. NoCal and Washington State seemed the least consistent. Of course, none of this is scientific, only subjective- but over 10k miles one gets a good feel for what's going on. So I'll suggest that your condition is a symptom of local fuel quality. The worst tank I had by far was somewhere South of Sacramento.
  7. Mine were tight enough that I used a 1/2-3/8 adapter and a 24" 1/2 breaker bar. (because that's the one that was at hand) All components Snap-On, and the Allen key was inspected for a good tip. It came right off then with no drama.
  8. On mine, that was the o-rings under the inside cyl. stud nut cover, the big allen plug.
  9. Two points are paramount, and ultimately far more important than max-lift flow numbers. First, Low-lift flow. The intake valve spends all but a short period of time at less than max lift, and the closer it is to the seat, the more slowly it moves. So 10CFM between .050" and .150" lift is far more productive than 10CFM at max lift. Secondly, port velocity. The higher the velocity, the more air can pass a given opening in a given period of time. To maximize velocity, the port has to be the ... uh ... 'correct' cross section and taper to match the curtain area of the intake valve ('curtain area' is the area open between valve and seat at a given lift). Your port guy who suggests a good valve job is right on the money; getting the curtain velocity up by shaping the valve head and seat can find big gains even without port changes. Where the Guzzi port fails, is that it's already large, to make up for the water-pipe shape; velocity produces inertia, and if velocity gets too high for a short turn, the air separates from the floor and gets turbulent, can't make the turn and kills ultimate volume. The ports on my LMIV are raised, floor filled, and tapered from carb to valve. (Not discussed is venturi effect from the smaller throat to larger valve opening). So a perfect port would simply be a velocity stack with a given taper (I don't know that perfect number) without a valve in it. Modern engines come as close to this as physically possible. Then, RPM, camshaft duration and overlap, compression, and exhaust scavenging all have an effect on intake timing and velocity as well. It's complicated.
  10. That pretty much covers it. The port floor entry into the valve is the main concern here- it can't have the radius increased without raising the roof to suit, and you can't raise the roof to suit without moving the port mouth to suit. My LM1000 heads flow about 240cfm, but they've been raised a half inch. That is a lot harder to do with EFI since the relationship between the two heads has to stay the same unless you do some serious rethinking of throttle activation and expense. I'm going to examine those possibilities this summer, see if we can come up with a significantly improved port that keeps the stock throttle bodies on their mount. The point of the exercise is not to make an extreme racer, but to find something economically viable, reliable, and streetable that you can install in your own garage.
  11. Yeah... Fav hammer for all things. Aaand...file too large. Didn't think that hammer was so big.
  12. Having made every conceivable mod to my '85 LM1000 (save stock displacement/pistons) and riding my stock-but-mufflers-and-ECM '97 1100 sport i 10,000 miles around the country last summer, I'd say the best return on dollar is having the heads done by a *very* competent and experienced porter. Guzzi ports are notoriously poor, but not easy to make enormously better without very specific knowledge; making it worse is that on an injected bike, you can't just raise the ports carelessly as the relationship between the throttle bodies can't change. I'm working that out this summer with my engine guy, but I'll probably have to have the bike in the shop to be certain it all works out. Conceivably it's a simple matter of geometry but I wouldn't take it for granted, and the 45* angle means you can't raise the port along the cylinder axis. Given the experience of the stock LMIV, stock 1100 sport, and the modded LMIV, I do not believe that a cam change will net you any satisfactory return for the work involved. You may find more RPM and upstairs performance, but that always comes at the cost of low RPM torque and drivability. Also you have to consider tuning; I installed a Jeffries MyECU and it's awesome, but would not be a lot of fun if you have no injection tuning experience. So if you can't resist tinkering, let your wallet be your guide; but if you just want to ride it, put pipes on it, tune it, and go faster from the saddle not the motor.
  13. The rod didn't fail, the lack of oil caused a seize and then it cascaded from there. The stock rods are actually quite stout. Until they're not. I don't know whether the Triumph and BSA boards have the same density, but Norton has *always* had running discussions about broken rods. My bike was well-used, but I put about a thousand miles on it before it blew it's guts at 60mph. Broke right above the journal.
  14. 1. Take twice as long as you need to. 2. Stay twice as long as you thought you would. 3. Stop for more pictures than I did. 4. Consider installing the INNOV K2 cameras. I still haven't put together all the segments, because...well I didn't have enough discovery before I left and have to stitch together a bunch of short clips. The camera isn't terribly expensive nor hard to install, and if you give yourself a week with it around home to tune the settings- and remember to clean the lens every time you ride through something you're sure you want to keep- you'll have some outstanding video of the ride with zero effort while riding.
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