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Gearhead

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Everything posted by Gearhead

  1. Gearhead
    One sage old engine machinist told me that modern production methods make more precise engine parts that last longer, but the biggest difference is EFI, primarily due to the difference at cold start. Here's why: an engine runs best at or near 14.7:1 air-fuel ratio (AFR). Carbs do an OK job of maintaining this, but EFI is much more precise. At cold start, though, the drops of fuel that come out of the carb jets don't atomize properly without the heat of a hot engine and much of it goes unburned. Thus the choke, to compensate, which can bring the mixture to as low as 7:1 (twice as rich), meaning HALF of the gas is not being burned. This fuel goes out the pipe, but also washes oil off the cylinder walls, sneaks past the rings in small quantities and contributes to acid buildup in the oil. This is the primary cause of engine wear and oil breakdown. By comparison, EFI sprays the fuel out atomized already and does not rely on the heat of the engine to do this. It has a cold-start injector, but that only runs for seconds on cold start. Similarly, the old 2-3000 mile oil change is no longer necessary. Nothin' wrong with it of course, but not necessary. The oils are better, but again the EFI is the major contributor. Jeremy
  2. Gearhead
    My first guess: connections to the TCI. JEremy
  3. Gearhead
    Yeah, Radio Shack is convenient though. That's good to know for next time. The factory noise filter has a choke and a cap. As I understand it, the choke does not go bad so I left the noise filter in place and wired the caps in parallel. Jeremy
  4. Gearhead
    Chuck, what fixed the hesitation? Was that present with stock carb settings? And another question: why does everybody want their bike to start with no choke? The choke is there because a cold engine does not atomize the fuel properly and so more of it is needed. If it starts with no choke, it's too rich methinks! Jeremy
  5. Gearhead
    Hmmm, my problem (much reduced now as I said) is with the radio or intercom, fairly equally. Interesting stuff about the possible causes. I bought my caps at Radio Shack for about 5 bucks each. GeorgeS had taken apart a factory noise filter and told me the caps in there are 2200 microfarad, so I bought two of those. I installed a 4400 or so microfarad cap at the regulator. The higher the microfarads, the lower the frequency it filters out, FWIW. They go from the hot wire to ground. Funny about the polarity, I didn't realize that and boiled one whilst learning the hard way. Jeremy
  6. Gearhead
    I don't but I can commiserate. A few months ago I stupidly rode with that lid unbuckled and lo and behold, it was gone when I got to work. I found it the next morning on the side of the road, but it had had a close encounter with a car tire methinks and was not quite the same... I did get another from Squid on this list, but I still haven't painted it to match... Jeremy
  7. Gearhead
    Yeah, that was me. Let's stop short of using the word "cured", but it did greatly reduce the noise problem. Sounds like your problem is the same as mine - alternator whine thru the power wires. Stock filter is actually two filters in parallel - one in main hot wire and one in the battery back-up circuit. And there is a factory stock cap near the alternator plug as George said. I installed 3 new caps - two in the two radio hot lines and one near the alternator plug. The other thing that helped me alot along the way was cleaning connections, especially ground connections. In fact, the single biggest change (other than new caps) was when I installed an extra 12 ga ground wire from the neg side of the regulator (soldered in) directly to the neg terminal of the battery. Also improved battery charging by .5 volt. Does your noise decrease as you add electrical load? Mine is less if I: - Run the blinkers (alternating of course - blinkers on, noise less) - Turn on the driving lights - Turn the Headset Attenuator on the handlebar or passenger pod down a notch and turn the radio volume up a tad to compensate. This makes a big difference. - Turn the Auto Volume feature down to minimum (off, essentially) Jeremy
  8. Gearhead
    Yup, normal. I'm in Tucson and can relate to your temps. The 87's fan comes on with the gage about 1/8" below the red, could call it 5/8 maybe on the gage, and shuts off at about 1/2. One trek across the Mohave desert, temps 108 (no fun, by the way) at 80-90 mph, the gage sat maybe 1/16" below the red. Fan must have been running constantly. Weird, seems like the extra airflow at speed would compensate, but evidently not. I do notice a slight tendency to ping with hot like that, so I run higher grade fuel on such a trek. Jeremy
  9. Gearhead
    Hmmm...that jet is called Pilot Air Jet #(1 or 2). It controls the air to the pilot circuit (idle and low throttle) through the coasting enrichers. Not sure how it would affect slide opening rate. Jeremy
  10. Gearhead
    Speed is killer on MPG. I'd guess the optimum is around 50 or 55. I think that over 65 the downward slide of MPG gets pretty steep. 5bikes, who started this craze of lowering the needles (Thanks Chuck!) was writing about 47 or 48 average, but he was also riding 50-60, all the time as far as I could tell. I ride almost exclusively commuting, about 1/3-1/2 Interstate. I usually push 80-85 on the Interstate and 10-15 over the limits on surface streets and rural roads, with moderately spirited acceleration. Not a good habit, but so be it. 5bikes convinced me to try a tank at lower speeds. So I ran 60-70 Interstate and gently up to the limit on other roads and improved from about 40 average to 43. That's after lowering the needles by .050". Jeremy
  11. Gearhead
    Reviving an older thread...what's the advantage of the floating rotors over solid? And Earl, it sounds like you kept the stock master cyl in front - yes? What about the piston size issue, since it is now pushing two calipers? Wouldn't that cause the lever to bottom out on the grip? Are you using organic pads then with the stock rotors? And finally, why did Yammy fit linked brakes? Aren't most VR riders going to have prior experience with bikes and thus be used to the conventional system? Thanks, Jeremy
  12. Gearhead
    Randy, is it possible that your perception of increased top end was actually due to a hole in the mid-range power? And vice-versa, now that your mid-range is back? At WOT and higher rpm's, my understanding is that needles are out of the equation - it's all main jets at that point. Masterguns, your mileage is not far from what I get on my 87 under the conditions you described. Mine might beat that by one or two points at best, maybe not at all. Those temps hurt my mileage. Before lowering the needles I averaged about 3 mpg less than I do now.
  13. Gearhead
    Jonathan, If you're doing 80-90 then 33mpg is to be expected, at least in my experience. When you get 36-38 are you going slower? Speed is HUGE in gas mileage. My only other thought is that your brakes are dragging, but replacing the pads really shouldn't cause that. You used moly grease on the axles - is that the grease problem? Do you mean the axle bolts that go all the way thru each wheel? The type of grease there doesn't matter, it's mainly to prevent corrosion. The wheel doesn't turn on the axle per se, but on the bearing. Jeremy
  14. Gearhead
    Any of you guys ever put a caliper (the measuring sort) on your rotors? I installed HH sintered pads on the RF brake (the one that works with the lever) about 19k miles ago. I had heard mixed reports that sintered pads can be hard on rotors, so I miced the rotor at installation, after a couple thousand miles, and again this morning. Then I looked in the manual. I included the boring details below for those of you inclined toward boring details, but in short, both my front rotors are under the min thickness spec. It seems that there is only about .020" from new rotor thickness to minimum thickness, which is a little chincy I think. So I wonder how many others have rotors worn below spec? How many ever measure to find out? EBC sells rotors for about $150 each for these bikes. Has anybody used them? Thanks, Jeremy BORING DETAILS! I checked out my brakes. The sintered pads have been on the RH front brake for 19k miles and are maybe 2/3 worn out. Interesting, because the LH front and the rear organic pads - which I have never replaced so they have at least 26K, and I don't think the PO replaced them so they have more than that - are still very thick. I thought sintered were supposed to last longer, although that's not why I put them on (I wanted the extra bite with the hand brake). Either that info is incorrect OR I use that one front brake (hand lever) a WHOLE lot more than the linked foot brake, which is entirely possible given old habits. Both front rotors have a ridge on them that measures .281, so that must have been the starting thickness. At 54k when I installed the HH pads, I measured .253, .243, and .240 working from just under the ridge toward the axle. Now at 73k I measured .248, .239, .234. So there's been 5-6 thou of wear. If you look at the original thickness, and figure that 5-6 thou" represents 19k out of 73k total miles, and that 19k had heavy usage on that brake, it's pretty reasonable wear really. I wonder if organic pads would have done the same? For comparison, the LH rotor today measures .255, .248, .246 (I didn't measure it before), which are closer to the RH "sintered" numbers than to the original .281. I just checked the manual and the listed minmum thickness for the front rotors is .260, so mine were under that before I got the bike. Hmmm...
  15. Gearhead
    I dunno about the specifics of any DJ kits for the Venture. In general they supply different slide springs and different needles, and they often recommend drilling out the vent hole. The DJ slide springs aren't necessariy weaker, though - just different; I've noticed in the past different spring wire diameter and different length. Since there's a whole new needle with different taper, all bets are off when trying to make sense of it. That being said, I spoke with somebody, maybe DJ tech support, not sure, who said that enlarging the vent hole in the slide doesn't cause MORE lift of the slide, but rather QUICKER lift of the slide, for supposed quicker throttle response. Jeremy
  16. Gearhead
    Johnathan, what happened when your mileage went down? Did you change anything? Did it start running differently? Did your riding habits or primary route change? I think "crinkled" is the normal state for used diaphragms. Hold them up to a light to lood for small holes. No holes, no problem. Randy, I ran at speeds of 85-90 one trip in 107 deg heat. I tried to outrun the dad gum heat, but just couldn't seem to get ahead of it :-) My 87 got 27 mpg - ugh. Jeremy
  17. Gearhead
    You're probably on the right track. When I first bought my 87 Virago (used), it would die suddenly now and then, or sometimes it would just run poorly and the light would get dim. I found that grounding the handlebars to the frame with another wire fixed the problem. Later I found a loose harness ground wire under the tank on the frame. Tugging on the clutch lever must give the system a backup ground path. Test is easy. Take a piece of wire, connect one end to the frame or even the neg terminal of the battery, then ground the handlebars (or whatever) with the other end. See if the problem clears when you do this. All grounds should be cleaned, greased and tightened anyway - batt to engine, engine to frame, harness to frame. Sometimes it's easier to make a new ground wire and install it that track down the old one. Jeremy
  18. Gearhead
    As mentioned above, antenna grounded to frame is a no-no. There is a special nylon shoulder washer to prevent this - do you have yours mounted properly? Disconnect the antenna lead and then use an ohmmeter between the antenna's metal base and the bracket - there should be no continuity. Did you use a "splitter"? Jeremy
  19. Gearhead
    I did the mod too. When I bought my bike, somebody had already fitted two really short, like 14", fiberglass (Firestik-type, not that brand though) antennas. I knew nothing about antennas, but the CB had very little range. One got broken, which led me down a path of learning about antennas because I couldn't find such a short one to simply replace what I had. In the end, I installed a single Wilson Flex 3' fiberglass antenna. It is significantly slimmer than Firestik brand antennas, and I like that. It's also available in 4'. I went this route for several reasons. CB antenna performance is very finicky. Actually, I think any transmitting antenna is like this. Tiny short ones just don't generally work that well (and if not tuned right can actually damage the CB), and it was recommended to me that a 3' fiberglass type is about the shortest you want to go. AM/FM reception performance is not nearly so finicky, and I'm not sure that my radio reception changed one bit. (Honestly, I haven't used the CB since - nobody to talk to - so I can't compare its performance.) I cover my bike at work. The old 14" antennas were just as high as the trunk rack and fit under the cover. The 3' does not! There seems to be only one fold-down mount on the market, as referenced in the Marshallmod writeup. It's a little loosey-goosey which bothered me at first, but I stuck with it and it works fine. There are quick-disconnects available at truck stops and online, but then you have to set the antenna somewhere. At any rate, one antenna means only one to fold down. Up front, I installed a Firestik "splitter" (not the right name, but you get the idea), which allows the antenna to work with CB and radio. My cabling was already "standard" since aftermarket antennas were installed by a PO, so I didn't have to deal with that. Mine has a 90 degree adapter connected to the antenna mount, then the cable connects to that. After installation, you NEED to tune the antenna for the CB to work right. This requires an SWR meter, and I have a friend with one. First tune the antenna connected right to the CB, then connect and tune the "splitter". Jeremy
  20. Gearhead
    I bought a brand-new one from Zanotti. Now, that was 2.5 years ago, and it was around 70 bucks. Jeremy
  21. Gearhead
    The speedo on my 87 is right on as well. Just lucky I guess. IMHO, it's not so much the RPM per se, but the speed and associated wind resistance that kills the mileage. Jeremy
  22. Gearhead
    Hey Randy, what were your average speeds on your 45mpg run? Does anyone else find that their mileage actually tends to be BETTER 2-up than single? I find that mileage is much more heavily affected by speed and throttle than by passenger-seat occupation, and my speeds tend to be lower with my bride on the back. Jeremy
  23. Gearhead
    FWIW, Dynojet adjustable needles generally have the clip slots spaced at intervals of .040", and they supply a .020" washer for adjusting half-way in between. So, they give an adjustment resolution of .020". Hardware store standard washers are generally at least .031 (1/32") thick, often more. So I shopped around a couple Ace's with my caliper, looking at all the different types of washers that fit in the slide, to find different thicknesses for better adjustment resolution. Jeremy
  24. Gearhead
    Whatcha gonna do, pull TWO trailers at once??? :-) Jeremy
  25. Gearhead
    You mean ride w/o a speedo cable? Sure, no problem, just no speedo! Jeremy
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