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emry

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Posts posted by emry

  1. They assume it's the ethanol. It may instead be something that's added along with the ethanol. I've got a lawnmower and a weedwhacker and a generator and a chainsaw that've been run on ethanol since the late 1990s and haven't had to rebuild the carbs on any of them. Maybe the gas companies don't add to cold Seattle's ethanol gas some chemical that's part of the additive pack added for warmer climates? In both cases, ethanol is in common but the problem is not. Why some refuse to look for any other possible cause should not surprise me.

     

    Not to drag this any farther off subject. I have a mid 70's Husky chainsaw that has ran flawless through the leaded 70's, the MTBE 80's & 90's and most of the 00's. Several months ago I had to begin the process of dismantling it because the paint inside the fuel tank (aluminum housing painted orange, inside and out) began to peel and bubble. Everywhere else the paint looks just fine. Hmmm. What has changed? Global warming? Further note, my Craftsman saw just got new fuel lines and a carb rebuild, it was new '05, So it has only seen ethanol fuels.

     

    On the up side after airing out my tank for the past week, it actually fit back on the bike. While it was still noticeably longer than OEM, at least the mounting bolt would make it near the slot. On the up side, where I had added rubber buffers (back in 02) to the inner leading edges of the tank to keep them from wearing on the front engine subframe I now have about 20mm of clearence on both sides!!! LOL.

     

    While I lived in AZ winter blended fuels (ethanol, was the main additive) tore up fuel lines and filters. We could tell when the mixture was switched because we would have a rash of previously good running cycles come back with clogged petcocks, shriveled filters, and melted floats. Customers that paid to have their carbs cleaned were very unhappy when they had to do it all over again a few months later. Luckily it only took two season changes to get that figured out.

     

    Those of you who read this thinking "WTF", be glad you have not run into these issues. While ethanol alone may not be the cause, it is to my experience the catalyst. YMMV.

     

    This does seem to be an in issue in the warmer climate states, I am trying to get some info from one of our gas tank suppliers, they may have some more technical insight.

  2. Just a little more background information. The last time I had the tank off was approx 1 year ago, I did not notice any fitment issues. While it could have been longer at that time, it come off and when back on with no drama. The bike was not ridden during the past year, it has sat in a garage. I would estimate average temp in the garage would be bewteen 35-95 degrees F. I work across the street so walking is my mode of commute. The tank was keep full, and the tip over valve has been removed since 02.

  3. Well after a little MSDS digging it dawned on me plastic, HDPE - high-density polyethylene, which is used for most gas tanks is really only capable of resisting its (gasoline) compunds for a number of years. The orginal intended life span for automotibes was only 10 years, the testing done of course to simulate that time frame was just simulated. Ultimately everything in gas will affect most plastics particularly when exposed to elevated tempueratures.

     

    http://www.calpaclab.com/pages/chart.html

     

    http://www.docs.citgo.com/msds_pi/UNLEAD.pdf

     

    So, as pointed out ethanol is not the only likely culprit. I guess maybe there is a market for custom Al tanks. :P:

  4. Been kept in a garage since I bought it new in 02, except when I ride of course, and doesnt UV make plastic brittle, not grow; you are thinking of plants. :lol:

     

    This made me think of the older plastic dirt bike tanks that did just fine until the past 5 or so years. The inner portion of the tanks have been breaking down and clogging fuel filter and jets, some of these tanks survived the 70 and the 80's. I have also seening this issue with older watercraft.

     

    I think the plastic was spec'ed right, for the fuels of the day. I think the science behind the push for ethanol use is flawed.

     

    If they rasie the limits to %15 we will all be on the side of the road. Looks like 100LL will be my fill up choice.

     

    If you want to try a little science experiment, go get some silicone fuel line from a hobby shop, it is only a few bucks. Soak in pump gas for an hour and come back and you will have a piece of hose that has doubled in size. Let it dry out for a few hours and it returns to its orginal size. I'll try it with some 100LL when I get a chance and see if it does the same thing.

    0208001817.jpg

  5. While I may be prone to blame ethanol, I will not (but I have seen a wide variety of plastic/rubber problems that can attributed to it). My gas tank has swollen. While doing a battery cleanup (PC545, seems to vent gases just as bad as other sealed batteries [but mine is several years old, so this is not a comlpaint just an observation, but that is for another topic) I needed to remove my tank. It was very, very, very hard to do. It wouldn't clear the front tail section mounts. Reinstallation is not going to happen. The tank is approx 10-15mm longer than orginal (judged by firmly pushing forward and trying to line up the rear mount).

     

    Something is going on, and ethanol does match the profile. Be warned. Since I rarely ride anymore (I live across the street from work) I will let the tank "dry" and see what becomes of it. I will post a pic later.

     

    Clearly this info is for those of us that are stuck with 10% ethanol fuels.

  6. We are seeing ethanol issues in some areas of the US. While the recommended maximum limit is 10%, our testing has found anywhere from 8% to 22% with an average of 12% across the US. 10% should not pose problems to modern vehicles, and is considered acceptable by all manufactures here (US) but older vehicles are experiencing problems with their plastics, fuel lines swell and slip off, floats distort, etc..

     

    While my tank has not seemed to swell, I also have not had it off to really check.... It does not surprise me that our tanks may be susceptible.

  7. After failed attempts with the OEM gasket I used Yamabond 4 or maybe Hylomar. It has been so long I really don't remember, should be in a post somewheres around here. I did pull the cover to clean the surface and get the crap power/paint out of the thread holes. Hasn't leaked since and that has been 6 or so years. If I recall the most daunting task for the non-mechnical is removing the stator. If you choose to do this yourself get an extra front crank seal, they are delicate and easy to nick, but cheap to buy.

  8. I have a Ducati 749 and temperature air sensor is located on front noise. No change in temperature despite the velocicty.The Guzzi V11 have the sensor on box air and the heat from motor changes the temperature. If you have high vel them low temp. , low vel. give high temp. What do you think change sensor position?

     

    Lubho, yes he did.

     

    "His observations ar right, ofcourse, which is the reason for a quite common mod done by many over here: move the sensor from the airbox to the front below/behind the headlight."

     

    He stated his sensor is already in the front.

  9. Velocity does not change the temperature of the air unless there is evaporation or convection. The current placement would be best, the OEM ECU was mapped for the sensor to read the air temp from that position. If you move the sensor, while it tempurature read may be more "correct" the ECU mapping will not. Unless you have methods of changing the mapping to reflect the changes in intake temps readings.

  10. Only things i'll add.

     

    Spring manufacturers know the rate of the springs they are winding/selling - call them or find another, if you don't know why to ask, you need to read more.

     

    I actually read Ratchs posts, he has done his homework on suspension and is offering useful information and some good links, but I offer one correction. Racers don't use progressive rates - straight rate only, at least I have yet to meet one who has. Progressive springs are popular with some segments of street riders though and have been used by some OEM's.

     

    Lubho - were you ever a left-fielder?

  11. You can strip the paint with carb cleaner, the spray stuff and a old toothbrush make pretty quick work of it. I didn't like the HD spray, price or finish. I used some (dont laugh) Rustolem Texture Finish Matte Black on my engine and it has been on there since 03. Price was cheap and it was available at Lowe's / Home Depot / Walmart.

  12. Luhbo,

     

    Educate yourself before you debate online. The reading is free. I understand the perhaps there maybe a language barrier and have tried to be sensitive of that previously.

    Clientele??? That has nothing to do with steering or mass production, per your posts. Please re-read your posts and my comments.

     

    Thanks for the decent post Ratchet!!

     

    This topic has been fun, but I have to agree just as it gets technical and also informative the hereitcs bow in. Shame really, particularlly for the those who actually have the desire to better understand the subject at hand. I feel for the new Guzzi owner who comes to this site to find information and has to wade though pages of bicker and nonsense.

     

    I really need a heretic picture Ratch. could you hook me up?? ;)

  13. It's very hard, if not , under commercial aspects, impossible, to do this rake thing just because you can't keep the vertical distance between upper and lower clamps constant or as designed. Tolerances and such things you know. It's no problem as long as you have the 3 boreholes parallel to each other. If you have them tilted you've lost. There you need the shims, between the clamps, not in the top view like RH's sketch.

    If you want to keep your assy line running this would mean Harakiri. For nothing. It brings no effect besides a slightly variing trail under different load conditions (wheelbase kept constant, of course).

     

     

     

    More trail makes a bike more prone to wobbling. You've probably watched wobbling shopping trolly wheels or maybe also the uncontrolled front wheel of a vintage sports plane. Good examples of wobble caused by trail. Remember that with a longer trail you also have bigger reaction forces which may make a steering damper indispensable because of the risk of an overshooting stabilisation (Greg's Death Wobble). Massive wheels, fenders, rifle holders, rollers and bullshit more like this at the front fork might multiply this risk.

     

    Hubert

     

    Sorry, Luhbo. You don't seem to have a very good grasp of steering. Please take the time to Google "motorcycle steering geometry" and do some reading, even wiki post will help you.

     

    The HD V-Rod and the Yamaha Raider both use raked triple trees on a mass produced assembly line bike. Machining has come a long way since they did it by hand.

     

    Quote from the Raider portion of www.yamaha-motor.com - raider feautres

     

    A 6-degree yoke angle—the first ever on a street-legal Star Motorcycle—makes it possible to achieve that custom look as well as neutral handling and straight-line cruisability: 33-degree rake plus 6 degrees yoke angle gives total rake of 39 degrees and 102mm of trail.

     

    No shims needed.

  14. That's fine, as you said it is not a clear cut issue. Chopper guys usually (or at least used to) list both the rake of the steering stem (as rake) and the extra angle the clamps add.

    In my opinion the problem with adding angle in the clamps is that while the forks are pointed straight ahead the extra angle is in line with the steering stem. But as you turn the forks that angle kicks the front wheel off to the side. It is no longer adding its angle to the steering stem rake entirely. The more you turn the forks the more of that angle goes off to the side instead of in line with the steering stem. This is not a big deal on choppers (they handle poorly to begin with) but on a sportbike anything more then a small bit causes wonkey steering geometry as the forks turn. This not only would kick the front wheel off to one side but would cause the trail to change as well. That is why it is used on choppers and drag bikes mainly. In fact, Kosman, who make them for drag bikes goes so far as to point out that it changes fork tube angle, not rake. But again, that is splitting hairs. The important part is that it is a crude wonkey patch that should have been done differently if at all. Guzzi engineering, gotta love it.

     

    Choppers rake out, sportbikes rake in (fork axis). It is well established that trail, not rake affect bikes stability, but this has never really acounted for how the bike really handles when the fork angle has a differential + or -. At least some chopper manufactuers have figured out what make their bike go straight and not kill people. Racers who rake in are nomrally very tight lipped. No compedative advantge to the neighbors ya know.

     

    In my opinion the problem with adding angle in the clamps is that while the forks are pointed straight ahead the extra angle is in line with the steering stem. But as you turn the forks that angle kicks the front wheel off to the side. It is no longer adding its angle to the steering stem rake entirely. The more you turn the forks the more of that angle goes off to the side instead of in line with the steering stem.

     

    Raking (out) a steering stem can produce "flop" at low speeds but raking the clamps does not, conversely doing the opposite to a sport bike increases turn in (less angualrity of the camber angle that produces the turn) and stability from the extra trail. Either of the later sounds like a benefit to me.

     

    But in Guzzi terms we are only talking 0.5 degrees. The trail advantage is much greater than anything else at that point.

     

    In my opinion the problem with adding angle in the clamps is that while the forks are pointed straight ahead the extra angle is in line with the steering stem. But as you turn the forks that angle kicks the front wheel off to the side. It is no longer adding its angle to the steering stem rake entirely. The more you turn the forks the more of that angle goes off to the side instead of in line with the steering stem.

     

    True, but is this positve or negative depending on speed, the results are not linear. Remember counter steering. The argument is not as cut and dry as the term "rake". Above slow speeds the steering rotation needed to turn a motorcycle is small.

     

    Many of these angles (OEM) are still achieved through test riders, the physics are not concrete.

     

    I hope all of this makes sense without to many gramatical errors, I have had a few tonight.

  15. I think we are using different definitions for "rake". In my experience the common definition of "rake" is the angle of the steering axis. You can not change the rake angle of the steering axis with triple clamps. You can change the trail by changing the offset or you can change the fork angle if you were to bore the top and bottom clamps offset from one another or some adjustable clamp set allow you to change the offset of the top and/or bottom separately to some extent and this would change the fork angle (the steering stem would still pivot at the same angle). The effect on trail of this would vary as the forks are turned and as the suspension compresses. Talk about piss poor engineering. How hard could it have been to just have them weld on the steering head to the frame at a 25.5 degree angle?

     

    I apologize, you are quite right. The problematic part is when the fork axis and the steering axis are no longer on the same plane. The definition for rake is rather old, forks and steering stems were always parallel, no issue. By definition changing the angle of the fork does not change the steering axis angle 'rake', as long as the vertical height of the steering head is constant.

    To be honest the jury still seems to be out on what and how (modern) rake should be calculated. Some consider the steering axis angle plus the fork axis (such as most custom chopper makers) or a variable of the two as effective or overall rake, some still say ignore it. In reality it boils down to the unknown of slip angle, camber angle, steering rotation (steering drop), and the transistion between normal and 'counter steering'. Effects of riding - a bump in the road or a dip how that relates to tire size plus changes of COG.

     

    Altering the fork axis relative to the steering axis has noticable effects on how a motorcycle behaves even when its trail is keep constant, I have to side with the custom chopper folks at this point (It might not be technically accurate, but it does a better job of mathmatically evaluating how a motorcycle will steer). But I am still waiting for a clear explaination of the forces and changes due to this 'misalignment'.

     

    When this is done right some very desirable handling characteristics can be achived without some of the short comings of the twitchy red frame demons...... sorry I just had too. Find me a demon Ratch...

     

    Sorry if I have caused any confusion folks.

  16. Offset bearings are a different thing. In racing you may change out the clamps for ones with a different offset but this has nothing to do with rake. It is about trail. Offset bearings are used to change the rake but they actually move the steering pivot. What Greg seems to be suggesting is different. He seems to be saying that they bored the holes in the clamps at an angle so that the fork tubes were not at the same angle as the steering stem. If this is not what he is saying them I'm sorry, I may be misunderstanding him. But if you change the rake "in the clamps" that is different to me then offsetting the steering stem (which is really just changing the steering head angle without the hassle of actually moving the steering head).

     

    Some change the rake with the clamps as Greg states. Changing rake on the clamps has a greater affect on trail than just altering the rake alone. Remeber trial is the difference between the point that the steering axis and the tires contact patch meet the ground.

     

    In racing changing the offset was a early solution to the increased rear ride height needed to get correct squat during acceleration. This also benefited of decreasing the rake, but often decreased trail to an unacceptable level, reducing the offset of the fork would remedy that. Some motorcycles already have a very good squat angle, raising the rear ride height can disturb this, adjustable rake & offset triple clamps can allow you to decrease the rake of the forks but still keep the trail accpetable, this quickens the initial steering input but will still maintain a acceptable amount of stability.

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