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I got some interesting answers. Some was from older EPA, CARB, RFA, and indepentant studies, others were with conversations with engineers in the fuel system field and related fields. Short Summury - It is a combination of ethanol and the aromatics that are used as an additive package. The local aromatic packages are different due to regional requirements and state legislation. Neat ethanol (100%) has little effect on HDPE, and is transported in said containers. HDPE is very susceptible to the aromaitcs packages - benzene etc. A major effect is swelling, (up to 40% depending on chemical exposure % and temperature) and softening. Note this is in high concentrations, the percents used in all regional fuel blends exhibit little dimension gain or loss of strength. But the aromatics allow the ethanol to permeate the HDPE, with up to 26% increase in permeation rates. HDPE that is experiencing ethanol permeation will swell and exhibit weight gain. MTBE had a resistive effect on the permeation of HDPE, approx -6%. The combination created a large increase in evaporative emissions which the major manufactors answered with sulfated or fluorinated and multi-layered plastics, mostly HDPE derivatives. Negative effects on other fuel system components was negliagble due the change in materials already undertaken due to changes in the fuel systems, ie. carbs to FI. Plastic tanks were prefered to their weight, and ability to be ecomonically formed into complex shapes. Metal tanks had zero problems with permeation but had problems with acids and salts that form as fuel ages. These effects on older automotive products are largely ignored (untreated HDPE), no one with 98 Toyota Supra ever noticed an increase in fuel tank size, with marine and other motorized product being similar, although many small engine builders had to quickly change carb materials. Motorcycles are rather unique in their fuel tanks are normally part of their design, even relativley small dimensional changes can be noticed. Most manufacters normally use treated steel, with very few plastics tanks used in an exposed location. AZ, TX and the metro Atlanta GA areas all use similar additive packages. WA, and CA are similar.

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.

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.

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.

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. 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.

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.

Wow, and I thought I had issues finishing a project.

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.

While it is rare for lubho and I to agree, I will wholeheartedly support his recommendation of Cliff's MyECU. A good desire to tinker will help you enjoy it even more.

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.

I used the top of a spray can (the plastic cap). Not very elegant, but it was easy and has worked well enough.

Lubho, yes he did. He stated his sensor is already in the front.

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.

Find Pete Roper. He will guide you and is from that area of the globe. But beware the rubber chicken.

Can't you gentlemen move your bickering to the 24/7 V11 thread. This is a "Technical Topic", correct. There are so many valuable threads that are filled with similar useless posts that getting the info out of them is next to impossible. Have a little consideration.

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?

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.

MyECU. Fits in the stock location, full tuning - fuel and spark. If you build it it is cheap. Add wideband "auto" mapping if you like. Big thumbs up from me. Cliff also answers his emails. Another big plus. Take a look here. http://www.cajinnovations.com/MyECU/index.htm Cliff also has set up a fourm.

Perhaps the starter solenoid got stuck.

I just have to peek. Greg, why do we bother... Don't we have better things to do or are we just hoping that good Karma will come of this??

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??

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. No shims needed.

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. 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. 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.

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.

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.