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Everything posted by GuzziMoto
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Clearly you do not race. The tracks you see on TV are usually pretty smooth, but the local tracks club racers race on are often anything but smooth. Racers need compliance over bumps, ripples, and undulations because when you are at or near the limits short comings often mean more then an uncomfortable ride. They just can't afford to give up proper suspension control for it. There is no reason you can't use progressive springs, many do. But there are reasons why few racers use them, mostly having to do with the direct relationship between spring rate and dampening. Having a spring rate that changes requires a dampening rate that changes to maintain proper suspension action. That is not feasible so progressive springs result in a compromise. And finally, spring rate, spring length, and spring preload are all inter-related so you can not have an educated discussion of one with considering the others. In fact with progressive springs spring length and preload directly effect rate. So feel free to express your satisfaction with your progressive springs, but that is not evidence of straight rate springs inferiority.
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Do progressive rate springs work? Well that depends on how you define "work". They do hold up the bike and they do bounce, but as mentioned racers don't use them. They certainly can work but they are not likely to give better results then a straight rate spring. The biggest problem with them is that the preload you apply to the spring will compress the lower rate coils first. This may or may not leave any of the lower rate coils to actually suspend the bike. Another issue with them is if they actually did work then how would your dampening work properly. You would either have too much or too little at some point in the travel as dampening and spring rate must work in unison to work right. Ask KTM how hard it is to get progressive dampening right. If and when they figure it out they probably won't say exactly what they did. Can you use progressive springs? Sure, and you may even be happy with them. Ignorance is bliss. But do they work better then straght rate springs. Not likely without serious alterations to dampening that are beyond your average guys budget and ability. But if all you do is putz around on the street you may be able to convince yourself that they are superior. Personally I have tried both and found there was nothing that progressive springs did better and there was a point where straight rate springs were better, but that was at a speed that I only would hit on the track. Straight rate springs are likely cheaper so I would go with them as things that are better AND cheaper don't come along often enough. Any spring that is the proper rate for your weight and style is better then a spring that is the wrong rate. Beyond that...
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The difference in helmets has always been one of comfort more then protection. The differences are generally that cheaper helmets do not have the level of fit, finish, and features, that more expensive helmets do. Testing helmets is a good thing but unless you know how your head will hit the pavement it is only a means of weeding out the completely lacking ones. I do place more weight on DOT standards for street use and leave Snell approval for helmets I would use racing (where your head tends to hit harder). And I do like Nolans as well but Arai's have a better fit for my head.
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Demise of a brand
GuzziMoto replied to lemppari's topic in Special place for banter and conversation
"Universal negative"? I would agree that that color does not look good, but in black or white it is a descent looking bike. In person it looks better then in pictures. I find it to have a mean, purposeful look. Just keep the red. I considered buying one at normal prices, and would love to buy one at these kind of prices, but my latest purchase has me in a tight spot and I don't think I could convince the wife that I need another right now. I would have to sell the Griso and that would be a losing proposition. Guzzi's do about as well on the used market as Buells. -
No problem at all. Some transmissions use motor oil. Most bike transmissions use the engine oil to lub the tranny. I would not give it another thought.
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When my wifes bike did that I thought it was the shift spring but it turned out to be the linkage was binding.
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Demise of a brand
GuzziMoto replied to lemppari's topic in Special place for banter and conversation
As another former and possibly future owner, I am very sad to hear of this. One of the best streetbikes I owned was a Buell Lightning and I probably will own another someday. I only sold it to buy my Griso, and quite frankly the Buell was a more enjoyable bike to ride. The Griso is just better looking and more reliable. -
got rid of pinning by ceramic coating piston tops
GuzziMoto replied to arek's topic in Technical Topics
Well, personally... seeing as your bike was pinging with 5k miles on it, if your bike puts another 5k miles on it with out pinging again and no signs of coating degradation (I doubt there will be as ceramic coating is tough stuff) I would say it is a valid option. As for insulating the piston and/or the combustion chamber with the coating not reducing combustion temps, that would likely be true. It should slightly raise the combustion temp as the piston would be absorbing less heat. But what it should reduce is the combustion chamber temps right before combustion takes place. That is where detonation happens and lowering those temps can reduce detonation. It is not after the the charge is burnt that detonation happens but right before and during combustion (in the parts that have not combusted yet). Preventing the piston from absorbing some of the heat from combustion and passing it along to the next charge as it is compressed can and will reduce the temp of the mixture and thus help reduce the chances of detonation. -
got rid of pinning by ceramic coating piston tops
GuzziMoto replied to arek's topic in Technical Topics
I have a bit of experience with ceramic coating parts. Coating the top of the piston is a good thing and it could reduce pinging if you have a hotspot developing on the piston causing the detonation. Did you coat just the piston crown or did you do the combustion chambers in the heads as well? I see you did the crowns and skirts. In my experience the crown coating will last a long time and the skirt coating will wear off. But they may have improved the skirt coatings since I used them last. Anodizing is a different can of worms entirely and has much less insulation value. Ceramic coating slows the transfer of heat into the part it is applied to. The part will still heat up but it takes longer and the final temp will be lower. If Hack does not see the benefit of a cooler piston in regard to detonation, well let's just say I am not surprised. ANYTHING you do that lowers the temp in the combustion chamber is likely to have a positive effect on detonation and performance. Good on you for doing what you did. -
You fuel tank is plastic/composite. It is not corrosion of the tank. It could be deposits out of the fuel. It could be water corroding the aluminum of the filler cap assy., but aluminum usually does not corrode like that. Normally once a surface layer of corrosion forms on a aluminum part that layer prevents further corrosion.
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Break away torque is a bad thing in steering heads or steering dampers on bikes. It is one of the ways a steering damper can fail, requiring more effort (torque) to begin to turn the forks then it requires to maintain them turning. It leads to weaving and bad handling. I know of no modern steering dampers that are friction based. Yes, they did it back in the before time but they don't do it any more because it is a bad idea. This does not mean the plain bearing idea is a bad idea, but I would rather have a higher quality tapered roller bearing. Plain bearing work well (but often not as well as quality roller bearings) because they use oil pressure to prevent contact between the two surfaces. Something like what Greybeard found would possibly work but I doubt it would work better then a quality tapered roller bearing. Plain bearings biggest advantages are cheap to make and install, quiet, and they last a decent amount of time. But as soon as they loose oil pressure bad things happen. Plain bearing materials that do not require oil pressure (oil impregnated, etc..) are not cheap. Cheaper is not better to me, only to bean counters.
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At first I thought you were looking for a touring bike to go long distances on in comfort. My favorite generic bike, the Honda ST1300 came to mind. Then I read further and you talk of cruisers. I don't do cruisers, too useless in my book, so never mind. The Buell is the only useful bike in that list to me. I have owned Buells and would buy one again in a heart beat. But it is not a typical high mileage touring bike. But it would be way more comfy then the others you listed.
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That was funny. The accident, on the other hand, was quite spectacular from what I was told. I was doing about 130 mph coming onto the front straight at Roebling Road when the back tire slide a bit then caught. That started a wobble that was completely out of control (in spite of the steering damper, they won't save you every time) and right after the bike left the track (I was no longer in control of where it was going) it slammed me into the ground seperating and destroying my shoulder then the two of us tumbled through the air ripping the front end of the bike off (breaking the forks) and by witness estimates the bike got about 25 ft into the air. People described seeing it above the tree tops with enough hang time that they were going "Hey, isn't that Scooters bike? Isn't Michael riding that this weekend?" while they bike was in the air. Unfortunately I don't think Hiaku's work unless you believe in them (much like demons) and I am a firm non-believer.
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Could be, but I have ridden TL1000Rs (and crumpled one of them up into a ball). They could be incredibly unstable in certain circumstances (like sticky tires and a race track). Turning up the steering damper wasn't going to make a difference. Even Computrack was only able to calm it down some but not enough. But the V-strom only shared the motor so it has little to do with the TLR. To this day TLRs make my shoulder hurt.
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Because my wifes V11 is one of the ones that does not have the triple clamps offset, which I consider to be a bad idea. So the fact that my wifes V11 is pre-offset clamp means that to me it is one of the good ones. Sorry if I was not clear.
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Sorry, your not getting it. You are correct, trail does not care where it came from. But if where it came from causes the amount of trail to change as forces act on the bike then that does matter. The problem is not with how you get the trail but how it changes as the suspension moves and the forks are turned. If part of your rake and trail comes from the fork tubes being offset at a 1 degree angle from the steering head (less steep), then you turn the forks 45 degrees to the right, you have now lost about 1/2 a degree (yes it is slightly less then 1/2 a degree, but this is just to give you an idea of what I mean) of virtual rake and gained a corresponding amount of trail since the front axle is now closer to the steering axis (which did not change when you turned the forks). And as you your self pointed out, when the forks compress on a bike with the angled clamps the trail will increase or decrease at a rate that is different then it would on a bike with normal clamps. Now, you could possibly use this to your advantage and make the bike more stable under braking or something like that, but it could also work against you if you don't consider all the ramifications of it when designing it. Motorcycle geometry is not a static thing, it is changing all the time as forces act on the motorcycle. Angling the fork tubes in the clamps changes the way the geometry of the bike changes as the forces act on it. This is not automatically a bad thing, but it can be if it causes the geometry to change in the wrong way at the wrong time. I am not saying you can't use offset clamps or that it won't work, only that I would prefer to make more common changes first to achieve the desired handling traits. Best of luck to you.
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Greg saying that he has seen the technical bulletin for a change to the triple clamps is enough evidence for me at the moment. If you need more that is fine, but him telling me he has seen it is enough for me. He has credibility in my book. Now, I would still like to see actual measurements showing the differences between the bikes. Are there changes to trail and wheelbase? I don't know but would like to find out.
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The steering head angle is the axis on which the forks rotate on. If you change the angle of the fork tubes without changing the steering head angle you can accomplish a few things but if you do it without changing wheel base then you have not accomplished much. The biggest issue with changing the angle of the tubes is as you turn the forks the difference in the two angles (the steering axis and the forks) changes the front geometry. When the forks are pointed straight ahead the two numbers add directly together (or subtract). But as you turn the forks the steering axis is still inline with the bike but the angle that the fork tubes are at isn't. It is hard to say what Guzzi accomplished without knowing how it effected wheelbase and trail. It would have made more sense to me to just change the offset and add a little more trail while dropping the front to weight the front wheel better if there was a problem with stability. But what ever. Hope this made sense. I'm better at talking then typing.
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Speaking only for my self, I consider it "proven" now. Thanks Greg for that info. I'm not good with belief in things I can't see, taste, smell, or touch, anyway. I'm a non-believer kind of guy.
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Uh...I was one of the first (the first I believe) to point out that changing the fork tube angle is not the same as changing the rake. And I do not think it is a good idea to do it in either direction. As far as Gregs claims I simply have no reason to doubt him but I have repeatedly pointed out that if Guzzi did do that it would not be the first or last dumb thing Guzzi has done (hydro valves?). And lowering the front can increase stability as long as you don't go too far and lose too much trail, but I believe you are wrong in that it has a smaller effect on weight distribution then it does on trail. As I said before, trail is a funny thing. You can take it away little by little with out much effect on stability until you get to the point where you now do not have enough trail and then it makes a big difference quite quickly. I have done it (dropped the front), along with jacking up the rear end as well. It can be a good thing in the right situation but it does have its down sides, especially if you go to far. But I don't need to do that to my V11 as it works perfectly fine the way it is. By the way, you do realize that you can accomplish much the same results by adjusting your sags front and rear to give a better balance to the bike with out physically dropping the front end?It is more a mental thing for some to be able to see the change they made so they can feel the improvements, but the bike does not care how you accomplished the ride height change, only that you did. And honestly, my V11 does not need a steering damper and it does not have one. I seem to have it set up quite well based on my own knowledge of geometry. If you choose another way to go that is fine and I wish you success, but for me my way works fine. Hope this clears up any confusion.
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It is a matter of opinion. And honestly, if you have screwed the pooch and made an error so bad that you are no longer in control of the situation and you are depending on the steering damper to save you, not only is that wrong to begin with but the steering damper may not save you anyway. The question is, is a steering damper worth the trade off. The answer to that question is not the same for everyone. It may be worth it to you but on a bike as stable as my V11 I would rather have the lighter, quicker steering and better feedback I get with out the damper. If you or any one else feels like they need a damper for any reason then run one. But please don't tell me that I need one because you do.
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You are right, luhbo, in that if they kept the same wheelbase and trail that raking the fork tubes would not help the stability of the V11 much if any. It does add a variable in that as the forks are turned from straight ahead the geometry would change from what it would be with normal forks. I see little to be gained and potential to make things worse. But I was stunned when Guzzi spent lots of money developing Hydro valves for bikes with valves that are incredibly easy to adjust, and then they did a poor job of it and screwed the pooch on that one. But all that aside, the fact remains that production bikes can easily be built with offset clamps or whatever you want to call it. And while I would agree that it is not a true definition of rake as I said earlier that is why they usually describe it as one plus the other equals a total of. If you choose not to believe Greg that is your choice, but none of your arguments to disprove him have panned out so it really just comes down to believing someone or not. That's your choice but it does not make a compelling argument. Sorry if this seems argumentative.
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Wow, thanks Hatchet Wack. That was actually a constructive post with real information. There is no reason you can't build a production bike with raked (either in or out) triple clamps by the thousands. Harley I believe does it. It is no harder then building a bike with "standard" triple clamps. Mind you, I see little value in doing so, particularly if you are not building a chopper. It is not likely to improve a bike like a Guzzi. There are things that would improve a bikes stability much more then this if it needed the help. This does not mean I do not believe Guzzi did it, they have done dumber things like the hydro valve idea. I have no reason to doubt Greg in his claim that they did this and until someone actually measures some bikes to prove one way or the other I will go with what Greg said. But I do think it was a stupid idea. Oh, and by the way. Funny thing about the effect of trail on a bike. As long as you have enough trail adding or subtracting trail make little impact on stability until you get below the threshold value where you no longer have enough. So changing the front end like dropping the front to steepen the rake (and decrease the trail) does not automatically make the bike less stable or more stable. Until you cross that threshold where you no longer have enough trail you may likely see an increase in stability due to the other effects of the action like putting more weight on the front and lowering the front ride height. This is not to say that changing trail does not effect other aspects of the bikes handling. Stability is only one thing that trail has a strong influence on. It also effects steering weight and feedback. Too much trail can be a bad thing just as too little is. It is all about finding a balance.
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Picture the front wheel and axle staying exactly where it is (since I don't yet have anyone saying they changed the wheelbase as well) and the fork tubes get rotatedback just a little so they are at a 1/2 degree shallower rake (that is a small amount). This would move the holes in the triple clamps back a little bit (the top would move more then the lowers) and would put the bores of the holes a little off perpendicular to the clamps. No shims or changes in trail required. Hope that helps.