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quote:Originally posted by T8erbug

I guess I just assumed most bikes' handling is enhanced by a nice little lowering job.. Center of gravity being lower and all that jazz. Thanks for the props though! You have any pics of your tank?
That is a flawed assumption. A motorcycle does not have a static CG like a car. Lowering the bike will ruin it handling. changing the rake, trail, dampning, tire size will all effect the handling. Guess what - wide tires make an old bike handle worse.
 

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Discussion Starter #22
Absolutely right but your side to side movement is quicker when lowered which reduces the time you go from one knee to the other. The wide tire stuff is good to know! Have you experienced this first hand? I was actually thinking about going wider thinking it would get me that much closer to sport bike handling so maybe it's a good thing I haven't! Can you tell me why handling is worse with a wider tire? Thanks for the voice guys! All your input is a HUGE help and It's exactly why I joined the forum.
 

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Wide tire is slower to turn in and slower to change direction because it is wider, you have longer to travel over the tire to get to the right lean angle.

Don't confuse lowered seat height with lower overall. Lower overall = less ground clearance and less lean angle, lower rider = better flickability
 

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Discussion Starter #25
The tail is high to raise the seat. If the rider were too low they would not be able to reach their maximum lean angle. If you look at a motoGP bike you will see they try to keep any bulk/heavy items as low as possible. I guess It's easiest to imagine what I was saying as a lever. If you have a lever fixed on the bottom (point A) and you move it with your hand (Rider) from the top of the lever (point B) it is like the front view of a motorcycle (tire to ground is point A, top of the bike is point B). Then take a 5lb weight put it between point A and B. The closer it is to point A the easier it will become to swing it back and forth. The same goes on a bike. If the engine were slung higher on the bike or the frame in general were higher it would be like moving the 5lb weight closer the point B. The rider would have to exert more energy/take more time to move the bike from lean right to lean left and vice versa. I'm not the best at explaining myself but I hope you get what I mean
 

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Discussion Starter #26
I guess the main thing is moderation. Too low is no good for obvious reasons. Rider up too high is no good for obvious reasons. I'd say the best handling would be achieved when you find the best of both those worlds without scraping the ground :)
 

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I used to have one of these, now I'm looking for another one. Just so you know, that brace you cut off the rear of the frame is needed. The ass end is all noodley without it so put another one on. Lowering this bike is no good, longer rear shocks helped mine tons and I still occasionally scraped. Get a Vance & Hines 4-1 exhaust for it, sounds great and gives noticeable performance when tuned right, I had k&n filters with proper jetting and had the carbs dyno synced. If you find wheels/hubs from the 77 you can lace up some alloy rims for a better wheelset.
 

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And grab an alloy swingarm off a GS1100 so you can run a wider rear wheel. You will be able to get a 180 tyre into an 1100 swingarm on a 5 inch rim (it's tight, but it's do-able).
 

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Discussion Starter #29
quote:Originally posted by hillsy

And grab an alloy swingarm off a GS1100 so you can run a wider rear wheel. You will be able to get a 180 tyre into an 1100 swingarm on a 5 inch rim (it's tight, but it's do-able).
I have heard that. I don't know if I am going to go as wide as 180 but I hear the alloy swingarm improves handling a bit as well as allow a bigger tire. Is it a direct bolt on? Would I have to move my rear brake master cylinder to make all the gear clear with rearsets?? I know that's kind of an abstract question since neither of us knows what my rearsets are going to look like yet but give it your best guess. Thanks!
 

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Discussion Starter #30
quote:Originally posted by muskies666

I used to have one of these, now I'm looking for another one. Just so you know, that brace you cut off the rear of the frame is needed. The ass end is all noodley without it so put another one on. Lowering this bike is no good, longer rear shocks helped mine tons and I still occasionally scraped. Get a Vance & Hines 4-1 exhaust for it, sounds great and gives noticeable performance when tuned right, I had k&n filters with proper jetting and had the carbs dyno synced. If you find wheels/hubs from the 77 you can lace up some alloy rims for a better wheelset.

Thanks a bunch! I figured it would stiffen it up a bit. I was planning on round a piece of tube and just welding end to end to give it a finished look but my rear tire would rub it in a big bump so I am going to go up and over similar to the stock one so it's hidden from view. After that I will just have to come up with a clever way to finish the bar ends. Vance and Hines are my top pick if I buy some but I think I may just build my own. I do know that the headers on the bike have a pipe inside the pipe.. I want to just take out the inner pipe and see how it runs after I build a 4-1( and proper jetting). Know anyone who has hollowed stock headers out?? I want to find some wheels asap and was going to go the wire wheel route so I appreciate the advice! I just need the hubs right? Then I can buy some allow rims from there? I have look for rims and I think the best thing for the money I have found so far is a company called Sun Rims out in California (not the Sun Rims in Idaho).
 

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You will have to make a new rear brake caliper torque arm to fit the wider tyre, can't really answer your question about rearsets and MC placement.

If you can find a spoked wheel off the first model GS750, you will be able to lace up a new wider rim and you'll be most of the way there. Then you need an off-set front sprocket and I think you need to machine down the cush drive so the chainline clears the shock / frame

Forget about trying to take the inner pipes out of your stock headers. It would be less work to re-create a stock system with just the outer pipes. But I'd guess you would lose power anyway due to the larger diameter header pipes (unless you port the head, big valves, big bore, etc).
 

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Actually, if you get an early GS750 rear hub you'll need to offset the rear sprocket as well as the front to clear the new rim, not machine down the cush drive (I was thinking of slotting in a GSXR wheel).
 

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Discussion Starter #33
Yeah I'm going to be messing around with the brakes back there anyway. I was wanting to put a new caliper and disc on the rear. I will have to machine a custom bracket and do a few things about the caliper placement. I think I will make a new caliper torque arm and put it under the swingarm that way the caliper is pulling away from the torque arm instead of pushing on it under braking. Getting the chain aligned and clearing everything is going to be a blast haha. .
 

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If you are going with new wheels and new suspension front and rear, this is the time to make some smart choices, starting with rim sizes. I would personally go with 17" front and rear and run SV650 size tires that being a 120 front and a 160 rear. If you go with a more period look then I would go with an 18" front and rear and run a 110 front and a 150 or 160 rear. I would try to get the rear raised up 2" from stock and the front 1" but I don't know the length of the forks you are going to use compared to the stock units. That bike will need to have all the ground clearance it can get.

Ken
 

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Nice work so far on that tank. I wouldn't do that personally but you look like you are taking the time to get it right and that counts for something round here. Low center of gravity requires more lean angle for a given corner speed. High center of gravity requires less lean angle and has more clearance to achieve it.

Side to side flicks are not an issue on the street, but rake and trail are and so is clearance. Grab a copy of Tony Foale's book on the subject or John Robinson's book on M/C Chassis.
 

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Discussion Starter #36
quote:Originally posted by kenessex

If you are going with new wheels and new suspension front and rear, this is the time to make some smart choices, starting with rim sizes. I would personally go with 17" front and rear and run SV650 size tires that being a 120 front and a 160 rear. If you go with a more period look then I would go with an 18" front and rear and run a 110 front and a 150 or 160 rear. I would try to get the rear raised up 2" from stock and the front 1" but I don't know the length of the forks you are going to use compared to the stock units. That bike will need to have all the ground clearance it can get.

Ken
Thanks. As I get going on the suspension and wheels I realized I really can't do much until I have a solid plan and goals. My goal here though is to stay away from 17in wheels mainly for aesthetic purposes. The forks I bought will lower the front end 2-3 inches but on the plus side they are much stiffer and tuned a lot better for track riding. As for the rear I may have to higher it according to everyone here so it's a good thing you guys are giving me advice ha. I will probably get shocks that sit around stock position with a range of adjustability so I can tune it to what works best. The stock set up is definitely way too soft for me. I weigh 185 on a normal day and It had way too much droop with me on it.
 

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Discussion Starter #37
quote:Originally posted by Teazer

Nice work so far on that tank. I wouldn't do that personally but you look like you are taking the time to get it right and that counts for something round here. Low center of gravity requires more lean angle for a given corner speed. High center of gravity requires less lean angle and has more clearance to achieve it.

Side to side flicks are not an issue on the street, but rake and trail are and so is clearance. Grab a copy of Tony Foale's book on the subject or John Robinson's book on M/C Chassis.
As I get farther into the tank I have thought, "What the heck have I done?" but it stays along the lines of my plans and I want to stay committed so I don't end up with something totally different than what I had planned for in the end ha. I wanted a bigger tank yet I didn't want in to look bulky so this is the route I chose. Cross your fingers it comes out nice! Oh and I also looked up that book. It's EXPENSIVE! I couldn't find anything Tony Foale had written for less than $100 ha
 

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I am afraid I am getting mixed messages about your intent. Do you plan on this bike being set up for the track? Do you have any racing experience? You talk about performance choices, like wheels, better suspension and better brakes and at the same time you are talking about style choices that are counter productive like longer tank (will put too much weight on the rear), 18" wheels (17" gives a much better choice in rubber), lowering ( the early inline 4s need cornering clearance. 4-2 exhaust ( 4-1 is less weight, better performance and better clearance) and fork gaiters (trap moisture and are not necessary). So, what you are trying to end up with will determine which suggestions I will be able to give you.

Ken
 

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Discussion Starter #40
quote:Originally posted by kenessex

I am afraid I am getting mixed messages about your intent. Do you plan on this bike being set up for the track? Do you have any racing experience? You talk about performance choices, like wheels, better suspension and better brakes and at the same time you are talking about style choices that are counter productive like longer tank (will put too much weight on the rear), 18" wheels (17" gives a much better choice in rubber), lowering ( the early inline 4s need cornering clearance. 4-2 exhaust ( 4-1 is less weight, better performance and better clearance) and fork gaiters (trap moisture and are not necessary). So, what you are trying to end up with will determine which suggestions I will be able to give you.

Ken
I need to find a good balance of old and new. I want performance. I am slimming my tire options down by going up a size but I feel like good performance can still be achieved. I realize even at the end of the day this won't be able to outperform the street bikes of today but I want a quick bike that will handle on the track without feeling like I need to limit myself entirely because of it's age. Exhaust plan has been 4-1. I want to run the collector dead center under the bike and kink it out between the back of the frame and swingarm. Hopefully the only things getting close to hitting the ground are the crank covers:D In the end it's all for fun and if it can go fast through some turns I'm sure it will scratch my itch. What are your thoughts?
 
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