Joseph Posted January 13, 2021 Posted January 13, 2021 (edited) Hello I've got my Katana R tuner bike out cause I need to give the W a rest Specs : 91 chassis 11R K7 fork and wheels Ohlins shock at 11R spec 89 11R swingarm This is give or take, the same spec as my 7W : K7 forks and wheels and a nitron shock the correct length. I know they are not the same bikes, but, the chassis are both however very similar in set up and dimensions, there are not major differences However sitting on the 7, my legs are flexed, feet flat on the ground Sitting on the 11, my legs are totally straight if i put my feet flat Riding the 11, it feels very very shaky when cornering, it really does not feel safe to turn in nicely, as if the rear end was much too high maybe ? Not that i have major knowledge of riding dynamics Is the swingarm linkage at fault ? I need to measure seat heights, maybe all this is looking at the wrong points but something feels off Edited January 13, 2021 by Joseph Quote
Dezza Posted January 13, 2021 Posted January 13, 2021 The use of the word "Katana" here is really confusing. Do you have a 91 GSXR1100 M frame, with 1000 K7 forks and a GSXR 1100 K swingarm? First, I would check the basics, especially from the symptoms described. Are the headraces correctly adjusted? Is there play in the swingarm pivot? Are the tyres at the correct pressure and are the wheels centred correctly and in line? Is everything tightened up as it should be? Is the frame straight? Check all the obvious first, then go from there. Quote
bluedog59 Posted January 13, 2021 Posted January 13, 2021 Is that swingarm longer than standard and do you have any "static sag" ? Quote
Joseph Posted January 13, 2021 Author Posted January 13, 2021 No its the shortest 11 swingarm. Not sure what you mean by static sag though Quote
mikeyd Posted January 13, 2021 Posted January 13, 2021 When you sit on the bike (feet on pegs, so get a buddy to hold the bike up) you should have between a 1/2" to 1" of suspension sag on the rear. And for the love of God, Adjust that chain dude! 2 Quote
Wee Man Posted January 13, 2021 Posted January 13, 2021 Here's how to setup a bike:- https://www.visordown.com/features/guides/how-set-your-bikes-suspension Quote
Joseph Posted January 13, 2021 Author Posted January 13, 2021 33 minutes ago, TonyGee said: why is that bike called a katana ? Because : A- the katana is just a dress up kit on a pre existing bike B- more importantly, i built it so i can call it whatever i see fit On a technical note, i put new bearings all over, and i think i did the stem setting properly However now you have got me doubting about the wheel layout Chain has been done, there wasn't even the seat on that picture Quote
TonyGee Posted January 13, 2021 Posted January 13, 2021 2 minutes ago, Joseph said: Because : A- the katana is just a dress up kit on a pre existing bike B- more importantly, i built it so i can call it whatever i see fit On a technical note, i put new bearings all over, and i think i did the stem setting properly However now you have got me doubting about the wheel layout Chain has been done, there wasn't even the seat on that picture fair enough Quote
Joseph Posted January 13, 2021 Author Posted January 13, 2021 Just a bit of fun, what bikes should be 1 Quote
colinworth79 Posted January 13, 2021 Posted January 13, 2021 For handling I would stick a 750 L or M ( depends which rocker you have ) swingarm in . The forks are going to be soft as oil cooled bikes are a lot heavier . I hope the clip ons are not above the the top yoke as those forks are shorter than the 1100 ones. Quote
Joseph Posted January 13, 2021 Author Posted January 13, 2021 Hi. The Spring rates between K and oil bikes are pretty much the same from what i researched I used LSL risers for the clip ons so that they clear the home made fairing Quote
Oilyspanner Posted January 14, 2021 Posted January 14, 2021 The angle of your swingarm looks greater than mine. I've got an 1100N, with gsxr750 k9 forks, 750L2 wheels and a Nitron race shock - I kept the std swingarm and linkage, so a few similar things. I've 12mm of static sag on the rear - the amount the shock compresses due to the bike's weight, if you have next to no static sag, ie the shock is near topped out all the time. Lift the rear of the bike at rest and there should be some movement until the shock is topped out. The shock has a 475lb spring on it now, the 500lb/inch spring only worked when I was really tramping on. The forks still have the std springs in them and have 30mm of sag, I think the 750k7 had .95kg springs in them, the 1100's were around .75kg, so plenty firm enough. My bike is 96lb lighter than it was and handles really well, feedback is great front and rear, they can handle really well. I expect it's just in the set-up Quote
Joseph Posted January 14, 2021 Author Posted January 14, 2021 It does indeed when compared to others I did have the shock rebuilt by the Ohlins affiliated specialist here. Maybe something in its set up has modified something ? But that said, is not swingarm angle down to static shock (spring) length coupled to the linkage length ? Pff this is no good, its definitely not the type of technical challenge my brain is wired for Quote
Joseph Posted January 14, 2021 Author Posted January 14, 2021 If anyone has one also, i have an angle finder I can verify the static angle if my bike as reference Quote
bluedog59 Posted January 14, 2021 Posted January 14, 2021 "Static sag" is the amount the suspension compresses under the weight of the motorcycle itself. "Dynamic/Rider sag is the amount the suspension compresses with the rider seated in the normal position. I'll let others with similar "Katanas" give you figures based on experience rather than theory because real life conditions have an influence. The key point is that you are looking for the suspension to be working in the mid area of its stroke in normal conditions, not starting at one extreme and moving towards the other. Swingarm angle is normally between 5-10 degrees unladen and just below horizontal with the rider aboard. Do not set your sag with the bike on a paddock stand ! It will affect your figures. Looking at your picture I would check your preload and shock length because the "ride height" look very high. Quote
Captain Chaos Posted January 14, 2021 Posted January 14, 2021 (edited) . @Josephwill understand Edited January 15, 2021 by Captain Chaos 1 Quote
Askamaskinservice Posted January 14, 2021 Posted January 14, 2021 What could possibly go wrong...... is that what you are implying, Joris. Quote
Captain Chaos Posted January 14, 2021 Posted January 14, 2021 translation of the last pic: "if you don't understand, don't fuck with it" 6 Quote
bluedog59 Posted January 15, 2021 Posted January 15, 2021 23 hours ago, Captain Chaos said: translation of the last pic: "if you don't understand, don't fuck with it" That would wipe out a big percentage of modified bike builds in an instant. Most of the collective knowledge of mankind has been gained by "fucking about" with things we don't understand. It's called "learning" for those that do it. 3 Quote
Hanma-shin Posted January 15, 2021 Posted January 15, 2021 There’s a difference between experimenting and fucking about. 2 Quote
Hanma-shin Posted January 15, 2021 Posted January 15, 2021 Sometimes get lucky and have great success with fucking about, sometimes death. 1 Quote
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