BUILDING AN I.C.B.M. KATANA 1100

[scotty]

we are all waiting Mark.
Kat i am exited about your bike too. I know i will need you for the swing arm mod when i get my toy back.
AIt is good that you and others also post some of the results because it tells the rest of us many things and also what we may expect with majir mods.

[katman]

the handling improvment is fantastic over stock. I am diving into the bandit swingarm install. It is all measured and fitted. The brake peddle pivot arm is reworked and all I need now is shock mounts which it will be going into my welders this week for. I may or maynot under brace it now but maybe later.

performance wise I am still tuning. With 700km on it I am into the mainjets now and they are lacking. I have some 135's and 140's coming cause the 130's wont feed her over 7000 @ full throttle. I am just enjoying the riding for a while and putting some miles on. 1/4 to 1/2 throttle is very quick and no problems.She cruses at 170kmh nicely very stable on the highway...like a rock...

I can get her healed wayyy over in courners so clearance hasn't been a porblem and I gave her a little blip @ 3500k in first and she stood up and said hi.

I am verrrrry happy with the suspension mods and as soon as I sort out the tuning....welll.......what can I say...it has all been worth it. I found a set of polished 93 rims that I have put on and I think they look even better than the blue ones.

As I was sitting on the garage floor looking at my creation....I had a thought.....don't be surprised if next year you see a new pic with an under seat exhaust????

[Anonymous]

Nice job

Nice job Katman. The bike looks very well thought out and your finish work is A plus. It is my opinion from looking at the pictures that the bike would benefit from increased rear ride height and more swing arm droop. Once you get used to riding it, see how well it finishes the turn, especially with the gas on. If it tends to run wide, and I suspect it will, you should consider more swing arm droop. This can be accomplished by adding shock length and or repositioning the shock mounts. you will not believe how much better the bike will steer. Look at the pics of the Yoshimura Superbikes from the early eighties. They did this for a reason. Steve

[Hoomgar]

SO your thinking about installing a seat heater huh?

That would look awesome

[katman]

Re: Nice job

Nice job Katman. The bike looks very well thought out and your finish work is A plus. It is my opinion from looking at the pictures that the bike would benefit from increased rear ride height and more swing arm droop. Once you get used to riding it, see how well it finishes the turn, especially with the gas on. If it tends to run wide, and I suspect it will, you should consider more swing arm droop. This can be accomplished by adding shock length and or repositioning the shock mounts. you will not believe how much better the bike will steer. Look at the pics of the Yoshimura Superbikes from the early eighties. They did this for a reason. Steve

That is being done as we speak. I just finished locating the shock mounts on my bandit arm and raising the rear about two inches. that is my limit as the chain will be eating the pivot if it goes any higher.

[Anonymous]

rear ride height

You are going to love what that does for your handling. I am very impressed with the bike. You should be proud of yourself, you did a really nice job. Steve PS I would be interested in hearing your comments with respect to the rear ride height changes once you get a chance to feel it out.

[RacingJake]

Those mono-shock swingarms are about 5 times the weight of a GS swingarm. I don't think you'll need under bracing unless your going for a certain look.

[Anonymous]

Sawing on swing arm.

Just read your post on the limits of rear ride height being the chainline intersecting with the nose of the swingarm. That is the practical limitation on the amount of swingarm droop that can be obtained on these older bikes . Often the handling would continue to benefit with even more swingarm angle but it just isn't physically possible. you can sometimes by additional clearance by using the largest countershaft sprocket that is posssible and then running the largest rear sprocket that makes sense in terms of your gearing rquirements. Generally, most bikes optimise at about 12.5 degrees of swingarm droop from horizontal when both front and rear suspensions are topped and both tires barely touching the ground. I measure fom the ground to the center of the swingarm pivot and the ground to the center of the rear axel and the length of the swingarm from pivot to real axel. Then I divide by ten(to keep the size reasonable) and plot it out on paper to scale and measure the angles with a protractor. The ground must be level and the bike must be raised enough so the suspension is topped out but the tires are touching. I use an under the frame stand, properly adjusted for height and a floor jack to raise the bike. 12.5 is the most common sweetspot, but difficult to acheive on the older bikes. Each bike is different but this is a goood place to shoot for. Most bikes are far from optimum in stock form even the modern ones. This is more of an issue with high powered bikes with lots of traction. your bike qualifies on both counts. One last comment, lowering the front of a bike reduces swing arm droop. This means lowering the front improves corner entry because of the reduction in rake and trail but hurts the ability to finish off the turn because the reduction in droop results in an unloading of the front under power. Steve

[katman]

Thanks Steve for the Tech info.

I am running the largest cogs I can. 17t front 47t rear. Whith the new running gear the rake and trail on thiis old beast has been dramatically changed already.
Handling has dramatically improved over stock as it is but I will run your numbers.....It can never handle too good so optimizing is in the plan. I am still sorting out the tuning then I will move onto handling.

I agree the bandit arm is far more arm then stock but the frame on a whole is weaker than new bikes and many still run bracing. I have braced the frame too but would like to reduce flex as much as possible and since the arm is off and at the welder, it is only a few more bucks to get it done now and no down time.....So that is my theory on that.

[Anonymous]

suspension

Your very welcome Katman. Feel free to vary from my sugestions as they are more recomended starting points than one of the ten comandments, but I believe you will find them close and the results worth the effort. You have done an amazing job on that bike and have made an effort to cover all the bases. It gives one a real sense of accomplishment when you are able to make real improvements on a product that in its own right was quite a technilogical step forward. Im sure if you were to ride a stocker and your project back to back you would be speechless. Please keep us updated on how things work out. How is the weather up there these days?Went to a local bike hangout yesterday and there were about thirty bikes there. I left mine at home but hope to get a bike out next weekend, weather permiting. Steve

[Anonymous]

Re: Sawing on swing arm.

Just read your post on the limits of rear ride height being the chainline intersecting with the nose of the swingarm. That is the practical limitation on the amount of swingarm droop that can be obtained on these older bikes . Often the handling would continue to benefit with even more swingarm angle but it just isn't physically possible. you can sometimes by additional clearance by using the largest countershaft sprocket that is posssible and then running the largest rear sprocket that makes sense in terms of your gearing rquirements. Generally, most bikes optimise at about 12.5 degrees of swingarm droop from horizontal when both front and rear suspensions are topped and both tires barely touching the ground. I measure fom the ground to the center of the swingarm pivot and the ground to the center of the rear axel and the length of the swingarm from pivot to real axel. Then I divide by ten(to keep the size reasonable) and plot it out on paper to scale and measure the angles with a protractor. The ground must be level and the bike must be raised enough so the suspension is topped out but the tires are touching. I use an under the frame stand, properly adjusted for height and a floor jack to raise the bike. 12.5 is the most common sweetspot, but difficult to acheive on the older bikes. Each bike is different but this is a goood place to shoot for. Most bikes are far from optimum in stock form even the modern ones. This is more of an issue with high powered bikes with lots of traction. your bike qualifies on both counts. One last comment, lowering the front of a bike reduces swing arm droop. This means lowering the front improves corner entry because of the reduction in rake and trail but hurts the ability to finish off the turn because the reduction in droop results in an unloading of the front under power. Steve

You can make it a lot easier on yourself by using some trig.

Subtract the rear axle center distance to ground from the swingarm pivot distance to ground, then divide by the distance from the swingarm pivot to the rear axle center. This is the cosine. Use a calculator or table to look up the associated angle.

You posted some good info BTW. I checked my swingarm drop on the project bike and it's at 9 degrees right now. In order to get the 12.5 degrees that you stated as optimum I need to add around another 1.25".

Once I get the front raised a bit more, I'll look into just that. I'm using a 2002 GSXR750 swingarm and it's easy to adjust the ride height using spacers. I'll have to look at the chain clearance real close.

[Anonymous]

droop

Hi Sammy. Just make sure the suspension angle is topped out front and rear, with the tires both just skimming the surface. You can not check this measurement with the bike sitting on its suspension or you will get a false reading. Also be aware that if you raise the fork tubes which lowers the front end of the bike you reduce swing arm droop. It is generally recomended that you get the rear sorted out first and then do fine tuning on the front. Raisng the rear really helps the bike finish off the corner, while it can also help on entry. Dropping the front seems to help more on entry but can can make corner exits worse. If you go too far on rear ride height, the bike will sometimes want to spin the rear tire on exits if you really drive it off the turn. This tendency can be reduced by running between a quarter and a half inch more total sag in the rear as an alternative to reducing swing arm droop. Many of these adjustments are simple on the modern bikes as their suspensions are so adjustable but sometimes mean a change in parts on the two shock set ups. I recomend that anyone who is running lots of rear ride height have a steering damper. The bike should handle fine without it, but you should still have one just in case as your trail figure is going to get pretty short with tons of rear ride height. The bikes I have built with these figures have handled really fantastic, like night and day from original, you can start dialing in throttle so early in the turn you wont believe it. Steve

[Anonymous]

bike attitude

One last comment about ride heights. I have found that a bike with too little rear ride height will leave a wider chicken strip on the front tire than the rear. If, for example you have a chicken strip that is a half inch wide in the front and a quarter inch or less in the back that is a sure sign that you need more ride height in the rear or less ride height in the front. Which you chose to move depends on a whole slew of variables and should be decided on a case by case basis.

[katman]

Re: suspension

Your very welcome Katman. Feel free to vary from my sugestions as they are more recomended starting points than one of the ten comandments, but I believe you will find them close and the results worth the effort. You have done an amazing job on that bike and have made an effort to cover all the bases. It gives one a real sense of accomplishment when you are able to make real improvements on a product that in its own right was quite a technilogical step forward. Im sure if you were to ride a stocker and your project back to back you would be speechless. Please keep us updated on how things work out. How is the weather up there these days?Went to a local bike hangout yesterday and there were about thirty bikes there. I left mine at home but hope to get a bike out next weekend, weather permiting. Steve

Thanks dude for your kind words. Weather here is very nice last week was sunny and in the 60's. This week the low 50's and rain. Next week we should be back to normal. It's a good week for pulling things apart.

[katman]

Do either of you dudes have the stock numbers for a gs or a kat? Just to get a base ine.