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Discussion Starter #1
There are alot of questions on engine mods for street cafe bikes,so this is what you need.
A good chassis........Thats what you need.Upgrade your tires ,shocks,rims,spokes,chain,fork oil fork springs,brake up- grades.Seat, tank(optional).


Lightening your bike take the stock seat and exhaust off, the second half of the rear fender, the big old lights ,remove heavey steel lower pegs,bob up your fenders(not much weight but they are very long and look better bobbed (shortened) on the er of some splash protection if possible or deflection of rocks in face or motor.

Now put all these parts on a scale ,throw in the ape hangers as well.and you will see just how much horse power you have gained POWER to weight is performance, less weight, is the key.

Now you will add a light solo seat ,lighter bars,rearsets,new tires are better then anything the racers had in the day,maybe get some alloy wheels to replace the stock steel rims(if wallet provides)

Bob the front fender add some light small turnsignals that are brighter then stock.A new chain.Maybe you can fit larger dual discs or large twin leading shoe brakes,fit new brake parts anyway with new better material.



Any and all engine mods will reduce streetability,increase stumbling stalling,hard starting.
If you have a strong responsive lighter then factory chassis,Tires that grip to turn and stop better then new,then you can use all of the stock motor which is more then capable to get you around allday everyday.
Most racing groups make you run stock motors, get it! They know there is a lot of performance in the motor when you have brakes wheels, tires and a frame,rid of stock heavy parts,so can use all of the motor has to offer.

Its very NEWBIE to start on the engine when a very experience builder knows the chassis is where you start.Speed money wisely you will have a faster, bike, maybe faster then you can handle, if you build a high performance chassis FIRST.

Your bike will be worth more safer faster and a hell of alot more fun then a motor that you thought you were getting a fraction of a horse power maybe,and loosing a lot of horse power somewhere else.

You just dont read or listen to someones engine mod and try it on your bike you may have heard half the story.

Any engine mod is tested on track or dyno,its time consuming,expensive and requires tools and talent to carry out with great success and you are gaining somewhere AND LOOSING somewhere else! On a street motor that can make you a very fustrated rider.

getting your chassis as light as possible and as performance upgrades in tires wheels exhaust ,light seat,bob fenders, cost little, work everyday allday,make your bike look killer and your able to start and ride all day long is a true performance bike.
STOP IT WITH EVEN THINKING of engine MODS
These motors arent new they have miles on them your mods should be getting it back to as stock as you can .Set points and timing ,adjust timing chain.Look to see if carbs are leaking gas or taking in air where they shouldnt.grease lube everything is your throttle smouth or does it hang up some where is your chain fresh and adjusted have you checked your tire pressure.
Change the oil like a mad man old motors like fresh oil.

BUILD A GREAT CHASSIS you will go fast...and get a few racing rider training books twist of the wrist one and two.Your mind is the other motor that needs work on to go fast. The engine is done leave it alone!




























Im so far behind ,that I think Im in first.

Edited by - LiLBull on Aug 25 2007 08:56:18 AM
 

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Ok, i did what you said and am now ready for engine mods. Here is my CB500T.






Edited by - jwood on Aug 25 2007 1:31:05 PM
 

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yo, dude, that picture is hilarious. where on earth did you get that from?

if at first you don't succeed, use a bigger hammer
 

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It's the Bombardier Embrio experimental prototype. Hydrogen powered and gyroscopicly balanced. A biker's answer to the Segway. Minimalist to the third power.

Cheers, Bret @ Glass from the Past
 

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Discussion Starter #5
gyroscopic is great ...I mean they have old people fly off segways like someone tripping seniors in a fire drill.
I think current Pres Bush fell off one and the british guy that judges on "america's got talent" .I think he cracked a rib,segwaying off his segway.

But that bike will be good for pizza deliver,and the hot dog beer guy at the stadium.Or for a quick run for some boob scotchhhhh!

Im so far behind ,that I think Im in first.
 

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Bull you left out the most important point: chassis mods are usually cheaper than engine mods. They also do the most in improving ride quality, which includes handling. Most of these bikes are 30 years old now and a lot are still running the original shocks. No shock absorber lasts 30 years, and espically not those fish oil fuckers that the factory put on. Even new stock shocks can often improve the way a bike rides.

A couple things to think about:

Dual discs are not an "automatic" thing, like to improve your breaking you should always put them on. Even if your brakes are shitty in the stock form, the less weight they have to slow the better they get. Dual discs are also very heavy, and in some cases even more than drums they sometimes replace, just because a setup looks light doesn't mean that it is. sure it is unsprung mass but it is reciprocating mass which can have an effect on your acceleration.

A true cafe racer is not a "Style" bike. It should be a racebike for the street. Everything on your bike should have a functional purpose. Form follows second. That doesn't mean you shouldn't think about how a bike will look and you can get creative for a lot of things. The best example of this I can think of is the Knee indentations everybody is so fond of trying to knock into their cb750 tanks. I am willing to say that a majority of the time knee cutouts, indents, etc have no business on a stock tank. Sure they "look cool" but usually they do more harm than good in the sense that they reduce your fuel capacity, and depending on how they were done compromise the ability of your tank to withstand a crash. You want knee cutouts? give yourself a reason to have them. Get a bigger tank, or set your bike up with rearsets and low bars so you tuck as close as possible to the body.
 

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Yup, chassis first. There is a surprising amount of potential for good handling in most old standard bikes. That includes UJMs. All I had to do to get good handling from the UJMs I've owned (CB500, XS650, TX500) is:

1. Put on good shocks (a little taller than stock)
2. Preload the fork springs to increase spring rate (and experiment with different weights of fork oil to improve the damping).
3. Replace the swingarm bushings and steering head bearings.
4. Install decent tires.
5. Remove excess weight.
6. Slide the forks up the triple clamps about an 3/4" to lower the front.
7. Put on a fork brace.

Suddenly, my UJMs handled like a T100R.
 

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so don't the old fenders like the ones on the cb350/450's act as a fork brace as well as a fender. this is something iv'e been wondering.

...connoisseur of slack...
 

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and one more thing....

There are other colors in the universe beside black. Not every bike looks good in black and some look downright awful. Some bikes despite looking good in black look even better in other colors like vincents for instance:

Factory Chinese Red (on export models, there is an even rarer “Egyptian Blue” on rapides that I couldn't find a picture of)



and BMWs:

Granada red R60/2, Dominican blue R50/2, Standard black R60/2


Grey


Dover White


and cafe's

British Racing Green:


silver:


so get creative.
 

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quote:
so don't the old fenders like the ones on the cb350/450's act as a fork brace as well as a fender. this is something iv'e been wondering.

...connoisseur of slack...
yes on almost all of the UJMs out there the front fender acts as a fork brace. With some of the lighter bikes it really isn't a problem unless you are pushing it hard, on the heavier bikes like the cb750 simple distortions on highway roads can lead to ill handeling and all sorts of scary front end flex.
 

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Discussion Starter #12
I agree top brace in old fenders but bobbing them shortening them still leaves the brace installed.
I do like the vintage unicycle over the segway cycle but again thats just me.
But common thread will be chassis first leave engine alone.And years before water was invented,back when you had to stir a telephone dial to call someone on the phone.
I wanted to boost the engine first too ,so I understand ,I used to be very fustrated with racing because they didnt let you do any or many engine mods.
But once you understand tire will grip more push more slide less ,turn in faster .shocks will keep all this together and a firm chassis /frame will help put all this to the pavement it takes years to realize the engine is the last thing to by uprated .
And style just so happens to be the first mod anyone chooses.Its natural to make something you purchased yours.In the easiest ,least expensive way you can, its natural ,human nature so style is a first gut reaction.
It takes a lot of study to come up with real solutions in performance its a journey.Most who have takin the journey soon forget the long and twisted trail it was to become knowledgeable.
But looks for me was what attracted me to a Ford gt 40 or a Lamborghini Muira before I knew what a spark plug was.


Im so far behind ,that I think Im in first.
 

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I must disagree with you Geeto. Red is not the color for a Vincent. BRG, maybe. Vincents look less than the sum of their parts in red. Shows off too many separate components. Black may be a cliche, but when it comes to Vincents, it makes the bike hunker together like one solid unit.
 

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quote:
I must disagree with you Geeto. Red is not the color for a Vincent. BRG, maybe. Vincents look less than the sum of their parts in red. Shows off too many separate components. Black may be a cliche, but when it comes to Vincents, it makes the bike hunker together like one solid unit.
Egyptian Blue really should be the color of the vincents but it is so rare few have ever seen one. The egyptian blue example I saw years ago was a dark "dress" blue that really made the bike pop. There was a black vincent rapide C next to it and the bike looked just plain jane next to it. The original New York Bike show vincent was an egyptian blue tank on a black frame with chrome fenders. I have seen one picture of that bike and I have to say, despite the fading of the color photo the bike was striking.

There have been document examples of black vincents with chinese red wheels and fenders and those bikes really look amazing.
 
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