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I know nothing
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Discussion Starter · #1 ·
This is probably a stupid question. I've heard of a few ways to increase rake without cutting the frame, but does any one have any ideas for a no-cut solution to decrease rake?

My bike has 30° rake, but I'd like it closer to 25° to shorten the wheelbase and bring the front end up a bit (I plan on raising th rear also, but that's a bit easier).

Cutting is an option, just looking for different ideas.
 

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V-4 for 4 life
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dont know but i would think trying to do this especially on aluminum will be a bad idea i think
i would probably say try to find some forks that fit and slightly raise them in the clamps for the desired wheelbase but will not fix the rake just lower the bike

other option would be to try and build a frame
 

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GURU of da poo poo
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5,717 Posts
different offset in the trips? that would change trail but not rake...
 

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I know nothing
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Discussion Starter · #4 ·
Building a frame is the long-term goal, more like a pipe dream at the moment though (materials are cheap, tools ... not so much). That's why I'm looking for a no-cut option. Something to test out ideas on by getting the stock frame as close as possible to the one I'd like.

It's a steel frame, and plenty of people have cut them to increase the rake.
 

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Newbie
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334 Posts
Yike man 5 degrees is a LOT.

What frame is this?

I mean in the racing world you can get adjustable clamps, but they are usually at most 3 degrees, likewise significantly shortening the dog bone if you have a mono-shock will have the same effect.
 

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GURU
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8,827 Posts
that is a lot and my inclination is that your bike will handle bad. You can have custom triples made where the bore for the fork(offset from top to bottom) is different. They do this a lot on choppers in the other direction to get more rake. Lowering your front end in the clamps and raising the rear is probably the easiest way but getting 5 degrees will be tough.

What bike are we dealing with here? Once you start raising the rear you change your weight transfer and also your chain pull, the progressive nature of your shock setup and so on.
 

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I know nothing
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Discussion Starter · #7 · (Edited)
I did a little more reading and the rake is 29° not 30° with 5.24" Trail, and I'm still trying to work out how much Trail I'd lose decreasing the Rake.

Tripped, I've got a mono-shock. It's an '83 Yamaha XV750MK. Not a sport bike of any sort, just an old standard.

Shift, my objective it to raise both the front and rear to increase ground clearance, and seat height (not that it'll matter much with a custom subframe).
 

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GURU
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8,827 Posts
well if you raise the front and rear you wont be changing your rake at all but you will be changing your swingarm angle which will have an affect on handling. Its a bit different when you are dealing with shaft drive though on that old midnight special. Which is another point. you can only do so much with a shaft drive in terms of swingarm angle. Also if i remember right that bike has a mono shock but no linkage, its a direct connection from the frame to the swingarm.
 

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I know nothing
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Discussion Starter · #9 ·
Raising them both is to increase ground clearance, not decrease the Rake. To decrease the Rake I'm looking for options dealing with fork, steering neck, and triples to decrease it.

I'm sure that everything I'd like to do will effect the handling of the bike, which is why I'm trying to use the stock frame as an imperfect test bed before I go out and make a custom frame (the only way to get what I really have floating about in my head).

It is a direct connection from the frame to the swing arm, but that connection can be modified. Ain't that this is all about?
 

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Newbie
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51 Posts
Wouldn't custom triples be about the same cost to have your steering neck cut off and re-welded to the proper angle? I'm sure you can find a competent welder. That strikes me as the proper, but relatively permanent, way to do it, but I'm a noob. That said, if racers us triples offset @ 3 degrees on their steeply raked bikes, I can't see the problem with 5 degrees on your bike. It would be custom($$$), of course.
 

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Build It Ride It Live It
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10,684 Posts
Chopping the neck and using the same triples could put the bike into negative trail. Which in that case, is going to be very dangerous. You really need to figure out the math on this one.

Measure up your bike and plot the numbers in here. http://www.rbracing-rsr.com/advchoppercalc.html

Idealy you want your rake to be no less the 3.75" at full bump. Even that is pretty short for most Superbikes. Practical for your bike I would sugest staying closer if not above 4" in trail.

Even if you were to cut the neck, you would still probably need new trees as well, cause now you've dramaticly changed the rake and the offset of the stock clamps probably won't work well with the new head angle. There is now quick fix for this kind of stuff. Even those stupid raked chopper trees that were real big once upon a time are dangerous stuff. They make the trail very short and now with a longer lower bike you get a twitchy frontend.

Even lowereing the front end can make that bike act wierd. I droped the forks on My Maxim 1" and now the front wheel has a little bobble over hard bumps. And that's with a 5" drop in the rear end as well. The rake on that bike is the same as the Virago. You really have to weigh all the factors when doing stuff like this so it doesn't get you eating pavment.
 

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GURU
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8,827 Posts
Chopping the neck and using the same triples could put the bike into negative trail. Which in that case, is going to be very dangerous. You really need to figure out the math on this one.

Measure up your bike and plot the numbers in here. http://www.rbracing-rsr.com/advchoppercalc.html

Idealy you want your rake to be no less the 3.75" at full bump. Even that is pretty short for most Superbikes. Practical for your bike I would sugest staying closer if not above 4" in trail.

Even if you were to cut the neck, you would still probably need new trees as well, cause now you've dramaticly changed the rake and the offset of the stock clamps probably won't work well with the new head angle. There is now quick fix for this kind of stuff. Even those stupid raked chopper trees that were real big once upon a time are dangerous stuff. They make the trail very short and now with a longer lower bike you get a twitchy frontend.

Even lowereing the front end can make that bike act wierd. I droped the forks on My Maxim 1" and now the front wheel has a little bobble over hard bumps. And that's with a 5" drop in the rear end as well. The rake on that bike is the same as the Virago. You really have to weigh all the factors when doing stuff like this so it doesn't get you eating pavment.

i run 3" trail at ride height:LolLolLolLol: I dont think negative trail would be a concern. As long as the stock triples werent raked(at 5" i doubt it) it would be a while before he would drop into an area of concern. Without air support in the forks you could have ground clearance issues on those things stock. My concern is dropping the front at all to decrease the rake will cause issues with this. If you want to raise it then you will be hard pressed to decrease the rake(on the cheap). The only way to do it is custom triples, hacking the steering neck or jacking the rear end waaaaaay up. Since you are trying to raise the whole thing, the rear will already be pushed to its max for the drive shaft. As it stands now the swingarm sits almost parallel with the ground and is designed to compress only. Im not sure how much raise you can actually get without causing issues but id guess taking the swingarm from 0degrees to 5degrees. And with the mono shock i was simply stating what you had not if you can modify it. The more info everyone has, the better responses you will get.

The way i see it, the only real option for what you want to do is to modify the steering neck. It will be the safest and most cost effective(if done right). To get everything to work out right in the back end you might have to consider either adjusting the swingarm pivot location and rotating the motor of having the modify the driveline so there is no binding.
 

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Build It Ride It Live It
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I think HD's are only thing that use a raked tripple off the showroom. And they only did that on a couple years.

The Virago does run a leading axle fork with a lot of offset in the trees though.

You seriously run 3" of trail? Your steering's ultra light, isn't it, lol.
 

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GURU
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8,827 Posts
I think HD's are only thing that use a raked tripple off the showroom. And they only did that on a couple years.

The Virago does run a leading axle fork with a lot of offset in the trees though.

You seriously run 3" of trail? Your steering's ultra light, isn't it, lol.

its actually a weird thing. The bike is very stable at speed but the tip over point where it goes to countersteering is much higher. Id say above 35-40mph. It has to do with the arc path your tire travels when you steer and how far offset the front contact patch is in relation to the rear. Its certainly not as easy to ride as a bike with larger rake/trail wheelbase but its a very stable ride.
 

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I know nothing
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Discussion Starter · #18 ·
Well dammit, I knew I should've logged-in yesterday.

Thanks for giving me a lot more to look at guys.
 
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