Topic: Front End Swaps

[jpfrk2001]

Im not sure if there is a thread on popular front end swaps for these bikes. So, I want to start one. Lets do a collection of swaps that have been done and what is needed to do the swap.

What type of fab work?
What type of custom Machine work and tech info on that?
What years and donors to look for (2001-2007 or 2005-2008)? and so on?
What did you do and why?
If you would do it again, what would you do different?

I'll start: Thread on a CB550 called Rusty Olive. Did a front end swap using a 2006 CBR front. Kept original font hub, machined a custom front axle, adapters for duel front disk to the modern front calipers:
http://forums.sohc4.net/index.php?topic=81683.0
Very awesome build. Lots of fabrication. Very sexy bike.

Next up: 1972 CB750, using a front end from a 2006 GSXR. Again, awesome build coming. Using a front hub from a 2013 Harley Dyna narrow? Alternative is a custom front hub found on the market. See links:
http://forums.sohc4.net/index.php?topic=126633.0
Vender for front custom Hub:
http://cognitomoto.com/
Kinda pricey front hub kit, but may come cheaper then having front custom Machine work done locally where you are at? I don't know.

Another: This is a 06 GSXR front end swap. Awsome info
http://forums.sohc4.net/index.php?topic=122950.0

And I found that there is the typicall GL1000 front end swap as well. I actually have one of these sitting in my corner.

My disclaimer: I am not a expert. I am only starting a thread to gather ideas, thoughts, and facts to aid in my new build about to start. I am sure this will aid others as well.

So, post up and share. Post links, with valid info. Lets try and keep this to a facts base only.

Or should I just go drink some bleach and buy a 2014 rice rocket? <-- forget that! I like to build my toys!!

 

[754]

Here is one i just did ,
Ceriani GP fork to custom frame, using cb 750 bearing specs.
 
Yamaha 18 inch mag,. Bearing snout milled back 4 mm.

6 piston caliper, mated to. Ducati floating rotor.

[jpfrk2001]

Nice.

"Bearing snout milled back 4MM"

What is the definition of "snout"?

Remember, I am stupid with this new type of tech. Can you explain?

[754]

Hey the part protruding past the rotor..i cut it off , in the mill with an offset boring head

[jpfrk2001]

Hey the part protruding past the rotor..i cut it off , in the mill with an offset boring head

Good info..

Anyone else? Would be cool for more to chime in

[Tews19]

I am doing the gsxr front end on my 550F... You last thread you put In your posting.....

I guess what bike are you using? That may help...


Check out FunJimmy's build....

Rusty's build has been an inspiration since before I even joined the site.....

What are your goals with the modern front end?

[jpfrk2001]

I am doing the gsxr front end on my 550F... You last thread you put In your posting.....

I guess what bike are you using? That may help...


Check out FunJimmy's build....

Rusty's build has been an inspiration since before I even joined the site.....

What are your goals with the modern front end?

My build platform will be based on a 1976 CB550 platform. Wide rear tire, little wider front tire, Keep similar spoke wheels for the classic look. Super bike brake performance up front.

Pretty much what Rusty Olive is like. Real similar. Just trying to do a cost compare of doing a CBR600 front end, which leads to a custom Machined front axle, Machined disk brake adapters.

Doing a GSXR front end, I am buying a complete hub assembly. Link in the first post.

Oh yea, I have no problem turning on a welder and melting metal together. Custom fabrication is nothing new to me. I just don't have any tools for custom Machining. That will have to be contracted out.

I pick up the basket case tomorrow.

[754]

If you are on the move near here.. i can machine good stuff into chips..

[jpfrk2001]

If you are on the move near here.. i can machine good stuff into chips..

I wish. Im in southern Arizona right now. Soon to move to Texas.

[Retro Rocket]

Too many of these conversions are done with no regard for the geometry of the bike. Frame rake , trail, triple clamp offset, wheel size are all important in having a good handling bike. The standard offset on GSXR and most modern front ends is 35mm, so just bolting them straight on gives a reasonably large increase in trail, modern front ends also use a different size wheel and have different rake. What really needs to be done is for someone to do all the calculations to determine what these numbers are if you are using for instance, the whole front end including wheel, which would mainly be 17inch, also for 18 inch, which is a popular conversion and for the stock 19 inch wheel. What the stock GSXR clamps actually do is increase trail which slows down how the front end reacts, it can make the front feel lazy even, while the back remains stock, which on these bikes is quite fast reacting, thats why stock, the Old Honda's have small trail numbers up front {under 4 inches}, its so the front and back work together, not against each other...

And Yes Frank, the OP asked....

[jpfrk2001]

Hey Retro,

I am taking into account for trail, rake, offset and such. I did read up a bit on that. So I know enough not to get my self in trouble. Plan is to use the same size 19" wheel up front. As long as I can find the factory specs of a CB550 of my year, I might be able to set up the bike as close as possible to the same specs. That's the goal.

EDIT:
here you all go.
http://forums.sohc4.net/index.php?topic=59903.0

And Retro, thanks for your post. That's the type of tech Im trying to fill this thread up.

no one has yet to confirm a range of years for donor front end. So far, I can only verify these two forks for bolt on's with a alls ballz bearing kit, which is available:
2006 CBR600
2006 GSXR (Is this from a 600? 700? 1100? etc..)

[Xnavylfr]

75/76 GL frontends (complete) are a direct swap, just need to change bearing  to ALL BALLS taper bearings and cups. Doesn't change trail with stock 19" rim, is 2" wider and 37mm tubes.. DUAL DISC front brakes. There are some aftermarket top trees to give you more choices in handlebars!!


Xnavylfr(CHUCK)

[jpfrk2001]

75/76 GL frontends (complete) are a direct swap, just need to change bearing  to ALL BALLS taper bearings and cups. Doesn't change trail with stock 19" rim, is 2" wider and 37mm tubes.. DUAL DISC front brakes. There are some aftermarket top trees to give you more choices in handlebars!!


Xnavylfr(CHUCK)

Yeap, very true. I already have one sitting in the corner AND calipers and master cylinder, along with a swing arm off a 1978 750F model for a disk swap also. But I am saving these two for my current CB750K I already am riding.

I plan to build the 550 over time. While building this bike, I have my 750 to ride. When the 550 is done, the 750 goes back on the table.

[jpfrk2001]

Found some info for you all:

[Retro Rocket]

Hey Retro,

I am taking into account for trail, rake, offset and such. I did read up a bit on that. So I know enough not to get my self in trouble. Plan is to use the same size 19" wheel up front. As long as I can find the factory specs of a CB550 of my year, I might be able to set up the bike as close as possible to the same specs. That's the goal.

EDIT:
here you all go.
http://forums.sohc4.net/index.php?topic=59903.0

And Retro, thanks for your post. That's the type of tech Im trying to fill this thread up.

no one has yet to confirm a range of years for donor front end. So far, I can only verify these two forks for bolt on's with a alls ballz bearing kit, which is available:
2006 CBR600
2006 GSXR (Is this from a 600? 700? 1100? etc..)

Yeah, I posted it as information generally, wasn't really aimed at anyone... , I have 2 GSXR front ends now, the are the last of the "right side up" forks from the 1990 GSXR1100 K, 43mm cartridge style forks with tons of preload and damping settings,  I prefer the older style look on these bikes...

[jpfrk2001]

Well, Im updating this thread to let you all know which route Im going. I talked to Cognito Moto this morning on the phone. Talking with him, and using the spreadsheet I posted here, it looks like the most desirable front end is from a 05-06 GSXR 1000.

This is due to the offset. I am planning on going with Cognito Moto front hub. I relize its pricey. Its either that or custom machining a front axle, brake adapters to use the factory front hub. So, I choose to go the easier route.

Any one else want to chime in? Besides the ones who already have.

[Retro Rocket]

As far as i know the offset is 35mm which is about 15-25 mm to small...? {CB750K offset is 60mm, F offset is 50mm}

[pamcopete]

I installed a Yamaha XS650 front end, including the axle, forks, hub, rim, spokes, caliper, disk and fender from a 1982 XS650 Heritage Special with the 64 spoke wheel on my 1974 CB750.

This is a simple replacement of the 35mm forks using the stock triples with no modifications required. I just like the more modern fender without the braces, the 64 spoke wheel and the better brake caliper. Installed a single piece stainless steel brake line and a new master cylinder as well.




The axle, rim, spokes, caliper, disk,  master cylinder and fender were bought brand new from www.mikesxs.com
The new stainless steel brake line was from http://www.spieglerusa.com/ The caliper pads are new ECB's.

The fork length and wheel / tire size are the same as stock so there is no change to the geometry as the stock triples are used as well. The speedo cable from the XS650 speedo adapter plugs right into the Honda speedo and both use the standard Japanese speedo rpm of 2240 rpm = 60mph

[jpfrk2001]

Look above for offset of said forks.

offset is 30 MM. If this is a smaller offset, this translates to tighter quicker steering? More nimble and responsive? But more unstable at higher speeds?

Lets do this. Post up stock OEM numbers caster angle/trail, including the source of info for:

CB500
CB550k
CB750K: 63 Degree / 3.74" (95MM), Factory Shop Manual.

[Retro Rocket]

Look above for offset of said forks.

offset is 30 MM. If this is a smaller offset, this translates to tighter quicker steering? More nimble and responsive? But more unstable at higher speeds?

.

Actually its the exact opposite, smaller offset slows down steering and lengthens trail making for slower steering that can make the bike feel like its falling into corners, a change of 30 mm from stock is a quite large change... I have a guy making me {when
i order them} custom clamps at 50mm offset but i'm using a 18 inch front wheel which also slightly changes things and a 1 inch longer swingarm to balance the whole bike, the Honda's were quite quick steering and the swingarm is quite short to balance this out, when making changes to the front it always a good thing to balance that at the rear, the F model Honda's had a slightly different rake with 50mm offset and a slightly longer swingarm, they are slightly more stable at speed than the K model, even the road tests at the time said that......

[jpfrk2001]

Hmm.. So maybe a a swing arm from a 750K into a 550k Frame could help. I have a Rear swing arm from a 750F sitting in the corner. Its a bit wider at the axle mount point, but same width dimensions at the frame mount point. So, this makes me change my mind on what year of donor. Im still going with a GSXR front end. There is one listed with a 32MM offset. It would help, but a big change from stock.

Any one have the offset of a stock 1978 550K.

[Retro Rocket]

Hmm.. So maybe a a swing arm from a 750K into a 550k Frame could help. I have a Rear swing arm from a 750F sitting in the corner. Its a bit wider at the axle mount point, but same width dimensions at the frame mount point. So, this makes me change my mind on what year of donor. Im still going with a GSXR front end. There is one listed with a 32MM offset. It would help, but a big change from stock.

Any one have the offset of a stock 1978 550K.

Not too sure what the offset is on the 550 mate,  also the 750K swingarm is used on 550;s and 500's to quicken steering, its actually shorter, not longer that the 550..  Get the tape measure out and start measuring    2 mm on offset won't make any difference at all, I have a set of 35mm GSXR clamps that I have a Honda stem in but I won't be using it on my bike, custom clamps all round for me....
Forum member "Terry in Australia" had a very well set up 750K with 18 inch wheels front and rear and 41mm FZR1000 forks, the guy that built is a race engineer and he hated it with the Yamaha clamps {smaller offset} because of its tendency to fall into corners so he made his own clamps at closer to the stock numbers, Terry said it is without doubt the best handling Honda 750/4 he ever road and he's had a few....   It looked mighty fine as well....

[jpfrk2001]

My bad, Its a rear swing arm from a 750F (rear disk set up). Maybe there is a difference. I will recheck the swing arm again.

[pamcopete]

Not sure how this thread about front end swaps became a discussion about swing arms..

[jpfrk2001]

Back to the top.

I think this discussion went into setting up a 550 properly using a modern front end swap.

Build thread to be published here soon. The build is commencing right now. Still waiting on some parts. Still havn't ordered the front hub.

I can't really start setting up till certain parts are on hand.
still need the front wheel built up
Still need the rear wheel built up

So what numbers should I really be shooting for then?