Author Topic: Converting my front end???? (Read 3580 times)

dec505 · « **on:** January 15, 2006, 10:08:26 PM »

I have a 78 CB750K and am in the process of completing the GSXR front end swap. On friday I took the my cb's sterring stem/bottom tripple tree and the 2001 GSXR 600 stearing stem to a machine shop to have them pressed out and swaped. When I got there the guy at the desk said no problem come back later in the afternoon and we will have it done. Went I went back to pick it up there was another guy there and he said it was impossible to press out the cb stem because it was welded in. I told him that I didn't think it was impossible because other people have done it but I would ask them. So tell me guys is he full of crap and shold I go somewhere else? or am I unique in that my stem is welded. My dad has draged raced bikes for 20+ years and he told me just to use the GSXR bearings but I don't think they will fit as well as the cb's. He asked some of his friends and they all said to do that and not even try to press out the stem's or to just bore out the cb's tree's to accept the new forks. I'm confussed and wasn't expecting this to be so hard.

ttr400 · « **Reply #1 on:** January 15, 2006, 11:43:59 PM »

The machine shop guy is correct, the stem on your CB is welded as are most other CB models. The GSXR trees are aluminium and I think the stem is also. Not a good idea to bore the CB trees as you won't have much meat left if any at all.
What I would do is measure up your stock CB stem and machine a new stem in stainless or 7075 aluminium and press this into the GSXR lower tree, this way you can machine the new stem with the extra length probably required for the extra thickness of the GSXR trees.
Or you could remove the CB stem by grinding the welds etc, check the diameter to see if it's compatable with the GSXR tree, if sizes look good then you can press the CB stem into the GSXR tree, you might have to bush the tree as I would imagine the GSXR stem being a bit bigger, but it might be too short at the top if the GSXR upper tree is thicker.

ALL IS POSSIBLE. Greg at Ohio cafe racers has fitted a GSXR front end to his CB350 twin.

Kevin.

dec505 · « **Reply #2 on:** January 16, 2006, 12:47:43 AM »

cd811 has done this conversion and I think he said all he did was press out the stem on his 750. What the machine shop guy said exactly was he was affraid he would snap the cb stem trying to press it out. I think the machine shop guy is a pussy so I'm just going to use the hyd press at my uncles shop to get it out if it brakes then I will try to figure something else out. Thanks for the help

ttr400 · « **Reply #3 on:** January 16, 2006, 01:09:34 AM »

If you are unsure about the welding, it is easly spotted. Turn the tree upside down and eye ball the stem and you will see if it has a bead of weld. before pressing it out, grind the weld and it will come out with no problem.
If you go for a new stem the lower part(were it fits in the tree) must be to the GSXR size and from there up it must be to the CB design.

Kevin.

dec505 · « **Reply #4 on:** January 18, 2006, 03:14:53 AM »

I got the cb stem out and the GSXR front suspension and brakes put in. Looks awesome the stance with the bigger forks is great. It's the same setup that Ebay bike used but I think mine looks a lot better. I will post some pics if anyone is interested once I go buy a new cable for my digital camera. I left my old one in the sandbox. Thanks for your help Kevin it was no problem pressing the stem out.

ohiocaferacer · « **Reply #5 on:** January 18, 2006, 04:16:13 AM »

Dec

Glad to hear your swap went good!!! Amazing how compatable these old bikes are with the newer ones.

Make sure to post those pics......were dieing to see'em!

Later,
Greg
www.OHIOCAFERACERS.com

Geeto67 · « **Reply #6 on:** January 18, 2006, 06:09:22 AM »

just to clarify, All cb750 stems are welded at the bottom and you have to grind the weld down before pressing the stem out. Whenever talking about this kind of front end swap people tend to overlook that step and think it is a press in and press out deal. it isn't, but it isn;t hard to grind down the weld either - a grinding bit on a dremel is all you need. Don't forget to weld the new stem in the bottom trees.

Also most sportbikes use an aluminum upper clamp but 90% of them use a steel bottom clamp with a steel stem. I personally have never heard of an aluminum stem but that doesn't mean they aren't out there. A good way so tell if your new trees are going to be easily accepting of a cb stem is to see what kind of lower bearing the sport bike trees take, if it is close in size then you should be good. some trees will require a shim to use the honda stem and that is why I suggest taking to a machine shop.

dec505 your machinist is a pussy.

dusterdude · « **Reply #7 on:** January 18, 2006, 10:05:37 AM »

damn geeto,get up on the wrong side of the bed this morning?

ProTeal55 · « **Reply #8 on:** January 18, 2006, 10:15:12 AM »

kyre · « **Reply #9 on:** January 18, 2006, 01:10:34 PM »

not related at all, just had to say ttr400, that your website has amazing stuff! that's the prettiest 400/4 engine I've ever seen!

fastbroshi · « **Reply #10 on:** January 18, 2006, 05:24:34 PM »

Good to hear the swap went okay, let's definitely see some pics. Namely the closeups of the triple tree and brakes. I'm thinking of doing this to my 750. Keep up the good work.

cbjunkie · « **Reply #11 on:** January 18, 2006, 05:41:48 PM »

chiming in to agree - mo' pix!

Greenbush · « **Reply #12 on:** January 20, 2006, 12:27:14 PM »

505;
WHERE ARE THOSE PICS?

I am in the process of planning this type of switch. So this is VERY interesting. What year GSXR front end did you use?
Does anyone out there know about trying to mount a 89CBR 600F1 front end to my 76 K. Any bright ideas?
Will the bearings be a problem?
I have the ability yet not all the knowledge to get this done.
Look what this guy in Sweden did to his 750. I like it and it is the idea I am shooting in the direction of.
Clay

GoatBaSS · « **Reply #13 on:** January 20, 2006, 01:25:57 PM »

What kind of swing arm, do ya think? The next CB will be frame up, and I need direction. Well I always need direction.

KCs76Cafe · « **Reply #14 on:** January 20, 2006, 07:31:42 PM »

Quote from: Greenbush on January 20, 2006, 12:27:14 PM

505;
WHERE ARE THOSE PICS?
I am in the process of planning this type of switch. So this is VERY interesting. What year GSXR front end did you use?
Does anyone out there know about trying to mount a 89CBR 600F1 front end to my 76 K. Any bright ideas?
Will the bearings be a problem?
I have the ability yet not all the knowledge to get this done.
Look what this guy in Sweden did to his 750. I like it and it is the idea I am shooting in the direction of.
Clay

Clay,

You have any specs on that bike from Sweden? Or a link to more info on it?

cd811 · « **Reply #15 on:** January 21, 2006, 12:01:13 PM »

505...
after I made the swap, I thought the new press in fit was enough until I ass. the trees( not a tight enough fit!!!!!!!!!!!!)...so with the stem properly fit and lined, I drilled a hole though the lower tree and stem and installed a roll pin...solid now!!!

cosmo · « **Reply #16 on:** February 04, 2007, 06:55:10 PM »

Quote from: dec505 on January 18, 2006, 03:14:53 AM

I got the cb stem out and the GSXR front suspension and brakes put in. Looks awesome the stance with the bigger forks is great. It's the same setup that Ebay bike used but I think mine looks a lot better. I will post some pics if anyone is interested once I go buy a new cable for my digital camera. I left my old one in the sandbox. Thanks for your help Kevin it was no problem pressing the stem out.

Bringing this back from the dead, you ever get some pictures? This is the swap I'm looking to do on my CB350 now, so some photos would be great

bill440cars · « **Reply #17 on:** February 04, 2007, 07:06:29 PM »

Quote from: cosmo on February 04, 2007, 06:55:10 PM

Quote from: dec505 on January 18, 2006, 03:14:53 AM
I got the cb stem out and the GSXR front suspension and brakes put in. Looks awesome the stance with the bigger forks is great. It's the same setup that Ebay bike used but I think mine looks a lot better. I will post some pics if anyone is interested once I go buy a new cable for my digital camera. I left my old one in the sandbox. Thanks for your help Kevin it was no problem pressing the stem out.
Bringing this back from the dead, you ever get some pictures? This is the swap I'm looking to do on my CB350 now, so some photos would be great

cosmo, go over toohiocaferacers.com and you can see some detail on how Greg did it. Or have you been there?

Later on, Bill

cosmo · « **Reply #18 on:** February 04, 2007, 08:46:47 PM »

Quote from: bill440cars on February 04, 2007, 07:06:29 PM

Quote from: cosmo on February 04, 2007, 06:55:10 PM
Quote from: dec505 on January 18, 2006, 03:14:53 AM
I got the cb stem out and the GSXR front suspension and brakes put in. Looks awesome the stance with the bigger forks is great. It's the same setup that Ebay bike used but I think mine looks a lot better. I will post some pics if anyone is interested once I go buy a new cable for my digital camera. I left my old one in the sandbox. Thanks for your help Kevin it was no problem pressing the stem out.
Bringing this back from the dead, you ever get some pictures? This is the swap I'm looking to do on my CB350 now, so some photos would be great

cosmo, go over toohiocaferacers.com and you can see some detail on how Greg did it. Or have you been there?

Later on, Bill

Bill,

I've been here alot lately looking things over

, just trying to figure out what he really did as he doesn't get too into it. Just states that he pressed it out, pressed the 350 back in, bolted it on and moved the steering stops. Just wondering if he changed the bearings to some tapered needles, etc.

News:

Author Topic: Converting my front end???? (Read 3580 times)

dec505

dec505

dec505

fastbroshi

Greenbush

cd811