Topic: Frame Modification

[Hooverr77]

Hello all,
Looking at closing the gap on my 77 Honda CB750 and wanting to know if I should cut the frame and put the loop or should I try to bend the frame up and add just a small loop on the end? below is a pic.. Thanks for the opinions 

https://drive.google.com/file/d/0B20h0pq23nyALUJ4aWNXYUNUdGc/view?usp=drivesdk

[slikwilli420]

Be easier to cut and add a hoop in my opinion. Make sure to use some slugs at the weld point for a more sound attachment.

[firebane]

Take into consideration that the cross bar under the seat is a good indication of how much wheel travel you need. With that said figure out your angle and chop off the material about 1-2" behind the shock mount and get a hoop and slug/weld it.

[Hooverr77]

Thank you for the help! Also I know that I cannot do to much because of the shock mounts. And is there a way to tell max tire travel??

[firebane]

Thank you for the help! Also I know that I cannot do to much because of the shock mounts. And is there a way to tell max tire travel??

I just gave you that information lol.

[calj737]

Thank you for the help! Also I know that I cannot do to much because of the shock mounts. And is there a way to tell max tire travel??

That is contingent upon suspension, tire profile, and rim diameter. If you stick with the stock specs, then the bridge under the stock seat is a very good indicator. Also, bear in mind that the hoop end will potentially contact the tire if it intersects the tire diameter (think the vertical axis under full suspension compression).

[Hooverr77]

SO if I keep everything above the cross Frame I should be golden?

[calj737]

Yes, and not longer than the stock frame ends

[SOHC4 Cafe Racer Fan]

You can also angle the hoop so that it is flush with the edges of the seat.  That upward angle will also provide more clearance.

[DaveBarbier]

You could compress the springs with a hydraulic press or ratchet straps (I've done it this way) and disassemble and reassemble the shocks without the springs. You'll be able to install them back on the bike and you can check actual clearance. I've heard you should add about 1/4" for tire growth and component flex. Just another option.


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[Geeto67]

You could compress the springs with a hydraulic press or ratchet straps (I've done it this way) and disassemble and reassemble the shocks without the springs. You'll be able to install them back on the bike and you can check actual clearance. I've heard you should add about 1/4" for tire growth and component flex. Just another option.

This, but you can get spring compressors at any auto parts store, so it isn't some black art to remove the spring.

For clearance you want 1/4" for the compression of the bump stop and 1/4" for the expansion of the tire so a minimum of 1/2". If it were me I would shoot for an inch of clearance at full compression.

[firebane]

You could compress the springs with a hydraulic press or ratchet straps (I've done it this way) and disassemble and reassemble the shocks without the springs. You'll be able to install them back on the bike and you can check actual clearance. I've heard you should add about 1/4" for tire growth and component flex. Just another option.

This, but you can get spring compressors at any auto parts store, so it isn't some black art to remove the spring.

For clearance you want 1/4" for the compression of the bump stop and 1/4" for the expansion of the tire so a minimum of 1/2". If it were me I would shoot for an inch of clearance at full compression.

Normal spring compressors are too big for the shocks on a bike. I rigged up a nice little tool for pulling springs off the shocks for my bike and cost me about $15 in materials.