CHOP CULT HOME
Email Password
Search
  1. #1

    Join Date
    Oct 2015
    Posts
    16

    Default 70s era CB750 Plunger Hellride

    Thanks to the gracious delivery of this 70's era plunger frame from New Mexico to Barber Vintage Festival by a buddy, I'm jumping into this chopper build with two feet. I've reached out to several forums, sorted through various catalogs and ads from the 70s, but have yet to identify the manufacturer with complete confidence. I think it's definitely a production style frame, considering the neck. It has two pressed in cups for a common neck tube. The CB750 triple tree that came with the frame has a modified stem to account for the longer neck. So far, my best guess is it's a Jammer frame with a plunger kit welded on.

    Click image for larger version. 

Name:	d84898423e40c89029a3a00698dd43fe.jpg 
Views:	12 
Size:	144.7 KB 
ID:	79214

    I'm in the sketching phase, so things can change wildly. Ultimately, I want to avoid some more common cues like peanut tanks....


    It took some machine work on the steering neck cups and the RM stem to make this RM front end work...

    Click image for larger version. 

Name:	4ab747e7d5fd850cd7123595a8ad1182.jpg 
Views:	5 
Size:	108.8 KB 
ID:	79217

    Here is sits with a 1994 RM250 front end and RM wheels front and rear. I like the dimension of the dirt bike wheels, plus they're aluminum. If I decide to go drum on the rear wheel, I may go 70s era XL350.

    Click image for larger version. 

Name:	9a8433f4e6ebe06b919e87ab1c3082f6.jpg 
Views:	10 
Size:	138.9 KB 
ID:	79218

  2. #2

    Join Date
    Oct 2015
    Posts
    16

    Default

    Fabricated a mount for the headlight...

    Click image for larger version. 

Name:	302063684e1307c8666b4196eb954b37.jpg 
Views:	0 
Size:	94.0 KB 
ID:	79219

    Click image for larger version. 

Name:	3ae0610d264c98ef3628196d39cc0c1e.jpg 
Views:	1 
Size:	107.5 KB 
ID:	79220

    Click image for larger version. 

Name:	54597f1455d72c1df2775a2419208875.jpg 
Views:	6 
Size:	157.5 KB 
ID:	79221

  3. #3
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Aug 2009
    Posts
    2,917

    Default

    Nice, I dig on dirt choppers.
    What are you doing to address the extra weight on that front end?
    Preload spacers? Heavy oil?

    I always thought those plunger frames were cool.
    But they really could benefit from a stabilizer bar and maybe some dampening...

  4. #4

    Join Date
    Oct 2015
    Posts
    16

    Default

    Quote Originally Posted by Sky View Post
    Nice, I dig on dirt choppers.
    What are you doing to address the extra weight on that front end?
    Preload spacers? Heavy oil?

    I always thought those plunger frames were cool.
    But they really could benefit from a stabilizer bar and maybe some dampening...
    Thanks, Sky. I had a conversation with Race Tech. The max spring they offer is .52 kg/mm vs the .36 kg/mm that comes stock with these forks. I'll see about working that angle with their gold valves, possible preload and oil to boot. Considering the rake, there's no telling what the true math is on these.

  5. #5
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Jun 2013
    Posts
    321

    Default

    This appears to be an Amen Savior or AEE frame.

  6. #6

    Join Date
    Oct 2015
    Posts
    16

    Default

    Quote Originally Posted by CarloFreeze View Post
    This appears to be an Amen Savior or AEE frame.
    Consensus so far is that it is a Jammer frame with a plunger kit welded on. Everything on my frame- tabs, peg mounts, neck gussets, etc- are identical to the Jammer frame in this pic. The VIN stamping, however, is not a manufacturers stamping or number plate. It was done by a private owner or customizer. This frame was smoothed out with Bondo at some point in it's life as I have a shitload to remove to bring it back...

    Click image for larger version. 

Name:	0906D255-E243-4F3F-B95E-695F14B74CA4.jpeg 
Views:	2 
Size:	38.4 KB 
ID:	79225

  7. #7

    Default

    Quote Originally Posted by deviant View Post
    Consensus so far is that it is a Jammer frame with a plunger kit welded on. Everything on my frame- tabs, peg mounts, neck gussets, etc- are identical to the Jammer frame in this pic. The VIN stamping, however, is not a manufacturers stamping or number plate. It was done by a private owner or customizer. This frame was smoothed out with Bondo at some point in it's life as I have a shitload to remove to bring it back...

    Click image for larger version. 

Name:	0906D255-E243-4F3F-B95E-695F14B74CA4.jpeg 
Views:	2 
Size:	38.4 KB 
ID:	79225
    I'd agree about the jammer with weld on.

    If you haven't already head over to hondachopper.com, pretty much everything you will ever need is there.

  8. #8
    Duane
    Guest

    Default

    It's a Jammer Velvet Ride. The rear ends came like that at one point. I'm building one now. Click image for larger version. 

Name:	jammer add.jpg 
Views:	14 
Size:	121.9 KB 
ID:	79427

  9. #9

    Join Date
    Oct 2015
    Posts
    16

    Default

    Quote Originally Posted by Duane View Post
    It's a Jammer Velvet Ride. The rear ends came like that at one point. I'm building one now. Click image for larger version. 

Name:	jammer add.jpg 
Views:	14 
Size:	121.9 KB 
ID:	79427
    Oh wow. Thanks for the info!

  10. #10
    Duane
    Guest

    Default

    No problem. That's what I'm building for the next Born Free. Something different for me. Click image for larger version. 

Name:	20171015_094929.jpg 
Views:	10 
Size:	306.9 KB 
ID:	79447

  11. #11

    Join Date
    Oct 2015
    Posts
    16

    Default

    I wish I had heard from you earlier, because by that point I had already converted to hardtail ...

    Click image for larger version. 

Name:	6d7143af75863e69a53b5544695f7785.jpg 
Views:	5 
Size:	155.0 KB 
ID:	79471

    I know plungers have their own special issues. Part of me wonders if I'll face regret, but as long as it comes out well I'll forget. Needless to say, it's caused much debate amongst friends.

    Here's a detail that shows off the boxed out axle plates recycled from the plungers. It also shows the RM250 rear brake and rim...

    Click image for larger version. 

Name:	c8bc2076103bfa936285c4d65aafb418.jpg 
Views:	2 
Size:	194.9 KB 
ID:	79472

    With the RM rims come a 520 sprocket conversion opportunity. I went with a 38T rear and a 14T counter sprocket from an 70s XL250. To accommodate the XL cs, I machined a spacer (VW Bug alternator shims which can be bought cheaply in packs of 10 can also be used to shim sprockets on 750s since they have a 25mm ID).

    Click image for larger version. 

Name:	bda6dc556e81d001a2602243ffd25c26.jpg 
Views:	1 
Size:	113.3 KB 
ID:	79473
    Click image for larger version. 

Name:	a3d9f27c5c82cb5503e18260dd779c90.jpg 
Views:	1 
Size:	180.3 KB 
ID:	79474

  12. #12

    Join Date
    Oct 2015
    Posts
    16

    Default

    Something common on dirt is a frame tab brake stay, instead of a rod. It's a nice, clean and inconspicuous setup. I machined and welded one to mount the brake...

    Click image for larger version. 

Name:	4c4ca1bd4d2182eb7148f1301887dcef.jpg 
Views:	1 
Size:	67.2 KB 
ID:	79476
    Click image for larger version. 

Name:	0535c302e1f12ea90d8db1330c977716.jpg 
Views:	1 
Size:	84.8 KB 
ID:	79477

    To finish out the rear brake, I machined an oil bronze bushing to press into the pivot tube. I have a 77 motor, and I believe the earlier 750s had a larger pivot shaft. This gave me room for the bushing...

    Click image for larger version. 

Name:	80313a456cababbcd34460e3d559ac4f.jpg 
Views:	0 
Size:	84.5 KB 
ID:	79478
    Click image for larger version. 

Name:	da49e5ee2ff4a32aa58530f094851437.jpg 
Views:	0 
Size:	118.1 KB 
ID:	79479

    Click image for larger version. 

Name:	78e5a62a5b653d4616539e56c7bed366.jpg 
Views:	0 
Size:	150.5 KB 
ID:	79480

  13. #13

    Join Date
    Oct 2015
    Posts
    16

    Default

    One thing of note: I'm a member at another site where this build is also happening. I'm trying to catch this up, so I apologize if I'm jumping around.

    I guess I didn't take any detail shots of process, but here's a first look at the seat pan I'm forming. You'll see a few changes in later pics...

    Click image for larger version. 

Name:	65253d8a587fb611022b8ea7b95b24a1.jpg 
Views:	3 
Size:	162.8 KB 
ID:	79481

    That pic also shows an XL175 tank. I have since gone to an XL350 tank. One thing unique about the pre-78 XL350s is the cutout in the tank for the offset carb. I like the shape and size of that tank and I had an idea I wanted to try on the cutout, so I fabbed switch box for the cutout...

    Click image for larger version. 

Name:	5f05dfe2e86a0e8fa522d23381e24d86.jpg 
Views:	0 
Size:	143.9 KB 
ID:	79482

    Made an under tank M/C so I can get the M/C and reservoir off the bars, but still have front disc brakes. I'll run a late 70s/early 80s Z50 front brake cable...

    Click image for larger version. 

Name:	Screen Shot 2017-10-23 at 9.24.46 PM.jpg 
Views:	3 
Size:	23.1 KB 
ID:	79483
    Click image for larger version. 

Name:	Screen Shot 2017-10-23 at 9.24.22 PM.jpg 
Views:	3 
Size:	29.4 KB 
ID:	79484
    Last edited by deviant; 10-23-2017 at 7:27 PM.

  14. #14

    Join Date
    Oct 2015
    Posts
    16

    Default

    I'm running a hinged mount for the seat that shares a mounting point with the tank...

    Click image for larger version. 

Name:	d80310c92675eaf160586fe37253e7c9.jpg 
Views:	2 
Size:	179.4 KB 
ID:	79485

  15. #15

    Join Date
    Oct 2015
    Posts
    16

    Default

    Progress shot. Still waiting on the good condition tank that's shipping to me and Iím crossing my fingers on a couple of eBay auctions for a rear fender...

    Click image for larger version. 

Name:	22638741_310293529376475_7383122444808093696_n.jpg 
Views:	10 
Size:	274.5 KB 
ID:	79487

  16. #16
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Jul 2013
    Posts
    2,614

    Default

    looking sweet

  17. #17

    Join Date
    Oct 2015
    Posts
    16

    Default

    Bobbed, shaved and stretched a Softail rear fender to run on here...





    I also machined an enclosure to house a micro-switch for turn signals and mounted it with an old bar end mirror mount...


  18. #18

    Join Date
    Oct 2015
    Posts
    16

    Default

    I'm running one side of a HD tail light, wet sanded and polish to look new.



    I also decided not to run a sissy bar above the fender...



    I machined a sprocket carrier for the rear RM hub with the idea of making my own cush drive. Then a DR350SE hub fell into my lap for the cost of shipping ($13). These can go for $150 on eBay, so I was pretty psyched to get it...


  19. #19

    Join Date
    Oct 2015
    Posts
    16

    Default

    Front brake work is complete...

    It utilizes a Z50 front brake cable to an under tank m/c...







    Stainless lines and 3an fittings. A straight fitting on the m/c and a banjo to an fitting on the caliper...



    Since these are dirt bike forks, they offer a fork guard. I took the top mounts for the fork guards, trimmed off the guard mounting tabs and made a cable guide for the brake line. The line runs through a machined acetal sleeve...





    Then a little Rub n' Buff helps the plastic blend...

    Last edited by deviant; 11-21-2017 at 7:33 PM.

Share This



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in