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Old 04-10-2011, 07:16 PM   #456
Airhead Wrangler OP
Adios Mexico
Airhead Wrangler's Avatar
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,548
further research on potential for weight reduction
Work in progress:

R100GS front end:

Forks with triple 26.3 lbs
Front wheel 13.4 lbs
Axle .9
caliper 2.75 lbs ($822.25 on maxbmw!?!?!)
rotor 4.59 lbs
rotor bolts (4) .6 lbs

total excluding small fasteners: 48.54 lbs (yikes)

WP 4860 front end w/ ktm wheel:
used numbers from G450X front end because it's probably pretty close and I still don't have all the 4860 parts to weigh
wheel 7.2
rotor 2.0
axle .75 (actual)
fork legs 20.5 (actual weight of 4860 legs with oil)
caliper 1.3
bottom triple 2.5
top triple 1.6

35.85 lbs total (13 pounds less than a R100GS)

Other potential weight reductions:
  • Muffler 9.52 lbs, convert collector box into muffler ala Paul Rooney
  • Engine top cover 1.23 lbs (ditch completely or make something minimal out of fiberglass or light gauge aluminum)
  • engine front cover 1.86 lbs (cap off bean can hole and make small cover for alternator and crank mounted ignition)
  • timing chain cover 4.3 lbs (able to cut away over half like this: Also, anybody want to tell me why this engine has one of the oil cooler lines attached to the LEFT side of the block?)
  • R100GS subframe w/ PD rack 13.07 lbs -> R80ST subframe 5.11 lbs
  • Airbox, 2.4 pounds, replace with homemade fiberglass or aluminum version similar to this, but with foam filter )
  • Valeo or nippon denso starter instead of the bosch. That should save ~5 lbs.
  • Shorai FX14A2-BS12 14 Ah battery - 1.6 lbs instead of BMW battery which weighs 13.7 lbs - 12.1 lbs saved
  • Crash bars and sidestand - 5.8 lbs
  • Oil pan (4.19 lbs) and bash plate (2.44 lbs) replace with HPN rallye sump, probably a little lighter, but not much. I'm not doing this to lose weight. Put a hole in your sump while you're alone in a desert and you won't want it to happen again.
  • Mikuni VM34 carbs instead of 32mm Bings would save 2.0 lbs.
  • Engine block - carve away ribs on either side of starter housing, like stagehand did to the fossa. ~ 1.5 lb of possible weight to lose according to Paul Rooney.
  • Baja designs 8" round headlight weighs 5.8 pounds. I might shelf it for a bit in favor of a DOT legal plastic one at about 2 lbs. 3.8 pounds saved.

    Turn this:

    Into this:
I'm guessing I can save about 12.7 pounds on the forks and front wheel, 9.5 on the muffler, about 5 pounds on the engine top, front, and timing chain covers, probably about 6 pounds on the subframe once HPN has reinforced it, maybe 2 pounds on the airbox, 5 pounds on the starter, 5.8 lbs on the crash bars and sidestand, about 1.5 pounds shaving excess metal off the top of the block, 12.1 pounds on the battery, 2 lbs on the carbs, 3.8 on the headlight and 1.9 lbs for drilling the cylinder heads.

That's a total of 67.3 pounds. ...or to put it in perspective, that's like getting rid of the 6 bowling balls I didn't realize I was carrying around with me everywhere I go. If I were to switch to soft luggage, 67.3 lbs would be a full RTW touring load. It would basically be the difference between riding a loaded bike and a bare one. Wow.
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.

Airhead Wrangler screwed with this post 09-29-2011 at 03:01 PM
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