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Discussion in 'Thumpers' started by hondabtr, Oct 18, 2017.
Awesome, how about yourself?
Can’t wait to see it back together on a scale (I mean the bike...)
Tires and tubes. Some will recall the tire weight discussion. It was decided at 4626 grams the Kenda 270 120/80-18 rear was a nice light tire compared to the stock TW 120/19-18 at 6123 grams, or 1497 grams less (3.3 lbs, Gertrude)!!!!!!! All rotational weight too. There is a huge difference in tire weights. If you aren't married to a particular tire it wouldn't hurt to consider weight in your decision.
Tubes. I blatantly stole this idea https://thumpertalk.com/forums/topic/993917-my-new-cr-125-afs-aluminium-framed-mugen-powered/?page=7 regarding tubes. I weighed a boatload of tubes and decided to use Surly fat tire bicycle tubes. SO much lighter! They are 3.00 to 4.8 inches so easily will fill a 120 rear.The tube I took out of the rear was 732 grams, the Surly weighed in at 360. That's 372 grams, Newt!!! 13.12 oz!!! Rotational weight!!!! It's a good thing.
The rim strip was equal to two wraps of Gorilla tape so nothing to save there. So just a rear tire and tube saved almost 4.3 lbs. That's a pretty darn significant weight savings in a very important area. I'll do the overall swingarm and front wheel reductions in another post
You can ditch that thing alltogether. Plus the little mounting brackets. Haven't run one after the first time oiling my chain. Never missed it. Maybe if I wore a dress when riding.
is that a chain guard? if so, right. just about nobody uses them.
Found another area to save weight I had completely overlooked till Rebuilder saw it. Old adjustment snails 180.3 grams
New aluminum CNC cut snails by Rebuilder 65.7 grams. -114 grams? Are you kidding me? That's crazy talk. I'm telling you Rebuilder is something else.
Awesomeness, that guy is really talented.
Yup. Wait till you see what we are cooking up for the next project. Looks like supercharging is back on the menu, boys
Finally got all the parts to reassemble the triple trees and install. Old weight 2422 grams
New triple tree assembly windowed and milled by Rebuilder, titanium bolts, titanium stem nut by Rebuilder, and aluminum top nut 2072 grams - 350 grams(12.34 oz) ... Blatant spam: I have an extra blue top nut $10 shipped to you.
This thread is my favorite kind of crazy!
How you doing yourself? Christmas season ain't friendly on human diets.
Thank you, Rick, for asking. To doctor on Tuesday so Ill know exactly. I do feel a lot better and my pants are really getting loose. I tried to maintain some measure of discipline through the holidays
Man, how disappointing. I'm holding steady in body weight, down 12 lbs from beginning, but just cant seem to get it going. My 60 year old body is having no part of this weight loss thing. Oh well, keep on.
We are coming to a close of this project. Won't be long now. Weighed in the rear caliper, milled and lightened by Rebuilder with as much titanium as is available, and an alloy banjo. 737 grams - 137 grams
Let's see if we can summarize the rear unsprung/rotational weight loss. A pound rotational weight is equal to 1.5 pounds static weight.
I am using stock tire weights for comparison only.
Kenda 270 120/80-18 4626 gr, stock 120/90-18 TW 6123 gr -1497 gr (3.30 lbs)
Rear caliper -147 gr
Adjust snails -114 gr
Remove chain guard -250
Titanium swingarm pivot -74 gr
Titanium axle nut -14 gr
Rear tube -265 gr
Alloy nipples -72 gr
Rear axle spacers -54 gr
Rear hub Old cush drive 2635 gr New machined non cush hub 1542 gr -1093 gr
43 tooth aluminum sprocket replaces steel 43 -344
Titanium sprocket bolts -71 gr
I could find no lighter substitutes for the chain guide, the rear rotor, rear rim, rear axle, and rear spokes. All small bolts were replaced with titanium but I didn't weigh them all.
Total removed (theoretical) weight is 11.23 lbs!!!!!! Holy crap, I had no idea there was so much weight in there. ALL beautiful unsprung/rotational weight. The engine won't have to turn it, and the shock won't have to absorb it. Gonna be sweet.
Dude. No weight gain over the holidays is a bigger victory than I can claim. I would have been ecstatic to have held steady!!
12lbs is amazing. Keep on keepin on! It'll come...
Colon cleanse! You'll drop an amazing amount and stun yourself (just do this while near home, ok?).
Diet, along with exercise is actually "essential" to get weight off - and keep it off. I have severe back trouble, so movement is always painful, but I have to keep moving to keep up a respectable calorie burn. Anaerobic exercise will dramatically increase calorie burn, so get in some of that every single day (like it was your new religion, seriously). So I just push through the pain. What you eat will have a huuuuge impact upon how your body processes the calories you're consuming. When I was getting prepped for surgery, I hit the machines pretty hard and heavy, it made a huge difference in my recovery time too. So just suggesting all these things as tips for how to get it off and keep it off.
I want to do what you've done on the DR350 to my DR650...
Great thread, thanks for all the info!
I can' wait to test ride :)
I do not think you get to count that awesome ti swing arm pivot and nut as unsprung though
Lets see if we can do the front rotational/unsprung weight now. A pound rotational weight is equal to 1.5 pounds static weight.
I am using stock tire weights as comparison only.
Stock TW 3.00x21 3810 grams Kenda 270 3.00x21 3765 -45 grams (Not much there)
Surly Fat tire tube 360 gr vs.IRC 3X21 tube 907 gr -547 grams
Alloy nipples -72 gr
Windowed axle cap by Rebuilder -6
Speedo drive -312 gr
Caliper Stock 857 gr v. CRF450X 674 -183 gr
Aluminum axle spacers -34 gr
Front hub machined -115 gr
Axle cap nuts -6 gr
I used titanium rotor bolts but forgot to weigh them
I could find no lighter substitutes for the front rotor,spokes, wheel, and axle.
Total weight saved is 1320 grams or 2.91 lbs. Not as mind-boggling as the rear but still something good.
I'd like to score a DR350 and do something similar. Can't wait to see the final product.
Hondabtr, great thread, great methodology. I love it. I have long had thoughts of doing exactly what you are. Of course I wouldn't have done as fine job as you have. Keep up the good work and thanks for sharing.
did you look into integrated master cylinders on your rear brake? eg KTM part 77013060044