Electra build gx100

Rats, my chain kept jumpin off. Alignment issues that can only be solved with a chain tensioner...so welded a derailer tab, and until I get a single speed tenstioner, this works. No more jumpin.
 

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Well it was worth the frame swap. Love the seating position. Gotta quiet it down...a little.
 

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Hey Scratch cant you cut the crank on the 3hp? I have shortened a bunch of cranks over the years takes all of a half hour.

Good to hear on the Nexus. I shift the same way. The best shifter I have is the one with the Sturmey Archer 3speed fixie hub. That one is so far indestructible. Doesn't matter how you shift it.

Make sure you have a cast iron flywheel. A aluminum(push mower) will fit, work and rev faster but its a hand buster if you don't take total command of it when starting.

Great looking build, as usual!
 
Yeah!! After putting the alum flywheel, I pull like I always do.... Wow! Yep, rotate to piston up, then be..like you say, total command. I thought, maybe the engine had mods...but then I remembered the head was stock. So, the iron flywheel really makes the pull easy. Would have never thunk it. I don't want to cut the crank. It is a stubby 3/4, that wont accommodate a clutch. Same thing with MTwice and his engine. I'll do like he's gonna do add a piece. If the 3 hp crank wont fit.
 
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Got ya on the crank.

The blade on a push mower engine helps with the flywheel effect. The cast iron makes starting easier and idles smoother. Doesn't Rev as fast if hi perf is what ur after.
 
Hey do you need a 3.5 crank, I got two of em here both long 3/4. Also iron flywheel if ya want it it. Bike looks comfy.
 
It sits and rides comfy. You don't feel bump's as harsh'ly with the longer wb. Yes I would be interested in the crank. Though it is testy to pull start, I prefer the alum flywheel, quicker revs. Had to swap bars. Looking for 8 or 10" rise BMX bars with long grip ends. Then remove the center bar.
 

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No stopping you with the welder is there. I like the welded bars!

Thing looks like it would run forever and be comfortable doin it.
Left handed shifter?
I shift on the right. Forces me to remove the hand from the throttle to make
easy shifts.
Once again great build!
 
"what'da mean its broke...i'll weld it...lol. Went ride'n around today..had to change out the bars..welded bars don't cut it. Need to go bigger on the primary Js, its now 11-36. And pulling 4th on a slight incline, not good. The bike is a bit heavier than the S jaguar was. Also take off is a bit sluggish. I already changed from a 32. CB can I change the cogs between a nexus 3 speed and the 4speed? The shift mechanism's are totally different. I'd rather have quick take off than top end.
 
If you are asking about the sprockets on the Nexus hub itself I'm not sure I have only run 3spds which take the common coaster sprocket. You can get these in lower 20s tooth count. Which should help if say you are running a common 18t.

Cant you change put a sprocket on the JS easier?. All my Nexus builds are thru the bottom bracket and run CG sprockets on the Nexus in the 40/44t range. I believe the Honda is 2.5hp? My 49cc 2stroke build is about 2hp and pulls a ratio around 20:1 overall as I remember. The Honda should pull some what lower numerically.

If you search around on the net(maybe Sheldon Brown) you can find the hubs internal ratios. This helps figuring the overall #s.
 
Hey guys, the rear is a 21 now. And the price to go up on the primary 4t, is 30$. Which will get me my sbp 207bb for the rear sus. Briggs re-build. And my freewheel side is a 60 #35 with a 24 #410. I switched from the 3sp to the 4 because the 3 kept moving on me....but I have an ......
 
Ok, what'cha think about this? Am I just cutting off non structural meat. If I cut the black line, I could use these axle keepers to stop the 3sp moving on me. I compromised the threads on the axle when I ran without the 'non-turn' washer on. Oh that little hole...heck I'll just fill it in with my trusty welder.
 

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That cut should pose no problem with the frame.

I'm trying to get an idea of what your overall ratio is I gather its 11/36 from engine to sprocket on the JS. Whats the count from the right side JS to the BB sprocket, then from the BB to the rear hub?

The 3spd Nexus internal ratios are 1st .733 2nd 1:1 3rd 1.364.


its increasing about 36% each shift that's a fair jump.

Realistically figure a high ratio of 16:1(3rd) this means 2nd is 21:1 and 1st is a stump pulling 27:1

The 24" build I am working with now has a 16.4:1 overall ratio. It calculates to 29mph@6500rpm. This would be similar to your bike with the 16:1 ratio in third. You can shift the range up or down a bit to suit your liking.

You may be thoroughly confused by now.
 
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Lol..yep...if you talk 1/16, 1/8, 3/4 I understand. This I have go to the conversion app...i have no idea what the 4sp ratio's are. My gearing is 12-36 over to 11-60 all#35. Then 24 back to the 21 on the rear. The 3sp has a quicker take off. So if I add those axle keepers I can put it back on. With the 4sp I skip 2nd anyway. Im gonna tighten up my chains and put some miles on before I cut the frame. Does the 27-1 and others mean, revs of the crank and one of the wheel? I'm not sure I run 6500 cruising...but it sure likes it when I do wind it out. I think id be in the 40's in 4th at 6500.....
 
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So looked up the Nexus 4spd. Its lowest ratio is 1:1 and it gets higher from there. That means you would need a very low overall ratio.

If I calculated correctly your overall ratio is 14.1:1 that's pretty high for that engine even with a single speed. You should be able to use the 4speed if you greatly lower the overall ratio.

Yeah the 27:1 is the reduction. Engine rpms/wheel rpms. When using IGHs ratio calculations get a bit more complicated.

I had a wonderful gear calc I could just plug multiple ratios into. I lost it on a damn Windows 10 update and cant find it on line anymore. Made all this so much easier than using a calculator and math.
 
scratchbuilder said:
Ok, what'cha think about this? Am I just cutting off non structural meat.

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If I cut the black line, I could use these axle keepers to stop the 3sp moving on me.
Click to expand...
Heck, you can take a flat piece of metal wider that your axle and ~3" long, a drill an axle size hole on one end, get the chain tight, and drill a hole through both the other end of the flat part and 'the extra meat' part and run a bolt and nut through to attach it.

Not ideal, and not adjustable without multiple holes but simply 'a way'.
I wonder if you can bend that 'extra' dropout mental out to provide to a hole for a typical adjustable 'axle tug'?
 
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