Weldangrind's New Lifan GY5

[SpudRider]

I think I saw that 'bike' in the pits at Bonneville last year. If not, I saw a few 'bikes' very similar.

[Weldangrind]

Originally Posted by mmprestine

A few years ago I started making some motor-bicycles. Around here the laws are very liberal for them, basically anything that has pedals is fine, all you need is a something that looks like a bike and an engine. I have always been fond of the old makes and their simplicity. I like the board track racers and this guy makes some of the best around. Check out his web and flickr page, especially the flickr page as the photos are awesome.

http://www.sportsmanflyer.com/bikes.html

https://www.flickr.com/photos/sportsmanflyer/

Walmart, Harbor Frieght, and Ebay really make this to easy and cheap. A word of warning - DO NOT look into it if you are week and have project issues like me! Its a sickness I tell people.

I have made a few and I am currently working on one and could start a thread on it or just on the engine part. The quality of these engines is pretty amazing for the price. And when you remove the governor and put a good carb on them they really rip.

I remember when I was about 7 and bought a Rupp mini bike at a garage sale for $15. Didn't run but I took care of that. Never had a Dad so Mom was pretty proud and that really started it all for me.

Matt

I always wanted a Rupp, ever since I read Mini Bike Hero in 1977.

Please start a thread on the whole project, not just the engine.

A gentleman on this forum did something similar, except he used a Zong engine: http://www.chinariders.net/showthread.php?t=13621

[Weldangrind]

Originally Posted by SpudRider

I think I saw that 'bike' in the pits at Bonneville last year. If not, I saw a few 'bikes' very similar.

Yep. Here's one of the bikes we saw at Bonneville:

[Weldangrind]

Well, the signal light flasher mod lasted almost one whole day.

The cheap Napa flasher I was using couldn't stand up to the vibration, so I substituted the flasher from the Roketa for now. It works great. Is suspect that I could find a heavy duty flasher at Napa, but I'll just find one online instead.

This is the Roketa flasher that I installed under Lifanda's seat.

[Weldangrind]

I failed to properly report that six (!) spokes broke while Son of Weldangrind was riding to Bonneville last year, so I dealt with that this year. I had custom stainless spokes manufactured at Buchanan's, and I believe the cost to be totally worth it. If anybody wants to order SS spokes from Buchanan's for an identical wheel, they now have the details on file. Send me a PM if you want the info.

When the spokes originally broke, the wheel looked like something from a clown car; the rim looked taco'd. I was shocked to learn that the rim is unharmed! The rim that looked so bad last year is back on Lifanda.

The problem is with the tire, since the broken spoke incident. When Bro-in-Law and I went riding last week, the front wheel had a wicked hop in it, despite considerable effort to balance the tire. Today, I pulled the tire back off the rim, removed the rim lock, covered the spokes with two wraps of Gorilla tape and put the tire back on. I spent about an hour inflating the tire up to 40psi, spinning the rim on the truing stand, identifying the bulged area, deflating the tire, adjusting it and repeating. The tire still has a slight wobble and hop to it, but it's much better.

I deflated the tire to 26psi and went for a victory cruise tonight. It's livable. I'll wait until this tire has a few more miles on it before I replace it.

[Weldangrind]

I really don't like the spark arrestor insert that's in the muffler I bought. I think I'll replace it with an insert that is like the one from my old '96 XR250R, since it's much less restrictive. I tried the '96 in my muffler tonight, and it was noticeably less restrictive. I'll need to rejet, but that's easy.

[humanbeing]

Originally Posted by Weldangrind

...but I'll just find one online instead...

http://www.ebay.ca/itm/121404217004
===
REAL cost in Guangzhou bike mart
http://item.taobao.com/item.htm?id=38700497132

[tankme]

Originally Posted by Weldangrind

Made a little more progress on the weekend. I wanted a free-flowing muffler that the USFS guys would approve of, and I wanted a cleanable spark arrestor. I found a 2001 XR250R muffler for a fair price on eBay, so I bent some tube and welded it together. The muffler came with a quiet core insert, but I also have a wide open insert on my '96 XR250R, so we'll see which one sounds better.

I also cut the heat shield mounting bungs off of the head pipe and re-welded them to accept a different heat shield that I had laying around. The original heat shield is really large, and I wanted something smaller. If I get motivated enough, I might build a custom shield out of stainless.





After I was satisfied with the fit, I painted the exhaust system with semi-gloss black heat paint. I also made some progress in fabricating a headlight mount. No pics for that yet.

Setting the bar high again! Really nice work Weldandgrind. It seems like I am going to be doing the same thing.

What type of steel pipe did you use for the mid-pipe area, or use typically for exhausts? Is this something found in a local pipe yard, or can onlinemetals.com satisfy for this small project? (Driving to town from the sticks costs me $32 so online is my first choice.)

Thanks!!
Jim

[Weldangrind]

Originally Posted by humanbeing

http://www.ebay.ca/itm/121404217004

Thanks! I'll order one soon.

[Weldangrind]

Originally Posted by tankme

Setting the bar high again! Really nice work Weldandgrind. It seems like I am going to be doing the same thing.

What type of steel pipe did you use for the mid-pipe area, or use typically for exhausts? Is this something found in a local pipe yard, or can onlinemetals.com satisfy for this small project? (Driving to town from the sticks costs me $32 so online is my first choice.)

Thanks!!
Jim

Thanks. I can't recall what I used, but I doubt that I would have used DOM, because it's not necessary for this task. Probably just mild steel tubing, and I was more focused on the size than the material.

The mandrels I have with my tubing roller don't match the specific size I was bending, so it creased the tube a bit. It still flows.

[tankme]

Hmm, what is DOM?

Thanks!
Jim

[tankme]

Ah, Drawn Over Mandrel.

Ok so this 4130 is what I am looking at: here Is this what I'm looking for? or is the A513 kind of stuff closer?

This OD matches the exhaust pipe's diameter. And what I think I'm measuring as thickness on it as well. So, pull the trigger or use something else? I only have square tube laying around and 4" pipe as well, nothing smaller.

Thanks!
Jim

[Weldangrind]

I'm not that fussy. If the tube matches the pipe, I burn it in.

[tankme]

Gotcha, I did order some mild tube as the local yard doesn't carry thin stuff. Also good to know you can weld it while it's on the bike.

I'll be lucky if my finished exhaust looks half as good!
Thanks!
Jim

[Weldangrind]

I only spot weld on the bike. Finish welding is on the bench.