head tube replace

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by scratchbuilder, Apr 27, 2015.

  1. curtisfox

    curtisfox Well-Known Member

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    May need to lengthen it as step through are usually have longer head tubes, but will check it out tomorrow and do that before i send it. In the mean time measure the head tube on yours build just to make sure................Curt
     
  2. silverbear

    silverbear The Boy Who Never Grew Up

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    I'll do that after the sun comes up. The extra long head tube on step through bikes no doubt was to make the frame stronger to compensate for the front down tube sweep. Better to lengthen the mtb fork tube than shorten the Schwinn frame tube, eh? Strong is good and safe.
    SB
     
  3. curtisfox

    curtisfox Well-Known Member

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    Every one i have run across are 1" longer or taller. Easy fix i cut one off a older fork to the right length, and put a sleeve in and weld back together............Curt
     
  4. silverbear

    silverbear The Boy Who Never Grew Up

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    I'm sure it's longer and will measure it. Your sleeving and welding sounds like the ticket.
    SB
     
  5. scratchbuilder

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    Well...forget headtubing changes. Found a guy on Craigslist that is hooked up with a friend who has a contract with WalMart,k-mart etc..and next month their getting in 100 bikes. The guy has a storage 8x20 filled. I picked a del Rio( I know alum.)hey I'm 4 strokin..my shift points are when the vibs shake the seat of my pants. Nice color on the bike. What I got was complete bike minus wheels....25 bucks. And their new!! Just scratches,bent fenders.Goin back sat. And spend some time pickin n grinin!
     
  6. Agreen

    Agreen Member

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    For future information, welding the steer tube is a pain to get right. I chopped a 1" steer tube to insert in a 1-1/8" tube (which fits really well) and extended it by 20mm. Not much of an extension, but it's what I needed. Getting the two pieces perfectly aligned is difficult to say the least. It takes a lot of patience, small tack welds, and a lot of straight edge checking.

    If you don't do that, you will end up with a banana shaped steer tube, which doesn't roll too well inside the head tube.

    Nice score on the Kent. Just FYI, I know a lot of people poo poo on the idea of aluminum frames, but so long as the engine is properly mounted you will have a long life out of it without issue.
     
  7. scratchbuilder

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    Yeah I've done a couple builds,a front box cargo bike with the 20" front 26" back and I ended up having to cut reweld what thought was true. I went for a test run today on Del Rio what I felt was promising,it had its usual vibrations, then after a certain rpm, the vibs went completely away!! Had to come in and tightin my spring bracket..so how cool would it be cruising with no vibs...i'll post tomorrow more results.
     
  8. dtv5403

    dtv5403 New Member

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    Venice motor bikes sells disc brake adapters for any style fork, no need to chop up your frame
     
  9. scratchbuilder

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    Wow..what a difference in weight. The vibs go away and the engine, like hits a sweet spot and everything seems to harmonically balance out. This little hs142 for my first build keeps impressing me. Got to get a tach. I got the hf 79 and its so noisy. Makes me wonder how impressive the 50 Honda is. Just might be worth the money.
     
  10. dtv5403

    dtv5403 New Member

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    You could get a silencer for the 79cc to quiet down the exhaust some. Its a good engine, a couple of my buddies have used them and it's what sold me on it for my first build. I haven't run the engine, but I'm not so concerned with noise. I got a Shorty exhaust from affordable go karts. No idea how loud it will be, but the description said it provides decent flow while still maintaining a reasonable exhaust note.
     
  11. scratchbuilder

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    Hey dtv, I like exhaust notes,its,want I'm thinking is valve train noise,sounds tinny. Also i like the acceleration compared to my hs142! I'm still working on the build. Its a 24 rear triangle,with beach cruiser front and upright engine mount. Lot of weld joints. I got this RCA 80 dollar tablet,but trying figure how to post pics is weird science to me. I'm sure I'll keep the build goin. Its gonna be faster than I'm willing to go that's for sure!
     
  12. dtv5403

    dtv5403 New Member

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    Speed all depends on gearing. I am gearing my bike to cruise at 30. The gear ratio calculator I use on my laptop tells me 31.6mph at 6000 rpm, and 30 at 5700 rpm. I will keep it around 30 to keep the rpms down a bit and keep the engine happy.
     

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