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Here's the monstrosity I built Schwinn Lakeside with a Grubee Skyhawk, now upgraded to a CNS carb, and SBP exhaust. Taken the exhaust off though since it was vibrating pretty bad and trying to find someone that can weld the sucker together so I can mount it and keep it stable. With the exhaust it'll top at about 36 MPH, with the stock exhaust it'll hit about 25 MPH and four stroke like hell. Last upgrade I gave it was a larger Whizzer style tank that holds drat near a gallon of gas but had to make a new gas cap gasket since it leaked worse than the stock tank
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Jul 10, 2012 07:29
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| # ¿ May 18, 2024 01:57 |
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I've not had any issues really. Went with the Kool-Stop brake pads and changed the rims to heavy duty rims with 12 gauge spokes. It stops on a dime with no issues. Hardly any vibration from the motor, you just need to mount the plates flush with the frame and not use those useless "vibration dampeners" aka rubber strips. I hardly pass 25, ever. No road around here I ride on has a speed limit beyond that. Hell, the Huffy I had prior to this lasted me four years with no issues and was finally put down by a car hitting it.
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Jul 10, 2012 16:05
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That's one thing I looked for, the steel frame. I originally planned on going with the Genesis 29" that's out there. Just make sure to grease the bearings all over first. But after seeing the frame was aluminum I decided not. Either the clamps would crush the tubes, the engine would vibrate through the frame, or one good bump would fold some part of it. Besides, 29" wheels are harder to find replacements for. The only thing I was worried about is the rear frame tubes being as small as they were. They're much smaller than the Huffy before so even the chain tensioner wouldn't fit. Had to quick fix that, but it's held up just fine over the past three months
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Jul 11, 2012 03:21
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OlDirtyBehrmann posted:Just make sure you stay on top of it as far as cracks go. Every single motorized bike I have seen locally has some scary poo poo going on. They definitely aren't made with constant higher speeds in mind. 13-14mph is a pretty average cruising speed so when you double that you are putting loads of extra stress on the frame. I'll wager they were mostly cheap *insert mart*-Mart bikes that did such and a lot of novice mistakes. This is kind of a find out as you go type thing. Ditch the rubber "shock" pads, they just allow vibration and pass it on to whatever else it can spread to. Make sure the muffler is attached to the frame, otherwise it's like a tuning fork as you ride. Keep the engine bolts tight. DO NOT drill through the frame like the instructions say you can. Don't build it on a bike with coaster brakes, they can't take the stress. If I had to add anything aftermarket I'd say find some heavy duty bike wheels. Some websites sell heavy duty 12 gauge spoked wheels that mopeds use. Mine have a rim width of 2 inches so the 2.125 tires fit on a bit wider and suck up some of the road shock. The shifter kits out there are fairly worthless, unless you have death on your wish list. It's nice having the extra power and speed, but it puts a lot of load on the rear of the engine case and there are speeds you should absolutely never do on a bike. Plus 200 bucks I really don't see the worth. It also doesn't hurt to put some lead shot (if you don't mind extra weight) or that expanding spray foam in the handlebars, it cuts down on vibration a lot. The pull start add ons are cheap trash. I haven't tried the centrifugal clutch yet, and since you need one of those cheap rear end pull starts, most likely never will. And for the love of God, lights! Light that fucker up. I've got the after market battery charger that hooks up to the engine so I run a few tail lights, brake light and turn signals. The headlight I use a 40 dollar Cree that shines like the wrath of a sun god at night
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Jul 12, 2012 03:36
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I actually built my own tabs for that courtesy of the hardware store and some angle brackets. I had that issue with my old Huffy while it was still a pedal bike. I've done straight forks on everything, are those springers really that strong? They always look weak and easy to break to me.
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Jul 13, 2012 05:44
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Four stroking? Smaller jet most likely. I've honestly never had an engine 4 stroke more with a new pipe on it
SocketWrench fucked around with this message at 04:32 on Jul 17, 2012 |
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Jul 17, 2012 04:27
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M4rg4r1ne posted:You will probably seize if you downsize your main jet from stock. Not sure what emissions regs were like when yours was new, but you can bet the stock exhaust and jetting were tuned for maximum fuel efficiency. Yes, but if your pipes allow better flow, it sucks more fuel through, you might have to decrease it some. Can always do a plug chop to see
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Jul 17, 2012 16:14
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ShaneB posted:This is not how expansion chambers work. Hope this helps. And I had no idea it was an expansion pipe
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Jul 18, 2012 03:28
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bsmack posted:Day 3: Still no run My petcock on my engine feeds at the same rate. So long as your engine doesn't drink more fuel than the petcock pours which you should be able to notice when at WOT when you're using the most fuel you can. I can't speak for your engine, but mine likes a little throttle when starting, just barely a twist of the grip. Some engines are quirky in old age. Of all the mopeds I've had only one that liked to have a choking to start. myself, I wouldn't be playing around with jets till I could at least get it to sort of run or as a last resort because it won't start.
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Aug 19, 2012 06:43
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Bovril Delight posted:Are motorized bikes allowed in here? I've been looking at a Grubee Skyhawk engine to throw on my bike, but the instructions range from poor to dreadful. I have a several year old GT Avalanche that I'm contemplating using as a donor, but I have some doubts over the frame size and the down tube. The clearance for the motor itself seems to be tight, but looking at pictures it seems do-able. The real problem seems to be that the down tube is massive at ~5" around, so I think I'd have some serious issues mounting it. I've a Skyhawk myself. They're fun little things to tinker with and get for puttering around small towns, but for anything more than five miles I'd keep looking. Mine runs fairly well, it can hit 35mph but i keep it around 25. Brakes are ok if you can find pads that won't wear down in a few stops. Disc or drum would be best since rim brakes suck in rain, and don't use coasters. I went the extra hundred and got some heavy duty wheels with thicker spokes, the same place sells drum hubs now that they'll build for whatever size tire ya want. Best to get a good bike too, not those cheepo Walmart bikes and definitely not that Onyx 29" bike, the aluminum frame won't hold up to the engine torque and vibration. Depending on what ya want it for, it will get expensive. I use mine to make the 1 1/2 mile trip to work so I've got a Cree headlight and battery for forty bucks off ebay, one of those cheapo brake/turn setups for bikes and built a dual 6 volt taillight setup for about 100. Plus the cops in my town are pretty easy going. I register them with the SoS just to be safe though. You just really need to remember one thing though. It's a bicycle, not a motorcycle, crotch rocket, dirt bike, moped or anything else. If you start pushing it like it was something more you will have a catastrophic failure (People in this thread, including me, have had the front fenders break loose on them and sent the rider flying). They get a bad rap a lot, but they can be lots of fun and hold up pretty well as long as you take care of it and respect it for what it is. As for the Skyhawk itself, I've had nothing but good luck with them. Stay away from those unbranded Chinese engines, they're kinda hit and miss. Had one that ran great for three years, had two others that were missing bearings and one that had a cracked piston. Custom Motored Bicycles (I don't want to link to a store site without the mods ok) has a lot of aftermarket parts to make things go a bit smoother and look less ugly (in the case of the gas tank). Some can look really good
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Jan 2, 2013 01:59
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Eh, I'm not so quick to throw the Chinese stuff under the bus. I've got one of those Chinese engine things for bikes and it's still going strong some 4 years and 15k miles later. I'm actually having my issues with the "made in USA" marked stuff. For just under 200 bucks I feel I've gotten my money's worth and more out of it.
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Oct 4, 2014 17:42
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Well, I got my holiday bonus, and looking for a new ride i figured what the hell and picked up this; It's a Roketa moped. I know, I know, chinese junk, blah blah blah. All the China hate aside, thus far it hasn't been that bad. Packing was rather lovely as the company I ordered it through did a full assembly and PDI before shipping, so meh. Few scuff marks here and there, both mirrors were crushed (being packed in a small box underneath, for some reason). I got the warranty too, so new mirrors aren't an issue. It's a bit different than the picture. the rims are 5 spoke aluminum with a thin strip of red reflective tape around the rim. The "information panel" (where the light/turn/gear display are) is a bit different that in the display. The Engine is a Honda clone and looks really tip top, not the rough casting and crap I expected. Once aside I filled it with gas, checked the oil, went around and made sure everything was tight and set to fire it up. Battery was almost dead (despite the shop claiming they gave it a full charge after upgrading it from the China special). So no starter I set to kick starting it, full choke and 1/8 throttle as the instructions state. No dice. After looking over the fuel system there are two cut offs. Alright, opened the second right next to the carb, which is open when the valve twists to the side rather than in line with the fuel line. Kicked it again, fired up and idled a bit, then died. Tried again, nothing. again and again, nothing. Had to go to work, so put the battery on a tender and left. Returning home I took the battery off the tender, reinstalled it and tried again with the electric start, nothing, wouldn't even crank.Feeling pissed I took to the internet to try and discover the issues. Via a website I found you need to squeeze the brake lever and then the starter will engage and the kickstands must be up because they have a kill switch that prevents the starter from working while the stands are down. Alright, went back and gave it a shot and bam, fired up but died soon after. Figured just for shits and giggles I'd check the plug. Gap was too damned wide (seriously, what kind of hosed up PDI was this?). Hit it again, fired up with no choke and idled really smooth. Shut it down and changed the oil. Alright, bundled up after letting it idle a bit. Pulled out onto the road and gave it some gas. Pickup is a bit poor at first (a better plug should fix that) but quickly accelerated uphill. Hit the shifter to get into second, it is a clutchless shift, so it hopped a bit when i let up on the foot shifter (better throttle/shifting combination should help that). Climbed through second ok and into third and at mid RPM was doing 25 MPH. Accelerated further, shifted into 4th and hit about 45MPH at about 5k RPM. Brakes are really responsive, the front disc works great and the rear drum grips firm. the digital gear display responded to every shift. Definitely gonna have to install a different shifter that lets me shift up and down with the toes as my heel can't push far enough down to downshift. Overall it was a nifty ride once I got used to the gear shifting and brakes. the engine runs solid and the shifter works really smooth. Shocks are adjustable by way of a twist nut that latches on a peg, every step climbs it a bit more to make the spring stiffer. Things to fix yet. the rear fender rubs against the tire when the shocks are compressed like going over bumps or as i already have, having groceries loaded on the back, so either need to drill some new mounting holes to move the fender further away or lengthen the chain to move the wheel back...likely be drilling holes. Plug upgrade, of course, might look up a replacement CDI as I hear they can get really unreliable. The turn signals stick out too far for my liking, I may get shorter LED ones. Need to find a red paint that matches to touch up some of the scuff marks. The plastic isn't very amazing, fortunately there's not that much on it. The oil dipstick cover was really frail plastic that snapped with a light twist, but the dipstick itself has two grooves in it that fit the wrench like tool the company sent with it so opening it can still be done. the wiring isn't too complicated, it's all easy to follow and connections are really clean. Prolly will remove the kickstart lever and store it on the bike somewhere as the lever juts out too far to let my foot rest on the peg without partially engaging the rear brake foot lever (at a size 14 this thing wasn't exactly built for big feet). Overall it seems to be really sturdy and decently built, I think it's been worth it for 800 thus far. Course I'm only 14 miles in, but so far it runs well. SocketWrench fucked around with this message at 17:58 on Dec 31, 2014 |
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Dec 31, 2014 17:52
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Hey, just reporting what I got. Far surpassed the "not gonna start at all" "parts fry/break off first time" that everyone screams about'em. By all means, if you can afford it or find a different bike, go for it over a Chinese, but jesus they're not the frail turds everyone badmouths them as being.
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Jan 4, 2015 01:10
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Yeah? Keep reading where I discovered you had to hold a brake lever in for the starter to engage. Boy it sure was broken, hur de hur hur. I swear, I never expect anything to work great fresh out of the box, but I guess if it doesn't that auto labels it as junk.
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Jan 6, 2015 18:25
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| # ¿ May 18, 2024 01:57 |
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Call of Cholula posted:I'm taking the pedals off the bike and replacing them with pegs anyhow since the pedals are pointless. I guess that's what Everyone ends up doing with Motobecanes. Way way back when i had my Moby that's what I did. The pedals sheered off, and this was like back in 96 before good info was available. Had it tuned to the point i could get it rolling and it'd kick over rather easy. The switch to kick it over from power to pedal always hosed the thing up anyways to the point i had to pull it apart and reset everything anyways, so it wasn't much of a loss. It was a good moped, not the quickest off the line, but could catch up with anything the other guys were using except the little Express I had. that fucker was quick, just could never get the fuel system to stay sealed so one day it caught fire.
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Aug 30, 2015 03:21
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