Pic of my 78 freespirt recently "finished". I see it has just now decided to leak fuel making a nice wet spot.
That looks great!
Well I just got back from Boston. It was my first time up there, and it's a fascinating city with great history. Pricey though.
Now that I'm back, once it stops raining I'm going to chain my transmission fluid to synthetic 10W30 - after reading a bunch on here it seems that's best for modded mopeds, and I do plan on doing more mods to mine. I was also thinking about rotational mass, and talking with my brother about it - he's got a Honda 919, and he put an anodized aluminum sprocket and lightweight chain on his bike, which saved a total of almost 4 pounds, and said he could feel a notable difference. It got me thinking, on something with such little power, I really should try to reduce the rotational mass on this bike, especially with my 2.75 rear tire. One of the first things I want to do is a lighter chain - a 410 if it will fit. I'm also going to drill out my front sprocket and possibly hollow a few bolts. Anything to save a bit. It'll all add up. But that will have to wait for better weather.
I'm almost ready to admit defeat and go with a standard size rear tire instead of my 2.75. It just looks so good. That thing is heavy as shit though, and absolutely kills my performance.
So I pulled the engine (mostly) apart yesterday and tried my hand at porting. My dremel bits kinda shit out on me at the end but I managed to enlarge the exhaust port so that it was the same size and shape as the gasket opening all the way through. When I bolted it back together though, I didn't really feel any difference, although it did run a bit better (still jetted kinda rich). My heavy rear tire and 420 chain pretty much cancel out any performance gains I would have gained.
The circumference of your 2.75 tire probably has more affect on performance than the weight of it - it will bog down your acceleration but you would have better top speed when you get there, eventually. Consider a smaller front sprocket to compensate, it's way cheaper and easier to deal with than swapping out Gazelles.
I use a cheapie 41 chain to dial in what's best then switch to 420 chain for the long run, because 41 chains stretch a lot and will wear the sprockets pretty quickly. Stick with a good quality 420 chain, any weight savings will be minimal at best for performance.
BTW, my Free Spirit is currently running 16T front and stock 45T rear sprockets with NOS Semprit 2.5 rear tire on an otherwise completely stock setup (with over 12,000 miles - cases never split, never touched the clutch) and the bike does pretty well with urban traffic.
I was going to pick up a 410 chain today just to see what kind of difference it would make, but when I looked at it in person, that thing was tiny. So I ordered a standard 415.
I took the moped for a ride today since the weather is so nice. After porting the exhaust port, I seem to have lost a bit of low end, although I did pick up 2mph on top end going downhill. I also dropped the jet from a 66 to a 64, since it was running rich. I still need to pick up a new needle and a few other little things to finish getting the carb from restricted 1hp to unrestricted 2hp mode.
Next paycheck I'm also going to get the 50cc treats cylinder/piston kit and a Hutchinson GP-1 rear tire, since they're some of the lightest ones. Undecided as to what size I'll run on the rear. I really like the look of the 2.75, I may just stick with a 2.50 for better performance though.
I know on my maxi I ran 2.25, while much narrower than the 2.75 you have, I think hutchinson's have a boat load more grip even with the smaller size. Just my 2 cents though.
If you're going to spend money on a cylinder, just get the treats 70 head/cyl combo.
From everything I've read/heard that 50cc unit is pretty gutless.
Wow, that was quick! Looks great, how were the welds around the headstalk? We just stripped my buddys 79 free spirit frame and found the welder totally missed the seam between the head tube and frame tube on one side, bead just went off course and ran along the head tube only, Gunter the welder must have been thinkin about Ingrid or in a hurry for his lunch break!
Dillon Ryan Wrote:
> If you're going to spend money on a cylinder, just
> get the treats 70 head/cyl combo.
> From everything I've read/heard that 50cc unit is
> pretty gutless.
I don't know enough about the engines to do that. Also it's more money, and with that kit I'd need to mess with my clutch and timing, and I'd like to avoid that. I'll probably upgrade my rear tire before I do anything else with the engine, because I know that's what's holding me back the most. I'm also picking up the correct atomizer and everything, to finish changing my carb from the restricted one to the regular 2hp style.
I read good things about the 50cc kit though, and it's a cheap and simple upgrade. I'm still new to this stuff though.
Rotating mass isn't just about the tire. Also think about the wheels. I also have a Free Spirit & have been using it as a daily rider since 2003. I do like the snowflakes, but if I was really going for faster acceleration, I'd change to ally wheels n spokes. Drilling the sprockets won't have much effect on MOI (moment of inertia), but may help with over all weight of the bike. Lots to be read in MC magazines about that subject.(MOI) Over all lightness of a bike WILL have a measurable difference in acceleration. The Hutchinsons are one of the stickyest tires out there & I'm sure you can drag a knee if you're wearing the proper gear, although the Pierelli 16" tire won the first Polini cup, however that could just as well been rider ability. I could go on & on, but just have fun with your Free Spirit like I have for the last 10 years.
Thanks Charles. Got my new rear tire in the mail yesterday, I went with a hutchinson 2.5", so once I put it on that should make a difference, along with the proper size chain. I also got the proper atomizer and the treats 50cc kit. I think all this stuff will get me close to where I want to be, which is basically my current downhill top speed but with much better acceleration.
The hutchinson 2.5" tire is so much smaller than the 2.75" gazelle, and a lot lighter. I installed that and the correct 415 chain and I was hoping that would make a difference. I also installed the treatland 50cc kit, and up jetted my carb, and installed the proper size atomizer. I ran it around the block and then changed the transmission fluid, with synthetic motor oil, since a lot of people on here seem to recommend it. It still accelerates slow as shit. There is a lot of drag coming from the front sprocket, almost like the brake is slightly on. I checked and the rear brake isn't the issue - it spins freely with the drive chain off, but put the drive chain on and it sucks. When it's up on the stand with the engine running, the engine can barely turn the tire at idle.
Everyone else who installed a larger front sprocket, did you have any similar issues? Did the larger front sprocket suddenly make it a lot harder to turn that rear tire?
Dude, oil that filter.
Well, I changed the front sprocket today, thinking that it may have been the problem. Nope. With the new sprocket on, the problem is just as bad. Also I think I need to tune the carb some more, it runs kinda rough sounding below around 1/2 throttle.
When the front sprocket was off, I turned the splined shaft coming out of the transmission with my hand. It was very stiff, much moreso than it should be. I don't hear any grinding or scraping, just the sound of gears turning together. The new sprocket is a 15t, so my acceleration is better, but this bike should be a LOT faster than it is.
So far I have ruled out:
rear tire size/type
Which leaves the transmission itself or possible the clutch. I have absolutely no clue how to mess with the tranny/clutch of this thing, so I'm at wit's end now. I would like to take it to a mechanic, but I have already spent too much money on this thing. I'm considering just selling it and being done, I am really really sick of this.
Bearings maybe? Take the engine apart and check. It sounds a lot scarier than it is. I had zero experience with any kind of engines and was able to do it just fine.
That's what I'm thinking. It might be the bearings or the clutch. I guess one way to find out.
Well it seems the problem was the clutch bushing. I swapped in a new one and voila, everything's good. It's definitely a lot more fun now. Now I just need to change the gearing to get my top speed back and see how well it accelerates. If it does well with the 17t front sprocket I might go up to an 18.
Good to know it was an easy fix. Keep posting what you find on sprocket experimentation, if you will.
Well it's an absolute pig with the 17t front sprocket, can barely go up a hill, and I don't have good top end either. Seems like I lost power or something, I dunno. It might be my pipe, but that's just my uneducated guess. I might need a pipe for better mid range. Maybe I just need to tune it better. I have no clue. I just know with my mods it should be a lot faster than it is. But at least the clutch bushing is fixed, so that's a step in the right direction I guess.
Well I've been riding it to work the past week and it's been doing okay, but I do have to keep my momentum and pedal when starting from a standstill, as the acceleration sucks. Thursday I was coming home from work and blasting down a hill and hit about 42-43mph and suddenly lost all power and coasted to a stop. Fortunately I have pedals and was able to pedal it home. The engine turns over freely but it seems to have lost all spark, so I guess I get to replace stuff in the ignition system. After that I'm going to get a new pipe, one with some midrange and tune my clutch to grab at a higher RPM. If it does well with that then I'll possibly try gearing it for a tad more high end.
Thanks, getting ready to kit this one as well, top tanks and me just agree.
Check the wiring in the left hand switch. The horn ground has made my Free Spirit quit on 2 occasions. It was a bugger to figure out the first time.
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