Not reaching top speed

Mike B said:
When you were low on gas the carb bowl was not full and so you had a "leaner" mix.

That's all the verification you need.
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Ok thanks. I had a really hard time jetting my carb. I my pin vice was off so the bit wobbled witch made it like impossible to drill. I might just order some.
 
Yeah, those pin vises can be a bit tricky to get the bit centered perfectly bt you can take the end off the pin vise and reverse the chuck, and I think there's another one in the handle so you can fit every bit in it without having to force them or being too loose after cranking down on it... check your pin vise, the rear piece that turns freely comes off, and so does the nut on the bit holder, Once you get the right chuck for the bit you're using it should line up perfect. A little bit of play or off center won't hurt but if it's way off then it won't let ya drill a straight hole.

I've used bits smaller than #80 in my dremel and drilled tiny holes thru brass and other metals by running it at the slowest speed and using a drop of oil to keep the bit cool, just used the weight of the tool to do the cutting because if I would have tried to push down it would have broke the bit. If you have the smaller adapters for the dremel you can use it but it does take a steady hand.
 
So I've finally got my jet sorted out and am now getting a constant 30 mph. If i really push it it can go around 33 but it sounds like its gonna kill me. I can keep 30 relatively easy. Thanks. Now I want to beat my friend! where to next?
 
thirdorangutan said:
So I've finally got my jet sorted out and am now getting a constant 30 mph. If i really push it it can go around 33 but it sounds like its gonna kill me. I can keep 30 relatively easy. Thanks. Now I want to beat my friend! where to next?
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Thats great to hear..... glad you finally got it sorted out.

What size rear sprocket are you using?
 
I'm using a 44 tooth. How much faster do you think it would go with a 36 tooth? I way around 105 pounds so not having enough torque shouldn't be a problem
 
At 105 pounds the 36 tooth should do you pretty well and get you closer to the 40 mark if you can hit 33 with it now. One advantage you have is light weight... most of us are over 200 lb so we gotta come up with other ways to get our bikes not only fast but also able to accelerate enough to reach those speeds in a decent amount of time... You should still be able to accelerate as well as his if not quicker if your friend is closer to the 200 pound mark...
 
I completely agree with Dave here, a 36T should do you a great job, Im over 200lbs and I run 34T, 36T, 41T and a 24" tire bike has a 30T all of these bikes are capable of 40+mph and they pull me up hills just fine and get up to top speed in what I consider to be a respectable amount of time.

At 105lbs if the engine is strong along with the gbetter tune you have now you could probably get away with a 32T, but the engine has to have the grunt for that size sprocket and just having a good tune isnt enough for it, higher compression, good exhaust, good port work and good overall balance of the engine is a must whenyou get below a 36T in my experience.

You being such a lightweight is to your advantage big time though so like Dave mentioned you can get away with more than us 200+pounders can.

If your bike has a typical size coaster hub you can get the whole setup from MZmiami of ebay shipped to your door for $50 or gasbike.net has them for $45+shipping, MZmiami also has the 32T sprocket set up if your engine is up to that task if you want a really fast top speed on the flat, but I personally recommend a 36T and then you could always spend $25 later on for the 32T sprocket only if you feel it pulls the 36T very good and has some power to spare.

Best wishes with whatever you decide.

Map
 
I also weigh about 225 so I like to keep mine with the 40 or 44 tooth sprockets to keep the acceleration decent but I get my speed from lots of port work and a really good pipe. My bike hits 41 mph consistantly with the 44 tooth rear sprocket and 43 with the 40 tooth with a slight loss of acceleration.
I'm working on a new ported jug to get more torque with the same type top end rpm and power, I should have it up and running this weekend or next weekend if I don't have time to mess with it tomorrow. This new jug I took it to the limit with port width so it may work great or it may snag a ring but ill soon find out...
 
Davezilla said:
I also weigh about 225 so I like to keep mine with the 40 or 44 tooth sprockets to keep the acceleration decent but I get my speed from lots of port work and a really good pipe. My bike hits 41 mph consistantly with the 44 tooth rear sprocket and 43 with the 40 tooth with a slight loss of acceleration.
I'm working on a new ported jug to get more torque with the same type top end rpm and power, I should have it up and running this weekend or next weekend if I don't have time to mess with it tomorrow. This new jug I took it to the limit with port width so it may work great or it may snag a ring but ill soon find out...
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hope it works out just like you want Dave, I guess one thing I forget to consider when I give people advice on gearing sometimes is that we dont all ride in the same conditions, I do most of my riding on open roads and main highway shoulders, very little town riding, but when I do r8de into town, my bikes with 34 & 36T sprockets will hang right on the bumper of 90% of the vehicles im behind when we leave out from a stop light with just a little pedal power to get me up to about 8-10mph so that is plenty enough acceleration for me, but for some it may not be enough.

The last bike I put together "The (Green) Grasshopper" bike has a 41T it does 42mph so far on the flat and gets there fairly quick, so Im fairly happy with how it runs, only complaint I really have is that the GT5 engine has a little less power on the hills with a 41T compared to my PK80 type 40mm stroke engines with 34T or 36T sprockets, it may just be the jug I have on it and a port timing issue more than a 2mm difference in stroke, when I get one of my other GT5 engines built up with the same jug and same port work as I have on the PK80 Ill know more about all of it, hoping a side by side comparison will give me solid evidence to base my opinions between the two on, Im still in the dark a bit since 8 havent actually compared apples to apples yet, but I will.
 
Ok guys, Ive got a quick question. My gas tank is leaking, not much, like one drop every 10 min. Its leaking from the back left mounting screw. I tried to jb weld all around it and its still leaking. Is there anyway I can fix it or will I have to buy a new one. I really don't want to spend much.
 
thirdorangutan said:
Ok guys, Ive got a quick question. My gas tank is leaking, not much, like one drop every 10 min. Its leaking from the back left mounting screw. I tried to jb weld all around it and its still leaking. Is there anyway I can fix it or will I have to buy a new one. I really don't want to spend much.
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Cheapest fix honestly is just to buy a new tank, many of these get a leak from the nuts being overtightened so be sure they're just snug on a new tank.
 
thirdorangutan said:
Ok guys, Ive got a quick question. My gas tank is leaking, not much, like one drop every 10 min. Its leaking from the back left mounting screw. I tried to jb weld all around it and its still leaking. Is there anyway I can fix it or will I have to buy a new one. I really don't want to spend much.
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If you don't want to spend another $15 on a new tank you can JB weld. What you have to do though is drain the tank. Clean it with sand paper then put a thin layer over the leaking area I say coverage area is better than a thick glob. Then test by filling the tank with water to see if it is still leaking. If it is start over or just by a new tank.
 
mapbike said:
Cheapest fix honestly is just to buy a new tank, many of these get a leak from the nuts being overtightened so be sure they're just snug on a new tank.
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This. Also use some rubber hose on the underside of the tank when mounting. This stops it from moving and it means it doesn't have to be as tight as the rubber will compact slightly and grip a lot better than metal on metal.
 
if the leak is small enough, you might get away with putting a tiny o-ring on that stud with a washer & then put an extra nut to press the o-ring against the bottom of the tank - be sure that you don't tighten that stud too much when you remount it
 
crassius said:
if the leak is small enough, you might get away with putting a tiny o-ring on that stud with a washer & then put an extra nut to press the o-ring against the bottom of the tank - be sure that you don't tighten that stud too much when you remount it
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mickey mouse fix, fuel leaking on a hot motor while you are riding.

I mean, like what could possibly go wrong? laff

A new tank is a cheaper fix than a flaming motorized bike!
 
I would have thought it obvious that one would not ride it if the leak persisted. A SLIGHT leak can be sealed this way.

The proper fix is too complicated for most folks. It is done by removing that stud and drilling thru bottom of tank. Then a piece of safety wire is fished up & out the filler neck, a bolt with a metal washer & neoprene washer is attached to the wire & pulled down thru the hole. Now, another neoprene washer and then metal washer goes on the bolt. Follow this with a nut, then double nut the end of the bolt so one can hold it from turning while the first nut is tightened on the bottom of the tank to squeeze the 2 washers - all done once the doubled nuts are removed from end of bolt.
 
Get a new tank.
Install it with some kind of cushioning between it and the frame and DON"T OVERTIGHTEN THE FASTENERS. The clamps and fasteners should only be tight enough to hold the tank against whatever you have between it and the frame.
There is a lot of discussion here on ways to mount a fuel tank with some great ideas to keep the stress off the studs and the tank.

http://www.google.com/cse?cx=partne...gsc.tab=0&gsc.q=mounting fuel tank&gsc.page=1


Tom
 
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