GIO 125cc build

boost_addict · 10-04-2009, 12:16 AM

Well I decided to upgrade my 125cc a little cause I can't leave anything alone.
Right now the motor is in pieces and I have all the parts I need to put it back together now, so sometime this week I'll have her running and I'll let you guys know how she does when I take her out next weekend.

The mod list is
inner rotor kit
copper headgasket
26mm mikuni carb and 26mm intake with uni filter
ported the head to match the intake
bci rev camshaft with 6.5mm lift
Cam breather
16 tooth front sprocket
hollowed out muffler
Fastace rear shock

I still have to get an oil cooler but I wont have time to get it on for the long weekend so it will have to wait.

Weldangrind · 10-04-2009, 01:22 AM

16 tooth! That'll be a land speed racer.

Do you plan on a new CDI as well?

boost_addict · 10-04-2009, 04:39 PM

well mine came with a 15 tooth on the front stock so I don't think 16 will be a huge jump. I had trouble deciding if I was gonna do the 16 or 17, I actualy chose 17 but they shipped me a 16, so 16 it is.

The inner rotor kit came with it's own cdi
Which sucks because I already had a no rev limit cdi on it.

The bike was pretty fast stock, it almost kept up to 250cc gio (with my gf on the 250 and me on the 125) until my 250 gets into 5th then it's gone. With all the mods I'm hoping the little bike will be alot more powerful. Then I can switch my attention to the 250 and see how I can upgrade it :twisted:

Reveeen · 10-04-2009, 05:05 PM

The inner rotor kit came with it's own cdi
Which sucks because I already had a no rev limit cdi on it.

I *think* the voltages involved are different, a before, and after, voltage(s) measurement would be helpful?

Copper head gasket? Where did you source it? What is your reasoning behind using one? (did you "need it?) How do you intend on stopping the resulting oil leaks?

boost_addict · 10-05-2009, 05:58 AM

i'm making it out of copper sheet metal. It's slightly thinner than the stock gasket so it will raise the compression ratio a little, the oil feed holes have o-rings around them and i'm gonna use that spray on copper headgasket sealer on it to stop any other leaks.

There are a few stores around that sell copper headgaskets for pit bikes. but I'm not sure which one my bike would need. I ordered a gasket set from gio for the bike and the headgasket and base gasket didn't have the right spacing for the head studs, I told them about it and they sent me a replacement kit and it was the same as the first one

so I decided to just make my own.

I got most of the bottom end assembled tonight I got it up to the point of putting on the new "flywheel" so pretty much it's just the top end left to assemble. The clutch was a pain in the rear, I couldn't find a honda dealer around to get a proper clutch spanner for the bike and they wont be open again until tuesday so I ended up buying a 21mm 12 point socket and did some grinding on it to make it into a clutch tool. It worked awesome only cost $2 and took about 5 minutes to make

phil · 10-05-2009, 09:12 AM

before i went through the trouble of making a copper headgasket i think i would rather get the head or jug shaved a little or maybe shave it myself if you have good steady hands you could do it with a belt sander thats basicly what a machine shop does. and the cdi that came with the inner rotor kit most likely has no limiter

Reveeen · 10-05-2009, 09:36 AM

Increased compression vs retarded valve timing, I guess you could slot the cam gear bolts, and degree in the cam.

suprf1y · 10-05-2009, 05:27 PM

The difference in valve timing will likely be insignificant, and these bikes usually have really early valve timing anyway.

Reveen, you going to answer my PM?

boost_addict · 10-06-2009, 02:02 AM

the timing chain looks like it was stretched a bit cause when I took it off it was half a tooth retarded maybe this will allow me to put it back to spec.

Is there anything else you guys can think of to squeeze some more ponies out of this little guy?

boost_addict · 10-08-2009, 06:10 AM

Well I got it to start today! It still needs a couple things to finish it, a new exhaust dohnut and I need to get a 1/4" NPT tap so I can put the fitting for the breather in the valve cover.

It was started in my shop and it was really loud but I think that has mainly to do with the missing dohnut, tomorrow after work I'm gonna run out and get one and hopefully get it on while there is still enough time to take her for a quick run around.

It's definatly changed in a big way, I havn't tuned the carb at all yet but I had to have it idle really high to keep it running, and it revs up way faster than before.

boost_addict · 10-14-2009, 11:20 PM

Well i took it up to princeton for the long weekend and rode it around a little bit. It was really cold up there and i was having problems with the carb icing on me so I didn't get much riding on it.

What I can say though is that it feels like a completely different bike, it's alot faster and sounds alot meaner too.

I did a little monkeying with the carb but I didn't have a proper bit for adjsting the air screw so I had to take the carb off the bike to change it. It was at 1.5 turns out and was bogging off idle so I put it to 2.25 turns out and it's alot better but I still have to do some more adjusting with the bike running now that I'm back home.

There is one more issue I need to fix and it has to do with the gears.
When I'm downshifting from 3rd to 2nd it will miss 2nd and go into neutral. When I had it apart I had a look at everything to find out what the issue was, all the gears are fine and there is no visible wear on anything. when i put the shifter into 3rd and pushed it to 2nd the hook on the end of the shifter rod that pulls the cogs on the shifter drum would slip off the cog and that would turn it just a little bit more and put it into neutral. Does anyone know what would cause this or how to fix it? the hook and cog both look fine and not worn. there is a spring that holds the hook up could that be weak and need replacing?

Weldangrind · 10-15-2009, 02:35 AM

I haven't split many cases, but I would guess that spring pressure is the culprit. Do you also have trouble finding neutral when you're stopped?

boost_addict · 10-15-2009, 02:41 AM

Yeah it was my first time having a case apart, but everything looked good. I have a feeling that it's the spring too

suprf1y · 10-15-2009, 09:52 AM

Where did you get that cam, and do you have any specs on it?

boost_addict · 10-15-2009, 09:56 PM

if you go to the sticky at the top of the pit bike forum page, for pit bike parts, it's the first company they give a link to, I believe it's called beatrice cycle. they have a verity of cams for the honda horizontals. measure your cams length and bearing diameters and find a cam that matches.

10-04-2009, 12:16 AM	#1
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	GIO 125cc build Well I decided to upgrade my 125cc a little cause I can't leave anything alone. Right now the motor is in pieces and I have all the parts I need to put it back together now, so sometime this week I'll have her running and I'll let you guys know how she does when I take her out next weekend. The mod list is inner rotor kit copper headgasket 26mm mikuni carb and 26mm intake with uni filter ported the head to match the intake bci rev camshaft with 6.5mm lift Cam breather 16 tooth front sprocket hollowed out muffler Fastace rear shock I still have to get an oil cooler but I wont have time to get it on for the long weekend so it will have to wait.
	0

10-04-2009, 01:22 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	16 tooth! That'll be a land speed racer. Do you plan on a new CDI as well? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

10-05-2009, 09:12 AM	#6
phil Join Date: Jun 2008 Location: wise va Posts: 636	before i went through the trouble of making a copper headgasket i think i would rather get the head or jug shaved a little or maybe shave it myself if you have good steady hands you could do it with a belt sander thats basicly what a machine shop does. and the cdi that came with the inner rotor kit most likely has no limiter __________________ halls auto l coolster, modcycles, yanmar & zongshen, dealer fired roketa,lifan and jet moto and apollo quit me who's next
	0

10-15-2009, 02:35 AM	#12
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I haven't split many cases, but I would guess that spring pressure is the culprit. Do you also have trouble finding neutral when you're stopped? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

10-04-2009, 04:39 PM	#3
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	well mine came with a 15 tooth on the front stock so I don't think 16 will be a huge jump. I had trouble deciding if I was gonna do the 16 or 17, I actualy chose 17 but they shipped me a 16, so 16 it is. The inner rotor kit came with it's own cdi Which sucks because I already had a no rev limit cdi on it. The bike was pretty fast stock, it almost kept up to 250cc gio (with my gf on the 250 and me on the 125) until my 250 gets into 5th then it's gone. With all the mods I'm hoping the little bike will be alot more powerful. Then I can switch my attention to the 250 and see how I can upgrade it :twisted:
	0

10-04-2009, 05:05 PM	#4
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	The inner rotor kit came with it's own cdi Which sucks because I already had a no rev limit cdi on it. I think the voltages involved are different, a before, and after, voltage(s) measurement would be helpful? Copper head gasket? Where did you source it? What is your reasoning behind using one? (did you "need it?) How do you intend on stopping the resulting oil leaks?
	0

10-05-2009, 05:58 AM	#5
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	i'm making it out of copper sheet metal. It's slightly thinner than the stock gasket so it will raise the compression ratio a little, the oil feed holes have o-rings around them and i'm gonna use that spray on copper headgasket sealer on it to stop any other leaks. There are a few stores around that sell copper headgaskets for pit bikes. but I'm not sure which one my bike would need. I ordered a gasket set from gio for the bike and the headgasket and base gasket didn't have the right spacing for the head studs, I told them about it and they sent me a replacement kit and it was the same as the first one so I decided to just make my own. I got most of the bottom end assembled tonight I got it up to the point of putting on the new "flywheel" so pretty much it's just the top end left to assemble. The clutch was a pain in the rear, I couldn't find a honda dealer around to get a proper clutch spanner for the bike and they wont be open again until tuesday so I ended up buying a 21mm 12 point socket and did some grinding on it to make it into a clutch tool. It worked awesome only cost $2 and took about 5 minutes to make
	0

10-05-2009, 09:36 AM	#7
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	Increased compression vs retarded valve timing, I guess you could slot the cam gear bolts, and degree in the cam.
	0

10-05-2009, 05:27 PM	#8
suprf1y Join Date: Oct 2007 Location: SW Ontario Posts: 408	The difference in valve timing will likely be insignificant, and these bikes usually have really early valve timing anyway. Reveen, you going to answer my PM?
	0

10-06-2009, 02:02 AM	#9
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	the timing chain looks like it was stretched a bit cause when I took it off it was half a tooth retarded maybe this will allow me to put it back to spec. Is there anything else you guys can think of to squeeze some more ponies out of this little guy?
	0

10-08-2009, 06:10 AM	#10
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	Well I got it to start today! It still needs a couple things to finish it, a new exhaust dohnut and I need to get a 1/4" NPT tap so I can put the fitting for the breather in the valve cover. It was started in my shop and it was really loud but I think that has mainly to do with the missing dohnut, tomorrow after work I'm gonna run out and get one and hopefully get it on while there is still enough time to take her for a quick run around. It's definatly changed in a big way, I havn't tuned the carb at all yet but I had to have it idle really high to keep it running, and it revs up way faster than before.
	0

10-14-2009, 11:20 PM	#11
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	Well i took it up to princeton for the long weekend and rode it around a little bit. It was really cold up there and i was having problems with the carb icing on me so I didn't get much riding on it. What I can say though is that it feels like a completely different bike, it's alot faster and sounds alot meaner too. I did a little monkeying with the carb but I didn't have a proper bit for adjsting the air screw so I had to take the carb off the bike to change it. It was at 1.5 turns out and was bogging off idle so I put it to 2.25 turns out and it's alot better but I still have to do some more adjusting with the bike running now that I'm back home. There is one more issue I need to fix and it has to do with the gears. When I'm downshifting from 3rd to 2nd it will miss 2nd and go into neutral. When I had it apart I had a look at everything to find out what the issue was, all the gears are fine and there is no visible wear on anything. when i put the shifter into 3rd and pushed it to 2nd the hook on the end of the shifter rod that pulls the cogs on the shifter drum would slip off the cog and that would turn it just a little bit more and put it into neutral. Does anyone know what would cause this or how to fix it? the hook and cog both look fine and not worn. there is a spring that holds the hook up could that be weak and need replacing?
	0

10-15-2009, 02:41 AM	#13
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	Yeah it was my first time having a case apart, but everything looked good. I have a feeling that it's the spring too
	0

10-15-2009, 09:52 AM	#14
suprf1y Join Date: Oct 2007 Location: SW Ontario Posts: 408	Where did you get that cam, and do you have any specs on it?
	0

10-15-2009, 09:56 PM	#15
boost_addict Join Date: Sep 2009 Location: Delta BC Posts: 74	if you go to the sticky at the top of the pit bike forum page, for pit bike parts, it's the first company they give a link to, I believe it's called beatrice cycle. they have a verity of cams for the honda horizontals. measure your cams length and bearing diameters and find a cam that matches.
	0