Ignition coil upgrade questions

kilo0195 · 07-22-2017, 04:28 PM

Does anyone know if the s40 boulevard coil puts out more voltage than the gz? I'm trying to figure out a least expensive and painless way to increase the voltage at the plug. What about any experience with msd, accel, etc coils? I'm installing a 300cc jug and piston kit as well as decking it .040 to up compression. I've already ported and opened up the intake and exhaust so this was the next logical step. I just want to make sure I'm getting the best burn I can with the changes.

kilo0195 · 07-24-2017, 08:33 PM

Ok so i just finished the 300cc conversion and the bike runs great around town under minimal throttle. More throttle than that especial higher rpm and it pauses/hesitates constantly. I'm guessing I'm not getting enough fuel. I had already put a 147.5 main jet and thought that would be enough. Should I try shimming the needle More? I hate carbs with a passion.

blaine · 07-24-2017, 09:18 PM

Quote:

Originally Posted by kilo0195

Ok so i just finished the 300cc conversion and the bike runs great around town under minimal throttle. More throttle than that especial higher rpm and it pauses/hesitates constantly. I'm guessing I'm not getting enough fuel. I had already put a 147.5 main jet and thought that would be enough. Should I try shimming the needle More? I hate carbs with a passion.

Yep...The needle controls 1/3 to 3/4 throttle....Main jet controls 3/4 to full.

kilo0195 · 07-25-2017, 04:36 PM

I put a larger pilot jet (Don't remember size) in because it was popping a lot at low rpm and running hot. Note, I need to get a tad smaller one as my mix screw is all the way in for it to not be rich at idle and low throttle. My 147.5 main jet seems to be good at full throttle. I had to shim the needle pretty far... I had to grind the top above the clip a bit so that the spring and retainer could push in far enough into the diaphragm to hold. The bike is unrecognizable now from a performance standpoint. I have the 16t sprocket and in 5th can peg my speedometer. Cruise at 70mph I'm probably @35-40% throttle. Whereas before to do that I would have been around 75%+throttle. Around town I don't notice the extra torque and power in guessing because of the carb design idk. Get it on the highway though and the extra torque is not only very noticeable but welcome as well. It may lead me to try a 40t rear sprocket with the 16t front to lower rpm at higher speed. I'll try that at another time as I rarely driver her that fast and it would be more to ease my mind when I travel to Springfield occasionally, doing 65+ for 30 minutes. Reguardless if anyone is wanting to do the 300cc kit you will definitely need the 16t front. I've done all the work myself and it's pretty easy (though I used to build cars to race) and can all be done in one long day. I got the kit from alliexpress $147 and free shipping from China delivered in 6 days via dhl... The seller was Sam's motor store (very Chinese name lol). You need to choose the correct year even though they list it as the older gn250. In my research I found people that have had to mill the kits they get from eBay or wherever whenever they don't get one for their year range. I thought it was all the same but that's what I found online from reviews and others that had done 300cc kits from China. I got my 2007 gz250 for $950 with 7k miles. The idiot had 3.5 quarts of oil in it and the head gasket seeped oil naturally lol. The exhaust from y back is 1.5 and the 2 runners are 1.25 I think. I had the exhaust shop match it to the inside of the exhaust port after I ground out that huge lip. Shorty muffler, re jetted, k&n pod filter setup, 300cc kit, 16t sprocket, 320mm adjustable nitrogen rear shocks, and head was decked slightly. All my work into it cost me about $700. If crazy power and speed is your thing then this isn't your bike. With the mods though I think my bike is a testament that you don't have to break the bank to get this bike to be a very nimble, fun, and capable city or highway bike.

kilo0195 · 07-25-2017, 05:11 PM

https://ibb.co/dAG4QQ
https://ibb.co/ghGSek
https://ibb.co/g3B4QQ
https://ibb.co/gbFLzk
https://ibb.co/iK4r5Q
Will upload pics of my needle shimming etc after I finish tuning. Didn't take pics of the 300cc work because I was just concentrated on getting it done. I just wanted to do cost effectively what everyone said would cost too much or be too much work... make the bike a capable performer for city or highway. Any questions I'll be happy to answer. Ps the question about the ignition coil still stands lol.

07-22-2017, 04:28 PM	#1
kilo0195 Member Join Date: Jul 2017 Location: Illinois Posts: 52	Ignition coil upgrade questions Does anyone know if the s40 boulevard coil puts out more voltage than the gz? I'm trying to figure out a least expensive and painless way to increase the voltage at the plug. What about any experience with msd, accel, etc coils? I'm installing a 300cc jug and piston kit as well as decking it .040 to up compression. I've already ported and opened up the intake and exhaust so this was the next logical step. I just want to make sure I'm getting the best burn I can with the changes. Login or Register to Remove Ads
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07-25-2017, 05:11 PM	#5
kilo0195 Member Join Date: Jul 2017 Location: Illinois Posts: 52	https://ibb.co/dAG4QQ https://ibb.co/ghGSek https://ibb.co/g3B4QQ https://ibb.co/gbFLzk https://ibb.co/iK4r5Q Will upload pics of my needle shimming etc after I finish tuning. Didn't take pics of the 300cc work because I was just concentrated on getting it done. I just wanted to do cost effectively what everyone said would cost too much or be too much work... make the bike a capable performer for city or highway. Any questions I'll be happy to answer. Ps the question about the ignition coil still stands lol. Login or Register to Remove Ads
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07-24-2017, 08:33 PM	#2
kilo0195 Member Join Date: Jul 2017 Location: Illinois Posts: 52	Ok so i just finished the 300cc conversion and the bike runs great around town under minimal throttle. More throttle than that especial higher rpm and it pauses/hesitates constantly. I'm guessing I'm not getting enough fuel. I had already put a 147.5 main jet and thought that would be enough. Should I try shimming the needle More? I hate carbs with a passion.
	0

07-25-2017, 04:36 PM	#4
kilo0195 Member Join Date: Jul 2017 Location: Illinois Posts: 52	I put a larger pilot jet (Don't remember size) in because it was popping a lot at low rpm and running hot. Note, I need to get a tad smaller one as my mix screw is all the way in for it to not be rich at idle and low throttle. My 147.5 main jet seems to be good at full throttle. I had to shim the needle pretty far... I had to grind the top above the clip a bit so that the spring and retainer could push in far enough into the diaphragm to hold. The bike is unrecognizable now from a performance standpoint. I have the 16t sprocket and in 5th can peg my speedometer. Cruise at 70mph I'm probably @35-40% throttle. Whereas before to do that I would have been around 75%+throttle. Around town I don't notice the extra torque and power in guessing because of the carb design idk. Get it on the highway though and the extra torque is not only very noticeable but welcome as well. It may lead me to try a 40t rear sprocket with the 16t front to lower rpm at higher speed. I'll try that at another time as I rarely driver her that fast and it would be more to ease my mind when I travel to Springfield occasionally, doing 65+ for 30 minutes. Reguardless if anyone is wanting to do the 300cc kit you will definitely need the 16t front. I've done all the work myself and it's pretty easy (though I used to build cars to race) and can all be done in one long day. I got the kit from alliexpress $147 and free shipping from China delivered in 6 days via dhl... The seller was Sam's motor store (very Chinese name lol). You need to choose the correct year even though they list it as the older gn250. In my research I found people that have had to mill the kits they get from eBay or wherever whenever they don't get one for their year range. I thought it was all the same but that's what I found online from reviews and others that had done 300cc kits from China. I got my 2007 gz250 for $950 with 7k miles. The idiot had 3.5 quarts of oil in it and the head gasket seeped oil naturally lol. The exhaust from y back is 1.5 and the 2 runners are 1.25 I think. I had the exhaust shop match it to the inside of the exhaust port after I ground out that huge lip. Shorty muffler, re jetted, k&n pod filter setup, 300cc kit, 16t sprocket, 320mm adjustable nitrogen rear shocks, and head was decked slightly. All my work into it cost me about $700. If crazy power and speed is your thing then this isn't your bike. With the mods though I think my bike is a testament that you don't have to break the bank to get this bike to be a very nimble, fun, and capable city or highway bike.
	0