2017 Apollo 250 Build - Have questions

Douglass · 01-17-2018, 05:52 PM

Ok, I got the bike put together today, and have a few questions.

What am I supposed to do here?

Does this need to plug into anything?

This is what it what the other end plugs into.

Last questions is the Throttle seems to get stuck just for a second or two it I open it full.

Douglass · 01-24-2018, 04:35 PM

Ok, I confirmed that both items are left alone, and are good as is.

I do have a few questions about getting a Mikuni Carb.

I am looking at this one here, which looks very similar the one in the bike now.

https://www.ebay.com/itm/Genuine-Mik...xZnOhg&vxp=mtr

I am also looking at this one too.

https://www.ebay.com/itm/Genuine-Rea...RYgVam&vxp=mtr

Which one is the one I would want to get?

Can anyone provide some tuning/jet info? I have no experience with tuning carburetors with the exception of RC nitro engines. If it helps, I am located in California close to see level.

Thanks for any help, I am planning on upgrading the bike next month. New Throttle, Handle bars with grips, rear sprocket 48-52T, new chain, and new carb. Just trying to get all my ducks in a row now.

Already Changed the oil to Honda 10w40, and flushed the original brake fluid out with some nice Dot 4. Checked all my bolts, just three that would have come loose. One on the engine, and two on the LH foot peg. Dove the bike around the neiborhood on Saturday. Had it through all the gears, drove great. No issues on start up. It fired up almost instantly.

Megadan · 01-25-2018, 04:15 AM

Quote:

Originally Posted by Douglass

Ok, I confirmed that both items are left alone, and are good as is.

I do have a few questions about getting a Mikuni Carb.

I am looking at this one here, which looks very similar the one in the bike now.

https://www.ebay.com/itm/Genuine-Mik...xZnOhg&vxp=mtr

I am also looking at this one too.

https://www.ebay.com/itm/Genuine-Rea...RYgVam&vxp=mtr

The first one is the correct bolt on option. That is the same Mikuni a lot of us Hawk owners switch to.

The second one you linked is a very different carburetor. It is a true 30mm smooth bore round slide, which means it has a larger throttle area. I have one of those exact carbs waiting to go on my Hawk once I install my ported cylinder head. It CAN be bolted to your engine with the use of a CRF230F intake, but the intake will need to be ported and some trimming to the rubber in order to make it work. I have a few pictures of this combination here - http://chinariders.net/showpost.php?...&postcount=308

Without some more serious engine work, I would say that the VM30-83 would not be a good idea for your bike. The VM26 is more than enough carb to support upwards of 20hp while having a good powerband and throttle response.

Now the first carb you linked isn't really any different from the standard Keihin clone that comes on most of these bikes. They have the same 30mm bore, and 26mm choke. They both utilize the same plate style choke, and if you sit them side by side you would be hard pressed to tell a difference. There is no performance gain from that carb, and the only reason many of us even use the Mikuni is because our stock Hawk carbs have a goofy pilot jet that can't be changed, and a needle with no tuning adjustments.

Just my 2 cents, but if your stock carb can be tuned - i.e. you can change the pilot jet, then I would say tune the one you have.

If you would rather just get the Mikuni, then I can give you some rough jet sizing suggestions based on my experience with the CG250, but it will still likely need a slightly different jetting setup.

Before I can really make any suggestions though, I need to know your altitude.

SycoCell · 01-25-2018, 07:34 AM

Shoot me a text when you're around today, Doug.

I ordered a mikuni from Amazon last night as well as some new jets. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I'm at about 800 MSL so I'll have to figure out how to tune this thing. Hoping it may help a little on the low end throttle response.

Did the brake fluid flush change the feel of the braking? As in, make it more responsive?

Megadan · 01-25-2018, 07:44 AM

With the carb you ordered from Amazon, you will need to change the pilot and main jets (20 and 100 respectively). They are too lean for a 230-250cc engine at lower altitudes (I am at 1000ft)

Pilot jets are VM28/486. At minimum you will be looking at a 25 pilot jet, I found a 27.5 to work better on my CG250 with about 1 1/4 turns out on the idle mixture screw. That will at least be a good starting point. https://www.jetsrus.com/a_jets_by_ca...-486_pilot.htm

Main jet - N100.604, I would say start with a 115 to safe. You may find you need some "half" sized jets to get the tune really dialed in, aka 112.5 and 117.5. If you happen to know the stock carb main jet size, I can translate it from Keihin to Mikuni size easy enough.

Needle clip position in the 4th notch from the top/1 down from center to start, with the right main jet you should be able to run the center clip position.

Douglass · 01-25-2018, 10:20 AM

Quote:

Now the first carb you linked isn't really any different from the standard Keihin clone that comes on most of these bikes. They have the same 30mm bore, and 26mm choke. They both utilize the same plate style choke, and if you sit them side by side you would be hard pressed to tell a difference. There is no performance gain from that carb, and the only reason many of us even use the Mikuni is because our stock Hawk carbs have a goofy pilot jet that can't be changed, and a needle with no tuning adjustments.

When watching a few youtube videos, people who installed them said the bike ran smoother, and had a more stable idle. This is the area where I am interested in improving.

Quote:

If you would rather just get the Mikuni, then I can give you some rough jet sizing suggestions based on my experience with the CG250, but it will still likely need a slightly different jetting setup.

Before I can really make any suggestions though, I need to know your altitude.

This would be great, from what I was able to find it looks like I'm at a wopping 69 Feet.

Quote:

Did the brake fluid flush change the feel of the braking? As in, make it more responsive?

I didn't drive the bike before I flushed the brakes, but I did have some air come out. The front, and rear brakes feel pretty solid. When I drove around the neighborhood they seemed to work and feel great.

Douglass · 01-25-2018, 10:37 AM

MegaDan: You have listed in your mods a CRF230 Exhaust from Ebay, do you know if this will fit the Apollo Too? If so, did you do it for performance, or to remove the Cat/emission stuff?

Is what you got something like this? Thank you for all your help!

https://www.ebay.com/p/Aluminum-Exha....c100005.m1851

Megadan · 01-25-2018, 02:37 PM

Quote:

Originally Posted by Douglass

MegaDan: You have listed in your mods a CRF230 Exhaust from Ebay, do you know if this will fit the Apollo Too? If so, did you do it for performance, or to remove the Cat/emission stuff?

Is what you got something like this? Thank you for all your help!

https://www.ebay.com/p/Aluminum-Exha....c100005.m1851

Yep, that's the exhaust I used. The only reasons I used that exhaust were mainly to de-cat the system and get a more free flowing muffler - all in the name of performance. I could have just as easily modified the stock exhaust as well, but for about 100 bucks for a stainless steel exhaust, it was hard to pass up. It's also quite a bit lighter than the stock exhaust was on my Hawk,

As far as working on your Apollo, it might work, but I do believe the 250cc Apollo bikes have a pretty decent exhaust from the factory. It is also a slightly different shape, so I couldn't tell you for sure if it would mount up the same. Hopefully another Apollo owner can have more answers for you.

As far as your interest in the carb and getting a smoother idle and better running bike. If you can change the jets on the factory equipped Keihin clone, then you can re-jet it and achieve the same results. None of these Chinese bikes come jetted very well.

If you decide the Mikuni is just what you want to do, then I would start you off with a 30 pilot jet and 115 main jet. Being at basically sea level, and given that particular motor, this would be pretty close. Obviously, you would still need to dial in the proper jet sizes to the engine, but I am a firm believer in being what I call "Safely fat". The Pilot jet is going to be the easiest to dial in first via. the idle mixture adjustment. With the engine up to temp, if it takes less than 1 turn out on the idle mixture screw, then step down to a 27.5. If you get a good steady idle between 1 and 2 turns out on the mixture screw, then it is just about perfect.

Once you have the pilot jet figure out, and the needle set in the 3rd or 4th position, you can then work on dialing in the main jet. A plug chop with a clean spark plug will reveal how the main jet is doing.

My only real suggestion would be to break in the engine first before trying to get a new carb dialed in. At least put around 300-500 miles on the motor.

Douglass · 01-25-2018, 04:48 PM

Quote:

My only real suggestion would be to break in the engine first before trying to get a new carb dialed in. At least put around 300-500 miles on the motor

Sounds like a good move. It's probably best to break in the bike, and drive it for a bit before making a carb/exhaust change.

The exhaust is fine, I would only remove it to get rid of the emission stuff. If I were to do it I would I would want to be able to put all the stock stuff back on if/when I sell it. What's your suggestion on checking the valve lash?

Megadan, thank you for the link to the hawk resource/maintenance guide. I didn't see it earlier, im going to go through the bike more after seeing the suggestions.

Megadan · 01-27-2018, 06:32 AM

Quote:

Originally Posted by Douglass

The exhaust is fine, I would only remove it to get rid of the emission stuff. If I were to do it I would I would want to be able to put all the stock stuff back on if/when I sell it. What's your suggestion on checking the valve lash?

Megadan, thank you for the link to the hawk resource/maintenance guide. I didn't see it earlier, im going to go through the bike more after seeing the suggestions.

Suggesting for checking the valve lash depends on if you have an OHC motor or OHV, but the basic principles apply. Set the engine to TDC on the compression stroke. Adjust the lash adjusters to the desired specs. You can find quite a few posts on this topic. The OHV motors like the hawk, you remove the valve cover to do so. On the OHC engines there are two hex head caps, one front, one rear, that you remove to gain access to the lash adjusters on the rocker arms. As far as the proper lash spec for the OHC engines, I do not know for certain. Hopefully an owner with one of those engines can chime in.

I still need to add more to my resource guides from the Hawk, but a lot of the setup and maintenance stuff is good to follow. Things like the fork oil level will obviously not apply, but the generic advice on setup works across all of the bikes and is worth taking the time to do.

Douglass · 01-27-2018, 12:28 PM

MegaDan, do you have any resources about carb tuning? I am interested in learning about how they work, and selecting the right size jets. I can provide an email if needed.

SycoCell · 01-27-2018, 04:58 PM

Do you have a suggestion on what to use for jets for me? I got that amazon Mikuni that I posted up and bought some jets - but this is all BRAND NEW to me. I don’t even know which jet is what. I live at 800’ MSL while most of my riding will probably vary between 500-2000’. Suggestions?

Megadan · 01-27-2018, 05:44 PM

There is a lot of info out there on carb tuning, so instead of going into writing a book on the subject, I can give you some basic and essential information to help.

First is to understand what jets will affect what part of the throttle opening.
In really simple terms...

Pilot jet: Affects the amount of fuel for the idle mixture as well as the throttle up to about 1/4 throttle, with the greatest effect up to 1/8th throttle.
The best way to determine if a pilot jet is too rich or too lean is by first setting the idle mixture. From lightly seated, if it takes less than 1 turn out on the mixture screw then the pilot jet is too large. If it takes more than 2 1/2 -3 turns out, this indicates that the pilot jet is too small. Ideally the mixture screw should be between 1 and 2 turns out to achieve a stable idle.
The second way to determine if a pilot jet is too lean or rich is how the bike acts when at very light constant throttle, say cruising down the street at maybe 25mph with the throttle just slightly opened. If it cuts in and out, hesistates, pops, etc, then you are likely too lean. If it feels like its just bogging out and losing power, it is likely too rich.

Needle and needle jet: This mainly affects the fueling between 1/4 and 3/4 throttle. Raising the needle with a lower clip position or shims will make this range of throttle richer, while lowering it with a higher clip makes it leaner. Since the needle mixture is also affected by the main jet size, it is usually best to tune the needle position last. Ideally the needle should be as close to its center clip as possible.

Main jet: This affects the throttle mainly from 3/4 throttle to wide open.
Some easy indicators for this when rolling to wide open throttle include:
If the bike hesistates for a second and then starts accelerating, then it is a good indicator of being too lean on the main jet. Go up a jet size.
If you roll on to wide open throttle and the bike boggs out, and may even cut out, it is too rich. Go down a jet size.

Once you get to a point where the bike does neither of these behaviors, then the best way to really determine if your main jet is appropriately sized is to do a plug chop on a fresh plug. A quick google search can bring up a lot of info on this.

Also keep in mind that all carb tuning should be done on an engine at operating temp (hot). This includes idle mixture.

The last thing to keep in mind is that even though each jet has the greatest effects at certain throttle positions, every jet still adds fuel, i.e. - If you increase the pilot jet size, it will add a tiny bit more fuel to the main jet as well. We are talking a very small level, around 10% of the total fueling at most, but it is something to keep in mind. If you set the idle mixture but then jump 2 main jet sizes, your idle may change a little and you will need to slightly adjust the mixture screw.

As far as jetting recommendations, what I would recommend is just a generic, and likely too rich setup to start with, but too rich is better than too lean. You will want to have a few sizes of each jet to really dial it in.
My recommendations still stand with a 30 pilot and a 115 or 117.5 main jet with the OHC motors. If you have an OHV motor like me I can give you far more precise jetting suggestions, because I have hands on experience with it, and I don't have an idea of how different, if any, the OHC engines are in terms of fueling.

I would say to buy a 25, 27.5, and 30 pilot. And have a 110, 115, and 120 mains, at minimum. If you feel like it, grab a 112.5 and 117.5 as well. With my bike, the 115 was a touch too lean, and the 120 was too rich, the 117.5 worked out the best for me - being just ever so slightly on the rich side, which is what I prefer with aircooled engines.

SycoCell · 01-27-2018, 06:34 PM

Awesome, thanks a lot Mega!

Douglass · 01-27-2018, 11:55 PM

Megadan - Thank you so much! you gave an excellent explanation. I am really trying to learn the functions. Of erverything on the bike this is probably the only thing that I am a little intimidated by. I can tune my car using a computer, but have the nessessary gauges to see what my fuel trims and WOT fuel readings are. If/when I decide to change the carb on my bike, I want to be able to do things with purpose, and understanding rather than guess and hope.

Thanks again, your explination I know took time to type up, and it is greatly appricated!

Douglass

01-17-2018, 05:52 PM	#1
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	2017 Apollo 250 Build - Have questions Ok, I got the bike put together today, and have a few questions. What am I supposed to do here? Does this need to plug into anything? This is what it what the other end plugs into. Last questions is the Throttle seems to get stuck just for a second or two it I open it full. Last edited by Douglass; 01-18-2018 at 10:08 AM.
	0

01-25-2018, 07:44 AM	#5
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 7,923	With the carb you ordered from Amazon, you will need to change the pilot and main jets (20 and 100 respectively). They are too lean for a 230-250cc engine at lower altitudes (I am at 1000ft) Pilot jets are VM28/486. At minimum you will be looking at a 25 pilot jet, I found a 27.5 to work better on my CG250 with about 1 1/4 turns out on the idle mixture screw. That will at least be a good starting point. https://www.jetsrus.com/a_jets_by_ca...-486_pilot.htm Main jet - N100.604, I would say start with a 115 to safe. You may find you need some "half" sized jets to get the tune really dialed in, aka 112.5 and 117.5. If you happen to know the stock carb main jet size, I can translate it from Keihin to Mikuni size easy enough. Needle clip position in the 4th notch from the top/1 down from center to start, with the right main jet you should be able to run the center clip position. __________________ 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2010 VFR1200F - http://chinariders.net/showthread.php?t=20708
	0

01-27-2018, 05:44 PM	#13
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 7,923	There is a lot of info out there on carb tuning, so instead of going into writing a book on the subject, I can give you some basic and essential information to help. First is to understand what jets will affect what part of the throttle opening. In really simple terms... Pilot jet: Affects the amount of fuel for the idle mixture as well as the throttle up to about 1/4 throttle, with the greatest effect up to 1/8th throttle. The best way to determine if a pilot jet is too rich or too lean is by first setting the idle mixture. From lightly seated, if it takes less than 1 turn out on the mixture screw then the pilot jet is too large. If it takes more than 2 1/2 -3 turns out, this indicates that the pilot jet is too small. Ideally the mixture screw should be between 1 and 2 turns out to achieve a stable idle. The second way to determine if a pilot jet is too lean or rich is how the bike acts when at very light constant throttle, say cruising down the street at maybe 25mph with the throttle just slightly opened. If it cuts in and out, hesistates, pops, etc, then you are likely too lean. If it feels like its just bogging out and losing power, it is likely too rich. Needle and needle jet: This mainly affects the fueling between 1/4 and 3/4 throttle. Raising the needle with a lower clip position or shims will make this range of throttle richer, while lowering it with a higher clip makes it leaner. Since the needle mixture is also affected by the main jet size, it is usually best to tune the needle position last. Ideally the needle should be as close to its center clip as possible. Main jet: This affects the throttle mainly from 3/4 throttle to wide open. Some easy indicators for this when rolling to wide open throttle include: If the bike hesistates for a second and then starts accelerating, then it is a good indicator of being too lean on the main jet. Go up a jet size. If you roll on to wide open throttle and the bike boggs out, and may even cut out, it is too rich. Go down a jet size. Once you get to a point where the bike does neither of these behaviors, then the best way to really determine if your main jet is appropriately sized is to do a plug chop on a fresh plug. A quick google search can bring up a lot of info on this. Also keep in mind that all carb tuning should be done on an engine at operating temp (hot). This includes idle mixture. The last thing to keep in mind is that even though each jet has the greatest effects at certain throttle positions, every jet still adds fuel, i.e. - If you increase the pilot jet size, it will add a tiny bit more fuel to the main jet as well. We are talking a very small level, around 10% of the total fueling at most, but it is something to keep in mind. If you set the idle mixture but then jump 2 main jet sizes, your idle may change a little and you will need to slightly adjust the mixture screw. As far as jetting recommendations, what I would recommend is just a generic, and likely too rich setup to start with, but too rich is better than too lean. You will want to have a few sizes of each jet to really dial it in. My recommendations still stand with a 30 pilot and a 115 or 117.5 main jet with the OHC motors. If you have an OHV motor like me I can give you far more precise jetting suggestions, because I have hands on experience with it, and I don't have an idea of how different, if any, the OHC engines are in terms of fueling. I would say to buy a 25, 27.5, and 30 pilot. And have a 110, 115, and 120 mains, at minimum. If you feel like it, grab a 112.5 and 117.5 as well. With my bike, the 115 was a touch too lean, and the 120 was too rich, the 117.5 worked out the best for me - being just ever so slightly on the rich side, which is what I prefer with aircooled engines. __________________ 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2010 VFR1200F - http://chinariders.net/showthread.php?t=20708
	2

01-24-2018, 04:35 PM	#2
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	Ok, I confirmed that both items are left alone, and are good as is. I do have a few questions about getting a Mikuni Carb. I am looking at this one here, which looks very similar the one in the bike now. https://www.ebay.com/itm/Genuine-Mik...xZnOhg&vxp=mtr I am also looking at this one too. https://www.ebay.com/itm/Genuine-Rea...RYgVam&vxp=mtr Which one is the one I would want to get? Can anyone provide some tuning/jet info? I have no experience with tuning carburetors with the exception of RC nitro engines. If it helps, I am located in California close to see level. Thanks for any help, I am planning on upgrading the bike next month. New Throttle, Handle bars with grips, rear sprocket 48-52T, new chain, and new carb. Just trying to get all my ducks in a row now. Already Changed the oil to Honda 10w40, and flushed the original brake fluid out with some nice Dot 4. Checked all my bolts, just three that would have come loose. One on the engine, and two on the LH foot peg. Dove the bike around the neiborhood on Saturday. Had it through all the gears, drove great. No issues on start up. It fired up almost instantly.
	0

01-25-2018, 07:34 AM	#4
SycoCell Join Date: Nov 2017 Posts: 10	Shoot me a text when you're around today, Doug. I ordered a mikuni from Amazon last night as well as some new jets. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 I'm at about 800 MSL so I'll have to figure out how to tune this thing. Hoping it may help a little on the low end throttle response. Did the brake fluid flush change the feel of the braking? As in, make it more responsive?
	0

01-25-2018, 10:37 AM	#7
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	MegaDan: You have listed in your mods a CRF230 Exhaust from Ebay, do you know if this will fit the Apollo Too? If so, did you do it for performance, or to remove the Cat/emission stuff? Is what you got something like this? Thank you for all your help! https://www.ebay.com/p/Aluminum-Exha....c100005.m1851
	0

01-27-2018, 12:28 PM	#11
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	MegaDan, do you have any resources about carb tuning? I am interested in learning about how they work, and selecting the right size jets. I can provide an email if needed.
	0

01-27-2018, 04:58 PM	#12
SycoCell Join Date: Nov 2017 Posts: 10	Do you have a suggestion on what to use for jets for me? I got that amazon Mikuni that I posted up and bought some jets - but this is all BRAND NEW to me. I don’t even know which jet is what. I live at 800’ MSL while most of my riding will probably vary between 500-2000’. Suggestions?
	0

01-27-2018, 06:34 PM	#14
SycoCell Join Date: Nov 2017 Posts: 10	Awesome, thanks a lot Mega!
	0

01-27-2018, 11:55 PM	#15
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	Megadan - Thank you so much! you gave an excellent explanation. I am really trying to learn the functions. Of erverything on the bike this is probably the only thing that I am a little intimidated by. I can tune my car using a computer, but have the nessessary gauges to see what my fuel trims and WOT fuel readings are. If/when I decide to change the carb on my bike, I want to be able to do things with purpose, and understanding rather than guess and hope. Thanks again, your explination I know took time to type up, and it is greatly appricated! Douglass
	0