Spark plug talk.

[Snow Camo 242]

Hey guys I am getting a few plugs to test now I have swapped the jets to run a bit more fuel. Here is a pic of the old plug that came with the quad. It's trashed and needs to be replaced. Looks rich and wet. 

 

How many steps hotter would you all go?

[Fishfiles 20,140]

wow , looks like you need a rebuild to me , did you ever do a compression test 

[Snow Camo 242]

Nope no comp test yet. I never even thought about it and chalked it up to the fact the last owner couldn't get it running as it was just dumping fuel due to the factory jets. After the jet swap thing runs like top. I see that same thing all over tho. Guy on the local Facebook going through the same thing. Can't get it to stay running. Another on the old forum I linked to the jets thread here same. Factory jetting on these is crap. Lol

[Snow Camo 242]

Getting a comp test is a great idea. I'll go back out today and rent a tester and post the results.

[_Wilson_™ 6,500]

A hotter plug would be a temp fix..... I have to run one in my snapper because it uses a tad bit of oil plus I'm sure the comp is low, but it's the oldest longest running 15ohv snapper on record at the ace store so.... As long as it runs they don't wont me to mess with it... maybe they want it later on for some crazy reason.... But, I'd op for a carb refresh... You've done the research and don't seem like a guy who half does things.. Not from what I've seen....so I'd go with fishes ideas 

[Fishfiles 20,140]

I think I would buy a cheapy before renting one , here is a $19.99 kit ,  it is something you would likely use  

 

https://www.ebay.com/itm/203467586107?hash=item2f5f9cfa3b:g:EPAAAOSwYsVg4YMB&amdata=enc%3AAQAHAAAA8Ae6h%2BIIEuleaFmEfqvuHyiMIWisnsrgBFuIror38fJupaH%2FOOLInwVvS7I1Wfyg14Pf3OC3ZgILG2k1RJSRrkEJLle1BD9PynP5yYpbCl2CqxR45ZhsM4XOSSt%2BjxWnW%2B80y442sLzy%2BgDDut0pVFlhKxb1Ua1GBPMISjN7EzO3cItAcIMJdJjVvGYN3C%2BYV%2F3H97al%2FBCmO3ZjonEPf7SOcpkWyGGaiiN%2BO8Twu7eovrMW5tr%2BCPMuJ0Ajs64ngF6NdiswgoVBBEQXqRaYg2fFGAhtYJSX5CyU0tWTEg3OV3AgL1kj67U0oWsYFNPXeA%3D%3D|tkp%3ABk9SR9iK19CoYQ

[Snow Camo 242]

Ok so I just talked with the guy who I got this from. He says the plug is from another one of his quads. 

 

Since I have had this one it does not burn oil. No smoke and the oil on the stick stays in the same place. 

 

You guys got me thinking about a comp test just to see what it truly is. Ugh I just left the store 30mins or so ago lol. I got a new plug and one ordered. 

[Snow Camo 242]

3 minutes ago, Fishfiles said:

I think I would buy a cheapy before renting one , here is a $19.99 kit ,  it is something you would likely use  

 

https://www.ebay.com/itm/203467586107?hash=item2f5f9cfa3b:g:EPAAAOSwYsVg4YMB&amdata=enc%3AAQAHAAAA8Ae6h%2BIIEuleaFmEfqvuHyiMIWisnsrgBFuIror38fJupaH%2FOOLInwVvS7I1Wfyg14Pf3OC3ZgILG2k1RJSRrkEJLle1BD9PynP5yYpbCl2CqxR45ZhsM4XOSSt%2BjxWnW%2B80y442sLzy%2BgDDut0pVFlhKxb1Ua1GBPMISjN7EzO3cItAcIMJdJjVvGYN3C%2BYV%2F3H97al%2FBCmO3ZjonEPf7SOcpkWyGGaiiN%2BO8Twu7eovrMW5tr%2BCPMuJ0Ajs64ngF6NdiswgoVBBEQXqRaYg2fFGAhtYJSX5CyU0tWTEg3OV3AgL1kj67U0oWsYFNPXeA%3D%3D|tkp%3ABk9SR9iK19CoYQ

Well that is cheap enough, but the misses has me on a spending limit, which is why I was going to rent one lol. I can wait though. I have time. Plus I still need to donate to the site first. 

[_Wilson_™ 6,500]

Whoops ha! Forgot this you did go with an NGK plug ? 

Edited December 24, 2022 by _Wilson_™

[Snow Camo 242]

The store had a champion in stock, so I got that. I ordered a ngk tho. Any other plug suggestions?

[Fishfiles 20,140]

184 + or • 14. So 170 to 198 psi.   

[Snow Camo 242]

Thinking about it I ordered a plug based off the plug that was installed. So I need to go back and correct that order. I'll rent that comp tester so I can get that money back and have two test results.

[retro 3,984]

Yeah, you will need to put the recommended heat range NGK plug in it. Champion plugs are garbage and likely to fail very rapidly in almost everything but mopars and lawn mowers.

 

Assuming that the air/fuel mixture is always optimal for a given motor, the major factor that determines the spark plug operating heat range is gross cylinder pressure under load, which is primarily governed by the dynamic compression ratio. The dynamic compression ratio is determined by the static compression ratio and the valve timings. So unless you add or subtract static compression (alter bore and/or stoke significantly, install a domed piston, milling of the head etc.) and/or change the camshaft and alter the valve timings significantly, such that volumetric efficiency exceeds 100% by a considerable margin somewhere in the operating RPM range, the factory recommended heat range should be sufficient.

[Snow Camo 242]

Thanks retro! I will stick with the oem plug. 

 

I just left the parts store and they can't find the factory plug in the system. I'll search rockauto and see what I can find.

 

Their compressor test adapter thread size is too large as well, so I'll have to wait till I order a new one. 

[Fishfiles 20,140]

This might help ,  

Both are OEM TRX200SX plugs 

NGK DR-8ESL = NGK 2923 = Honda OEM # 98069-38716 or 98069-38716

Denso 24ESR-U = Denso 4101 = Honda OEM # 98069-58726

[Snow Camo 242]

Got it. Making the order

[SlammedRanger 1,536]

Yep i run one step hotter for my 12:1 big bore stroker 400ex. Stock plug for sure! Get like 4 so you can do some plug chops. Welcome to the world of tuning! Its a pain but well worth it in the end! Btw. Didnt take a video but i started my quad today. It got up to 6 degrees so a heat wave lol. Did choke it but it fired on 2nd revolution. 400s are notoriously cold blooded. But mine isnt at all. Proper tuning makes all the difference in the world!

[Snow Camo 242]

28 minutes ago, SlammedRanger said:

Yep i run one step hotter for my 12:1 big bore stroker 400ex. Stock plug for sure! Get like 4 so you can do some plug chops. Welcome to the world of tuning! Its a pain but well worth it in the end! Btw. Didnt take a video but i started my quad today. It got up to 6 degrees so a heat wave lol. Did choke it but it fired on 2nd revolution. 400s are notoriously cold blooded. But mine isnt at all. Proper tuning makes all the difference in the world!

Man a big bore 12:1 comp motor sounds good right now! Rock on man. I will pickup a hand full of plugs. I definitely have time on my side and really would like to get these jets dialed in 100 percent. I started thinking wideband, but that is the last on the list if any. 

 

While we're talking plugs. I noticed this engine likes the gap set at .024. That's the lower end of the factory spec. Just something to note. 

 

Little off the topic, anyone know where the vacuum port on these carbs actually went or goes to? It would not matter if it is a different engine. I have been thinking hard about tying it into the exhuast like vehicle engines via egr. I do not think it can hurt to try it out. If anything I would likely need to adjust the air screw while at idle. 

[retro 3,984]

18 hours ago, Snow Camo said:

While we're talking plugs. I noticed this engine likes the gap set at .024. That's the lower end of the factory spec. Just something to note.

 

The spark will be fatter and hotter (bluer) with the gap wider. So I'd set the plug gap at its max spec. for performance. If you feel that the ignition coil won't overheat and fry you can gap the plug a bit wider than spec. It's a gamble....

[retro 3,984]

18 hours ago, Snow Camo said:

Little off the topic, anyone know where the vacuum port on these carbs actually went or goes to? It would not matter if it is a different engine. I have been thinking hard about tying it into the exhuast like vehicle engines via egr.

 

There are two hoses on the carb, the overflow/drain hose on the bottom of the float bowl -- and the float bowl vent to atmospheric pressure hose that is high up on the side of the carb. EGR kills peak combustion temps, efficiency and performance so you don't want anything to do with that.... and as you guessed you mustn't ever connect the float bowl to the exhaust system. Else a Polaris-like fire is likely, if the motor even run seeing much higher than atmospheric pressure on the fuel head. 

[Snow Camo 242]

56 minutes ago, retro said:

 

There are two hoses on the carb, the overflow/drain hose on the bottom of the float bowl -- and the float bowl vent to atmospheric pressure hose that is high up on the side of the carb. EGR kills peak combustion temps, efficiency and performance so you don't want anything to do with that.... and as you guessed you mustn't ever connect the float bowl to the exhaust system. Else a Polaris-like fire is likely, if the motor even run seeing much higher than atmospheric pressure on the fuel head. 

 

Ok so this is the fuel bowl vent? I should be able to leave this one open while the engine is running if I am correct. 

 

I will check the ignition coil. Maybe it's out of spec. I figured it should be better with a wide gap. I'll give that another shot when I get new plugs in.

[retro 3,984]

Yeah you'll want to leave the fuel vent hose open to atmospheric pressure. You can put a longer hose on it if you need to route it up high above the motor.... for instance if you were planning on riding in deep water.

 

The coil should handle a plug gap .002 over spec safely but honestly, as long as you're running on pump gas there'll be no benefit for a wider gap. 

[Snow Camo 242]

I'll leave it open and find a vent or filter to put on the end of the hose. 

 

I will also check the voltage going to the coil. I am sure it won't make much difference but it's all in the name of fun. Plus it keeps me busy. 🍻 

[Goober 1,555]

important to keep the carb overflow hose routed below the elevation of the carb bowl. If the carb float was to stick open, fuel needs to go somewhere. If the overflow hose isn’t stopped up, fuel will drain straight down the hose and leak out on your shed floor. If it cant leak out the hose, it may rise in the carb and leak into the engine.

 

you can test drain function by 1) put a pan under your quad, 2) close the petcock and 3) unscrew the bowl drain screw. You’ll see a bowl’s worth of fuel drain from the hose. Screw in the drain and Turn the petcock back on to test you have the drain securely closed.

 

To protect the drain hose function, some older machines came with a one-way valve on the end of the carb overflow hose. I got one off an 87. I have not been able to source one, but I’m sure subs are available. My guess is they weren’t very reliable.  

Edited December 26, 2022 by Goober

[Snow Camo 242]

Good deal. I will route it as such. I do not plan to go mudding with this little quad. It will be a dirt thrower lol