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All 650's Spark Plugs

motorider

2019
CBR650R ABS
May 6, 2021
Riding Since
1986
When replacing the spark plugs, check the owner’s manual or service manual first to determine the correct spark plugs for your bike. Unless you have a heavily modified bike and you know what you are doing, you should not deviate from the manufacturer’s specifications. Honda recommends either NGK or Denso spark plugs. Neither of those brands requires the application of anti-seize to the threads of the spark plugs. Do not use anti-seize on the plug threads. The spark plugs come pre-gapped, but double check the plug gap with a wire type feeler gauge, do not use a coin type gauge. Coin gauges will not give you an accurate measurement because they have a sloped surface. Be extra careful when checking the gap on Iridium plugs, they have a very narrow electrode that can be easily damaged. When installing the new plugs, be careful not to over tighten them. The installation procedure in the Honda service manual is to 1) hand tighten the plugs, then 2) tighten them to a specific torque using a torque wrench. If you do not have a torque wrench, get one (see link below). The torque may vary based on model, so check the service manual for the proper torque.

Torque Wrench

Spark Plug Socket Set

Sources:
Honda Service Manual https://650f.bike/resources/cbr650r-cb650r-service-manual-oem.40/
NGK https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs
Denso https://www.denso.com/global/en/pro...e-parts-and-accessories/plug/pdf/t-manual.pdf
 

Atucker

2019
CBR650R
Aug 18, 2020
Riding Since
2001
Appreciate the heads up on the anti-seize for these brands. I'm old school - a.k.a. never reading directions on sparkplugs so I would have used it and possibly regretted it later!
 

kkweon

2019
CBR650R
Oct 16, 2022
Riding Since
2022
I couldn't reach the two middle spark plugs.

The two ends are barely reachable from the air ducts. But, no angle for the middle two.

Should I also remove the radiator?
Any tool recommendations?

This is what I have:
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
Loosen the radiator at the bottom and move it out of your way, that usually gives you enough room.


Otherwise I’d say download the service manual and see what they recommend.
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
Riding Since
1993
Not sure how the radiator is in the way of the plugs.

Once the airbox is off, the plugs are almost looking at you and are in front of the rad at that point.

Service manual definitely tells all as Mike said.

2&3 are easy, number 4 is "ok" and plug number 1 needs funky tools and bad language to get to.

J
 

kkweon

2019
CBR650R
Oct 16, 2022
Riding Since
2022
I have read the service manual. The service manual doesn't really say much. I also have the haynes one.

It's just one line: remove the spark plugs. they don't tell how to remove or what tools to use :(

1692736724866.png

It's more like I don't have right tools. I was only able to remove the rightmost one.
I think I will need a bunch of swivel joints and extenders, but I'm not sure which one exactly.
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
Riding Since
1993
Use a plug removal socket.

Be prepared to get creative with the ratchet and drive bars, here's what I used to get the plugs out:

Plugs 2,3 & 4:

2019-02-17 22.07.43.jpg

Plug 1:

2019-02-17 22.25.19.jpg


J
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
I have read the service manual. The service manual doesn't really say much. I also have the haynes one.

It's just one line: remove the spark plugs. they don't tell how to remove or what tools to use :(

View attachment 14172

It's more like I don't have right tools. I was only able to remove the rightmost one.
I think I will need a bunch of swivel joints and extenders, but I'm not sure which one exactly.
It does tell you, under Removal/Installation:

Remove air cleaner (and the stuff you have to remove to get to that like bodywork and tip the tank up).
Then remove the plugs.

As far as the tool it's listed in the beginning of the book under needed tools. I have a spare of the Honda tool they used to include int he toolkit which is one of the best spark plug removal tools ever. But honestly any properly sized plug socket will work.
 

kkweon

2019
CBR650R
Oct 16, 2022
Riding Since
2022
It does tell you, under Removal/Installation:

Remove air cleaner (and the stuff you have to remove to get to that like bodywork and tip the tank up).
Then remove the plugs.

As far as the tool it's listed in the beginning of the book under needed tools. I have a spare of the Honda tool they used to include int he toolkit which is one of the best spark plug removal tools ever. But honestly any properly sized plug socket will work.
I did remove it including the air duct in the side fairings. Otherwise, plugs aren't even visible of course.
Still, it's very tight to reach. My hands were barely able to grab the cap from the side.

Use a plug removal socket.

Be prepared to get creative with the ratchet and drive bars, here's what I used to get the plugs out:

Plugs 2,3 & 4:

View attachment 14173

Plug 1:

View attachment 14174


J
After trial and error, I realized I need a much shorter arm on the socket. And, your setup and the toolkit photo show the same.
So, I've ordered one with a shorter arm.

Just for reference, I have https://a.co/d/74C7eLW, but it was way too long.
 

RC74daniel

2016
CBR650F ABS
May 13, 2024
Riding Since
2024
Just wanted to thank everyone in this thread, especially Brammers for providing us with their contraptions. Thanks to you I was able to do my first spark plug change.
Things I'd recommend:
  • Make sure to remove the PAIR control solenoid, it's easy to remove and will give you a lot of space.
  • Use a ratchet to loosen the plugs initially, after that just unscrew the plugs with your hand to get more feel. Do the same for the installation, start tightening by hand. I used a torque wrench for tightening.
  • Start with the easiest plugs if it's your first time. For me, the middle ones were the easiest.
  • Use a magnetic spark plug socket. My rubber one wouldn't hold the plugs. Test your socket with the new spark plugs.
  • Make sure the plug caps are installed correctly after you're done. If they aren't oriented the right way, you may not have enough space to reach your fingers around to pull them up. You can get them off by rotating them whilst pulling up but you have to pull a lot on the end of them, which is probably not ideal for the cables. Use the holes from the cover as reference, the previous shop didn't, as you can see here:

    1741799599127.jpeg
Finally, here are images of the extensions and joints I used alongside their lengths:

1741800303030.png
1741800414984.png
 

Rijack

2019
CB650R ABS
Sep 27, 2025
Riding Since
2025
This was a useful thread after doing mine today. Couple of things I picked up along the way:

• these plug tools worked really well as they had the moving attachment already on them to help with angles. Meant all I needed was one extension bar and one other joint and I could access them all (if the link to the item works)


• I underestimated how difficult it would be getting the air pipes out from the side boxes into the air filter housing to remove all that. In hindsight i probably would have been quicker disconnecting from the side boxes. But reinstalling was a bit easier as I eased it in with some grease which I washed away after so to not crap up the air flow or get anything stuck to the grease like sand etc in clumps. I could only do that once I realised how easily they disconnected from the air intake boxes on the side though.

• removing the hose that connects what looks like the engine block to the air filter etc housing helped massively as it was really in the way of number 2.

• removing the fuel tank gave so much space to work rather than just propping it up with ratchet straps


The placement of them, yes it was difficult but tbh with a little bit of patience (and one scary moment - more below) it was all quite straight forward. Removed them in the order of 4,1,3,2


The scary moment:

I stupidly dropped my magnetic plug tool into one of the holes not thinking how far down it actually goes, mild panic followed with my frantically trying to attach one of the extensions to the end of it blindly….

two issues:
The little metal clip that goes over the air filter housing box ended up falling down along the tube out of reach.. so improvised with a nice tight cable tie…

I also lost this rubber from somewhere. It looks like a seal of some kind but for the life of me I couldn’t work out where it has come from. Either way as soon as I picked it up it snapped, but it was only laying on the floor AFTER i reattached the fuel tank….? It looks too small to be from the air filter, too big to be from the oil filter, so I have no clue..
 

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