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Help brand new 2017 450x exhaust glowing red

Posted: Wed May 09, 2018 7:26 pm
by Carcass213
So I have a 2017 that hasn't even been broken in yet the pipe is glowing red just at the start of the header just after a few minutes of starting up. I would like to know what steps I should take to even know if this is normal or how to fix it if its not.

Re: Help brand new 2017 450x exhaust glowing red

Posted: Wed May 09, 2018 9:28 pm
by JimDirt
Welcome to the site !! \:D/

This is normal , first , the bikes are lean from the factory , use the jetting guide below to jet it correctly for your elevation , also , ALL , modern 4 strokes are extremely hot at the header (about 1500 degrees , so DO NOT touch the header , it will literally melt your skin) , so if they idle or run without air flowing thru the radiators they will overheat in no time , especially when stock jetting is in place

Rejetting will help as would adding a cooling fan (they sell fan kits for them here , in the link i provided below the Jetting Guide) will help if you ride in tight trails or any street use , or just putt around a lot , but neither will eliminate the glow , nor it overheating to some degree , your best bet is to not let it idle for more than 1 minute without airflow (basically moving/riding) , but the exhaust will always be extremely hot , if you fire your bike up at night , it will astound you as to how red the header actually gets ..... Stock jetting will most likely be around a 42 Pilot and a 142 Main Jet , which is way too lean , but needed to pass emissions so the bike can be sold , so you will be replacing the Pilot and Main jets with what is recommended on the list below ....... hope that helped some ;)

Jetting Guide for Main Jet:(pilot 45) CRF450R/X

Sea level....165
2000 ft.......162
4000 ft.......160
6000 ft.......158
8000 ft.......155


Temperature/Elevation:
One main jet size (up/down) for every 2,000 feet or 25 degrees in temp.


Fan Kit : https://www.crfsonly.com/catalog/produc ... ts_id/5360

Re: Help brand new 2017 450x exhaust glowing red

Posted: Thu May 10, 2018 4:32 pm
by Moneypit
So if they roll out from honda lean and glowing is it ok to ride like that or is that a guaranteed way to new valves?

Re: Help brand new 2017 450x exhaust glowing red

Posted: Thu May 10, 2018 6:45 pm
by JimDirt
Being lean has not much to do with valves , dirt getting by the air filter and hitting the rev limiter like Justin Barcia is what kills valves ;)

The bikes need to pass emission standards to be sold in the U.S. , the same way your car is set lean to pass emissions (Hydrocarbons) is the same reason the factory installs just large enough jets to allow the bike to run , they expect you to jet to your elevation as shown in the settings i posted , which is why you can go to a Honda dealer (or any bike shop for that matter) and buy larger jets to make the bike perform like it was built to , Honda expects you to jet it , same reason you can buy Mapping tools for EFI bikes , so you can alter the Fuel Mapping for Performance , not restrictive emissions so the bike can be sold , if your bike pops when you let off the throttle , then its too lean , pretty much any new bike does because it was set up for emissions , not to provide the buyer with the claimed performance specs and HP ratings that they get on a dyno when the bike is actually tuned correctly ...... :cry:

Re: Help brand new 2017 450x exhaust glowing red

Posted: Thu May 10, 2018 6:57 pm
by Moneypit
Ah makes sense. Thanks for the info.