2007 tr450er will not start when hot - Honda TRX Forums: Honda TRX 450R Forum
 
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post #1 of 9 (permalink) Old 05-17-2017, 12:32 AM Thread Starter
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2007 tr450er will not start when hot

hey guys ,

Im needing help on my trx, The bike will start right up with hardly any choke but when i run it for a little while and turn it off the starter sounds like its struggling to turn it over and will not start after i let it sit for a little while it starts up again any sugestions on what it could be ????

The bike is runing stock with no lid on the airbox and the header turn bright red when ran for a while im thinking maybe the f/a screw??
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post #2 of 9 (permalink) Old 05-17-2017, 12:29 PM
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What time of day/night and what was the temp when the pipe turned red??
Have you rejetted since the lid is off??
When is the last time you adjusted your valves???
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post #3 of 9 (permalink) Old 05-17-2017, 12:53 PM
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Adjust your decompressor, got to be a bit too loose, set it to 0,021 (if ex clearance is in the ballbark of 0,011+-0,001), compression increase when engine is up to operating temp.
For the red pipe, decrease your idle

2008 TRX 450ER XC racing
FMSQ # 281
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post #4 of 9 (permalink) Old 05-19-2017, 09:02 AM Thread Starter
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Ok so here is the update , i set my decomp at 60 for some reason it was at 75 or so the bike struggled to turn it over when hot , so the bike is running ok it boggs down at wot and it was leaking oil from one of the vent tubes i had recently done a oil change so idk if i may have put more oil than what the engine calls for or if its another issue.
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post #5 of 9 (permalink) Old 05-19-2017, 10:49 AM
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Quote:
Originally Posted by iesca93 View Post
Ok so here is the update , i set my decomp at 60 for some reason it was at 75 or so the bike struggled to turn it over when hot , so the bike is running ok it boggs down at wot and it was leaking oil from one of the vent tubes i had recently done a oil change so idk if i may have put more oil than what the engine calls for or if its another issue.
if you are bogging at WOT and your pipe is glowing red you are definitely LEAN! if you have not rejetted since going to open air box you need to. wide open throttle would mean you are on the MAIN jet. 165 to 185 is the area you will most likely end up. take your spark plug out, willing to bet it is ash white colored, should be a light brown clean burn color, white=lean black =rich
Hope that helps
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post #6 of 9 (permalink) Old 05-19-2017, 11:37 AM Thread Starter
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I put the lid back on yesterday , also when i pulled the plug out it was black ultimately idk how long its been like that but i replaced it , and the bike bogs at wot and when i throttle it to fast it bogs as well, do you have any idea what the oil from the vent might be?
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post #7 of 9 (permalink) Old 05-19-2017, 12:38 PM
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some oil in the vent is ok. there is a reason those tubes are there and a reason they run to the breather box. my best suggestion is still to pull the carb off, use youtube as your guide if you have never done one, go through the carb and clean it as well as you possibly can, check for any o rings or seals that my be missing and or old and brittle... replace them as needed. while you are there and have your jets out take a look at the numbers stamped on the side and write it down. It is always good to know your machine in and out. number one it will help with many questions being answered on the forums or at a shop, and two if you know your machine and know when something is different it becomes easier to avoid catastrophic failure!
also do you have the downloadable SERVICE AND REPAIR manual...(not the owners manual)?
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post #8 of 9 (permalink) Old 05-19-2017, 01:38 PM Thread Starter
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Ok i will be taking my carb off today to clean it and look the jets, and no i do not have the service manual , also the header is getting really hot because of A/F mixture or because of idle?
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post #9 of 9 (permalink) Old 05-19-2017, 03:36 PM
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The header is getting hot because of a lean a/f mixture. at idle you are running off the pilot jet, not the main jet. your pilot jet may be too small, or you could have your air fuel mixture too lean. (turning the screw in leans the fuel out, turning our richens the mixture with more fuel) the factory setting for a a/f screw is 2 1/2 - 2 3/4 turns out from all the way in. All bikes are different so are everyone's climates and elevation levels, so this is just a good starting point. Try to set it around those specs and then set your idle to work with that fuel mixture. The idle should not be real high, about 1700-1800rpm.
jetting sucks to learn how to mess with and get right but well worth it in the end as it will run longer and perform at its very best when it has the right a/f combo!
here is a link to download the pdf file for service manual. it has every factory spec info you will ever need.
https://www.manualslib.com/manual/10...a-Trx450r.html
enjoy!
EDIT: Also this thread is the best write up i have seen on our carbs!
the MOTHER FCR info / tuning guide

Last edited by Morris33; 05-19-2017 at 03:46 PM.
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