Timing / carb issues. Any ideas. - Honda TRX Forums: Honda TRX 450R Forum
 
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post #1 of 9 (permalink) Old 05-04-2019, 12:39 AM Thread Starter
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Timing / carb issues. Any ideas.

Just rebuilt my TRX 450 R with a 470 kit. 96 mm piston. It was running great before with huge bottom end power. I don’t know what cam it has but I know it doesn’t have the stock cam. The cam has a number three engraved in the gear side with no notches on the other side, and Had a big valve head. Now have a stock head. Original jetting was 180 Main 55 pilot. And stock carb. And I already had the 470 kit to begin with. Now with stock head it acts as though you’re hitting the rev limiter around mid RPMs with wide open throttle.Any ideas would be greatly helpful please.
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post #2 of 9 (permalink) Old 05-07-2019, 12:50 AM
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My first question is why did you go back to a Stock head?

1. Are you running an Air Box Lid? If so remove it...

2. Might have to big of jetting go down to like a 168 (= to a 152 DynaJet) or like a 170 (= to a 154 Dynajet)

3. What brand jets are you using? If it's DynaJet that's equal to like a 205 Keihin jet seems way to big in my opinion. Remember richer is not always better.

To me sounds like your fuel mixture is way to rich.

Check to make sure your cam timing is correct. At TDC you wanna have the Intake Cam Lobes pointing to the back of the quad and the Cam Sprocket Screws directly up and down

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post #3 of 9 (permalink) Old 05-08-2019, 10:53 AM
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You also need to find out about the cam If that head was built for the cam, shorter guides or something, then you could be getting interference on the stock head. Either way changing heads is more than likely going to require a jet change.

04 450r
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post #4 of 9 (permalink) Old 05-23-2019, 03:41 PM Thread Starter
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Thank you for your input. Really do appreciate it and I found a big part of my problem. A/f screw was missing an oring. Replaced it and now it’s running but still having issues. Running great but having a strange blog about quarter throttle while pulling. Free revs great with no hesitation from idle to rev limiter. And after running for about 15 minutes it all of a sudden decides it doesn’t want to crank.
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post #5 of 9 (permalink) Old 05-23-2019, 03:43 PM Thread Starter
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And my wallet made me get a stock head after my original head broke a valve and gernaided.
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post #6 of 9 (permalink) Old 05-24-2019, 05:52 AM
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Sounds like a stator issue or a combo of tight valves and low slide needle

2008 TRX 450ER XC racing
FMSQ # 281
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post #7 of 9 (permalink) Old 05-24-2019, 08:15 AM Thread Starter
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I have an extra stator. I’m going to try it this weekend. And I have the b51 needle on the 4th clip from top.
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post #8 of 9 (permalink) Old 05-24-2019, 08:17 AM Thread Starter
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And I’ve checked my valves 20 times or more. Intake are loose .006 and exhaust are a good .011.
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post #9 of 9 (permalink) Old 05-28-2019, 09:30 AM
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You really need to get the info on that cam, it may not be working well at all with a stock head. Bog is mare than likely a fine tuning on the jetting issue.

04 450r
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