Lack of Compression after Valve Adjustment - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 29 (permalink) Old 09-17-2019, 04:22 PM Thread Starter
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Lack of Compression after Valve Adjustment

I have a 72 Daytona T100R and adjusted my valves per the workshop manual specs (first time doing this, last time I had a friend do it). I went to start the bike and the kicker lever has little to no force on it. When I press down on the lever I can hear air being sucked into the carb filters. Is this because I accidentally set the intake settings too wide and need to recheck them? Or do I need to back out the slider screw on the carbs, start the bike and reset the carbs? Thanks for the assist!
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post #2 of 29 (permalink) Old 09-17-2019, 04:33 PM
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Quote:
Originally Posted by 72Daytona View Post
I have a 72 Daytona T100R and adjusted my valves per the workshop manual specs (first time doing this, last time I had a friend do it). I went to start the bike and the kicker lever has little to no force on it. When I press down on the lever I can hear air being sucked into the carb filters. Is this because I accidentally set the intake settings too wide and need to recheck them? Or do I need to back out the slider screw on the carbs, start the bike and reset the carbs? Thanks for the assist!
LEAVE THE CARBS ALONE

DO NOT START THE BIKE! or you may be doing a valve job.

You either set a valve or valves at the wrong clearance or didn't set them at TDC with BOTH valves closed.

You created the problem so go back to square one. If you're not sure then get your friend to help.
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Last edited by justalurker; 09-17-2019 at 05:31 PM.
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post #3 of 29 (permalink) Old 09-17-2019, 08:01 PM
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+1 go back and do valve adjustments again.

OOh looke a custom signature !
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post #4 of 29 (permalink) Old 09-17-2019, 08:39 PM
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post #5 of 29 (permalink) Old 09-17-2019, 09:15 PM Thread Starter
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I readjusted the valves and it fired right up! Thanks for the input, it was much appreciated
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post #6 of 29 (permalink) Old 09-18-2019, 09:01 AM
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Problem presented, solution posted, successful conclusion reported.

Good thread.

(the "moved thread" deal was before I saw it)
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post #7 of 29 (permalink) Old 09-18-2019, 03:21 PM
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That could have ended very differently... Glad you got it sorted without any valve damage. 🙂

Out of interest (and for anyone else arriving here with similar issues in the future), what was the problem? Presumably it was the tappets too tight and the valves were not closing but what did you do differently to fix the problem?

Cheers,
Ian
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post #8 of 29 (permalink) Old 09-18-2019, 04:20 PM Thread Starter
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I went back and properly set the valves. As you mentioned the tappets were too tight and air was just being forced out of the openings available rather than compressing. I must have gone out of order due to my lack of caffeine and/or sleep. Whatever the case, it is all good now! I'm pumped that you guys were here and so speedy with a response.
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post #9 of 29 (permalink) Old 09-18-2019, 05:07 PM
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The common mistake newbies make when setting 4 stroke valves is NOT finding TDC on compression.

The next most common mistake is not knowing how to use a feeler gauge.

Then there's the "I set it right" but then they tighten the jam nut and the clearance decreases to little or none.
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post #10 of 29 (permalink) Old 09-18-2019, 08:08 PM
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Quote:
Originally Posted by justalurker View Post
Then there's the "I set it right" but then they tighten the jam nut and the clearance decreases to little or none.
Daytona's "little" as standard - 2 thou inlet, 4 thou exhaust ... bugger to set accurately ...

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