Author Topic: Exhaust valves have no clearance at TDC  (Read 391 times)

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Offline 350fmainmark

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Exhaust valves have no clearance at TDC
« on: May 12, 2024, 03:27:47 PM »
I have a repair manual and clearance is supposed to be .002" at TDC. Using The 1-4TDC mark and checking which piston is at TDC and then checking 2, 4, and 3.  In each case the intake valve adjust and has clearance but the exhaust vales are tight. I have not attempted to start the bike until I have the valves set correctly.  When I purchased the bike it had spark so the next thing I was checking were the valves.  The were extremely lose so following the manual I now have the tight exhaust valve situation.

Offline grcamna2

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Re: Exhaust valves have no clearance at TDC
« Reply #1 on: May 12, 2024, 05:00:47 PM »
Can they be adjusted/loosened-up to the correct(.002")spec ?
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
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Offline newday777

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Re: Exhaust valves have no clearance at TDC
« Reply #2 on: May 13, 2024, 02:49:36 AM »
I have a repair manual and clearance is supposed to be .002" at TDC. Using The 1-4TDC mark and checking which piston is at TDC and then checking 2, 4, and 3.  In each case the intake valve adjust and has clearance but the exhaust vales are tight. I have not attempted to start the bike until I have the valves set correctly.  When I purchased the bike it had spark so the next thing I was checking were the valves.  The were extremely lose so following the manual I now have the tight exhaust valve situation.
What bike are you working on?(please tell that when you ask for help)
I'm guessing you are trying to adjust your valve lash when you say clearance? You know that you can't adjust all 8 valves in one spot don't you? You adjust the 4 valves first, then rotate the crank to the second mark to adjust the other 4 valves (most likely your problem??)
Stu
Honda Parts manager in the mid 1970s Nashua Honda
My current rides
1975 K5 Planet Blue my summer ride, it was a friend's bike I worked with at the Honda shop in 76, lots of fun to be on it again
1976 K6 Anteres Red rebuilding project, was originally my brother's that I set up from the crate, it'll breath again soon!
Project 750s, 2 K4, 2 K6, 1 K8
2008 GL1800 my daily ride and cross country runner

Prior bikes....
1972 Suzuki GT380 I had charge of it for a year in 1973 while my friend was deployed and learned to love street riding....
New CB450 K7 after my friend returned...
New CB750 K5 Planet Blue, demise by ex cousin in law at 9,000 miles...
New CB750 K6 Anteres Red, to replace the totaled K5, I sold this K6 at 45k in 1983, I had heavily modified it, many great memories on it and have missed it greatly.....
1983 GL1100A, 1999 GL1500 SE, 1999 GL1500A