Author Topic: timing advancer mod  (Read 1007 times)

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Offline Don R

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timing advancer mod
« on: December 30, 2021, 04:49:54 PM »
 Here's what I noticed when I was making sure the Gerex ignition had advance and it was working. It needed a clean and lube. It's an 836, high compression, RC315 cam, 4-1, smoothbore carbs. 323 advancer and a welded weight. I think the springs need tightening also.
 
  It was sticky, it would advance and then just hang there. Now it at least returns on its own. If I can cure the engine rattle I'll work on the advance.
« Last Edit: December 30, 2021, 10:39:40 PM by Don R »
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Offline Tracksnblades1

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Re: timing advancer mod
« Reply #1 on: December 30, 2021, 05:44:34 PM »
Alcohol ?
Age Quod Agis

Offline Don R

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Re: timing advancer mod
« Reply #2 on: December 30, 2021, 07:55:33 PM »
 No, but it was street/track driven up until 1987 so maybe he limited timing due to poor gas. It is possible it had the turbocharger on it at least for a bit. I got a 64mm burned RC piston and it's three brothers in the stash. It's a 71 motor so probably wasn't born with the 323 TEC advancer.
 I probably have one of every advancer made. There's an old advancer thread around here with some good info.
« Last Edit: December 30, 2021, 08:25:42 PM by Don R »
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Offline Don R

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Re: timing advancer mod
« Reply #3 on: December 30, 2021, 10:19:42 PM »
 I read everything I could find and got a lot of info about advancers and springs, not a lot about what total timing and curve rpm is desirable in a modified engine. It seems the older 300 hitachi advancers worked better for performance then the 323 TEC. I however don't have points to bounce so the advantages would be in total timing and all in rpm.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline Don R

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Re: timing advancer mod
« Reply #4 on: December 30, 2021, 10:34:56 PM »
http://forums.sohc4.net/index.php/topic,113338.0.html

 Advancer information. Google turns up the best sohc4 threads.
« Last Edit: December 30, 2021, 10:47:09 PM by Don R »
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Online PeWe

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Re: timing advancer mod
« Reply #5 on: December 31, 2021, 12:46:36 AM »
I can recommend to cut the springs 1/2 wound!
Idle will be more stable and advance will not kick in too early.
For stock and modified engines.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Don R

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Re: timing advancer mod
« Reply #6 on: December 31, 2021, 03:41:56 PM »
Agreed on the springs, the advance cam has been replaced by the Gerex rotor. The 323 advancer may be a part that was modified by Gerex. The PO does not remember modifying it, so I won't tempt fate by swapping it out without more information.
 
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.