Author Topic: compression test  (Read 584 times)

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Offline neilc

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compression test
« on: May 26, 2013, 08:56:03 AM »
just did a compression test because i am having a problem with #2 cyl not firing every time,here are the numbers
#1 165  #2 175 #3  165  #4 160 swapped plugs with 2 an1 i runs fine 2 got better but not heating up as quick,swapped coil wires with 2&3 stayed with #3 was okay 2 still misfiring

Offline Old Scrambler

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Re: compression test
« Reply #1 on: May 26, 2013, 09:41:17 AM »
What color was the plug.........black.......sooty.........wet.........gray.........light-brown?   It it was light-brown going to white you have a fuel problem.  When you switched the plug-wires you may have solved-created the problem by slightly twisting the caps on the wires. You may try pulling each cap and cutting off about a 1/4-inch of insulation and wire. Then re-install the caps to good wire.

Your compression is good and typically uneven.......it could be a little higher but then everything would be like new.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
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Offline neilc

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Re: compression test
« Reply #2 on: May 26, 2013, 02:16:30 PM »
glad commpression check came out like it did ,changed plugs,solved cylnder not firing problem also when i went to accell yellow wires i had to put caps on the end of the plugs,said hell with that and put my stock boots on the yellow 7mm wire and again she fires on all 4,i just have to figure whats causing the fouling my plug issue

Offline Old Scrambler

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Re: compression test
« Reply #3 on: May 26, 2013, 03:08:15 PM »
I did the same wire and cap switch about 30-years ago...........same results. Stock coils and wires should be on your shopping list.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
CB750 Classic Bonneville Racer thread - http://forums.sohc4.net/index.php/topic,135473.0.html
'63 CL72 Project(s)
'66 CL77 Red
'67 Triumph T100C
'73 750K3 Owned since New
'77 750F2 Cafe Project
2020 ROYAL ENFIELD Himalayan

Offline neilc

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Re: compression test
« Reply #4 on: May 26, 2013, 03:51:10 PM »
Yup going back to point s and stock coils