Author Topic: noticed an air leak coming from behind the rocker box on my A7  (Read 520 times)

Offline vittoriobravo

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Hello All,
Notice my engine does not rev smoothly, i thought all along it was the carb. But what i notice an air leak coming from the rear of the rocker box. Could this cause problems on how the engine revs.sorry if this is a stupid question.
Regards
Vitto

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G'day Vitto.
I gater it's sucking air at the carb to manifold joint. That will lean out the mixture. Easiest way to test is have the bike running (idle) and spray some WD or card cleaner over the joint. If the idle drops or changes it's sucking air and must be fixed.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline vittoriobravo

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Thank you for that. I give it a go tomorrow.

Offline vittoriobravo

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Hi Guys.
Got a serrious issue now. Found the air leak, was a gasket not properly sealing. Fixed it.
When i placed  the push rods in their rocker cups. I then slowly tightened the four rocker cover bolts.
I turn the engine slowly by hand. When a horror sounding click and the exbust right push rod had dislodged from the the rocker cup. Went through the pain process with a torch and got the push rod back in, when the same thing happened again.
So took the old iron head off to examine and make sure the lifters were doing their job. Looked all fine.
Went through the whole process again. By now I was getting good at getting the push rods into their rocker cups.
The same problem happen again when i turn by hand the engine. The right exbust pushrod clicks out of the rocker cup.
I tbought next time i will try and isolate the problem by only installing the  left and right exbust push rods into their cups and leave out the inlet rods and see if the same problem still happens.
Let you guys know the out come. Thanks.
Regards
Vitto

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G'day Vitto. Fun isn't it?
Make sure the push rod is seated correctly in the cam follower cup. With a bit of oil down there, give the rod a twist as you seat it. You should then be able to lift the follower with the rod a bit. Are there any marks on the push rod? It has been known for them to rub on an ill fitting head or rocker box gasket. Are you using the comb? (I don't)
Strange in that the ex ones usually go straight in and you have more trouble with the inlet. I had to have two goes at one last week. Don't give up.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7