Oil in Intake

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Jul 8, 2018 | 09:20 AM

sleighcrane

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From: Parksville B.C.

Oil in Intake

I have a 67 ironhead and it seems that I have excessive oil in the intake and cylinder and it will start to foul the plugs after I ride for 50-60 miles
Compression front 135 rear 130 lbs. The bike runs fairly well it seems starts right up so I am thinking that I
might need guides rather than pistons although once I pull the heads I will do whatever to correct things.
Does this scenario seem the most likely?

Last edited by sleighcrane; Jul 8, 2018 at 09:26 AM.

Jul 8, 2018 | 09:29 AM

Mattbastard

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From: Tampa

Why don't you just route the breather under the bike instead?

Jul 8, 2018 | 10:04 AM

sleighcrane

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From: Parksville B.C.

No breather Just air and gas but I did do that on my TC. This is the bike I am referring to

Jul 8, 2018 | 02:04 PM

Mattbastard

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From: Tampa

Ok, I'm not following you. In your original posting you say there's excessive oil, but in your reply it's air and gas? The only way I'm aware of oil getting into the intake is from a breather. If you have excessive blow-by the only fix (other than a rebuild) is route the breather under the bike so it'll **** oil at every parking spot.

I still don't understand why you can't reroute the breather to under the bike. Yea you may have to buy a custom intake, or modify the one you have, but it should eliminate your problem without ripping the top end apart.

Jul 8, 2018 | 02:24 PM

bustert

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the iron never did breathe into the engine, has a down tube on the cam case at the generator drive. the iron does not have valve guide stem seals. worn guides will def increase oil usage but hd wasn't concerned until it was more than 1 qt/500 miles. if you are indeed having oil in the intake tract, i would suspect valve recession also. if the valve is shrouded, flow will suffer and possible oil from guides is not being drawn with the intake charge.
nows the time to install stelite seats

Jul 8, 2018 | 04:52 PM

sleighcrane

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From: Parksville B.C.

No Matt this isn't like the newer bikes as far as the head breathers. I have an issue with the internals be it rings guides or valves possibly all three but the motor is supposed to be "rebuilt". The top of the pistons also seem oily or wet a little bit so I have just put in a hotter plugs to prevent fouling. Bike runs pretty well and hope to make it to the fall before I go into the top end. With the compression at 130/135 I think that the oil must be coming in through the guides into the intake area and then into the combustion chamber. Does this sound logical? Thanks

Jul 8, 2018 | 05:02 PM

Max Headflow

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From: poway

You initial diagnosis is correct, Valve guides are likely loose but I'd do a whole top end.. 67 is over 50 years old.. Don't know for certain what you'll find.