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Been awhile since I have posted anything but I do visit the forum frequently looking to learn new stuff from all of the knowledgeable folks here............and it looks like I'm about to learn more.
I have a 98 Dyna convertible with just under 30k miles that I picked up a few years ago; I really like the bike but its performance has always been underwhelming.
So after some research here and elsewhere I was inspired to improve upon that and installed an HSR 42 which changed the whole personality of the bike.....it's actually been more fun to ride. Shortly thereafter I noticed an oil sheen was burning & smoking on the rear exhaust header. Upon closer inspection, I think I may have a leaking head gasket.
Bike seems to run fine and is firing on the rear cylinder, but I see a slight puff of smoke coming out of where the head meets the jug. So I guess I'm surprised that the rear cylinder is actually firing because I thought a leak would cause the compression stroke to be non existent due to the leak.
So,will I cause any damage to the motor if I continue to ride the bike with this leak?
Also curious what would be the likely cause of this? Rich or lean condition maybe?.....Riding the bike a bit more aggressively?......oil too low or too high?....valve issue?.....ring issue? I have looked through a lot of threads but couldn't really find anything that clears this up for me.
Bike also has a weeping base gasket on the rear jug so I figure on replacing that too when the time comes for the top end to come off. And when that happens......well, more money, more money, more money! But just did my taxes and it'll prob be a little while before I can get to pulling the bike down. Thanks IRS.
OEM head gaskets leave a lot to be desired.. And are known to blow out, not a lot but it does happen. Seeing that the base gasket is leaking as well it could have been an issue with original torqueing when assembled. who Knows but regardless it has to come apart. Might as well shave the heads to clean it up a bit to pop the comp a little... .020" will do it nicely without having to change out the pushrods... Consult your local indy on the head work....
Last edited by 98hotrodfatboy; Apr 10, 2019 at 05:35 PM.
Someone probably giving too much throttle and load on it before it was Warmed up... Very Common... and any leak at the head gasket will quickly turn into a burned gasket surface...even flame cut... not gonna be much oil tho... rocker covers and Base gaskets are a Common oil leak..
Couple pieces of advice here are good info. Don't ride it until it's fixed and the bike may not have been warmed up enough b4 riding. Older Evo's tend to have issues with base gaskets at some time in their life. I do most of my own work but also have a good Indy friend.
He has told me, and I've heard him tell other EVO owners to make sure it's warmed up before you take off. He said this alone may be a gasket eater. He also says use good gaskets when making repairs like this and do "both" cylinders not just the one that's leaking. Also do the valves while it's apart. I've always taken his advise and never had a problem.
Last edited by Bass Player; Apr 10, 2019 at 07:52 PM.
IF it is a leaking head gasket you'll want to get it fixed soon. Personally, I wouldn't put any more miles on it until it's repaired.
Agreed.
Originally Posted by Dan89FLSTC
When you have it apart, have your machinist true the bottoms of the cylinders in addition to honing the bores. Thanks. Planning to do this as well as install a new cam and prob get some head work done too. gonna call Scott from Hillside next week to see how to go about this.
Check the cylinder hold down studs, there may be an issue there.
I'll check this too.
Originally Posted by Racepres
Someone probably giving too much throttle and load on it before it was Warmed up... Very Common... and any leak at the head gasket will quickly turn into a burned gasket surface...even flame cut... not gonna be much oil tho... rocker covers and Base gaskets are a Common oil leak..
Probably me..........but I always let the bike warm up prior to riding and take it pretty easy for the first few miles.
My 86 started w/ a base gasket leaking , after the tear down , I had the heads cleaned up, fresh rings and hone , all new gaskets,runs great now and no leaks.Head work ,parts and my labor around $ 600
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