98 EVO lower end question
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Joined: Feb 2008
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From: San Jacinto CA
98 EVO lower end question
I have a 98 Ultra EVO engine. I had a rist pin bushing failure and damage to a cyl. I replaced the complete top end, but have a rattle on the lower end. I suspect that there is bearing damage to the rods. I have ordered new rods with a new crank pin and bearings. Other than seals and gaskets, what else might I need before I open the lower end up? Any suggestions would be greatly appreciated. BTW it is not the chain or lifters.
Thanks
David
Thanks
David
HDF Community Team
Joined: Dec 2005
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From: NC USA
I have a 98 Ultra EVO engine. I had a rist pin bushing failure and damage to a cyl. I replaced the complete top end, but have a rattle on the lower end. I suspect that there is bearing damage to the rods. I have ordered new rods with a new crank pin and bearings. Other than seals and gaskets, what else might I need before I open the lower end up? Any suggestions would be greatly appreciated. BTW it is not the chain or lifters.
Thanks
David
Thanks
David
A defective compensator washer will make a knocking noise/feel deep in the engine as mentioned. Also, though not common, I've seen cracked pinion gears that would give a deep knock all thru the rpm range. Typically, rod bearings will knock on acceleration and at higher rpms and be quiet on decel and at low speeds.
I don't know how you're fixed for tools, but you will need a lot of $$$ in special tools. I'll be glad to send you a list of specialty tools as well as an additional parts list of other things you must address while you're in there, but I will wait for another post or PM from you.
It's a lot more involved than a top end rebuild and rather time consuming and tedious the first or second one you do, but with reasonable mechanical ability there's nothing magic or scarey about it
Grand HDF Member
Joined: May 2008
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From: Picayune, Ms.
Have you checked the crankcase for debris?? Maybe just turn it upsidedown and see if anything falls out....Also could try pulling the plug in the bottom of the crankcase and check for debris there.
Big Kahuna HDF Member
Joined: Mar 2007
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From: Oregon
A rod should be quieter under load, and louder when running free.
You might make the rod go completely quiet by disconnecting the spark wire to the offending cylinder. The knock is usually caused when the engine fires.
While stopped, put the bike in gear, hold the brake, rev the engine a little until the knock occurs, and then begin to slip the clutch out to put a load on the engine. If it's a rod, it should quiet down noticeably under load.
If it gets louder or if there's no change, it's probably something else.
You might make the rod go completely quiet by disconnecting the spark wire to the offending cylinder. The knock is usually caused when the engine fires.
While stopped, put the bike in gear, hold the brake, rev the engine a little until the knock occurs, and then begin to slip the clutch out to put a load on the engine. If it's a rod, it should quiet down noticeably under load.
If it gets louder or if there's no change, it's probably something else.
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From: San Jacinto CA
Just an update and what I found out. I removed the engine and pulled the cases apart, I found that the rear rod did not move very freely. I ordered a new set of S&S rod kit. I took it to the dealer and spoke with the lead mechanic there. What I was told, is that over time these rods will under normal operation stretch slighly, when they do the hole is slighly egg shaped. This will cause a small bind which in turn causes the piston to slap the cyl. From what he was saying is that the slap is and the way it wore is normal for an engine with this many miles on it, 60K. We replaced the crank, new pistons again, and now the engine runs great. I have heard the rattle complaint by a few over the last year, slight rattle and would change under load, this may be the same issue for many, I dont know. Just wanted to give all an update as to what we found as it may be helpful for someone else.
David DeLeon
David DeLeon
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Joined: Dec 2007
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From: SoCal
I am glad your bike is fixed. I hope it gives you many years of good service.
If I read your post correctly, the mechanic told you that your rod problem is normal.
I would not call it normal for an engine with 60,000 miles on it to develop a problem like that unless they were very hard-ridden or poor-maintenance miles.
The main thing is ya got it fixed.
If you maintain the engine with on-schedule oil changes and letting it warm up before ya hit the throttle too hard it should last a long time.
If I read your post correctly, the mechanic told you that your rod problem is normal.
I would not call it normal for an engine with 60,000 miles on it to develop a problem like that unless they were very hard-ridden or poor-maintenance miles.
The main thing is ya got it fixed.
If you maintain the engine with on-schedule oil changes and letting it warm up before ya hit the throttle too hard it should last a long time.
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HDF Community Team
Joined: Dec 2005
Posts: 5,422
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From: NC USA
It is normal for the rods to "egg" but understand that distortion is normally less than .0005 and when adding .00025 worth of normal bearing race wear, they are, for all practical purposes, "egged." Nothing abbynormal about that However a rod that does not moving freely cannot be caused by this condition, as the sides of the bearing ends do not shrink proportionately. Which brings me to my first question - did they mention finding any bad rollers?
Also happy to hear you're up and running and appreciate the update on your original post.
Second question - are your old rods for sale or giveaway?
However a rod that does not moving freely cannot be caused by this condition, as the sides of the bearing ends do not shrink proportionately. Which brings me to my first question - did they mention finding any bad rollers?Also happy to hear you're up and running and appreciate the update on your original post.
Second question - are your old rods for sale or giveaway?
