I know, another vibration thread, but think I've read the whole internet and still haven't found a definite answer.

Some history... My bike has 105k miles on it and for the past 10-15k miles an engine vibration at certain rpms and speeds has gradually increased to the point that it is no longer fun to ride the bike. I am the original owner and I've kept very good care of the bike over the past 14 years. I change the dino oil and filter every 1500 miles, primary and tranny every other oil change. It hasn't been to a Harley dealer since the warranty ran out in 1997. I've done all of the maintenance myself and used a good wrench for things I am not able to do.

It's mildly modded: ev27 cam & timken bearing, mikuni hsr42 carb, chromoly rods, single-fire Dyna 2000 ignition, SE intake and V&H pipes, M6 primary adjuster. At about 50k miles I had the top end done: refreshed cylinders, SE high comp pistons at .010 over, valve job, gaskets, etc. I have not done that again. The bottom end has never been opened up.

Last year I brought her in to my mechanic for this complaint and he replaced the motor mounts and the upper stabilizer and put in a new primary chain. He checked everything out inside the primary and gave it a good bill of health. He also tinkered with the carb some and resolved a vacuum leak. None of this helped.

I had checked the timing and noticed it was not advancing off idle so I contacted Dynatek and they bench tested my ignition module and confirmed it was malfunctioning, so they sent me a new one and that helped wake the bike up again, but the vibrations are still present.

I did 1300 miles over the long weekend and noticed oil pushing out from the timing cover. It's enough to splash onto the torque arm, but not the front pipe. This could just be a worn seal, or a post I read somewhere said it may be an indication of a failing bottom end. With the increased vibrations and lack of resolution with all the mounts done, it's starting to sound plausible.

The motor makes no weird noises, starts perfectly cold or hot, has power, doesn't burn oil, and other than this new minor leak, doesn't even drip a drop of oil on the garage floor. When the motor was opened up at 50k my wrench commented how clean and free of "rotten egg" smell it was. I attribute that to frequent oil changes and using quality oil.

Is there any way to determine the health of the bottom end without opening up the motor? I'm prepared to throw more money at this, but I want to be smart about it. The MoCo will rebuild my Evo V2 engine to factory original condition inside and out for $2295 (with a 12 month unlimited mileage warranty), plus the labor for a local dealership to r/r it. But if I don't need a full rebuild, I don't want to go for that. I also don't want to spend $2k trying this and trying that and then end up rebuilding it anyway. My reading shows "evo bottom ends are pretty much bullet proof." But for how many miles?

I have a 2 week trip planned for July and I do not feel like I can bring this bike that far from home. I'll be traveling with one other bike and nothing would suck more than to have my bike die and leave them somewhere far away to ride home alone. I gotta get this sorted out.

Any wisdom to share?

 

I can't say what might be causing your vibes but I woould advise against the harley reman for your bike.

I had my engine remaned by the MoCo around '02...they put it completely back to stock, meaning you will lose your cam, pushrods, and any other goodies, and they will put in the inferior INA cam bearing....so you are probably better off finding a wrench with a good reputation to do your rebuild if you decide to go that route and you will probably save money that way too.

The Harley reman program worked out better for me since I needed new cases and Harley restamps the new cases with the original VIN so there is no hassle with the DMV...but I did end up back with the stock cam, pushrods and INA bearing. Other than that Harley did a fine job with the rebuild.

 

How many miles were on your bike and what symptoms were there that lead you to do a reman?

I agree... the improvements I've made I cannot be without. I couldn't get out of my own way when the bike was new. The cam and carb transformed the bike.

 

My problem was not vibration. I had a defect in the case that was causing engine oil to seep into the primary. There is a race that is pressed in and oil was leaking there. It is a fairly well known problem on Evos in the mid-to-late '80s or so...Harley even replaced some cases under warranty and free even past warranty but mine didn't start leaking until it was about 9 or 10 years old so they didn't cover it.

It started leaking at around 50k miles...but i lived with it until I was ready for a rebuild at nearly 100k.

 

OK, cool. I have an appointment with my wrench for Saturday to discuss the situation.

 

REad your post and then went to my Service Manual.
It suggests a few things, but what caught my eye is "loose engine to transmission bolts"
Shot in the dark, but maybe something to do with that, or with your torque arm (I assume you mean a Carlini?)

Hope it works out and you find the issue.
Meanwhile I'll sit back and watch. My 98 will hit the big miles eventually too.

 

Thanks for your comments. I will double check those bolts. And yes, it is a Carlini. I've had it on there since year one of ownership. One of the best additions I made too.