11strings

So I've got this Hawk with 85k miles on it. 99% of these miles were more touring related (I'm lucky enough to know the original owner). She's in pretty good shape. Doesn't make any strange noises aside from a little valve chatter which I'd expect at that age. Doesn't smoke, and the only oil it uses is, I think, due to a small leak in my oil pan gasket that I just haven't had time to fix yet. I've been wanting to get this bike back to a younger condition, so that leads me to questions.

I've been told that it'd be easier to buy a used, low mileage motor and just do a swap. I agree that that's PROBABLY the best, but just for curiosity's sake, I'm asking all you experienced mechanics out there this question. Knowing what I've told you (and anything else that you ask, I'll answer), if I wanted to try to rebuild this motor just for commuting (not track), what all would I be looking at replacing?

I'm not a complete mechanical idiot, so I'll do my best to understand your answers....I'm just not sure I know enough about this motor to know what's worn besides EVERYTHING. haha
Thanks in advance!

killer5280

There are examples of Super Hawks with well over 100,000 miles. If it runs good and doesn't smoke, why not just run it until it really needs to be rebuilt?

lazn

Ya, I see no reason to rebuild a working motor. That one is just getting broken in.

The only reliability issues on our bikes are: the Cam Chain Tensioners (why you see people doing the APE CCT swap) and the Voltage Regulator. The rest of the bike will just keep running for as long as you do regular maintenance, # of miles hardly matters.

psyclown

One thing I would definantly check would be anything saftey related. Wheel bearings in particular.

and +1 on killers statement that if it aint broke, and you just want to use it to commute anyway, then don't fix it.

for the valve chattering, you should check your clearances and adjust your lifter shims to spec. as neccesary. This is a simple enough task that is outlined in the service manual pretty clearly.

L8RGYZ

If you need a newer motor... I totaled my bike & have one with "only" 59,000 miles on it. j/k. Good luck with the rebuild. Wish I had the skills to do that.

motojoe

Something you could do first is a leak down test to see if your loosing compression anywhere. If not, no sense in tearing into the motor. If it does not leak oil or have loss of compression don't mess with the cylinders. But I would only go as far as pulling the heads and taking a look at the cylinder walls for scarring. If they are scarred, then you can hone them and re-ring and install new pistons. But while you have the heads off, inspect the valves. You may want to clean the ports and get new valves and valve seals and guides if they look bad. A light three-way valve job to clean up the valve surface wouldn't hurt either if things look bad. Otherwise if your within spec from the leak down test, don't mess with it.

autoteach

had a subaru engine apart last week. 98k on the motor, needed head gaskets. Cylinders still had a large majority of the cross hatch left. I would say it was even at a 98% quality. All I am saying is what others have already said, don't F$%^ with it, and it will be nice to you.

PUSHrod

Do ya have something to ride in the mean while? There are so many 'unexpecteds' that come up during a tear down and rebuild that without a spare bike, you end up with withdrawal symptoms in good weather.

If time is in abundance, get the original factory service manual for perusal during private time in your, um, reading room. Nothing enhances quality like information. Then troll through here for advice, I assure you, we have made mistakes and would love for you to benefit from our tuition.

Assuming that your bottom end is within tolerance, my bet is that you can get by with a freshen up on the valves and seats and since you are already in there, new CCTs.

Should you go forward with this project, how about a running diary and pictures? It would give our community substance for a little while.

Tweety

Seriously 85K isn't high mileage... It's somewhere in the middle territory... Nicely broken in, but not really in need of a rebuild... I'd probably check valves/shims to see if that needed adjustment if it makes a mild noise...

And FYI it's more likely to be the carbs making their clickety-clack at idle then the actual valve train, lot of people get those confused... If it IS the valve train, stick a pair of manual CCT's in there and adjust them correct and it should quiet down...

Other than that, until it does start acting up, keep up regular maintenance and ride the snot out of it and all is well...

My bike is at 40K miles with this engine (CCT failure) and before that it was I believe at around 60K-65K ish... The other engine is still around, being re-worked with some go-faster bits...

RCVTR

My son and I rebuilt his '95 Subaru Outback engine last summer. It had 170k and needed head gaskets. I had always planned to build an engine with him, to "show him the ropes". It was a really great project. We put the original pistons back in and ball-honed the cyclinders. Pistons and bores measured within spec - just barely. Valve guides were acceptable. We cut new valve seats and refaced the exhaust valves. New rings, bearings, seals and gaskets and it runs like a champ.


So you can "freshen up" a high mileage engine without getting in too deep. You have to turn your expectations down a bit, because making it new will cost some money. The cylinders will be tapered.

After 80k miles the valve seats and valve faces are badly pitted - exhaust valves especially. If it were me, I would put new valves in (you can't reface the valves), and cut new valve seats.

If you are going to bore, hone, install new pistons and new valve guides, it gets considerably more expensive. The fit between the lifters and lifter bores may be getting rattly, as well. but if it has always had fresh oil in it, the lubricated parts are probably in pretty good shape.

Rings, bearings, gaskets and seals are not a big deal, if you are doing the work yourself. I have a set of low-mileage stock pistons (~12k miles) that I'll sell for $50 delivered. I'll send photos if you are interested. Skirts measure within tolerance.

11strings

Ok ok...so maybe I shouldn't have used the term "rebuild." I like the "freshen up" a little better. That's basically what I was looking for was suggestion of what should be freshened. CCTs I knew about, but still have the factory ones on. I was considering just purchasing new stock CCTs, which I know everyone's gonna tell me not to, but if I'm just cruising around with the occasional "spirited" ride, do I REALLY need to worry about manual CCTs? Valves I already had in mind of doing, and the carbs are definitely going to get a makeover. Wheel bearings are fairly cheep on bikebandit, so I'll probably do that as well.

As to photos, I'd love to post some, but I doubt I'll be doing this job myself. I'm a cop in a college town and live in apartments. I don't have the time to sit down and do all this in a session, and don't have a "shop" to keep it in while I'm doing it. As much as I hate to, I'm going to have to pay someone to do it.

RCVTR - thanks for the offer on the pistons. If you're not in a hurry to get them out of your way, I may holler at you a little later. I'm going to have to get with my mechanic buddy and see when he can fix it. If he tells me the pistons have to go, I'll be contacting you.

Anyone else think of anything that should be freshened up?

Thanks for all the info already guys... And I'm glad to know 85k isn't bad. I-4 riders laugh at me when I tell them I've got so much.... Guess they're missin' out.

killer5280

There have been a lot of CCT threads, but manual ones are a no brainer to me. They simply won't fail.

There are plenty of I-4's with well over 100,000 miles also; they're all built pretty well these days.

RCVTR

You really can't go wrong with these. I guarantee yours will not llok like this:

zmaniv

If you need a new set of rings I have a spare set that I bought by mistake. 75.00 shipped to you.

11strings

RCVTR & zmaniv - Thanks so much guys. If either of y'all are in a hurry to lose those parts, by all means, don't wait on me. But if they're not bothering you where they are, I'll see what ol' boy says when/if we jerk the heads off. I love this forum.....where else do you find good natured folks like this?? lol

zmaniv

No problem they have been sitting in my closet for 9 months now what is a few more going to hurt.