View Full Version : Top end rebuild

03-08-2012, 09:50 PM
Time to tech up this section of the forum with some graphic photos of my work in progress. Purpose of the tear down is to get is ready for the upcoming season. I've replaced the piston and cylinder on the PW-80. Never tackled a 4stroke before. Purchased a timing chain tool and went at it today. Also disassembled the Reklus clutch. I'm about 4 hours into the project. Piston had some carbon I cleared off, cylinder looks perfect to me. The valves/seats look good to me an still have adjustment left in tappets, but I'm sending it out anyway unless someone thinks I'm wasting money. Any feedback welcome.

03-09-2012, 09:35 AM
Did you have to remove the brake lever to get the case off? Or do you not have a brake lever since that's what your clutch was?

03-09-2012, 10:48 AM
Any particular reason you are redoing the top end? What are the symptoms?

I've not had the XR650 apart to that degree since 2000 (never in other words). Never even did the KLX300 though I removed the cam compression release and put in a manual and recarbed and reexhausted and...

03-09-2012, 11:59 AM
Like Tim, I too like to take things apart. Part of what I enjoy about motorcycles is the pieces are small enough to deal with by myself and I can afford the tool and down time on the bike.
Symptoms, Hard to start after events like looping the bike or tumbling down ravines.

Sent the head to Dave Hopkins in WA, to polish and re-valve, about $300.

I've got a JD jet kit and feel I have it set up about right. I've adjusted the valves, a handful of times. Plug looks good to me. I replace them about every 3500 miles
Was the teardown necessary, probably not. But I purchased the bike used with 1,600 miles on it. It's now just over 9,0000. I want to know that I'm good to go for the summer. I believe the service interval is 9,5000 miles for KTM. I wanted to give it a good clean and replace any worn parts.

List includes, rear wheel bearings and seals, Chain and sprockets, plastic chain guides around swing-arm, upper shock bearing, kickstart seal, carb cleaning and re-jet.

There is a little more drag in the Reklus than there used to be, inspected clutch plates/carrier for wear or anything out of the ordinary.

Mostly just giving it a good look through.

Tim I removed the brake pedal last summer when I changed the clutch cover gasket(big one) I punched a hole in my clutch cover last summer and am installing a new one. I think the foot brake is unnecessary for me and is just waiting to punch another hole in the cover when it's on there.

It there somewhere to get carb breather/overflow tubing in bulk instead of the $80 KTM set?

03-09-2012, 12:13 PM
It there somewhere to get carb breather/overflow tubing in bulk instead of the $80 KTM set?

What's special about that tubing compared to fish tank hose, or something else you could get at the Depot? Is it higher heat resistance or something? I discovered two of my lines are cracked, down at the bottom of the carb where it all scrunches through some tight opening. Thought about replacing it, but then thought what difference does it make if stuff oozes out there, or 3" lower? :confused:

edit: Like here's a 50' role for $31.. did I guess correct on 1/8" ID, 1/4" OD?

03-09-2012, 12:28 PM
yea - I just used the bulk clear tubing from the hardware store on mine. Nothing special as far as I can tell....

So are you replacing the piston/rings, or just having the top end cleaned up?

03-09-2012, 12:51 PM
You want the tube to be fuel resistant. The stock tube is polyurathane. The hardware store tubing (tygon) is pvc and is not very fuel resistant. I bought a 10 ft length of tube from Sun. It wasn't really cheap but its less than KTM OE

03-09-2012, 01:04 PM
10K miles, yeah, that makes sense. A few years ago I went through the XR pretty thoroughly though not a top end tear down. The chassis, including swingarm bushings, bearings, etc, definitely needed it and they tend to ship from the factory with, um... 'minimal' grease.

Guess I'm old school on clutches and foot brakes. Made the big switch from left to right after the Bultaco and I think I still have active synaptic paths from that one. :lmao:

03-09-2012, 06:15 PM
Found some. But it's orange. http://www.ktmcyclehutt.com/ktm-parts/ktm-parts.php?sku=7723199700004&title=KTM-Vent-Hose-Orange&year=&ktm-model=&category=Carb&fitment=bigbikes

03-09-2012, 07:18 PM
Cleaned the box. There is a good amount of wear on the aluminum subframe where it meets the plastic. I carry a good sized fender pack that rattles the rear fender pretty well.

03-21-2012, 09:56 PM
more progress, top end is back. New valves, and cam bearings.

03-22-2012, 10:07 AM
Purty. I remember when watercooled first came out, I hated it because they looked like water pumps, not motors. Which they kinda are...

Ah well things change.

03-22-2012, 09:59 PM
Head is back on. Not torqued yet, but back on. I ran out of time before having to pick kids up from ice skating. This parenthood thing can get in the way sometimes. Having a ring compressor was a must. Made it much simpler. Also picked up another spark plug wrench. I've lost 2 tool bags and their content in 3 seasons now. Current bag is bolted on and I've taken to carrying "b" grade tools on trail. Water pump slides onto the camshaft you see sticking to out of the pic on the left.

Air cooled is children's bikes and for riders that dress like pirates. Not for rock crawling machines.

03-22-2012, 10:11 PM
Sweet, I love building top ends for bikes. Huge return for the investment. I can't wait till you fire it up. Breaking in a new motor is one of the things that makes me happiest. It's the only time you actually have to be "nice" to a motor, and it's all so you can flog it later.

03-22-2012, 10:50 PM
I didn't replace rings, piston, or cylinder. Just valves and cam bearings. Do I still have to be nice to it? Did gaskets to, so maybe I should be kind of nice. Please school me. What is the break-in process? Drive easy for 50 miles and check valve clearances? I change oil about every 10 hours of riding. Oil is shared with engine/clutch/tranny. Uses about a liter.

03-23-2012, 08:54 AM
Fresh oil, don't overheat. I take it easy for a bit, change oil (especially if you have a liter capacity!!!) and flog it still not overheating. Heat is the enemy. You are basically micro work hardening the surfaces so heat is a killer.

03-28-2012, 02:24 PM
Did you use the the Kibblewhite valves? I had Dave H use those when he did my head. So far, the valves have needed no adjustment.

Have you run it yet?

03-28-2012, 09:53 PM
More progress. Skiing and Snowboarding in the 60 degree weather are getting in the way. Clutch cover o-ring arrived today so I have all the parts to fill it with fluids.

03-28-2012, 09:56 PM
reklus z-start clutch :)

03-28-2012, 10:40 PM
lookin' sweet dude.

I'd probably just run it easy for the first tank, then check valves, change oil, and rip it up.

did you have an auto clutch in there before?

The bike I got has an auto clutch and a left hand rear brake lever. still kinda getting used to it.

J Kimmel
03-28-2012, 10:45 PM
LOVE my rekluse :)

03-29-2012, 09:04 AM
Bike had the rekluse and rear brake lever when I bought it. I love it!!! Rear brake on the bars is just awesome on technical downhills.

J Kimmel
03-29-2012, 09:48 AM
Bike had the rekluse and rear brake lever when I bought it. I love it!!! Rear brake on the bars is just awesome on technical downhills.

can't bring myself to the brake lever though...my clutch still operates as a normal clutch, and I ride a lot of track still :)

03-29-2012, 11:57 AM
can't bring myself to the brake lever though...my clutch still operates as a normal clutch...

that's going to be my plan, when I ultimately do the Rekluse. I rode Farnham's and definitely locked up the back tire a few times pulling the clutch in :rolleyes: :D.. I guess you get used to it though. Still, I think for a lot of pavement time having a lever-actuated clutch is a good thing.

/hijack.. engine is looking good, Farnham! Can't wait to experience the results in about 4 weeks.. :cool:

04-02-2012, 08:17 PM

New battery. pulled choke. Pushed magic button. Yin,Yin,BBBBRRRRRPPPPP!!!!!!!

Took it around the block added a splash more oil.Then a couple more laps. Pics to follow.

04-02-2012, 08:54 PM
Replaced rear wheel bearings, upper shock bearing, sprockets & chain, swing-arm sliders, JD jet kit, clutch cover, new front fenders and shock guards. Some random hardware, a new battery, and a bunch of elbow grease. I'm am very pleased with myself, first 4 stroke top-end rebuild. I own a timing chain tool if anyone needs to borrow it.:wrench::wrench:

04-03-2012, 10:55 AM
Nice. Put some miles on it so it's broken in before Utah... if the snow has melted enough.

04-04-2012, 09:27 AM
I tried to fit in a short ride yesterday, didn't happen. Trying for today. It's my last day of work for the ski season. Bittersweet. Nice to get the time off, little frightening to know the money faucet will be off for a month.

04-05-2012, 07:04 PM
Went for a test ride today. Ran very well.

04-05-2012, 07:35 PM
Nice, it looks happy.

04-05-2012, 08:40 PM

04-05-2012, 10:12 PM
sweet :)

glad to hear it is running well!

I love the feeling of running a motor you built :) Makes it more fun :)

J Kimmel
04-08-2012, 09:14 AM
awesome, you bringing it to CM?

Good friend is coming down from SLC with his KTM, I'm riding a day or two :)

04-08-2012, 10:59 AM
I plan on Pre running Poison Spider and Hells on Thursday with it. As I'm trail leader for those Fri and Sat. I think I'll be a little too busy socializing to get in much more than that.

For those unaware, Motorcycles May NOT, follow along during Cruise Moab Trail rides.

J Kimmel
04-08-2012, 08:53 PM
thats a great idea, leading spike thursday what a great way to pre run!