93 XR600R Top End Rebuild

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93 XR600R Top End Rebuild

Post by 4Strokes » Fri Jun 03, 2016 9:59 am

Topic: 93 XR600R Top End Rebuild - What to know, tools?
Author: cjjcmg
Posted: 03/26/2008 2:29:36 PM

So I am an amateur but very mechanical and technical. I have taken an online course on motorcycle mechanics as well as I have gone through the manual several times. Sometime in the next couple of months, I am going to attempt to rebuild the top end of my motor, mostly to replace the rings. I will do all the tear-down, will have the shop check most of the measurements and handle anything I cannot do without getting all the tools and presses.

1993 Honda XR600R - First of all, can I do this with the motor still in the bike? What do I have to look forward to? What do you suggest as must have special tools, chemicals? Anything else I should think about doing while I have the top end apart? And don't tell me to forget doing it myself, won't help. I am excited to attempt it. Worse case, I bring a box of parts to my favorite mechanic with my tail between my legs and have it done right. Done it before. :)

Reply by Reggie on 03/26/2008 7:50:12 PM
Yes you can do it with the engine in the bike although I have never tried it.I far prefer a clean area where I can get all the various sockets and wrenches in without having to worry about other crap getting in the way so I take the engine out.. Takes about an hour to do that.Then you just tear it down. Getting the Cam Chain Tensioner arm back in on reassembly is about the hardest job you will run into.. that's if the 93 uses the same system as the 83 to 90 model. don't have a 93 although I have the manual so can't be sure without looking it up.You can get a special tool for the job but I just use a plastic cable tie. Anyway when you begin pop back and let us know and we can guide you through the trouble spots. Luck to you.

Reply by mitchner9g on 03/27/2008 12:01:19 AM
No one here would be saying for you to not tear your bike down! We're all a bunch of gear heads to some degree or another. That said, I second Reggie's advice about yanking the engine and getting it onto a bench where you hopefully have better light. And yeah, the cam chain tensioner is a pain but there are threads on this forum that we've posted in to do a search on :)

special tools? make sure you have a decent torque wrench (some people would say that isn't really a "special" tool, but I didn't have one before doing my top end). safety glasses are always a good idea.

Reply by letank on 03/27/2008 10:28:26 AM
Another.. when you read the torque values make sure that you match the column for your settings N/m and Ft/lbs. yes basic but having worked on mostly US specs. where the first column was standard. yep I torqued that head to 57 ft/lbs and the threads stripped. The tensioner w the zip tie is a good point. discovered it myself after dealing w bailing wire that is a paint to twist. use small zip ties that are easy to cut off.

Reply by cjjcmg on 03/27/2008 10:49:00 AM
I figured I'd get some good support here. I have a couple more races before it get's hot so I hope to begin then. So I knew I had to tie out the chain so it didn't fall into the lower. I read I should remove the chain tensioner. I'm guessing it's one of those, hold it in place while doing four other things jobs? So a torque wrench and three hands are the best tools, eh? Thanks for the help guys!

Reply by mitchner9g on 03/27/2008 11:08:52 AM
three hands can be helpful, but I've found holding tools in my teeth to be nearly as effective. spend some time reading up front.. The RFVC design is probably very similar in your '93, or at least the general concepts are probably the same.

Reply by cjjcmg on 03/27/2008 2:51:29 PM
Funny thing tho, the more hands you have, the more you lose. We've all lost a tool in our left hand, right? Kinda like losing your sunglasses on the top of your head.

Reply by tikigod65 on 03/27/2008 3:47:02 PM
Make sure you have all gaskets and parts required to do the job before you start. This makes it so you can disassemble the motor and put back together while you still remember where everything goes. Also take your head and block to a shop and have the surfaces milled to insure that they are flat. Also have them install new valve seals and lap the valves. Almost any auto parts store can do this for you. I just had mine done and it cost about $90 bucks

Reply by b_king on 03/27/2008 6:36:31 PM
To add to what others have said and a couple of things to keep in mind. I would take your head and cylinder to a shop to check for warp prior to machining off material, it's a lot to take it off than it is to put it back. Also, I would suggest to get the cylinder bore measured for taper, out of round and such by a reputable shop. Do this with the piston, don't arbitrarily just put new rings and then find out the bike runs like crap cause the piston was worn out and slapping around inside the cylinder. You will most likely have to go to the first over size which will require the cylinder to be bored. Also, take the complete head(valves in) to a shop where they can disassemble it and inspect the valves and seats for wear. You will most likely be doing a valve job and buying valve judging by the year of this bike, unless it is a really low mileage. Have the cam journals inspected for unusual wear. It's a good idea to get the head bead blasted to remove all the carbon and such, should be done if you are getting a valve job. The problem with just lapping used valves is that the face where it contacts the valve seat is actually cupped and thus the seat is rounded. So depending on how coarse a lapping compound you are using, you will only further wear out the valve face. To ensure good valve seal, a fresh 45 angle must be cut as well as the locating 60 and 30. Then either replace the valve, or cut the new angle on the valve. Valve guides should be inspected for wear. The valve springs should be measured to ensure they are within spec. New valves seals are cheap and considering the RFVC motors are prone to leaky valve seals, I'd throw a set at it. Have the shop you are taking your motor parts to just inspect the bottom, it would be a shame to have done all this work to the top end and then have the rod let go after a couple of hours. Keep in mind by freshening up the top end you are instilling more pressure and stress on the already old bottom end so it may be running ok now, but after all the work could be a different story. Needless to say, XR's are pretty resilient and bullet proof so you should be ok. I'm interested to see the outcome of all this, keep us posted as things turn out, show up, etc. Hope this helps! Good luck! Robb

Reply by cjjcmg on 03/27/2008 9:35:00 PM
I was just reading about a valve job so I actually know what you are talking about. Very technical, but I completely understand. it is an old bike. I have no idea the last time anything was done to it. The guy I bought it from had put an aftermarket cam in it is pretty much all I know.

I will take the whole thing in when removed. I understand all the measurements however don't want to purchase every measuring and removal tool. I assume I will have to do a lot of replacement of parts so I can only be pleasantly surprised if I can actually keep a part.

Wow, so now with the new compression I may blow the lower? That sucks. I guess I can only cross my fingers and hope that I don't have to get a whole lot of lower rebuild experience.

I have so many that tell me to sell the bike and get a new one. I love projects! I don't want a new bike. I don't hear anyone telling me that their KTM is "bulletproof". I'll keep my pig and be proud of it!! Oh and blast by them with a wave in the middle of the desert!

Reply by DGXR on 03/28/2008 2:16:10 PM
It's usually very helpful to take pictures for reference during re-assembly. Otherwise it sounds like you've got all the help and information needed to keep the piggy thumping along for years to come.

Reply by cjjcmg on 03/28/2008 2:20:05 PM
I thought about that. I am afraid of getting to a step and forgetting where something went. I will take pics, and post any that may be helpful.

So I read that when I do the ring job, I should break it in for 10 hours. I ride once maybe when not racing and maybe for a couple of hours. Although I trust the books and the 10 hour suggestion, what do you think? When should I start getting on it again?

Reply by cjjcmg on 03/28/2008 2:20:50 PM
By the way, DGXR, looks like you just completed your top end. Run into anything that might help? How'd it go?

Reply by cjjcmg on 03/31/2008 11:54:47 AM
So I have spoken of poor starting in the past. I just went through another great weekend with my 600. Funny thing. All my buddies telling me to get a new bike had hard starts. After not running for a few weeks, I held the compression release, kicked it 4 or 5 times, never taking my butt off the seat, brought it to TDC, kicked once not leaving my seat, started right up. Gotta love my bike!

Ran the USDR race at Stephen's Mine this weekend and it ran great! I hope I don't regret taking it apart when I do get to it. Lower is a bit noisy tho. Always afraid it's going to be my last race. Won't truly trust the motor until I have become intimate with it.. so to speak.

Reply by Reggie on 03/31/2008 3:51:24 PM
According to the mechanic who does the main tech work on my bikes the rod, big end assembly on these things are virtually indestructible..never need replacing. I've just got my 600-R back up and running following a rebore and many months of various technical difficulties mainly due to me not getting a proper job done on all the necessaries when the engine was apart the first time so I second Mr Kings comments regards pistons etc.Its cost me about 3 further pull-downs than where necessary had I had everything done at once and I might add a heap more money..Long story which I won't go into in detail.To be honest if your bikes not smoking I wouldn't be touching things. My 6 still rattles a bit even with new engine bearings, cam chain, piston,rings, valve guides. but it's pretty normal for an 86 model.Can never get everything as good as new unless you want to get into replacing heads cams etc, prohibitively expensive.

Reply by cjjcmg on 03/31/2008 4:27:13 PM
Well, I will have to ride it hard for the next couple of months then. Maybe I can break it. Thanks Reggie for the input. I hear the same from many that my motor is bulletproof. I guess, no matter what I do to it, I won't ever completely trust it until I have a new, well-maintained motor, which will never happen with my good-ole XR. I will absolutely take your input into account as I get closer.

Reply by Eurobiker on 04/05/2008 11:43:26 PM
My 92 is in mid rebuild. I found the cam chain tensioner tool handy, but I was lucky enough to borrow one. I also went with Total Seal Gapless Rings. As others have said, go ahead and pull the motor out. You'll need to in order to get the long 65 mm cam cover bolts back in anyway.
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Reply by rskybiz on 01/08/2013 07:03:18 AM
Glad to read this thread as I am putting my head back together after a new crank piston and rings installed the prior owner could not figure out how to re install cam chain tensioner. Zip ties it is many thanks for your posts. Be glad to thump around with the 88 Joel

Reply by Reggie on 01/08/2013 10:28:17 AM
Time flies,,Since my previous few posts in this thread I've done a few more engine jobs. Easiest zip tie to use is one of the smaller variety as has been said. Easiest method to get it out is to use a red hot very small coping saw type blade. Just heat it up and slide it down for the cutting..one touch and the things cut ,far easier than trying to use any other method. The tie has to be orientated correctly when it's on the tensioner mechanism to enable you to pull it out once it's cut. Just play around with it a bit before you put the mechanism in place and you'll figure out the correct method. It's all to do with the tie locking mechanism, must be in the right spot when it's cut or you won't be able to pull the thing out.

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