1982 xj650 complete engine rebuild and bobber conversion

Hey guys, I'm new to the thread here, and I have just acquired my first XJ bike. This will be my first bike to modify. What I'm looking for is some help so that I don't mess anything up. Engine ran ok, but doesn't anymore. Pulled the valve cover off, and found intake cam gear missing. I'm guessing the previous owner didn't know what he was doing, and now I have a dead engine.

So now I have broken cam gear pieces at the bottom of the engine. Surprisingly there's no damage to the head. Just a few scratches from when the cam gear snapped. I realize that this requires a complete engine tear down, in order to get them out. Another thing that I've read is that the shifter fork can become bent/damaged, resulting in second gear not working and so on. What sort of things should I be doing to rectify that situation so that its doesn't happen to me when I have the cases split?

I'm looking for some "how-to's", or advice on what i should be replacing in the engine since it'll all be completely apart. I figure since it's all apart, might as well put everything new in there. Money isn't really a factor. So whatever this bike needs, I'll buy it.

The next thing I'd like to know is where you guys find your parts from? Obviously Ebay, but are there any other companies out there that specialize in parts specifically for this bike that can't be found elsewhere?

I'm thinking that since it'll all be apart, I might as well change all the bearings, starter clutch, clutch plates, etc. So I'm going to need some help sourcing out information and parts for that. I'll be buying the clymer manual here shortly. Is there any special tools that I need? If so, where do I get them?

The next thing I'm after is I would LOVE to put a Springer front end on this bike. I've done some reading, and have only found two companies that make the Springer front ends, however, they are only for the XS650. I have also read in some posts that they are compatible with each other. Has anybody in this forum done this swap before? If so how did you do it? What modifications need to be done in order to install it on this bike? Come hell or high water, that Springer is going on this bike lol.

As for the rest of the bike, I'm chopping the rear of the frame off to build a bobber. The only thing I can't decide on is if I want to some how incorporate the rear suspension in it, or just leave it as a hard tail. What are your thoughts? I like the clean look without the rear springs, but is my back going to suffer? I've never owned a hard tail before, so I have no experience to speak on the matter.

I'd like to find a decent exhaust kit on this bike, as I absolutely hate the look of the stock exhaust. Anybody have any ideas on that? I'm thinking I'd like to go with the wrapped look, but I'm not 100% sure on it yet.

I'd like to go with some spoke rims on this bike. How do I find some rims that will match up to this bike? What measurements need to be taken? Can someone recommend where to get a decent set of rubber with white wall?

And lastly, if there's any cool modifications that you guys have done, or know somebody else has done, gimme a shout! I'm open to all ideas right now. The head light is going away, as well as the turn signals and stock gauges. I'm going to be putting something a little more modern on the bike.

This bike is going to be for the wife, so every small detail will not be overlooked. I'll need all the help I can get! I'd like to have this thing built in 6 weeks or less. Thanks in advance guys, I'll post some pictures soon.

 

Hi,
This is a very ambitious project. And unless you can work on it 24/7, I'd say not possible in 6 weeks, especially since this is your first bike to modify AND engine work is involved.
If money is not really in issue, why not buy something running that already has most of what you are looking for? And keep the bike you have and slowly transform it into what you described above.
Click the top right banner for parts. Len has everything.
And you sure your wife would like a hardtail?
Break your post into individual threads, and you'll get answers faster.

 

Taking 6 weeks off work then or are you retired?

 

Welcome and wow wanting to complete it in 6 weeks is a lot, you will want to look at the catalogue at http://www.xjbikes.com/forums/forums/xj4ever-supporting-vendor.23/
And then contact Chacal. He has parts and tools for rent. He has several kits available I would look at getting kits, and complementary kits and individual parts as well.(I myself am still going through the catalog for my xj550 parts, I was planning a weekend engine rebuild, now planning for winter rebuild so I can ride in the meantime) If this is for your wife and it will be her first bike, not really sure I would make it a hard tail.

 

I already have a nice bike for myself . I have aaaaaaa lot of experience with fabrication.

 

Lol i don't work as much as I used to. Got a lot of free time now!

 

So does anybody have any info in regards to the Springer installation using either a DNA or tc brothers Springer kit?

 

One quick question. Is this a Seca or a Maxim? If it's a Seca 650 then I suggest that you take time to reconsider your plan. That was a one-year bike in North America, and a lot of people are nolstagic for it, so long-term it will have greater value if left stock.

When the engine is apart, rebuild the starter clutch and replace the alternator chain guide. The second gear dogs can be undercut, but second gear dog slippage is not nearly as much of an issue in the 650 as in the larger displacement machines.

 

15U000589 is my vin if anybody can some how check it.

 

Should I start an export business then ? 650s don't fetch much here and we only got the 'Seca'.

 

Lol I dunno, I just wanted something to do instead of sitting around.

 

Seca.

VIN decoding guide here: http://www.xjbikes.com/forums/threads/tech-topic-model-id-and-vins.14577/

 

Well then it's gonna be one of a kind seca then!

 

Get it reunning perfectly in stock form before you start doing modifications. It will save you time in the long-run.

 

I'm doing that outside of the bike itself.

 

Does anybody have a quick list of all the bearings required to be replaced inside the case on this engine?

 

There's no quick list. You need to plastigauge all of them once you split the case and see what's within limits. If one or more is out of spec, then you have the fun task of determining what bearing is in there currently and sourcing the correct one. There' a few threads on here where members have rebuilt their motors and have some how to pics on bearing sizing etc.

 

Oh I should've clarified, I meant roller bearings not main bearings.

 

don't remember anyone ever replacing the roller bearings.
now you're down to 5 weeks and 6 days

 

Lol engine is half apart as of last night, doing the rest tonight and hopefully plastigauge soon.

 

i won't get much done until the play-offs are done

 

Polock, dear friend, your sums are poor. I make it 10 days in so only 4 weeks and 4 days remaining.
'Easy,easy..' I hear them chant.

 

It would be quite unusual for any of the roller bearings to need replacement, which is good since at least one of them is NLA.

 

If you have no snags, and all you really need to replace are your gaskets, you could be done sooner depending on your available free time and part availability.

 

I've been busy for a little while. However I do have a question. What size of bolt is required to remove the alternator rotor?

 

Try messaging Chacal he probably has that info or the bolt you need....

 

Ok thanks! Got that sorted out. On a side note, what kind of specs am I looking for when it comes to doing a plastigauge?

 

I believe these are the specs you are looking for

Valve Clearance Intake: 0.11 - 0.15mm ( = 0.004 - 0.006")
Valve Clearance Exhaust: 0.16 - 0.20mm (= 0.006 - 0.008")

I could be wrong though. (it does happen from time to time)...lol

 

All of that info is in the service manual, and you will want to have both the Yamaha service manual and the Haynes on hand as you reassemble the engine.

 

Ok thanks man, will do.

 

So fellas, been working on the bike off and on for a little while. Just wanted to put up some pics to see progress.

 

So here she is

 

All gutted

 

Here's the Springer front end we bought for it

 

Here's the tank we took home to try and get an idea if it will work or not. What do you guys think? I think it's too big to be honest.

 

And here's my issue with the bearing races. Left race is the new one, right race is the stock one. Gonna have to do some digging to figure out if I can get a bearing that small, otherwise I'll have to get some machining done :/.

 

The new race will fit. Search for the thread on roller bearing swap.

 

Nah it doesn't fit, the race is 2mm larger than stock

 

Larger in diameter? Then no it won't fit, and it should not be machined thinner, nor should the headstock be bored out to accommodate it. The stem from the stock triple should be swapped onto the springer triple.

If it's 2mm taller, then it will fit as long as the springer stem can accommodate the increased height.

 

The race for a tapered roller is taller vs. a ball bearing race. The replacement kit for the stock ball bearing kit is taller but works just fine (ask the hundreds that have upgraded). Like k-moe said if the diameter is good, try it and see if the springer front end can accommodate the additional height.

 

Not really sure if it was seated a little better it may make a difference, the way it is sitting now it doesn't follow the flow so it could be skewing the vision.

 

Too late, getting machined right now as we speak lol.

 

Well I figure that if I were to use that tank, I'd have to cut it up and make it fit to the frame. I'm honestly thinking of just taking the bike to a metal fab guy, and having them custom make me a tank that will fit perfectly instead of just trying to find one that will fit "ok" if you know what I mean? Unless someone here has a better idea?

 

Taking 2mm off of the diameter? The race will fail when you least expect it.
Taking 2mm off of the height? The bearings won't fit correctly, and will eventually fail in a bad way.
Roller bearings really need the full support of the race, as it was engineered. There is some room for machining, but 2mm is a lot of material to remove.

 

Sorry I should've clarified. The machinist is taking off approx 2mm of width, and about 3mm in height. It'll be fine, there's plenty of meat left over. How does a race "fail", other than being neglected without any oil or grease and it grenades itself? I'm a heavy duty mechanic, and i've seen tons of bearings over my career, and it takes quite a substantial amount of abuse for a tapered roller bearing to fail.

 

If the race wall has enough thickenss then it will be fine. In my experience most roller bearing races for motorcycles don't have much wall thickness (particularly when the bearing is replacing a ball bearing setup), and that can lead to uneven loading as the race distorts. One thing that can kill a modified roller bearing is lack of full contact for the roller. A rige can form along the edge of the roller that contacts the cut-down race. So long as the rollers get full contact along the bearing race then it'll be fine.
I tend to err on the cautious side where modifications to the headstock and bearings are concerned. You've got the part in hand, and I do not, so your judgment is likely more sound than mine.

 

Yeah, there's a tad more than 1/16" of meat in the neck after it gets machined, so I'm not worried. I just liked the idea of a tapered roller bearing because I can actually get parts, vs using the stock ball bearing set up, plus there was even more hassle if I just went with the stock ones. I looked up the tapered roller bearing kit that all balls sells for my bike, but that wouldn't have worked either because the ID is still 25mm, and the stem I'm using on my springer is 1" which is slightly bigger. Plus the height of their bearings were something crazy like 15mm, and the set I have the height is slightly over 10mm. I think it'll be gravy and fit like a glove once I get the frame back next week. On to my next hurdle is that damn spoke wheel that I want...

 

Just took this at the machine shop!

 

Little further away

 

Looking good.