1983 XJ650 Maxim bringing back to life

So,
Last motorcycle I owned was in the early 80's when I was 14.
Last motorcycle I rode was in the 90's in College (room mate had bike, I had car, many borrowing going on here).
Learner's permit (required in MD) scheduled but will attend rider safety course in the spring.

Friend purchased this 1983 Maxim 650 for $1K and I took it off his hands when he learned his son did not want the bike. I knew before going into this, I had a lot of work to do over this winter but that is the fun part. I've worked on small 2 cycle engines for large scale RC planes and did some engine work in HS and College on my cars so I"m no stranger to DIY repair. Looks like the owner friend purchased it from did not ride it much if at all. There are some things noticably buggered up and I"m sure he did not want to fix it. I'm told he just purchased another bike over a year ago. It already has new tires on it.

I'm not a mechanic but I am up to the challenge and if I don't have the tool, I'll buy it.
I am ordering some stuff from xj4ever for the carbs.

I have started on the Carb build but on initial assessment and many hours reading up on this bike I so far have my list in order of priority:
Carb Rebuild
New Plugs
Gas Tank rust remediation and sealing (its not too bad).Petcock Rebuild or replace (someone bypassed the vacuum line plugging it up)
Fuse box. One fuse holder snapped on me during inspection.
Both axles were missing cotter pins.
Rebuild front caliper/Brake system including new brake lines
Rear Pads

In between waiting for parts I'll clean it up too.

I have lots of questions to ask but will try to put in separate posts.

When first seeing the bike at my friends house, I noticed someone rebuilt the carbs and put the bowls on the wrong carbs so the drain screws are in the wrong direction. This gave me the thought to do a lot of inspection here.

 

Welcome to the party, @Melnic!!

Your story sounds a lot like mine - getting back into it later in life and ending up with a 650 Maxim in the garage!! I'm not saying I hope you end up with a garage full of XJs like me, but it's not the worst hobby somebody can have!

That's a pretty nice looking 650 Maxim. Should be more fun than a barrel of monkeys.

Sounds like you are well on your way.

I would add a couple things to "the list" that you may or may not want to consider looking at (just my $.02):
- Check/adjust valve clearances (do this before trying to sync carbs)
- Steering head bearings (how many miles are on the bike?) - easy upgrade that is worth the peace of mind
- Wheel bearings - again, easy to do while the wheels are off, its nice to know that they are new and in good condition
- If higher mileage, then maybe even swingarm bearings
- Maybe test the ignition coils just to make sure they are in spec

How bad is the rust in the tank? If it's not that bad maybe it's not worth risking damaging the paint to put a liner in (??)

Have fun!

 

Bike has 25K miles on it.
I know it had been serviced but can make no assumptions on what was done.
I'm going to try to get pics of the tank soon. Rust is spotty.

 

If I were you I would replace the steering head bearings at this point. It's no fun riding around with a "notch" in the steering. As long as you're doing all this work might as well.

The originals are ball bearings and in my opinion, 25k is enough. The replacements are an upgraded tapered roller bearing.

The steering head bearings don't require any special tools or pullers or anything to get the old ones out - just kind of a big old flat screwdriver to use as a drift. Once you get the old races out you can use them as a tool to tap the new races into place.

Then you will be able to experience the joy of nice smooth steering and finding ball bearings around the garage floor for years to come.

 

Welcome to the forum. Looks like you do have a nice project bike there. In good shape and well worth the time. Take your time on them carbs, as you mentioned you have done a lot of reading. I do hope that the "Church of clean" was on that reading list? You will have to do a really good job of cleaning them carbs.

Sounds like you know the safety issues should be taken care of first to make it road worthy. As for the tank....depending how bad it is I would not seal it either. I have done many tanks sense starting to play with older metric bikes. Depending how bad they are depends on what I do to or with them.

Evapo Rust even thought cost $20+ per gal, is a really good product. Just needs to sit in the tank at room temp to work. Can't have it in cold or freezing area it will not work so well. If you just have some small rust patches then it should be easy to take care of.

I would recommend a inline filter after the tank cleaning. All the work you will put into the carbs can be reversed with bad gas and bits from the tank really quickly.

Keep motivated and just take your time. Winter is here and in out area so enjoy the winter project. Lots of pics when you start to get in there.

 

it looks like you have 2 wrong float bowls on there, as you say 2 should point one way and 2 the other way, i dont think the bowls can be turned round, otherwise they would be pointing towards the engine

 

Number 4 needs to be swapped with number 2. All fixed!

 

Can I put the inline filter right at the output of the petcock and just run a longer fuel line down to the Carb 1&2 Tee?
Any issue with filter running horizontally?


Rotors, These look like a 1980 Led Zeppelin vinyl record, Do I buy the ebay rotors that are slotted or can these be turned or something else? I have time cause I'm not buying anything yet that does not have to do with getting the engine running.

I did not read the church of clean post, but am reading it now.
I pulled one carb apart to start with leaving the other 3 together. There are slight differences in the machining that I am aware of and marked the carb bodies. I had already been taking LOTS of pictures.

 

but they would still all be facing the same way

 

The outputs (drain holes) will always face to the rear. The screws need to face the outside of the bike. #1 and #2 to the left side and #3 and #4 to the right side. Swapping the two bowls will do that.

 

Yes, I know what I need to do for the bowls.

 

nope, still dont see that,
1 2 3 4
/ / / /

his screws are all pointing the same way, swopping 2 with 4 they will still face the same way

 

His #1 and #4 screws face left and #2 and #3 face right. Look close.
1 2 3 4
/ \ \ /
Swap #2 and #4 and all is good.

 

Huntchunks has it correct.

BTW, took apart Carb 3, The boss /peg for supporting the float pin/axle was bent up and I barely touched it and it snapped off. Will JBweld it and I cut a groove, to put in some reinforcemnet.
I already measured the spacing in order to put the bowl cover back on so I know how much room I have.

Carb #2 and Carb #1 did not have the screens installed under the Brass fitting where the bowl fuel shut off Peg goes down.
Carb #3 did not have the washer for the Idle mixture set screw that goes between the spring and the O ring there.

All 4 carbs, the idle mixture screws were between fully closed and 1/4 turn open. I don't get how this could have idled reliably.

 

Forgot pics.
I did not feel comfortable drilling in and putting in pins and getting the alignment right so I'm taking a long 2mm screw and cutting head off then adding it as a JB welded splint.
Cleaned the body and degreased in prep for JBweld. Purchased a new set of tubes today and will mix up a test batch to verify it hardens. years ago, I used a mix that was old and did not like it as it hardened so pre testing the batch is a good idea for something like this where messing it up can be costly.

 

Looks like the well in the casting at the inside of each pillar could be a place to anchor a support up the inside surface of the pillar.

 

Yea, I think I may put a splint on that side but not dig a channel. Good suggestion. I need to look at the float and the interaction the next time I'm working on it.

 

A link to a repair I did, which also contains some repairs from other folks. I was hesitant to drill for the pins also, but it worked well after I flatted the broken area with a file and center punched.

https://xjbikes.com/forums/threads/broke-carb-now-repair-replace.130735/

 

This might work. Assuming the drilling could be done accurately which is critical I wonder if a roll pin would work to bridge and strengthen the joint plus using quicksteel putty or a suitable alternative. The roll pin would need to grip enough without being too tight in case it burst the post.

 

Car JB weld done (need to get a pic) .
While pulling 2 of the carbs apart, I had to use an easy out to get 2 of the air jets out, so ordered some from xj4ever. In the process found that whomever did a rebuild on this, tweeked the jets and put in bigger main fuel jets (130 instead of 110 Main and 45 instead of 40 pilot). The air jets were sized like an older carb and a day after ordering the air jets, read up on the thread size of the air jets being different on the older carbs. I'll find out and compare when the new jets come in. I do have enough parts to put the rack together and put the jets in after I'm done. I could also set the float bowl levels if I wanted to on the bench and put jets in later as I believe Jets missing wont affect that. (I can put the original fuel jets in to hold the emulsifier (?) tube in till the jets come in.

I put in a blade fuse block and noticed that the cover is rather tall. I feel it pushes on the bottom of the seat and don't like the idea that so I 3D printed a slightly lower profile cover. The original main fuse was hanging on a thread and my buddy who sold me the bike said the tail lights were intermittent (he bought it 2 weeks ago himself as a project and turned it over to me for the $ he had in it).
Next I'll make labels for it. In another thread, I learned to jump out the headlight relay w/o starting the battery so the main electrical seems operational.

 

some pics of blockages and crud I had to clear/remove.
I also pulled the gas out of the tank and am removing petcock to rebuild or replace. Seems like a fuel filter between tank and carb inlet is a tight fit unless I run it along the outside. Need to research how others have done it.

 

That's pretty cool @Melnic.

There is an area on the forum for sharing 3D print related stuff: https://www.xjbikes.com/forums/forums/xj-3d-printing-stl-files.40/

If you'd be comfortable sharing your designs, it seems like something that a lot of people would be interested in.

 

Pics of the tank. going to start the vinegar soak tonight.
Need to also paint the bare metal under where the petcock gasket will go.

 

Doing good work....I like it. That tank does not look bad at all. That should come clean fast. I still like the Evapo Rust better then anything out there....that is just me though. Keep up the good work.

 

Getting closer and hope to start it up this weekend.
I have been vinegar de rustifying the tank for the past week and looks good enough to drain and dry out.
Stock Jet sizes to replace the ones someone changed out came in this week and put in the air jets. Will finish putting everything together tonight, then Saturday when I have more time I will test the float levels then hopefully put it in the bike and start up using the plastic external tank.
I'm pledging to myself to keep this bike ethanol free. I have a place on the shore 2 1/2 hours from here and the bike will reside there. plenty of ethanol free gas stations over there. I have 1 gallon right now and will drive to a local shop that has ethanol free "race gas".

 

Looking good!

if you can avoid the ethanol that’s great. If you need to run it occasionally that’s ok, just don’t let it sit around with ethanol in it for any length of time.

 

IT'S ALIVE!
So, finished up the carb build last night, I tested the float valves and 1 & 3 were not filling up right, pulled the bowls and found that the drains were plugged. After all the checking and double checking the passages, I neglected that one. I did get the enrichment jet on the bowl bottom (even baptized myself with some carb cleaner to the face) . Pulled all the bowl cover off and cleaned and checked them. Heat and silicone lube to the rubber boots and I did not need any straps or anything to put the carbs in. I did curse the first time before I realized I forgot to heat up the intake boots, once I took a brake, came back and heated them up, it went in with some moderate force. Cleaned all the boots before starting. Put the Carbs onto the intake boots first w/ the air box boots removed. With the air box boots clean, warmed up and lightly lubed, took about 15 minutes or less to get them on and not bad at all. Hooked up the temp fuel tank and let it sit a few minutes. came back turned on fuel enrichment and nada. Tried a few times and nothing. Took another brake, then a quick squirt of starter spray after pulling the air filter and bam, started up and revved up waaaaay tooo high. Turned off fuel enrichment, still 6000rpms. Idle screw was waaaay too high. I got it down to 1000 rpm and it would idle for a while then shut down. At 1500 it was holding. Shut it down and measured pipe temps with thermocouple. One was waaay hotter and one was noticably cooler but not so cold it was not running. So, time to clean out the YICS tube and then sync. I had been soaking the tank in vinegar past 5 days and today I had the time to deal with that w/o stopping so I moved to that next. Came out great.
Thx everyone for the help and support so far.

 

Cleaned the YICS port, a 40 caliber bore brush fit perfectly. Cleaned with the brush first, used some Hopps #9 then some patches. Used the YICS clean out pick/tool also from XJ4ever. used the YICS tool and synced carbs. Don't know if it was just cause it was hot, but the tool was not pulling out. I used a solid rifle cleaning rod and slowly pushed it out from the opposite side after pulling the bolt out. Idles much better and was holding a 1500-1700 rpm pretty solid for 5 mins. It failed the starter spray test on #2 intake boot though. so I was dreading having to take those intake boot bolts off. Will have to do that this winter. I need to get a color tune kit and check valve clearances next. I know I'll have to sync it again but wanted to get it running the best I could right now. Going to finish putting the tank on and have him do a road test here in the neighborhood to see how well it runs before spending more $ on it.

 

Good for you, the great feeling of that motor staring up and running the first time. That makes thing all worth it when she does run. I don't do anything with the YICS system. I just treat the bike like it does not even have that on it.

 

Before proceeding any further check the valve clearance first. Any changes in the shims will effect the tune of the engine. It is a bit of a high you get when things you work on actually work. I makes you want to do the happy dance. This is why I love to fix things.

 

Yes, Planning to do valve clearance, just trying to figure out when.

 

So, pulled Valve cover and measured Camshaft/shim clearance.
Little curious here because all of them would FIT a 0.10mm and NOT FIT 0.13mm which I read is at the tight end of passing spec.
2 of them were off however
IN4 0.03mm Fits, 0.04mm Not Fit (So this is too tight)
OUT 3 0.15mm Fits, 0.18mm Not fit (This is at the high end of Spec)

I am awaiting the tool to remove and look at shims, I'll be curious to pull IN4 and OUT 3, I'm wondering if someone adjusted the shims and swapped 2 of them. Otherwise I'll be ordering 2 shims to bring them all closer to each other.
Sound like a good plan? Should I be looking for anything else while the cover is off?

 

Being prompted to look again at specs, Out1, Out2, and Out4 are all too tight.

 

You can make your own tool to remove shims. Bend a piece of house wiring to 90 degrees and run the bent end into the spark plug hole after you manually position the cam to fully open the valve. Put the wire into the open valve and rotate crank so the valve closes on the wire, propping it open and allowing the removal of the shim for inspection/measuring/replacing.

 

Or google the zip-tie method.
Also, a pair of hemostat clamps is invaluable for fiddling the shim out of its bucket.

 

Tool came in today and I pulled and recorded the shims.
Took me a short while on the first one to get the feel of how tight to make tool and how much you have to pop the shim out. Used Hemostat to pull them out firmly
Someone can check my measurements and plan please.
SO, on my measurements, I did not have every value of shim so I can only know a range it is. Example, .10 fits, .13 does not, so gap is somewhere .10-.12

Out 1: Measured .10-.12, Y265, Install Y260 to bring gap to .15-.17
In 1: Measured .10-.12, Y285, Install Y280 to bring gap to .15-.17
Out 2: Measured .10-.12, Y270, Install Y265 to bring gap to .15-.17
In 2: Measured .10-.12, Y280, Install Y275 to bring gap to .15-.17
Out 3: Measured .15-.17, Y270, Leave as is
In 3: Measured .10-.12, Y270, Install Y265 to bring gap to .15-.17
Out 4: Measured .10-.12mm, Y275, Install a Y270 to bring gap to .15-.17mm
In 4: Measured 0.03, Y285, Install Y270 to bring gap to .18mm

Have:
1 Y265
2 Y270
1 Y275
1 Y280
2 Y285

Need :
1 Y260 (Need 1)
2 Y265 (Have 1, Need 1)
2 Y270 (Have 2)
1 Y275 (Have 2)
1 Y280 (Have 1)



Even though I just need 2, I Will Purchase:
Y255(2) Y260 (2), Y265 (2) Y270 (2)
Should be about $50
This way I'll have some spares in case I need to go smaller (larger gap)

 

Start a conversation with @hogfiddles, he runs a shim pool.

 

It looks like you have the spec wrong for the intake - some of the manuals are wrong

Correct numbers are:

Inlet 0.11-0.15mm (0.004-0.006in)
Exhaust 0.16-0.20mm (0.006-0.008in)

 

So, I should leave IN 1-3 alone for now?
If that is the case I would do this:

Out 1: Measured .10-.12, Y265, Install Y260 to bring gap to .15-.17
In 1: Measured .10-.12, Y285, Leave as is
Out 2: Measured .10-.12, Y270, Install Y265 to bring gap to .15-.17
In 2: Measured .10-.12, Y280, Leave as is
Out 3: Measured .15-.17, Y270, Leave as is
In 3: Measured .10-.12, Y270, Leave as is
Out 4: Measured .10-.12mm, Y275, Install a Y270 to bring gap to .15-.17mm
In 4: Measured 0.03, Y285, Install Y275 to bring gap to .13mm

Pull:
1 Y265
1 Y270
1 Y275
2 Y285

Replace :
1 Y260 (Need 1)
1 Y265 (Have 1)
1 Y270 (Have 1)
1 Y275 (Have 2)

 

So this gets ambiguous because the general consensus is if they are in spec then they are in spec with no need to try to adjust for the middle. Since you posted numbers of .10 to .12 for the intakes then . 10 is out of spec and the .11 and .12 would be in spec. As for number 4 intake it looks like you are on track selecting the correct shim.

I suspect you have the same set of metric gauges that I have:

0.03
0.05
0.06
0.07
0.08
0.09
0.1
0.13
0.15
0.18
0.2
0.23

You can stack individual blades to get the missing .11, and .12mm, but that is not my preference as I am not comfortable with stacking because it is cumbersome and there is also an accuracy factor that occurs with tolerance stack up.

I have tried both methods and I get much more repeatability by just using the SAE feeler gauges which are readily available from .001 to .010 with incremental steps of .001. With the SAE and checking the intakes it gets so much easier just to say .004 fits, .007 does not, or with the exhaust .006 fits, .009 does not. The only drawback might be if the valves are significantly off then converting SAE to MM to get the correct shim is a bit more difficult.

The above has been discussed before and most here will suggest stacking and will ask for metric numbers if SAE numbers are posted, so the above is just my opinion. However, until you post unambiguous numbers no one can say your math is correct

 

I don't follow the "in spec is in spec rule" because if the gap is on the lower limit it will become out of spec before the other valves do and possibly in a shorter amount of time than the inspection interval. I go for the middle to high end of the range if possible considering the small range of high to low limits. It is tricky no matter how you do it. Conversion is easy, SAE x 25.4 = Metric.

 

I go by whatever the EXACT measured clearance is.
And
In-spec is in-spec.

If it’s in-spec but just barely..... it’s still in-spec, and it may stay there for for the next 10 checks, too. Of course it may be out by the next one...... but the same is true for in-spec to the high side too ...it may be in spec for the next 10 check, but it can also be out by the next one. That’s why they are CHECKS. If it’s out, you change it. If it’s not, leave it til next check.

 

I read that gaps tend to get smaller over time due to valve wear. Is this what you all have experienced?
Its interesting how most of them ended up the same gaps but one in particular ended up REALLY tight.

I was thinking to not change much if in spec and to inspect again next winter. Now that I have done this once, its going to go much faster next time.

 

The gap decrease is due to the valve receding into the head from the constant pounding of the valve against the valve seat. As the valve recedes, the end of the stem gets closer to the cam which reduces the clearance. Thinner shims are installed to re-establish acceptable clearance.

 

So, went back to check in 1,2,3 again by stacking a .07 & .04. First stacked a .07&..03 and verified it passed under In 3. Then tried .07&.04 and it also passed In 3.
Went to In 2 and .07&.04 passed, but when I went back to In 1 which previously passed a .10 no longer did and I had to go down to a .06 to get it to slip in.
This was with the cam pointed 90 degrees to the surface of the shim. I then moved the cam some and kept checking. Turns out I can get up to .10 with the cam about 80 degrees
So wondering if I should Change In 1. Well, I won't have a 280 right now so will have to do that at another time if I do.
other shims coming in today

 

Today's winning post on the Internets!

 

The raised portion of the cam lobe should be pointed 180* away (directly opposite) from the flat plane of the shim.

 

In vernacular... exactly perpendicular to the shim plane

 

Exactly

 

Yes, when I say 90 I mean straight up. I was comparing the cam lob to the plane of the shim. So 180 degrees from maximum compression.

Shimming is all done
Going to sync carbs and colortune this weekend, hopefully put tank back on and let a friend who is an experienced rider take it for a ride in the neighborhood.
If all is good, I'll be ordering some brake lines and rebuild the brakes.