XJ600 Cafe Racer project

Hello there,

This is my project that is about to get finished. It's based to 1990 XJ600 that I bought in a good condition. Things I did include:
- rear frame modifications
- XJ 550 gas tank
- aftermarket British style, 7" lamp
- led turn signals and rear light - bought on ebay, nothing fancy
- powder coated rims
- reduced wire loom
- custom made seat (epoxy resin)

 

Brilliant, at last. I always wanted to see a 550 tank on a 600. In 1984 I had a XJ550 and in 1991 a XJ600 but I always much preferred the look of the 550. Because of that I put a 600 engine into a 550 rolling chassis in the past year or two.
But I always fancied mono-shock look too.

Did the tank go on OK? No chance to fit teh side panels I guess. BTW I just had some 598 decals made in the style of the 550 an they look good - better than the avatar - just need to finish spraying my spare panels then fit-up..

Thanks for sharing, more pics please

 

I also prefer the 550 look Unfortunately, I could not find any bike in good condition. XJ600 seems to be more popular, spare parts wise as well. The tank needs minor changes - XJ 600 has a bit wider frame just below the tank, the difference is minimal, barely 0,5 cm - 1cm. I had to hammer the insides of the tank a bit and I used a insulation tape to wrap up the frame in possible contact points - just in case. You will also have to modify the rubber cushions (sorry if I mix up the terminology, obviously English is not my mother tongue ) - they have different length - I used 80 grit sand paper. I don't remember for sure, but I have welded new " U" shaped mounts for the rubber cushions. In my case I wanted to lower the tank to get more aggressive posture of the bike. It's quite probable that you don't need to re-weld the mounts. If you are planning to run clip ons - your handlebars might collide with the tank, depends what clip on angle you prefer. I don't have this issue. In general, it's more or less plug'n'play swap

 

more pics pls! looks good.

 

Some pics I took yesterday. The last one shows a side cover from aluminum sheet. It will be bare aluminum for some time, alter on I'll have it powdercoated.

 

looks really good! the one thing that stood out to me was the tach/speedo, I would lower it to the top of tank level...but very cool

 

It will be mounted in a different way once my custom top triple tree clamps are finished The one mounted on the bike is just temporary.

 

You making them? I made them for my project.

 

Nice work guys - thanks for posting

 

Hey, I managed to start the bike - runs like a charm I also took a photo of my custom triple clamps. I need additional milling to do - 1mm around the bolt. For the moment it looks like this:

 

Looks great!

 

Thanks I borrowed an ellectronic manometer from a friend, hoping to synch my carbs. Also, I found a small oil leak around oil filter.

 

Nice job! What did you use to make slots for the pinch bolts?

 

If you mean those two bolts that tighten the clamp around each forkleg, I haad them drilleed at a local cnc Shop. I think they have used a drill press or something.

 

Oh I thought you made them....cost a lot?

 

The clamp was measured and cut by a friend of mine so it's a little bit different. I know thaat he makes them for others from time to time. I can ask about a price.

 

Carbs - locked and loaded

 

The seat has arrived

 

So, I fired it up and had a ride around the hood. The throttle cable needs shortening and re-routing - at the moment it's under the tank but when I turn right the "wire" inside the cable gets pulled and the bike revs up. Also, one of the exhaust manifolds needs some wiggling as I can hear some exhaust leeks.

 

So, my happiness didn't last long. It turns out that my bike has cold starting issues. When I try to start it cold, without choke it starts right away and after a 2-3 seconds it revs up a bit and goes down until the engine dies. After that I need to hammer the start switch for 30 min until the battery is dead until it starts again. Luckily, I have a battery that's used as back up for audio installations ( high power stuff). So these are the facts:
- Originally it the bike was 54 hp but I switched carb boots from 72hp version. I did not change any jets as I concluded that new boots would give more air making the mixture too lean (apparently it's otherwise)
- the bike runs stock airbox, new filter, original 4-1 exhaust
- I asked a friend of mine who runs a shop to clean the carbs, I assume he did a good job
- one of the pilot screws was stuck and got destroyed while removing. I managed to get my hands on a single carb (#4, first from clutch side). I replaced the carb body, using all needles and removable stuff from my original carb. Here's the first mistake I made - I did not check the needle valve/seat. I put it on back together.
- I managed to start the bike, when the engine was warmed up, I balanced and synched the carbs.
- after 2 days bike has a hard time starting when cold.

What I did so far:
- I found a small air leak from one of the exhause manifolds ( will get it fixed this weekend)
- sparks (brand new) - black, sooty residue
- I can feel some unburned gas ( might by the gas that I spilled on the floor accidentally )
I am no expert but all signs on heaven and earth point to rich mixture

What I plan to do:
- replace all needle valves and set the float again
- check floats if they're stuck
- check for gas smell in the oil

Is there something that I may have skipped? Should I check something else?

 

Did you check to make sure the stock jets are in there? The previous owner might have changed them.
As you mentioned, check the floats. Also, set the fuel level/float height. My bike was running way too rich cause the the float bowls were overflowing. Once I set the proper float height it went lean, which is what I expected as I'm running pods (yes I'm running pods and I'm perfectly happy with them ). After that it was a matter of putting in the proper jets to get it to run properly.


BTW, do you live in the Tricity area by any chance?

 

Yes, the stock jets are there. I've checked the needle valves and it turns out that #3 and #4 are worn and they leak. I wanted to put pods as well, but my friend adwised me agaainst that. He switched to pods on his xj600 and it was a bad idea. On his second project with Xj600 he made a custom airbox -like pods setup and that actually worked.
I live in Warsaw, thats around 350km to Tricity.

 

So I replaced my needle valves and wanted to set the float height. First I checked it with ruler - #1, #2, #3 were 22 mm, #4 23,5 mm. I set all to 22 mm. Since the manual says XJ600 floats should be 16,5-18,5 mm and I could not find what is the reference point for this height, I decided to check the fuel level with a rubber hose. After hour of looking for something that would work as an adaptor for the hose-bowl nipple, I finally checked the fuel level :
#1 - ~3mm below the bowl - carb mating surface
#2 - 4mm above the line,
#3 - 6mm above the line,
#4 could not unscrew the bolt, but it was clearly above the line as fuel leaked out of the carb

I don't know what to make of this - if the float height is higher than the specified height, there should be less fuel in a bowl and engine should run lean. Instead, there's too much fuel.
Could it be that I measured the float height wrong? Or valve seats need replacing?

 

If there's too much fuel, try adjusting the tabs on your floats so that the valve is closed sooner (with less fuel in the bowl). There's a great PDF on xj4ever on setting the floats: http://www.xj4ever.com/setting fuel levels.pdf

Try playing around with the floats. If you're still getting too much gasoline then it could be the valves leaking.

 

I've been playing with those tabs all afternoon and managed to set the right level on carbs #1 and #3. On the remainin two I can't bend it the right amount, it's either too much or not enough. Is there any trick for bending the tab?

 

Make sure the floats aren't upside down. I'm guilty of that

 

After few hours of bending the tabs up and down 3 carbs are set, one more to go

 

Good point, been there done that

From what I noticed, even slight bends can have a significant impact on the fuel level in the bowl. Can be frustrating, but you gotta be patient

 

I've used electronic callipers the take measurments. Every 0,05 mm counts. Maybe it's due to the age of my bike, but for each carb there was a different height. I tried to set them according to the manual - no luck, I checked with the rubber hose method and each fuel level was different. After some time, I measured how much each tang protrudes above the flat surface of the float assembly. For one carb it's 1,65mm - this gives me the exact level of fuel in the carb. I tried exactly the same 1,65mm on another carb and the result was slightly different. Is it possible that each float has a slightly different displacement after 26 years of use ?

 

So I 've been having this issue lately - the bike doesn't start when cold. I need to use a few sprays of starting agent into the airbox, then it cranks several times before it finally starts. When it warms up, the engine starts like a charm.
I've checked so far:
- no air leaks around carbs and air intake
- pilot screws set
- carb balance and synch - done
- new spark plugs
- float level - set
- I've checked the ignition coils resistance - it's 2,3 Ohm - according to the manual - 2,8 +/- 5% - can this result in weak spark ?

Yesterday, I borrowed a compression tester and it showed 100 psi on #1, #2, #4 and 105 psi on #3 cylinder. I performed the test on cold engine. When I sprayed some oil into each cylinder, the compression jumped up to 125- 130 psi. According to the manual, the min should be 142 psi. I was quite surprised at the results as the bike would start with no problems before I took it apart. Then I remembered that I changed oil according to the manual - fully synthetic and the PO must have used a thicker oil, possibly some "engine doctor" as well. As a result my new oil has flushed the carbon deposit making the engine loose compression. Am I right to suspect the low compression as the main culprit behind hard cold start issues? Should I check something else?

 

If your compression is that low, you might want to think about replacing the piston rings and checking the bore sizing and warping. It really not that hard to do. just a lil pricey. The head gasket alone is like 80 - 100 depending where you get it. For all the gaskets + grommets + rings and other various things it will cost around $300-400+. Also while she is apart go and check the valves and clean then.

 

That's my plan - replace the rings and check the valves. Indeed, prices are in 300 - 400 usd range. I hope the cylinder head is ok.

 

The manual should say that the compression test should be done with the engine warmed up and throttle held wide open so comparing a cold test to the manual specs doesn't give you an accurate indication

If the bike started fine before you took it apart then chances are it's something you've done, I can't see one oil change making that much difference, I've done that in plenty of bikes and it's made no difference

 

I did hold the throttle open, engine was cold as I wasn't able to start it. I was told by a Kawasaki tech guy, that compression check performed on cold engine is only slightly lower.

As for the oil change, switching from mineral or semi-synthetic to synthetic may result in flushing the gunk and carbon deposit.

 

Within one oil change? I doubt it would happen that fast

 

Is your bike an xj650 82 seca by any chance? I could really use the final measurement for the custom triple tree if you have them!!

 

Double post

 

My bike is XJ600 1990 and I don't have the measurments. They guy who did all the work took all measurments from the original tripple tree clamps.

 

WOW thats awesome!! a cup full of impressed, cup of amazing, a table spoon of jealousy, mix with 2 gallons of inspired...........i love that bike!!!!

 

Hello guys, much time has passed and not much work done. I had to focus on my house refinishing and other small to-dos around the household.

Few days ago I resumed working on the bike. I pulled the engine out of the frame and removed the cylinder block + head for measurments. The main reason was to replace the leaking head gasket but I thought that it's a good opportunity to check all the insides and replace what needs replacing.
What I did so far:
Pistons measuring and checking for wear - all of them are within specs, and show minimal to no wear.
Piston rings - so far checked only cylinder #1 - rings #1 and #2 thicknes is according to the manual, ring gap is.
Ring thickness - both rings as specified in the manual
Ring gap - according to the manual - standard gap is 0,15mm - o,3mm, max 0,7mm
#1 ring - 0,35mm
#2 ring -0,45mm

I have also notices two scratch like marks inside the cylinder #1. They are not deep, definitely not detectable by touch. It appears to be more like a discoloration. Today I'll check the piston - cylinder clearance.

 

Quick update:

I took off the oil pan and found these little fellas. Any idea what it might be ? It looks lika some kind bearing parts

 

They look like rollers from the clutch throwout bearing.

 

Great ...... every single thing I touch needs fixing or leads to another thing that needs fixing. I hope this bike runs like hell when I finish.

 

I feel your pain.

 

Welcome to the classic motorcycle hobby.

 

Funny part is that it run nice before I removed the engine and changed the oil. At leasr the weather is bad for riding, gives me motivation to speed up with the work.

 

Guess I found the culprit:

 

WOW!. OK, now you have to ask how the hell did THAT bearing fail? It's constantly bathed/splashed in oil.
Look closely at everything for signs of oil starvation.

 

I am going to take a closer look this weekend. My friendly motorcycle mechanic said that there is a slight chance it is just leftovers after somebody replaced that bearing earlier.

 

Hi There. New to the forum.
I have a 1983 Maxim 650.... Do you know if the tank will work on my XJ Maxim.. like it did in the case of your XS600?
OR.. do you know of any other make/model tank with the same look that may be made to work?
My project is on hold until I find the tank to match the look.
Thanks!