Purchasing xj650

1. Yes. Hogfiddles runs the airhead shim pool, so any that you don't need can be sent to him as a donation.

2. The original shims will vary in thickness, and be ink stamped with a capital Y followed by three numbers designatng their thickness.

 

29mm shims are common. There are several manufacturers of them, both aftermarket and OEM for other brands (BMW for example).

The primary reasons for seeing mostly OEM shims when changing them is that hardly anyone does the maintainace as required, and back in the day most people had the dealership do everything.

 

Sorry I should have posted the pic.

The only issue is I'm in the UK so after postage and import tax its not worth sending over.

I'm currently in the process of stripping the carbs ready to be put in the ultrasonic tank

 

Another question... so my idle screws had the brass caps on so I'm assuming they have never been touched.

Once the screw is removed I looked down and noticed that only one of the slots doesnt have a metal disc on top of the rubber. If this is from factory, will it really make a different?

 

1. Those are the OEM valve shims. There is no definitive way to know if they are the shims that were in the machine when it left the factory, or if they were installed during a valve clearance check.

2. What you are seeing is the washer that protects the o-ring from the spring, and the o-ring.
They tend to get stuck in the bores. Take a darning needle, heat the tip, and bend a small hook into it with pliers. You now have a washer/o-ring retrieval tool.

The order of assembly onto the idle mixture screw (while holding the screw) is: spring > washer > o-ring. You will need to use new o-rings. The screws, springs, and washers can be reused (unless the needle tip of a screw is bent or broken).

3. Your macro-photography skills are quite good.

 

Thanks k-moe.

I cant take credit for the pictures, it's my mobile phone that does it!

I'm stuck on carb 3, I cant see to take this (see pic) off in order to get to the o rings.

 

The throttle plate is out, and tha'ts usually the difficult part. Have you undone the nut that's under your thumb?

It looks like there was some fuel leakage (and oil leakage). You will probably have to wiggle on the spring retainer (L shaped bit on the end of the shaft) to get it to come loose.
Since you're replacing the throttle shaft seals you could just go ahead and soak the carb body as it is now to help free things up.

 

Yes I removed the nut, gave it a wiggle and leverage with a screw driver but nothing budged. I'll soak it in the morning and see what happens.

I've already soaked 2 of the carbs with decent results - soaked for 20 mins at 80 Celsius

 

Thanks to everyone for the help with this. Over the last 24 hours I've stripped, cleaned, replaced seals and rebuilt my carbs. Here is some before and after pics.









I bench synced them using the little holes in the top method and I've hooked them back up to the bike. At first start up the revs didn't even soar and it idled at a steady 1100 revs but my preference is around 1400/1500 as the bike sounds healthier.

I replaced my spark plugs and instead of being carbon fouled, the the overhanging part (that creates a spark) had cleared up, a sign of running better perhaps?

So now I'm onto the syncing stage. I've been looking to invest in a Morgan carbtune pro however I've not done anything like this before. I searched the forum but couldn't find a how to on how to use it alongside the yics tool (which I already have). Can someone point me in the right direction?



Maximus.

 

1. Set your idle speed after the bike is fully hot. 1400-1500 RPM full hot is a good place to be.

2. You don't need to use the YICS tool to synchronise the carbs. You'll get 99% of perfect without it.

3. The ground strap should be fairly clean (greyish is fine), and the insulator should be grey to tan. There should be no grey bumps on it (a sign that you are too lean and the aluminum from the piston crown is melting). Nor should there be soot (a sign of leanness and of richness, but more typically richness).

4. As you synchronize the carbs you will be adjusting the idle speed again, and do a final idle speed adjustment after a 10 to 15 minute ride.

If you hear any popping on deceleration (as you rapidly close the throttle like you would coming to a full-stop) the idle mixture is set too lean.

If you have any concerns about your fuel mixture post pics of the plugs so we can have a look. Good light, neutral background, lined up left to right cylinders 4-1, insulator, base ring, and ground strap all showing.

 

2) I dont need the yics?? So I've wasted $50, great!

3) no grey bumps at all, if you remember from my previous post the plugs were carbon fouled and one was wet - insulator is black but ground strap is now grey... I'll post pics tomorrow at some point

I dont suppose you would know how to use the yics in conjunction with the morgan carb tune?

 

there are 2bolts, 1 on each side of cylinders at rear they are just below the level of the carb boots .
remove them clean the tunnel with gun solvent and cleaning rod then tool is inserted locked and then sync carbs.

some have tried to remove bolts and cracked/broke the passage. that is why I do not use the tool

bolt upper left

 

You can use it, but you don't have to.

The YICS manifold is just below the head on the back of the engine. Carefully remove the bolt and crush washer (the washer will have to be replaced or annealed before closing the manifold back up).
Insert the YICS blanking tool and tighten it to expand the seals.
Synch the carbs as normal. #3 is the master, everything synchs to it. Synch #4 to #3, then #1 to #2, and finally (using the #2 synch screw) synch the 1-2 pair to #3.

Here's the part where the overheating discussion matters. When using the YICS tool the engine can get hot enough to melt the seals on the tool (depending on who you bought it from and what the seals were made from). Using an electrical cooling fan blowing across the engine will keep the manifold cool enough that the seals won't melt and get stuck.

Following the synch, remove the tool and allow the engine to cool before installing and tightening the manifold bolt. Treat the bolt like it is a oil-pan plug. Tighten it enogh to crush the washer for a seal and no more. The reason for allowing the engine to cool, and taking care when tightening, is to help ensure that you don't accidentally cause a crack in the manifold (this comes up occasionally, and is difficult to diagnose since even a very small crack will result in a vacuum leak in a location that one would not normally expect).

 

No you didn't.... you bought a tool to show off at the next Carb Clinic you go to..... you show them what it is and you say "THIS is the YICS tool that everyone think they need to get. Look at it close. Memorize what it looks like, Cuz you'll never need to see one again".

BTW, I have one and it's still in the package. I show people at the carb clinic what it looks like.

 

Silly question but if I block off the left passage (sitting on the bike) would I be then be adjusting #3 & #4 or #1 & #2?

I thought the yics ports were to block off individual cylinders so imagined there would be 4 ports

 

The tool blocks off all of the ports when installed. The synch order will not change regardless of what side you insert (or do not insert) the tool into.

Sitting on the bike, cylinder #1 is on the left.

 

Well that just confuses me even more so.

Do I only need to insert the tool into one side to do the entire sync with the yics tool? If so why is there two ports?

 

Also, gunson colortune prior to vacuum sync with morgan carb tuner- yea or neigh?

 

yes color tune sync check color again if adjusted re sync

 

http://www.xj4ever.com/HCP5460 YICS tool.pdf