XJ650 Turbo restoration

didn't think there was a prime on these?

 

yup opposite to RES is PRI

 

Remember this is a turbo he has, not just a regular seca.

 

doesn't mean the petcock valve should be different. still gotta get fuel into system when its cold

 

But since Turbos have a fuel pump, there's no need for a vacuum operated petcock. It's of the ON-OFF-RES variety.

If your bowls are empty, and the fuel system works, there is a fuel circuit relay under your right fairing with a ground bypass wire. It has a female end and sleeve to prevent grounding in normal riding. With the petcock to ON, turn the ignition on. Now you need to ground the wire (fork works). You should hear the fuel pump running.

The relay prevents the fuel pump from running when the bike is not running (alternator isn't providing voltage) or when it gets a signal from the tip-over sensor. But if your bowls are empty, it won't run and fill them so you can start it.

I spent a whole day verifying my fuel system (tank, petcock, pump, carbs) OFF the bike, and it was well worth it. See my thread here: http://xjbikes.com/Forums/viewtopic/p=3 ... tml#359741

 

learn something new everyday.

 

Whoops, sorry, it should be under the LEFT fairing. It's the only relay with an extra wire sticking out, but I can't remember the wire colors

 

Thanks guys, i've found the root of the problem - the carbs are gummed up, i've just removed them and the bowls are black and sticky. So its a strip down!

I've got a manual from Jeff, but its missing the fuel chapter, does anyone have a manual or some tips on how to strip these down?

thanks for all your help

 

Look here, the 650 Turbo carbs ar very similar in design to the ones on your bike:

http://xjbikes.com/Forums/viewtopic/t=31061.html

 

well i had a go today and had to give up, they were so thick in tar that i took the top off the pilot jet, so i thought that enough was enough and took them down to my local bike shop who are going to service them for £35 which is a bargain!

I'll let you know how it all works out when i get them back

 

I've got them back and fitted, all the pipes attached, pump working.. and it started! took a bit of time, but it did.. but then..

The engine started to slow down and i turned it off, fearing the worst.

I notice that the fuel may have run out and filled it back up, now it wont start, checked the compression, that seems ok, check the spark - thats ok.

There only seems to be fuel coming out of the 2 outside carbs from the float bowl drain screw, is this right?

Can anyone suggest anything else to check before i start stripping it down?

 

so i stripped the carbs down and the guy did a really bad job, the set has now been back to him 2 times, but on the plus side i've got taaaaaaking them off and on down to a fine art..

So tomorrow it'll hopefully be the last refit..?

 

If you are trusting someone else to rebuild your carbs, for £35, you are just going to be disappointed unless that mechanic REALLY owes you a favor. It takes hours to properly tear down, clean, and rebuild a set of turbo carbs, and the state you described mean that an entire overhaul is really needed.

I've done it (turbo carbs) and others on this site have too. Doing it yourself is best. And rebuild kits from BDesigns are a really good idea. You won't see an end to "re-fits" using mechanics, it's just not worth their time. And their time = money.

Number of carb installations is inversely correlated to how good of a job you do on them yourself. It isn't the last "refit" until the bike runs perfectly and can be tuned properly.

 

i think i'm learning that lesson, they were really sludged up and a bath was deffo needed.

 

everythings back together - and it started - but not for long now the fuel pump has stopped.. i feel i'll be chasing this bike around for a while!

 

I have now restarted this project, between a XJ750 that I have now sold, so I have managed to get her started - I bought a R6 fuel pump from ebay, gave it some fuel and its started and running...! wahoo!!

So now i'll start stripping it down and replacing the bits I don't like.

First point of call is to replace those dodgy fuses

 

I'm jealous! I want a turbo for a cafe build! nice find man!

 

With a more powerful fuel pump, you'll want to be sure the pressure regulator is functioning properly, or it'll empty you tank into the engine/carbs in a hurry.

I know it's a complete pain, because I've done it twice, but I STRONGLY recommend you wet set your fuel level/float height off the bike, with the ENTIRE fuel system plumbed, including your new fuel pump. You'll fix any overflow problems there, without needing to change your oil constantly and fouling your plugs.

Replacing the fuse box on these old XJs is always a good idea. Also check your charging system output and fix any issues there, as this will kill batteries in a hurry.

 

Oh bugger.. I've put the carbs on, cleaned them and set the floats but not wet set them, as I don't really have a clue how to do that with a fuel pump running.

I might just chance it and se how it goes?

As far as the charging system, shall I put a multimeter in line and test the output?

 

You might be taking the carbs off and on a lot. Chancing it can overflow your carbs in a hurry. Sure you can do it, but from my experience, rushing on a Turbo Seca just ends up more frustrating. I hate pulling the carbs as much as the next turbo owner, but I'd get used to it until EVERYTHING is working perfectly.

You wet set them like any other XJ, except that instead of letting gravity flow fuel to the carb, you use the fuel pump. You can't really use a test tank, because you need the fuel tap with the return port. Use a couple of leads or make a connector to connect the pump to a 12V source (I used a car jump starter). You'll really want to be able to switch it on and off.

What you are doing is two fold:
1. There is an extra 2 psi of fuel pressure, in addition to gravity, that is pushing fuel into the bowl, and the float positioning/fuel height needs to account for this (although I don't know EXACTLY how small this difference is vs gravity only, it may not be a big difference)
2. You are testing the pressure regulator's ability to regulate the pressure of 2 psi. The stock pump outputs 14 psi, and that is enough to overflow your bowls. Your R6 fuel pump likely outputs 20-30 psi.

Charging system should output 14.5 +/- 0.3V, between 2500-5000 rpm on the terminals of a fully charged battery. Anywhere outside that range, and you need to troubleshoot.