XJ550 Issues and Woes

So I bought an XJ550 as my first bike after passing my test. It was advertised with no mot but seemed good and the seller was a nice guy so I went for it.

Here are some pictures from the day I bought it.



Anyway, I put it in for an mot and it failed on some electrical issues and a few other bits so off it went to the local mechanic who sorted the issues and got it through an mot for me.

I enjoyed the bike for a few months - despite some electrical issues but then the bike decided to stop starting. It became difficult to start and then wouldn’t start again at all.

I sent it back to the mechanic who told me the carbs were flooded and needed cleaning out and back it came. I managed to start it a few times but then we went back to the same old starting issues.

The battery was weak by this point and wouldn’t hold charge so decided to buy a shido lithium job.



And a battery box for it;



Which I then painted black;



Also bought a seat hoop with an led strip as wanted a shorter look;



So back again we go to the motorcycle shop for all this sorting. He had previously told me that my starting issues could also be down to the rubber boots being perished on the bike so I bought some new ones to get fitted.



Anyway, a few weeks pass and I get a call from the mechanic informing me that the boots don’t fit. I call the guy who I bought the bike from and he informs me that he fitted XJ650 carbs to the bike.

I get the bike back and it won’t start at all. Managed to faff about with it and it jumped off and then would start fine. Leave it over night and it won’t start at all.

I’ve got the old rubbers off the bike and they don’t look too bad. Cracked on the outside but not on the inside and they’re showing this part number;



So not sure what bike they’re supposed to go on.

The carbs themselves are Mikuni ones;



So that’s where I am at the moment - I have some unknown carbs on my bike, it won’t start and I’m left frustrated and broke after spending a fair chunk of money on it. It is getting spark and there is fuel so not sure what the issue is.

Let me reiterate, the bike ran fine until the starting issues so not sure what has gone wrong.

Here’s how she looks now;





Any hints and tips on what might be the problem would be appreciated! Also, if anyone knows which inlet rubbers I need that would also help.

Thanks in advance!

 

One issue to look at is your bike has PODS mad your jetting maybe way off this can cause starting and running issues . Your old boots you can try RTV and an inner tube of same diameter and try repairing , I make my own gaskets for the intake boots, you should be able to buy the material at most auto part stores , cut the out with an xacto knife using boots as template . This is if the gaskets in your pics don't match up to the boots.

 

those carbs with the enrichment circuit on the side are defenitly not 550 carbs the fj600 has side enrichment circuits (choke)


https://www.yamahapartsnation.com/oemparts/a/yam/500425e5f8700209bc78839e/carburetor

 

the 49A part number on the intake manifolds indicate they are from an FJ600 (perhaps XJ600 in your part of the world) and so I would assume that the carbs are off a similar bike.........

 

Thanks, it appears they are off a 600 so at least I know what to replace them with. To be honest, now I have got them off, they don’t seem to look that bad! There is cracking on the exterior but the inside walls look totally intact.

 

Those are definitely not xj650 carbs....

But THESE are---

 

Thanks, I think I’m happy they’re not 650 ones now.

 

Doesn't look like the carbs are all the way into the boots. Probably too big for the manifolds.

 

Firstly I notice that not only the carbs but the complete motor looks to be from an XJ600. Does the V5 say 528 cc or 598 cc by the way ? My suggestion for starting issue are as follows.. 1) make sure your valve clearances are adjusted properly - I'm convinced this can caused starting difficulties -your mechanic can do this but wit will cost a fair amount so better learn how to do it yourself. 2) If this does not cure the starting issues you should consider reverting back to using an airbox/filter set-up but that will probably mean dropping the engine as they are a right bastrad to do with engine in situ. You should also strip and clean the carbs yourself at some point - most folk here will tell you not to trust anyone else's work (unless it's Dave (Hogfiddles). Finally what version of the igniter (black ignition box) do you have?

 

This is my engine number if anyone can decipher it?

 

51J is the European XJ600 model https://www.cmsnl.com/yamaha-xj600-1984-51j-europe-2451j-300e1_model38082/partslist/
Doesn't look half bad. I'd like that myself.

 

So, I now know that my 550 has a 600 engine fitted. Last night spent some time on it, removed the carbs and cleaned them up, checked the inlet rubbers and they were still ok, gapped the plugs, put new fuel in and it still wouldn’t start.

Bumped the bike off (started on the first attempt) and ran it around the block. Switched it off and then it would start up first time with no problem. The bike then started up first time and kept starting with no issues! The bike ran sweet after this, and really sounded well!

Went back to it this morning and she wouldn’t start again. It gave a little cough but then nothing!

I don’t really want to have to do the running jump every time I start the bike but I’m running out of ideas for what the issues might be.

 

Sounds like you need a new battery...and your carbs need cleaned

 

It’s a brand new battery!

 

Have you tried turning the fuel taps on to PRI, prime, opening the choke or enrichment circuit and then hitting the starter button?
If that fails sell the bike to me. Lol.

 

check the charging voltage of bike start bike put meter on battery hold rpm at 2k rpm should read just over 14 volts. if not then you need to look at charging system

 

That doesn't mean it's good. Do a voltage test anyway......

 

Im new here and i don't even have an XJ, but cold start issues can be valve related. The deteriorating starting issues makes me think this is more likely. Have they been adjust recently?

Does starter fluid help any?

Ive had starting issues that turned out to be fuel screw adjustment issues, but that was with a custom build when i was first trying to get the carbs set... so probably not that.

Make sure its on prime and try different choke positions.

Make sure you have good spark on each plug.

Sweet looking bike though!

 

All sorted now. I just needed to have it on pri for a bit to start! School boy error.

 

Wondered how you'd got on. Glad you sorted it. Just remember to turn the taps back to the ON position afterwards or you might run out of juice instead of going onto RES, reserve.

 

Cheers, did some more on the electrics last night and ordered the seat and some flat bars. She’s getting there!