XJ650 Seca Seized Engine Help

idle adjuster would be setto where the butterfly on # 3 was just showing the 1st pilot circuit hole in the top of the carb throat, this would have been done at bench sync.

 

Idle speed screw initial setting:
Coarse thread: 1.5 turns out
Fine thread: 2.5 turns out

Sounds like circuits may be clogged in a carb yet-----Or some jets in the wrong places.

Butterflies - I'd check to make sure that all the butterflies are even:

Turn the idle speed screw BACK so it's not touching anything

Put the straightened end of a paper clip under 'fly #3... let the fly hold the clip in place.

• If it's too loose and the 'fly isn't holding it, you have another waaay out of adjustment. So, play with appropriate screw to open THAT fly more, etc.... til you get just fly three holding that paper clip.

NOW-get another paper clip of the same size, open the end, and adjust each of the three remaining 'flies until you get the same firmness of 'pinched clip' at all four butterflies.

Remove the clips and let the buuterflies close.

Turn the idle screw in until 'fly #3 opened enough for the first hole at the top to be half covered.

Adjust the sync screws so the other three are the same way.

Snap the lineage open and shut a few times

Check and adjust screws if needed

Now you're ready to install try again.

Keep us posted, feel free to send me a conversation if you need specific help.

dave

 

If only there were some one here who knew everything about these carbs... I'd make that guy a moderator!

 

I did a thorough bench sync when they were off the bike but I bet after stuffing around with the idle speed screw, they're probably out again now? Time to pull them off again.

hogfiddles - I'll double check the circuits. They were clean but I wonder if something got back in there. Jets are in the right places but a double check won't hurt and I'll post the results here to make sure.

MattiThundrrr - those mods are wise men aren't they? ;-)

 

The idle speed screw will not affect the synch screws. It's not a bad idea to re-check the bench synch though.

 

Alrighty, so today I pulled the rack again and ran through your valuable checks. Air jets are standard and in the correct positions. I checked all the sliders for the "clunk" test and they're good. Pulled apart all the idle mixture screws/springs/washers/o-rings and there was a bit of crud in a couple of them, so I am cleaning that out. This is new so I'm a bit concerned and will strip the float bowls again to clean everything up. It looked like white crusty build up. I'll also put a another new filter in place just to make sure.

While I was at it, I made up a mixture of rubbing alcohol and wintergreen oil to soften the boots and manifold rubbers per this article : http://v4musclebike.com/forums/showthread.php?t=13477 . Will let you know what the outcome is.

...and I ripped out my battery negative terminal lead and made a new one. The old terminal connector had bitten the dust ages ago and a bent standard terminal just wasn't cutting it, so I made a new one up from some scrap metal I had. Will take a photo when I'm out there next.

 

Boots and manifold rubbers came up real good. Not much more flexible but they look brand new and re-fitting the rack was significantly easier.

So I fired it up and no more run away idle/throttle! Drove it around the block and it looks like I have a viable bike Must have been a vacuum leak.

 

Quick question - when I get her warmed up, I'm getting a little smoke from the exhaust headers. It appears to be coming from right down the bottom, almost inside the pipes but I can't see any visible oil leaks at all. Nothing on the floor of the garage either. Any ideas?

 

A bit of dribble from last oil change?

 

Mine did same when I first got it running after years of sitting. Condensation / old oil burning off

 

^^ that.

 

Thanks guys. "Ride it some more" is the answer I was after

 

It's pretty rare that I have parts left over but these two bolts and concave washers have me stumped. Any idea where they're from?

 

They look like the 2 bottom bolts holding the oil cooler in place.

 

Because that's what they are. Good eye!.

 

Waddayaknow! Well spotted Simmy!

 

Finally found a local supplier for shims and got all valves within spec and she runs really nicely. Next up I'll vacuum sync the carbs but to be honest, it's pretty nice at the moment. Only real problems are a bit of a hung idle (comes down but slower than expected) and I think a leaky exhaust but I'll go over all that when I have some more time. My only other MC experience is with a V twin and EFI so it's a bit hard to know what to expect. Is the throttle and rev to idle normally quite snappy or a bit slow?

 

I think if you did a running vacuum synch you will find your idle drop will become quick and smooth.

Add a Colortune and final synch and she will be purrrfect.

 

Congrats on a job well done!

 

Thanks guys! A couple of more tuning jobs and I get to do the fun part - ride!

...after I get it across the pits and licensed.

 

Should an electronic flasher relay drop straight in to this bike? No LEDs, just normal globes and I have unplugged the cancelling unit to rule it out but I get nothing on a new relay. Reason for the swap is that the thermal one was playing up so I thought to swap it out. I'll go over all the globes and sockets tonight with dielectric grease but I find it strange that it just doesn't do anything at all with the new relay.

Checked these (very helpful) threads for info:
http://xjbikes.com/forums/threads/turn-signal-problems.73794/#post-481325
http://xjbikes.com/forums/threads/how-are-the-blinkers-supposed-to-work.113790/#post-570448

 

Which relay did you buy?
Not all relays have the same terminals, and the substitute for the stock realy is a 2-terminal, not a 3.

 

Damn, I bought a 3 terminal based on those threads. I bought a Tridon Electronic Flasher Relay - 3 pin : http://www.supercheapauto.com.au/Pr...sher-Relay-Unit-12V-3-Pin-Load-Sensitive/6162

I'll go look for a 2 pin version. So load to the load pin and +12v to the other pin. Should be fairly straightforward...

 

'supercheapauto.com' sound like my kind of shop!

 

Hehehe, yes it's not bad.

So I re-wired the 3 terminal relay to work by putting in a negative wire. Works a treat.

 

My XJ's turn signals quit flashing - just stayed on if switched left or right. I priced a new Yamaha flasher, but the $110 scared me off. I tried an electronic led style flasher - no lights. Finally I bought a two prong $4 incandescent flasher suitable for an older car. If you plug it in with the "L" terminal (found on the bottom of the relays) in the proper position, it works!
IT WILL NOT SELF CANCEL so be careful.

 

Understood Barry - I've never had a bike with auto cancel before so it hasn't been any problem just cancelling it myself.

Another question for the brains trust... I seem to have a cold cylinder - #3, but not all the time. I have new plugs, new caps, ohmed everything out to check the coils and the leads and I can see good spark when I test. The bike runs well through the gears but idles a bit rough and plug 3 tends to foul over time.

Is it possible that I have something wrong with the idle circuit in that one carbie?

 

Imo yes. Did you clean the carbs?

Gary H.

 

Carbs have been to church. Thoroughly.

I think I'll pop that one open and go over it though.

 

How do these look? I'm thinking #3 is ok, maybe a touch lean and the others are a bit rich? This is a tune without a Colortune. The bike idles ok, then stumbles to about 3,000rpm and then runs great from there.

 

Well the Colortune was a good investment and showed me that cylinder 3 is misfiring a lot. Like I said in a previous post, it's poor until 3,000rpm then takes off so idle/pilot circuit is what I'm looking at.

Carbies are off the bike and I've stripped #3. It looks pretty clean and throttle cleaner blasts through it from the pilot jet pipe out the air jet and out the mixture screw area. Anything else I should look at while I have it here?

 

Check flow through the idle / transfer ports for that carb, and maybe the others too. I drilled an old pilot jet to fit the straw on the carb cleaner, plugged the air jet with a wooden Q-tip with heat shrink applied, and installed the enrichment screw less the O-ring 3 turns up from soft bottom.



If flow looks good consider float fuel level set again and condition of throttle shaft seals - or other possible air leaks.

 

Have you checked the fuel port in the float bowl

 

Thanks Rooster - those instructions were spot on. Everything looks clear and clean.

Toomanybikes - yep, double checked it. I don't have any issues starting the bike but it's good to go over it anyway.

Reassembling now and I'll see how it goes.

 

good read.I'm at the very beginning of this story myself

 

Good luck with it Doc. Let me know if there's anything you want in the form of photos or reference material. It's sometimes hard to find or daunting to look at from a new user perspective.

Update on the carbies : The bike runs better from 2000rpm now but still stumbles a bit up to there. I'm about to do a ton of mods (block your ears purists - it's going cafe) to it so I'm sure I'll have them off again at some point and I'll triple check everything.

I did notice the floats are shedding some of their plastic - small plastic bits in the #3 float bowl so that could certainly be a source of trouble.

 

Nooooooo!

It's already a cafe! Don't do it!

 

I get it, I really do and I have a bit of a goal to make it completely restore-able. Sometimes I keep some of these plans to myself because this forum tends to be a bit more focused on restoration than modification but hey, it's my bike

Oh and these "Seca" bikes aren't nearly as rare over here as they are in the US.

 

I agree 190%
I love these bikes out back to original condition, but yes- it's your bike, make it what's right for YOU, and yes-it's only a "rare" model for the USA, not for where you're at.

Carry on

Dave

 

Only kidding of course...

Send some over, we'll take them.


...or should I say, Dave will take them!

 

So here are a couple of photos to show progress. I'm still having a hard time with stuttering at low revs so I'm worried about the plastic I saw coming off the floats and it might be time for a new set. Has anyone had their floats perish and crumble before?

 

Typically, the Hitachi floats are pretty indestructible, but if they are starting to flake apart (or have large chunks missing from them, then it might be time to replace them............we do have new and good used floats in stock, and of course can fly them right over to you!

 

Thanks Chacal. Considering ripping the carbs off again and I'll check the state of all 4 floats and get back to you.

Before I do that I've been removing the spark plugs and adjusting the mixture based on what I see. Initially all 4 were black and sooty so I reset the screws to 2.5 from soft-bottom as a starting point. So far I've had to lean (turn in clockwise 1/4 turn at a time) each of them off significantly. I'm at 1.5 from soft-bottom for #1 and #2 and they're still sooty. #3 and #4 appear ok around 1.75 turns. This feels like a long way in. Is there anything odd about that?

My symptoms are the same - very little choke needed (and not for long) and once the engine warms up, I get severe spluttering on take-off through to about 3,000rpm when the main jet kicks in I guess. So just querying my next steps again with you please guys :
- Keep going with the 1/4 turns to lean out cylinder #1 and #2
- Pull the rack and double check all the pilot circuits and maybe float levels again?

Here's a photo of the plugs but #1 and #2 (left) are a lot blacker than the photo shows. Maybe #3 is a touch lean now?

 

Are you using hitachi jets or aftermarket ones?

 

Stock standard Hitachi. Checked the numbers against the jet numbering at the Church. I have an aftermarket 4-1 exhaust but I thought that would have the opposite effect on the mixture at idle?