[mshowe]

QBS, thanks for your reply.

Can anyone corroborate QBS?

[Prophet Of Doom]

Can anyone corroborate QBS?

Absolutely - both carbs should gush fuel if you remove the mains.

[QBS]

A way to evaluate fuel flow and flush out float valves without carb removal:  Remove tank.  Remove fuel line from each carb.   Open carb drain screws.  Acquire a large volume syringe such as turkey baster.  Attache a 6"-12" piece of fuel line type of tubing to output end of turkey baster.  Fill turkey baster with fuel or, for extra points, carb cleaner.  Attache turkey baster fuel line to one of the carb fuel line attachment spigots.  Push in the turkey baster plunger to forcibly inject fuel through the float needle valve and into the float bowl.  Observe fuel output from the carb drain.  Draw your own conclusions regarding injection resistance and drain output.  Best case scenario is little injection resistance and large drain fuel flow.

New idea.  I have never done this.  The same evaluation process as described above, but with less control and evaluation precision: Leave the bike assembled, open one of the carb drain screws, start the engine and observe the drain fuel flow.  Do the same thing with the other carb.  The rate of flow should be the same from each carb.  For extra environmental correctness points establish some sort of fuel catch/recovery procedure.

[ArrrGeee]

please don't do that, you'll burn yourself and your house down.

your carbs are dirty and need to be cleaned properly and rebuilt.
carb kits are available on ebay for reasonable money now and you
can clean them yourself somewhat reasonably.
http://www.ebay.com/itm/YAMAHA-XZ550-CARB-REPAIR-KITS-2-REPAIR-KITS-INCLUDED-CI-XZ550CR-/161841845141?hash=item25ae869395:g:KHkAAOSwuTxWCirA&vxp=mtr


you need a 5 gallon bucket, a large bottle of Pine-Sol, a bottle of lemon juice
and 3 gallons of boiling water.
teardown and strip the carbs, leave the gaskets, put it all in a clean dry 5 gallon bucket.
next pour in the bottle of lysol   correction: I meant Pine sol
and the bottle of lemon juice followed by the 3 gallons of water,.
let everything soak for 30 minutes, using tongs or rubber gloves pull the main pieces out
and have a look are they clean yet ?  if not looking perfect give them another 15 to 30 minutes.

pull them out and using compressed air, blow everything out and dry.

reassemble with the new parts and in your case I would try to find a float, that one in the picture is damaged
and will make a difference imho.
set your float level properly, put them back on the bike, syncronize and set the mixture screws
and it will run like a new bike.
trust me I've done this exact procedure many times and it does work if done correctly.

good luck and let us know how it all came out.

-Ron

http://ingredients.thecloroxcompany.com/images/products/large/originalpinesolmultisurfacecleaner.png

[mshowe]

I do have the carbs back off.  It does appear the obstruction is in the float valve.  At first I could get air to come through one fuel line and out into the bowl (well, if it were assembled).  After some time, I did start to get it coming through the other fuel line input.  I'd like to take the valve out, but as warned, the pin holding the float seems very snug and very breakable (at the posts). 

so, seems at least off the bike, fuel may have a chance to flow.   Are float valves part of a rebuild kit?  Someone give me a link to a reputable kit as I see a pretty large variance in pricing.    Someone mentioned a different jet.  A link for that and whether you think I should mess with it would be appreciated.

Thank you.

[Prophet Of Doom]

The float pin is a bit intimidating, here are some comments on removing it http://ridersofvision.net/rovforum/index.php?topic=15456.msg142088#msg142088

Float valves were not part of the rebuild kit I was given.  They are available from Yamaha though and often on ebay.  Usually though, they just need a clean and a new o-ring which is available from any industrial seal supplier if you take in your old one.  They have a spring inside so make sure the end that the float hits moves in and out freely.  The pointy end can usually be cleaned up to a shine with a pencil eraser.  Carb cleaner should take care of the inside parts.  Ask for petroleum AND alcohol resistance for the o-ring.

I would stay clear of playing with jets unless you are confident in your tuning abilities.  The stock ones work OK enough if everything else is in good shape.  If they are damaged, replacements are available from most bike shops, or JetsRUs.com amongst other places as they are common Mikuni items.

[mshowe]

I am getting plenty of flow out the main after my last cleaning.  The running behavior is still the same.  I know it's the front cylinder.  It appears to be getting good spark.  The plugs are new and gapped correctly.

So, here's what I am considering.  Taking it to the shop, or, if someone has a confident idea of what - in the carburator that I should focus on  -  I may consider getting a rebuild kit.  I've done a pretty thorough cleaning of it; although, it didn't "appear" to be that dirty.  I did not do the pine-sol dip.  I'd like to get more corroboration on that before I do it.

Any chance it's electrical - coil pickup, etc.  Perhaps the fact that it's "getting spark" is a very gross measurement.

I'd be interested in what a number of you think, and I'll make a decision/proceed from there based upon the feedback.   

Thanks for your patience.

[Walt_M.]

Have you run a compression test? Fairly easy to do and may show you more. When I put my Vision back on the road in 2003, I thoroughly cleaned the carbs and reinstalled at least 3 times. I was beginning to hate them. But I didn't have to touch them again until the ethanol and redkote killed them.

[mshowe]

It has life!!!!!

Someone, several posts ago, asked about when the problem occurs, how long has it been running, etc.

Well, before I decided to take it in (and of course awaiting some additional thoughts before I did so) - it was idling pretty nicely.  So I just let it idle.  After about 10 minutes or so, I hit the throttle, and the bloody thing runs nicely.  Front cylinder running, runs great.

So, would that eliminate carbs? 

Thoughts?  I am soooooo happy that at least I see my old vision back and there is hope.  BTW, I didn't do a wheelie, but I suppose if I did so  - I could initiate the problem.   

[Walt_M.]

So I assume you rode it. I got my FZR conversion running pretty much like that but I haven't put it under any load. BTW, if your carbs are functioning, they can be made to run fine. My conversion is only a last resort for those whose carburetors are fubar. If your carbs aren't broken and you can't get it to run right, you probably won't be able to get the FZR conversion to run right either.

[mshowe]

Yes, I rode it.

I'd like a few comments from the experts here, given the latest information, to see if anyone else has experienced this and what they found to be the problem.

Thank you.

[fret not]

Considering your problem is intermittent I think it is more likely to be electrical.  Like an intermittent connection, which could be a worn through spot on a wire, a loose connector, a failing ignition switch, a loose ground on a coil, etc.

There are a lot of wires on these bikes and they have been out in the world for more than 30 years.  One possibility is the ignition box.  If you have access to a known good one you could change them for a test.  If you need a new one the Ingitech folks in Slovak Republic would be my choice to ask.

[mshowe]

I did end up putting another of my TCI units on it.  My problem disappeared.  Wow, wish I would have tried that a couple years ago.   As Fret Nut said, I suspect I disturbed some corrosion on the TCI, TCI Connectors (or worse), some other wire during the switch out. 

Been enjoying riding the old-girl the last couple of weeks.  I'd like to put more than 11,700 miles on it the next 30 years - which will put me at 89 years of age. 

After it get's nice and warm, my throttle roll seems to be worse than I remember, however. 

Thanks to everyone for walking through this with me.

[Walt_M.]

Good to hear you got it sorted.

[davecut]

Please tell me what is pine-sol its not available in UK. Do you know what the UK equivalent is. Dave.

[fret not]

Pine-Sol is a pine oil based cleaning solution, usually found in the washing detergent and soap area of the super market.

[Rikugun]

Try UK ebay
http://www.ebay.co.uk/sch/i.html?_nkw=pine+sol