Motorcycle Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
Hi, I have a XV500 which I have recently purchased, its a 1982 and has been stood for many years, when I took off the float bowls it was half full of black crud,after a good clean out I had it running a bit rough, upon restarting it would then only tick over, the slightest throttle would kill it, so Ive had the carbs off 3 times and given them a good clean ie strip, jets out ,carb cleaner etc, I still have the same problem of dying when given throttle, having read many forums I now think that a passage or 2 may be blocked (pilot side of carb) the pilot jet and pilot air jet and everything or squeaky clean but I cant tell if the passages are clear, any suggestions as how to clear these
 

·
Super Moderator
Joined
·
12,907 Posts
Might need to look for a good used set of carbs but before you do that.............
Getting a healthy dose of Berrymans B12 Chemtool into some fresh gas and then running it long enough to get that into the carbs might help. Run it a few minutes every 8-12 hours over a couple of days.
I assume that you are using full choke (or close to full) when you run it, right ?
And that a stock air box and filter are in place ??
 

·
Registered
Joined
·
9 Posts
Discussion Starter #3
Thanks for the reply Easy Rider, the bike is stood in the garage ,air temp around 10c, starts without choke and ticks over nice, touch the throttle and it dies. Not stock air filter inside original air box, the bike has only done 6000 miles and is in vgc for 39 years old, good chrome work, slight corrosion on some ali parts, no rust on frame,all paint work good but faded,seat in perfect condition, what i'm trying to say is the carbs are good except the supposed blockage and 6000 miles seems to be genuine, great even compression on both cylinders (150 psi aprox)
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
All jets squeaky clean ,can see thro all the holes,poked out with dentist interspace brush (like a small pipe cleaner) emulsion tubes clear, as far as I can tell its a blockage in a passage, not a jet
 

·
Registered
Joined
·
6,933 Posts
I would suspect the pilot/idle jets....just after the venturi...they are tiny and provide extra fuel at the transition from idle to when the main jet and needle take over. A plug chop might give a idea what the mixture is doing.

Good luck
 

·
Super Moderator
Joined
·
12,907 Posts
Thanks for the reply Easy Rider, the bike is stood in the garage ,air temp around 10c, starts without choke and ticks over nice, touch the throttle and it dies. Not stock air filter inside original air box,
Just to clarify:
You NEED the choke to start from cold. It will not only enrich the mixture some but will "fast idle" it too.

The fact that it will fire without the choke means NOTHING. You need the choke while it is warming up.

As it warms up and the idle speed starts to go up, you should be able to reduce the amount of choke.
IF.....it has a high flow air filter, that will just make the mixture even more lean and make the choke even more important.

My bet is that once you do that......and get it good and hot, it will run just fine with the choke off. But you might need to find a stock air filter too.

It would still be a good idea to give it a dose of Berrymans B12 Chem tool or Gumout.
Other products are not as good.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #8
All jets squeaky clean, if you familiar with downdraft carbs inside the float bowl is a small aluminium casting which the pilot jet and main jet screw into,I have just (and I mean just) 5 mins ago found that the 3rd passage on the right side (the one with no brass jets) is blocked, the front cylinder carb is clear, the rear cylinder carb is blocked ,I'm not sure if it should be blocked, but I don't think so, hope I'm making sense, I'm having to run some errands at the moment and won't get back to it till later to try it, all other passages will squirt through with carb cleaner so I assume they are clear, fingers crossed
 

·
Registered
Joined
·
9 Posts
Discussion Starter #9
Hi easy rider, you might have given me a direction to go in, having got carbs off again, the downdraft type, in the float chamber is an aluminium casting which holds the pilot and main jets Also a passage up to the choke/enricher, this was blocked, I'm going to put back together and keep my fingers crossed! All other passages seem to be clear(hopefully)
 

·
Registered
Joined
·
9 Posts
Discussion Starter #10
Hi, bike now running although still a bit rough, cleaned carbs AGAIN, refitted and away it went, one thing I noticed at the begining the pilot screw was out about 6 turns, I thought that was too much and someone had messed with them, advice from other forums suggested 2-3, so thats what I set them at, now i'm at 4 turns and now it will pick up and rev, more to do but getting there, was it that all along or did something get unblocked when I cleaned again? I think it has been several issues from being layed up for so long and all carb related
 

·
Super Moderator
Joined
·
12,907 Posts
was it that all along or did something get unblocked when I cleaned again? I think it has been several issues from being layed up for so long and all carb related
I've been wrenching on bikes for over 50 years.
Did you pay any attention at all to what I said......about the choke and the air filter and about some good carb cleaner in the gas ??
It appears not.
ALL of that is really important.
My last comment.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #13
Hey easyrider, I am 62 years old and been messing with bikes most of my life (not professional ) If I am understanding your comments rightly I don't like your tone, if its my misunderstanding then I apologise, I might say this bike is work in progress and not been on the road for years, it has no tyres, petrol tank off,panels missing ,no battery etc, I was only asking politely for some friendly advice, if you don't like giving advice (whether taken or not) then dont bother giving it any more, I really don't understand what I've done to offend you, I've taken your advice onboard and it was greatly received, sorry if I have offended you in some way it was unintentional
 

·
Super Moderator
Joined
·
12,907 Posts
I really don't understand what I've done to offend you, I've taken your advice onboard and it was greatly received, sorry if I have offended you in some way it was unintentional
You have made it appear that you ignored everything that I said.
Review the replies that you have made and see if you don't agree.
It gets really frustrating when giving advice about not overlooking the basics and it looks like nobody is listening.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #16
My apologies if it has come across that I disrespected you, I have taken notice of your good advice, I also take advice from other forums one thing in particular was the contents of modern petrol over the old type ie addatives, methanol, bio etc, he said it could be the wrong jets for the modern petrol being its 39 years old and not been on the road for many years, this advice came from someone who have been tuning carbs for a living for over 20 years, I'm not saying he's right, I'm not saying he's wrong, but to me it sounds logical, as does your advice, maybe I'm trying to run before I can walk, we all like a short cut, sometimes they are worth it ,sometimes it needs more time, sincerly best wishes and merry christmas!
 

·
Super Moderator
Joined
·
12,907 Posts
he said it could be the wrong jets for the modern petrol being its 39 years old and not been on the road for many years, this advice came from someone who have been tuning carbs for a living for over 20 years,
IF any changes to the jet sizes are necessary because of the specific chemistry of the fuel available from station pumps, it would be a very small change. Might not run at peak efficiency but certainly would NOT keep it from running in an acceptable manner. Does that make sense ? It should because it is TRUE.
 
1 - 17 of 17 Posts
Top