professional mechanic stuffed my carbs !

[JWSanders]

To post pictures you have to use a photo hosting site like www.photobucket.com then link to the photos you post there using the IMG tag.

There is a pretty good description of the process in this thread:

http://www.xs11.com/forum/showthread...posting+photos

[Hired_Goon]

Originally posted by s head
I live in australia ,

Fraser motorcycles

Frasers in WA or NSW?????

There are a few Aussies becoming active lately so let us know where you are as some of us may have a few handy spares tucked away.

Originally posted by s head

It says in the forum rules YOU MAY NOT POST ATTACHMENTS how do you guys get your pictures posted on the threads?

Rules???, What are they?

Open up a photobucket account and load your pics on there. Then just paste the IMG tagline into your posts. Pic miracoulously appear.

Cheers
HG

[s head]

Frazers nsw.But I live in melbourne.Will get onto photo bucket tomoro.
Thanks

[s head]

Finally got back to this bike today and started to assemble the carbs.The old parts have cleaned up
ok so have decided to use them and save the K&L rebuild kits until I need them.
Did not get far when I realised that the rubber seals for the pilot screws are missing altogether and were never there when I pulled the carbs apart ? .I only know they exist from looking at the carb kits over a cup of tea.
Question 1 .where do they go in the order of things?
Q2.What would be the effect of not having them there?

[Ken Talbot]

Here's the assembly order:



Without the o-ring, you would have a vacuum leak.

[s head]

Thanks Ken.

[s head]

Now the carb holders are suspect.Bike runs fine from 3000rpm up all the way to red line and responds immediately when the throttle is opened from 2000 to 3000 but wont idle evenly and stutters off idle until 2000rpm.Also does not like an even throttle at anything below 4000rpm .Plugs are black and sooty when left to idle too long.
Float height are correct and bench tested float needle seals.One carb venturi showing a slight amount of wetness but others dry.The one with the slight leak is unrepairable as an oversized pin has been forced in and one post is already cracked
it will break if I try and remove it,so hope this is not the problem.All the plugs show a rich mixture down low so dont think this is it?the pilot screws are 1 and 1/2 turns out.The throttle is hanging up slightly when shutting the throttle from 2000rpm which means the carb holders might be cracked through.If they are you would think this would cause a lean mixture.Air cleaner is clean.Are the after market carb holders ok?
Thanks for any help.
Any suggestions on what to try next.

[TopCatGr58]

Hey there S Head,

First, IF the float that the cracked post is on is slightly tilted, then it can throw off the float action, etc.! I had a broken post that I repaired but didn't get exactly level, had intermittent float sticking and flooding. I finally REBROKE the repair, cleaned it up, and reglued it, and it now works flawlessly! SO....go ahead and break the post, get some JB Weld or MagnaSteel/Aluminum type stuff, repair the post and get the proper fitting pin for it. IF the pin is too thick for the post, may also be too thick for the float, and it may not be spinning freely?

Secondly, your symptoms are all related to the pilot circuit. You said the Pilot jets looked different than what you had seen on this site?? See this diagram from MikesXS:

Note: BS 30/96 type Pilot Jets WITH Side bleed holes and those without side bleed holes are completely interchangable.

MikesXS agrees with Prom about the vented vs. non vented pilot jets....providing they are the BS type, and not the VM type!

Also, hanging idle indicates need for vacuum synching of the carbs. Doubt the intakes are bad, but can be tested with carb cleaner/Wd-40, spritz around them while idling, listening for rpm change which would then indicate a vacuum leak, but like you said, would be lean if existed! But the aftermarket holders from Ebay, Partsnmore are all good! BTW, check the vacuum synch port caps...can harden and actually not sealing well=leak!?
T.C.

[s head]

Thanks TC
The float is moving freely and the slight weep has gone over night .I wound the pilot air screws in 3/4s of a turn which leaves them 3/4s of a turn out from lightly seated and took it for a run.About the same maybe a little worse and the plugs are still black and sooty on all 4 cylinders?Its like it has over sized pilot jets but they are stock 42.5s.If the carbs are still dirty from sitting and not clean enough it beats me how this leads to a rich Idle mixture ?
It requires no choke to start from cold and run worse once it warms up.I tried removing the air filter but it did not seem to help much.I need to get it running reasonable enough to get some starting point to sync the carbs,I can borrow some guages.I have lost all faith in professionals lately having witnessed to of my bikes butchered by workshops but I am starting to think its time to start looking for someone who actually knows what they are doing?Carbs are complicated science it seems.The bike goes like a bat out of hell when the throttle is opened and I am keen to start riding it.

[TopCatGr58]

Hey again,

Okay, recapping, it's a n 80 MNS! You got it, a previous set of mechs worked on carbs, possibly replacing the pilot jets? You say they are OEM pilot jets....how do you know??? They very well could be K&L's from the previous mechs work? When you got them out, did you ensure that small bristles from a toothbrush would go thru the small vent holes in the sides of the pilot jets?
Being able to cold start without choke is also indication of richness in the pilot circuit. It is winter there isn't it?

It runs great above 3k rpm, which is the transition to mains. You have black sooty plugs. HAVE you tried to check plugs while doing a throttle chop technique....running at~2/3' throttle for 30-45 seconds under LOAD, preferably going slightly up hill, then pull clutch, hit kill switch, coast to stop, pull plugs and see what condition? IF still rather dark, then float height may be too low(when upside down), and you might try raising them a 1mm?

Finally, Yamaha used some mixed parts during the transition from79-80 year models, and so they had some carb bodies that still had the shared fuel tunnel going between the main jet tower and the pilot jet tower, although the 80's were supposed to NOT have this tunnel!! IF it exists, then the pilot circuit is getting fuel from BOTH the bowl and the main jet IF the pilot tower is NOT capped off! But IF this tunnel is not there, then the pilot tower is NOT to be capped off.

But IF the tunnel IS there, then the pilot tower needs to be capped off, but surprisingly the mains should be larger than the 110-120 sizes listed in the manual for this year carb, because it's sharing it's supply with the pilot jet. Another solution to keep the properly sized 110-120 mains IF the tunnel is there, is to plug the tunnel with appropriate fuel proof sealant, and then leave the pilot tower uncapped! Hope this makes sense!?

Also, I'm sure that someone would be willing to send you a set of real mikuni BS series pilot jets to ensure that you have the right kind/size!
T.C.

[s head]

Think I will pull the carbs again and start over.Will check what model/type they are .Then check the pilot jets for correct size.One fuel tap is also leaking so will have to get a new seal.Do 2 AND 3 on the octapus go to the prime outlets on the taps or does it make no difference?I just pulled the motor out of 2006 triumph speed triple to have a broken engine mount repaired and it took
6 hours which is about half the time I have spent on these carbs so far

[TopCatGr58]

[mro]

Originally posted by s head
One fuel tap is also leaking so will have to get a new seal

How did you find out it was leaking?


mro

[s head]

I took the tank off to look at the carbs again and noticed a small amount of fuel on the work bench the next morning even though it was in the off position .When I took it apart and the seal with 4 holes in it is slightly torn.I turned it around and it stopped it for a day but now its back .Its not much but one of my float needles is suspect so I want the fuel to be off when its supposed to be.

[s head]

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Test post of for photobucket.
This is the beast that looks good but runs like crap.