Help have bike on Dyno last 3 days they can't get it

[Wild1_Robertson]

Background 92 1100 with Yosh exh and KN filter, rejetted by dealer in Az

When I bought the bike at 7K miles it was lean below 4K ( backfiring at cruze speed.) Ran fine over 4K person I got it from said ya it was like that, just keep it over 4K

Moved to Colorado and ran a little better I drove it very easy 35 mph for 4 miles and then when warn would open it up a little the last mile to work. Would not idle so I would close choke a little when slowing and open it fully when running.

After ~ 800 miles it lost power and started using gas parked it in "shop" see other thread. 5 months later picked it up and while letting it idle it smoked looked more blue then black but hard to tell. It cleared up but was way down on power.

Filled it with gas found a shop with a dyno ( and a lot of GXRs in back ) used full tank of gas in 50 miles around town.
They found a bad plug cleaned and rejeted the carb's strapped it on the dyno and it filled the shop with smoke. They rejeted it again and it made no power, and showed rich.

After 3 days on dyno it is up to 75 HP and the curve is smooth up to 4K then it falls off and gets very ragged and blows smoke and shows rich. Max is 7K RPM

Help they will have it on dyno one more day. Are thies CV carbs could the slide not be opening correctly? Any ideas?

This is the shop 4-play

They thought smoke might be rings they did compression test and it was good, but it could still have bad oil ring, on the cyl. that the plug was bad on.

[Wild1_Robertson]

I will try to get Dyno sheet from him and post it

[The CyberPoet]

Could be something quite simple, such as a worn needle or worn needle clip seat (they do wear out with time and vibration). Or the slide could be sticking (clean & coat with a little spray silicone).

My advice at this point:
Find another set of carbs off ebay or from SpecialK and start from scratch with a known-good jet kit (i.e. - new needles, springs, jets) -- or get SpecialK to verify the carbs before he ships them.

You may find that it's a case of the wrong jet kit being installed (such as the kit for a set of 36mm carbs into 32mm carbs), or just worn parts. After so much time/effort, I'd chuck out the carbs (figuratively -- keep them for spare parts or resell after you know you've got your problem resolved) and start from scratch -- cheaper, easier and more reliable.

I'll cross my fingers for you.
Cheers
=-= The CyberPoet

[Mojoe]

tell them to remove the airbox. You will see that bores on the carbs have a small half-moon shaped opening just above the bore. take an air hose with a blower attachment and blow across that opening. I do mean across....not straight into it. Just give it a steady stream of air not too much. your slides should start to rise and open fully. Cut the air and they should fall back into place. Check each one. If they are dirty, or if the diaphram has a pinhole and leaks, it will not open as should. This would certainly cause you to run rich. I had that problem 2 years ago. A new diaphram on one of the carbs cured it.
Cyber's advise is sound as well, but at least check the diaphrams/slides. it is simple to check without removal of the carbs.

[Wild1_Robertson]

Thanks WOW that was quick you replied in less time that it took for me to type it ( after I I looked for the same already posted ) Thanks again.

[Anonymous]

Thanks WOW that was quick you replied in less time that it took for me to type it ( after I I looked for the same already posted ) Thanks again.

That's because the above are whores.

[The CyberPoet]

Thanks WOW that was quick you replied in less time that it took for me to type it ( after I I looked for the same already posted ) Thanks again.

That's because the above are whores.

No, you are the whori... we actually contributed instead of just spreading ourselves around...


=-= The CyberPoet

[Anonymous]

[Wild1_Robertson]

Could be something quite simple, such as a worn needle or worn needle clip seat (they do wear out with time and vibration). Or the slide could be sticking (clean & coat with a little spray silicone).

My advice at this point:
Find another set of carbs off ebay or from SpecialK and start from scratch with a known-good jet kit (i.e. - new needles, springs, jets) -- or get SpecialK to verify the carbs before he ships them.

You may find that it's a case of the wrong jet kit being installed (such as the kit for a set of 36mm carbs into 32mm carbs), or just worn parts. After so much time/effort, I'd chuck out the carbs (figuratively -- keep them for spare parts or resell after you know you've got your problem resolved) and start from scratch -- cheaper, easier and more reliable.

I'll cross my fingers for you.
Cheers
=-= The CyberPoet

He did clean the carb's before starting to work on it. Are thies the correct carbs?
E-bay carbs

[Mojoe]

Could be something quite simple, such as a worn needle or worn needle clip seat (they do wear out with time and vibration). Or the slide could be sticking (clean & coat with a little spray silicone).

My advice at this point:
Find another set of carbs off ebay or from SpecialK and start from scratch with a known-good jet kit (i.e. - new needles, springs, jets) -- or get SpecialK to verify the carbs before he ships them.

You may find that it's a case of the wrong jet kit being installed (such as the kit for a set of 36mm carbs into 32mm carbs), or just worn parts. After so much time/effort, I'd chuck out the carbs (figuratively -- keep them for spare parts or resell after you know you've got your problem resolved) and start from scratch -- cheaper, easier and more reliable.

I'll cross my fingers for you.
Cheers
=-= The CyberPoet

He did clean the carb's before starting to work on it. Are thies the correct carbs?
E-bay carbs

Those carbs would work, but those are not the ones that come on your kat. I can see differences in those and what is on yours.
If you look at the little opening that I have circled in this pic, that is where you blow the air across. like I said...not too much. A big blast of air in there can damage the diaphram. For the record, these are not your carbs either. This is a pic i took off ebay that is similar.

[img][/img]

If one of the slides do not open, it is part #5 in this diagram. It looks like a bowl on the top of the slide. In reality, it is a thin rubber material that will raise and lower by vacume/spring and operate the slide. If it has a hole in it, which is somewhat common on older bikes...especially if they have been sitting a while, it can leak. If one of the slides do not work, I am betting it will be the one that feed the cylinder that had the bad plug you replaced. It's not a bad thing if it is...it is a fairly easy fix. I had my carbs off, but I think you can fix it with the carbs on the bike.

[img][/img]

[Wild1_Robertson]

thanks again got off work a few hrs ago heading to shop with this printed

[Mojoe]

I should have added that you have to watch carefully when you test this. if the leak is very, very small, the slide could still function...especially if you give too much air. just slowly open the air until the slide starts to slide up. Do it with all 4. If one requires more air, that is the culprit. I should have told you this before you left. Sorry....it was late when I posted.