2001 ZX6-R Starting Issues

[V1]

I just ordered the workshop manual to help guide me through this process. When I get it, I am going to disassemble the carburetor, soak every screw, needle and jet in cleaner, replace all of the o-rings throughout, and air blast each orifice in the carburetor itself. It might take a while due to my work schedule, ordering the shop manual, then ordering parts.

I also just discovered that one of the 'T'-shaped vacuum fittings is cracked.... so maybe a vacuum leak is part of this whole dilemma. I'll keep all y'all posted. Thanks again!

Needless to say, this bike has been abused. My brother beats the snot out of it. He redlines the thing and it goes
"WAAAAAAAAAAAAAAAAA-GA-GA-GA-GA-GA-GA-GA-GA-GA!" Hahaha. I'd never do that to my bike!

 

[sunruh]

V1,
to explain just how darn finekey they are.

i knew my bike was going to set a while.

i drained the carb. removed the bowl plug. and left it out!
not only that, but i had been using howell 002 fuel for over a year that is 7/7/7 quality.

ya know what? the pilot jet plugged. no amount of carb cleaner would get it right. $5 later with new brass in, all runs fine.

ya got some gunk in them thar passages. remove all the air /pilot/fuel screws and jets

just saw the update. a leak in a "T" could cause he77!

 

[V1]

Behold, pictures:

First of all, you can see how the rubber T-fitting is a little chewed up on its left side. There is another one just like this between the other two carb funnels. Both T-fittings are similarly damaged. The next pic is where things get interesting.

Notice how the metal nipple has been cut away where the rubber fitting attatches to! It has been ground down with a tool. Looks like someone tried to modify this carburetor. No clue what they were trying to do, but now I have to figure out how the new T-fittings are going to seal up properly.

 

[Craig750]

Looks broken to me. If that is used for the IAP (Intake Air Pressure) sensor you could plug it temporarily and run the IAT off the other two carbs only. Then do a quick run to see how it goes.

 

[sunruh]

V1,
you may become very close with JB Weld in the near future.

the split is at the same point the metal is gone. major air leak to that sensor.

 

[boraticus]

Find a thin piece of tubing that will fit inside the broken nipple, cut it to length, coat it with JB Weld, insert and allow it to set up.

Fill the missing piece of the original nipple with more JB Weld. It will be best to do this repair with the carb off. JB Weld will flow and fill the void but the piece has to be kept at the correct angle to allow it to form correctly. For that job, I'd use JB Quick and let it set up a bit before applying it. It will be easier to manage. When finished, it will be a permanent fit.

 

[V1]

Well, I traced the hoses and they go all the way to the forward part of the intake. Right at the front of the bike. So what exactly is the purpose for these IAP lines? Why does the carburetor need to "sense" IAP anyway? It surprises me that such small leaks have any impact on how the bike runs if all it is is IAP.

As far as the metal goes, it looks like it was deliberately cut by a tool. Not broken. Both sides have the identical half-circle cut.

Good idea, boraticus. I have some JB Weld, actually. Who knows, maybe it's coming out soon. Haha.

 

[AuthorEditor]

I personally think you'll never get those carbs back on without breaking the connection if you do the JB weld repair with them off the engine. I think I would try getting a new T fitting and then sealing around it and the broken off nipple with something like stretchy silicone plumbers tape. That stuff can be stretched quite tight and then it welds to itself forming a pretty strong seal that can also stand some heat and fuel. In the long run you will want to find some used carbs in good shape. Try eBay. That big a leak can cause all sorts of fuel-air ratio problems.

 

[boraticus]

Originally Posted By: AuthorEditor
I personally think you'll never get those carbs back on without breaking the connection if you do the JB weld repair with them off the engine. I think I would try getting a new T fitting and then sealing around it and the broken off nipple with something like stretchy silicone plumbers tape. That stuff can be stretched quite tight and then it welds to itself forming a pretty strong seal that can also stand some heat and fuel. In the long run you will want to find some used carbs in good shape. Try eBay. That big a leak can cause all sorts of fuel-air ratio problems.


Have you ever used JB Weld? It's very tough stuff. If the nipple is fixed as per recommendation, it will hold up. With the piece of thin tubing inserted and the original outside nipple built out to proper diameter, the carbs should go back in just fine. The trick would be to put the carbs on loosely, attach the rubber fittings then secure the carbs if it's possible to do it that way.

The tape you're talking about is "vulcanizing" tape. I use it quite a bit on electrical work and the odd plumbing leak. I don't think it likes gasoline though.

 

[AuthorEditor]

I haven't had as much luck with JB Weld as some others. If you can get it to work, good for you. The tape I was thinking of is made of silicone and is resistant to fuels and heat up to 500 degrees. Here's a link: Rescue Tape

 

[boraticus]

Originally Posted By: AuthorEditor
I haven't had as much luck with JB Weld as some others. If you can get it to work, good for you. The tape I was thinking of is made of silicone and is resistant to fuels and heat up to 500 degrees. Here's a link: Rescue Tape


Thanks for the link. That looks like better stuff than what I've been using. I'll have to get a couple rolls of that.

 

[Craig750]

I was thinking of fuel injected motors when I was trying to figure out what was with those tubes. A carburettored bike probably wouldn't need an intake air pressure sensor.

Having another look at the tubes and a parts fiche it seems they might be for float bowl air inlet. There are some galleries that seem to run down to the float bowls.

But that wouldn't make the bike misfire, so I give up.

I am sure there is a Kwaka forum that will have all the answers.

If it was a Suzuki GSX-R I would be more at home.

There is a thread on this forum that seems to indicate they are used for RAM air equalisation.

http://www.kawiforums.com/zzr600-zx-6r-o...bes-work-3.html

 

[V1]

Here's the latest:

With guidance from the workshop manual, I removed every jet and needle from the carbs, and thoroughly cleaned out every single passageway. The manual helped me tremendously. After getting a closer, more detailed look at the carb innards, I found that two of the main jet passages were partially blocked. The carburetor system is now totally clear.

I ordered new o-rings, t-fittings, intake gaskets, fuel filter, and spark plugs. Verified that all four cylinders have spark, and that the fuel pump works proplery. When all the parts get here later this week, I'll pour some fresh gas in and take her for a ride, hopefully. If it doesn't run, I'll be both surprised and confused.

My last ditch effort will be to replace the battery, per sunruh's suggestion. Its had its @$$ kicked a few too many times, and is about ready to be replaced anyhow.

By the way, those t-fittings lead to the float chambers. So they clearly have to do with float bowl equalization as was said.

 

[V1]

Well, the bike is finally running again! I took it for a ride today, and the motor no longer dies out. Everything feels pretty smooth overall.

So now the only thing I need to do is to properly set the mixture screws. When I removed the screws, I was supposed to count the number of turns they were off of the seats. That was not possible because they were all very tight, and I could not determine when they were seated. During reassembly, I started out with a setting of 2 1/4 turns out. Not sure if it needs more turns out (richer) or more in (leaner). How can I tell what it needs?

 

[boraticus]

You might want to go to a forum specific for that particular machine or machines with similar engines. 2 1/4 turns seems like a lot. Usually, it's around 3/4- 1 1/2 turns on the Mikuni carbs I work on.

The air screw is for adjusting the idling and low speed circuits. A good way to test the setting is to see how well the engine transitions from idle to higher rpms. A well tuned engine will jump from idle high rpms with a quick twist of the throttle with the bike in neutral. No lagging or blubbering. All carbs should be set exactly the same.

 

[V1]

It seems as if there is some throttle lag between idle and 5k RPM. The engine is smooth, but that initial RPM gain seems slower than it should be. Above 5000, the RPMs jump up very quickly.

 

[boraticus]

I'd turn the air screws in until they seat then back them off 3/4 turn, test throttle response and adjust until throttle response is crisp from idle. I work on old 1970's RD350/400 two cycle engines and dialing in the carbs can be a bit tedious. Lots of trial and error. When you do have them properly set, you'll know.

 

[V1]

I tried everything from 1 turn out to 2 turns out, the RPM's come up fine, but they seem to hang a little when I release the throttle. They are kind of slow coming back down to idle.

 

[boraticus]

If the throttle doesn't drop quickly that's more than likely a linkage/cable issue. Those aren't CV (constant velocity) carbs are they? CV carbs use a different system to control the slides. They work using diaphragms and vacuum to control the slides.

 

[V1]

Yes, the bike has a diaphragm/slide/ needle system that works off of vaccuum pressure.