BAD imbalance in my engine

[legaleli]

The good thing is that my clutch is now awesome.... on to the bad:

For the past few drives I noticed an imbalance in the engine... it was as if a cylinder was not firing. Power is good in the bike. After testing the clutch today I parked my bike and just for giggles I put my hand behind the exhausts. The pre-muffler is replaced on my bike with straight pipes so 1 and 2 cylinder are the left pipe and 3 and 4 are the right. The mufflers on either side are original and stock.

There was a lot more air puffing out of left than right. I looked for leaks in the pipes and they are fine.

I then thought briefly that there may be an obstruction in right pipe... which may be the case I don't know.

I pulled the right #4 plug wire from the plug and started the bike and reved it and it sounded exactly the way it did with the plug on. I then got a spare plug and put it in the wire and fired up the motor and there was spark. I thought it was then a fuel or valve issue.

I pulled the plug from the cylinder after replacing the plug wire for a moment and running the engine. The plug showed no sign of fouling or flooding... in fact, it looked like a normal plug.

I checked the header pipes for heat and #4 header pipe was hot... as was 3. I didn't touch one or two pipes.

Does it make sense that this could be a fuel issue - if the barbs were not feeding enough fuel to #4 could this cause the lack of pressure out the pipe? it would see to me that the same amount ot air - pretty much... should be coming out whether or not there is an ignition... not as noticeable as it is...

Do mufflers get clogged? Is this a reasonable first place to look?

The bike seems to work fine but there is a definite imbalance in power and exhaust pressure...

I guess what I'm asking is... what is the proper order for troubleshooting here?

 

[Guest]

Check the temp of the pipes at the head.

 

[legaleli]

Check the temp of the pipes at the head.

Is there a special tool for this? I'm new to this!

 

[Guest]

Is there a special tool for this? I'm new to this!

Yeah, your finger..

I use one of these.
http://www.techinstrument.com/acata...Thermometers&gclid=COfDoMK5gqICFQ0hnAodsgInDg

 

[legaleli]

Yeah, your finger..

I use one of these.
http://www.techinstrument.com/acata...Thermometers&gclid=COfDoMK5gqICFQ0hnAodsgInDg

HA!

OK... that was an interesting exercise. I started the bike with my hand on #4 header and ran the bike for about 20-30 seconds. The pipe (which was already warn from my ride) got hot. I stopped the bike.

# 4 was hot
#1 was less hot than #4
#2 and #3 were the least hot of all the pipes - but they were all hot.

 

[Baatfam]

Can't remember if you mentioned it before...

But have you checked/adjusted the valves and have you cleaned and balanced the carbs?

 

[TheCafeKid]

Yeah, your finger..

I use one of these.
http://www.techinstrument.com/acata...Thermometers&gclid=COfDoMK5gqICFQ0hnAodsgInDg

Jesus Octain..

DONT use your finger. The temps of those pipes at the head is well over 1000 degrees. Your finger will be burnt before your brain even registers that it hurts. If you cant find a little digi surface temp thermometer, or dont want to spend the dough, use a spray bottle of water. Those pipes are hot enough at the head that the water will vaporize almost instantly. If one isnt, then its either cooler than the others, or cold. What colour was your plug in #4 anyway? If it was white, or no new colour at all, chances are you may need to richen that carb up a bit. If you've rebuilt your carbs, and set the mixture adjustment screws to 2.5 turns out, that is just a baseline, it may need adjusted in or out depending on whether its rich or lean. Also, to TRULY have the bike sucking and blowing nearly the same on all cylinders, you need to have your carbs synced properly, and your valves should all be adjusted if you havent already done that..

 

[legaleli]

Jesus Octain..

DONT use your finger. The temps of those pipes at the head is well over 1000 degrees. Your finger will be burnt before your brain even registers that it hurts. If you cant find a little digi surface temp thermometer, or dont want to spend the dough, use a spray bottle of water. Those pipes are hot enough at the head that the water will vaporize almost instantly. If one isnt, then its either cooler than the others, or cold. What colour was your plug in #4 anyway? If it was white, or no new colour at all, chances are you may need to richen that carb up a bit. If you've rebuilt your carbs, and set the mixture adjustment screws to 2.5 turns out, that is just a baseline, it may need adjusted in or out depending on whether its rich or lean. Also, to TRULY have the bike sucking and blowing nearly the same on all cylinders, you need to have your carbs synced properly, and your valves should all be adjusted if you havent already done that..

I knew it was going to be hot and was going to make a joke about burning off my fingertip but... I started with the pipes quite cool and just let them warm up to "hot"... as in hot to the touch!

It was my intention to do the carbs next - this bike is totally new to me and there were more immediate issues with the bike... which are now addressed... so it's on to the carbs and the valves.

I have a complete o-ring set from "that guy" who sells them (got the link from this site). What else do I need to do a carb rebuild?

Also, when it comes to mixture... I'm confused about it... the way I read it here there are "2" mixtures; idle mixture and throttle mixture... and they sort of meet somewhere in the middle or something... it's quite confusing... but I think that the screws adjust idle mixture and the jets determine the other... I think...

 

[Guest]

Jesus Octain..

DONT use your finger. The temps of those pipes at the head is well over 1000 degrees. ..

Dude ya dont do it after the bike has been running for hours.
Never touched your pipes?

 

[Guest]

I knew it was going to be hot and was going to make a joke about burning off my fingertip but... I started with the pipes quite cool and just let them warm up to "hot"... as in hot to the touch!

It was my intention to do the carbs next - this bike is totally new to me and there were more immediate issues with the bike... which are now addressed... so it's on to the carbs and the valves.

I have a complete o-ring set from "that guy" who sells them (got the link from this site). What else do I need to do a carb rebuild?

Also, when it comes to mixture... I'm confused about it... the way I read it here there are "2" mixtures; idle mixture and throttle mixture... and they sort of meet somewhere in the middle or something... it's quite confusing... but I think that the screws adjust idle mixture and the jets determine the other... I think...

You have CV carbs so only one adjustment screw. As long as your jetting is correct ya just set em to the highest/best idle.

If you have the orings the only other thing you may need are bowl gaskets. Some dont replace em if they're on good shape but for the money I would, and do.
Dont forget to change those plugs with NEW ones too.

 

[legaleli]

OK... sounds good... from reading other threads |I'll need carb dip and some brushes... I will order the bowl gaskets...

so I:

remove the carbs
taken them apart
clean them
put them back together with the new o-rings
reinstall them
adjust the screws
adjust mixture with my colortune
sync them with my carbtune

then I do the valves...

Am I on the right track?

 

[SqDancerLynn1]

Do the valves FIRST

 

[legaleli]

Do the valves FIRST

I was wondering that...

 

[mike_of_bbg]

Yeah, you have to sync the carbs whenever you adjust the valves.

Hmmm - nobody mentioned buying new pilot jet plugs. They're usually pretty rotten if they haven't been replaced recently.

http://www.z1enterprises.com/detail.aspx?ID=1962

Hey, did anyone notice this?

http://www.z1enterprises.com/SearchResult.aspx?All=True&KeyWords=zsm

Fuel rail, tee, and fuel level gauge tool? OK, the gauge tool is the most interesting of those, since the others rarely go bad. Though I've seem some complaints about the fuel tees since they don't have replaceable o-rings.Nice option, and for $14 does sport replaceable o-rings.

 

[legaleli]

Wow!

OK... do I need to do a FULL job:

FULL O-ring set
1 Fuel Gauge
4 Carb Rubber Passage Plugs??
(are these the pilot jet plugs - doesn't look like it and I searched Z1 for "pilot jet plugs") and came up with nothing.
1 fuel pipe joint
2 fuel rails
4 bowl gaskets
and
carb dip

Right or wrong?

 

[mike_of_bbg]

Unless you have a reason to, there's no need to replace the fuel rails or tees. Your O-ring set will include new O-rings for the fuel rails - can't imagine the actual rails go bad too often! If you're leaking from the tee you could consider a replacement but if not then save your cash. I just pointed them out because I had not noticed them before: not because you need them

Here's where the pilot jet plugs come in (sorry, Z1 is referring to them as "passage plugs" or whatever their proper technical name is):

http://www.thegsresources.com/images/carbs/043_Pilot jet plug pointed out.jpg

You'll see they're right below the pilot jets. The pilot jets are intended to feed fuel out of the main jets, and those plugs ensure that happens.

My ideal "basic carb clean" kit would include Mr. Barr's O-ring kit, intake boot O-rings, the passage plugs, new float bowl gaskets, and maybe a couple extra idle screw washers ('cos they're so small and easy to lose - ask me how I know).

 

[cowboyup3371]

4 Carb Rubber Passage Plugs??
(are these the pilot jet plugs - doesn't look like it and I searched Z1 for "pilot jet plugs") and came up with nothing.[\quote]
Legaleli,
I found them online and at the local shop using carb plugs as my search term just as someone else mentioned to me. Check your local shop's website as they might have the schematics online (mine does). Or you can see my shops website at www.apexsportsinc.com