Author Topic: problem child (possible breakthrough) (Read 6786 times)

S-Dog · « **on:** August 09, 2007, 07:08:58 AM »

I just had my carbs rebuilt(cleaned and new everything) and also had new plugs put it. I never drove the bike before it was rebuilt but after getting it back I have a backfire coming out of the 1st exhaust pipe. It seems to rev up fin but seems a little choppy when maintaining speed. Is this normal for a 75 k5? From what I have read the 1st cyl might be running a little lean? Any help is appreciated... I want to get this back to the bike shop if this isnt right.

333 · « **Reply #1 on:** August 09, 2007, 07:28:29 AM »

Adjust the valves. Check the timing. What is happening is the exhaust valve is still open when the spark fires. It could be the advancer is sticky also.

S-Dog · « **Reply #2 on:** August 09, 2007, 07:31:45 AM »

I will take a look on how to do that and make an attempt this weekend... thanks.

TwoTired · « **Reply #3 on:** August 09, 2007, 01:28:16 PM »

Quote from: S-Dog on August 09, 2007, 07:08:58 AM

I just had my carbs rebuilt(cleaned and new everything) and also had new plugs put it. I never drove the bike before it was rebuilt but after getting it back I have a backfire coming out of the 1st exhaust pipe. It seems to rev up fin but seems a little choppy when maintaining speed. Is this normal for a 75 k5?

Of course it's not normal. Ask your mech why he thinks it is. See how much more money he wants to fix it.

Cheers,

medic09 · « **Reply #4 on:** August 09, 2007, 02:05:09 PM »

TT, I denote a touch of sarcasm in your post. Are you getting cynical?

andy750 · « **Reply #5 on:** August 09, 2007, 03:18:34 PM »

I think Scott (S-dog) has spent way more than enough money on this bike already and if it was me Id be taking it back to the mechanic and have him sort it out free of charge.....and no its NOT normal for a K5. As 333 says its likely valve clearances or timing.

I agree Medic but I also agree with Llyod on this one....but hey I was mechanically inept at one point in my CB750 life and Ive managed to learn a few things along the way so now Im only marginall inept

....get a manual/service book Scott and get learning and ask lots of questions here. You`ll soon find great satisfaction in not having to spend any more money on getting your bike serviced and doing it yourself instead.

good luck,
Andy

TwoTired · « **Reply #6 on:** August 09, 2007, 04:11:37 PM »

Quote from: medic09 on August 09, 2007, 02:05:09 PM

TT, I denote a touch of sarcasm in your post. Are you getting cynical?

No no. I've been cynical for a long long time.

If his mech is decent and honest, he'll deal with it with minimum hassle.
However, far too many mechanics believe that their primary job function is to extract as much money from a customer's wallet as they can. They often find other things to fix during a "return complaint" in order to be paid for correcting their previous incomplete repair.
I think it is a counter response to customers that try to get something for nothing. It then becomes a fact that some customers take and some customers give. They stay in business and prosper when they have more customers give than take.

Don't you remember the 60 minutes sting a few years back? They took a perfectly good car into a full service station for a fill up, then walked to the restroom. The hidden camera then captured the attendant with an oil squirter duck under the suspension of the car. When back from the rest room, the attendant courteously pointed out oil drips. Lo and behold the shocks were leaking, and they could just fit the repair into their busy schedule. Further surprise, they happen to have the shocks in stock, only will only take a half hour and the car will be as good as new! Why is this? Cash flow!

I've had shops try and get me to pay for replacing all the ball joints in my car "discovering" them worn beyond limits during tire replacement. I knew the wear limits were .250 In from reading the service manual. They showed about .125, and claimed nearly all the Mustangs that came in were worn out, "very common problem" they say. I quote actual wear limits and they get indignant, claiming their experience is far superior to my own, no, they will NOT show me the actual wear limit specification. Saved myself a bunch of money with that knowledge and learned that place had either incompetent or thieving personnel. Another shop doing the front end alignment confirmed all was fine with the car. And then, shook their head about the tire shop diagnosis.

Electrical issues are even worse, batteries, regulators, and alternators changed all at once when only one of them was bad.

Go ahead, call me a cynic. Conspiracy theories exist because sometimes, it's not just a theory.

It will be interesting to learn what kind of mech S-Dog is dealing with.

Cheers,

S-Dog · « **Reply #7 on:** August 09, 2007, 06:16:46 PM »

I was kidding when I asked if thats how it should run..... I think I know what kind of mechanic he is..... but he is the only one in the area who fixes old bikes. I really wish I found this site 2 weeks ago... I am going to give him a call tomorrow and see how it goes. He did say that my electric start was not working properly and I figured out that he was not putting the bike in neutral

.... I will update tomorrow.

As a side note I put about 250 miles on the bike today and rode with my dad for the first time..... just awesome... now if I can just get this small issue fixed I will be all good.

gaustin · « **Reply #8 on:** August 09, 2007, 09:56:46 PM »

I'm not sure if this is the right thread but I'm getting the exhaust to backfire constantly when ever I let off the gas, even ever so slightly? Could this be a carb issue? Or and exhaust issue since I just about knocked out all the baffling I possible could?

S-Dog · « **Reply #9 on:** August 10, 2007, 12:52:03 PM »

here's the update. I just talked with the mechanic and he said it was a sticky valve from sitting. The bike has no issues with power when accelerating but is noticeably hunting when keeping a steady speed.

As a side not it is also leaking a bit of gas. I asked him about this and he said it is normal for the jets to leak a little because of the pressure of the gas above it with the petcock open. I think it might be leaking with it closed too but now I am not sure if I was just putting it on reserve.

Any thoughts would be fantastic.

andy750 · « **Reply #10 on:** August 10, 2007, 01:10:32 PM »

Get a refund! ;-)

No but seriously....more info required on the leaking gas...where is it leaking from? Carb bowl gaskets? Overflow tubes? petcock? Freshly rebuilt carbs with $125 carb kits should NOT leak gas!!! I can leave my petcock on all day and it wont leak gas. This is NOT normal.

Ill leave the "sticky valve" to someone else as Im not sure.

cheers
Andy

S-Dog · « **Reply #11 on:** August 10, 2007, 01:19:36 PM »

I will have to a little more digging to find out where the leak is coming from exactly...

TwoTired · « **Reply #12 on:** August 10, 2007, 02:41:30 PM »

If you're the only game in town, you can get away with a lot.

Sticky valves? What valves? Intake and exhaust? Compression test will determine that. And, there should be some change in behavior after 250 miles.

Sticky carb float valves? That should be (have been) addressed during the carb rebuild. Leaking gas from the carbs? Again a carb rebuild issue. Could be many things including a float issue. Note exactly where the carbs are leaking from.

The jets are not exposed to the outside environment. Even if they did leak, the fuel would stay inside the carb. The main float valve works against the pressure of the fuel in the tank. When the bowl fills, the float rises and closes this valve. That's its job to maintain constant level in the carb despite the pressure of the tank contents.

Do a compression test, and if the numbers are within 10% across the cylinders, then the carbs need to be addressed. If you didn't get some kind of warranty from your mech, or he won't honor the one he provided, then cut your losses and fix it yourself. And, remember your mech's actions the next time you need work on your bike. See if you can get parts through him at a discount. If not, then don't worry about remaining amicable with him. It's starting to sound like he's playing you.

Cheers,

333 · « **Reply #13 on:** August 10, 2007, 03:04:24 PM »

I can believe the sticky valve story, but I'm with Andy on the carbs. A fresh rebuild with new parts should not leak at all.

edbikerii · « **Reply #14 on:** August 10, 2007, 06:32:18 PM »

Ain't no excuse for a leaky $700 carb rebuild. He didn't even try to rectify the leak for you?

S-Dog · « **Reply #15 on:** August 10, 2007, 09:44:10 PM »

I called hime today and he said that it was normal..... I will have to give him a call again or stop by and tell him what is up.

I am guessing I wouldd need some sort of compression tester....

andy750 · « **Reply #16 on:** August 11, 2007, 05:13:16 AM »

Scott,
I dont think you mechanic is very good. First he rips you off over the price of a carb rebuild. Second its NOT normal for carbs to leak gas or valves to stick. Why would this be normal? Is there a benefit for flammable liquid to leak all over your bike? No of course not. Bottom line is he messed up the expensive carb rebuild and he dosent want to fix it. If I were you Id ask for a partial refund unless he can fix the problem.

Ive had a couple of carb rebuilds over the years and none ever leaked any gas. Why? Because the carb rebuild were done right.

I really hope you get this sorted out.

good luck,
Andy

dustyc · « **Reply #17 on:** August 11, 2007, 11:42:36 AM »

Quote from: edbikerii on August 10, 2007, 06:32:18 PM

Ain't no excuse for a leaky $700 carb rebuild. He didn't even try to rectify the leak for you?

Where did the $700 figure come from? I didn't see a price attached.

Quote from: andy750 on August 10, 2007, 01:10:32 PM

Freshly rebuilt carbs with $125 carb kits should NOT leak gas!!! I can leave my petcock on all day and it wont leak gas. This is NOT normal.

Or $125... How much did you pay for this S-Dog? That will give us an idea of what to expect from the mechanic. Was it a carb cleaning? Or a partial rebuild? None of this is normal operation. I leave my petcock on all the time with zero leaking.

The hunting and backfire says a full tune-up is in order.

If this is your only transportation, find a GOOD mechanic. This guy sounds like a hack, but that really depends on what was expected from the job. If you paid 50 bucks and said you wanted it to run, that's a different story.

If you have another vehicle, sink your money into tools and start learning to be your own mechanic. You will be way better off if you can do it yourself. If you did indeed spend $700 on getting your carbs rebuilt, you could have spent that on tools and had everything you need(for normal repair and maintenance) and a couple tools that aren't necessary, but make life easier.

edbikerii · « **Reply #18 on:** August 11, 2007, 12:02:09 PM »

Quote from different thread:

Quote from: S-Dog on August 09, 2007, 12:46:11 PM

champion motorsports in woonsocket RI.... it was 700 for the carb rebuild and 300 for the rebuild of the front brake...

It is still not running perfect... I have a mild backfire in the first cylinder.

Also note that my response was very similar to yours, dustyc:

Quote from: edbikerii on August 09, 2007, 04:03:48 PM

Holy COW!!!!!! $700!!!!!! Holy COW!!!!!!

I'm sorry. I'm just shocked. $700 for a carb rebuild? Lets assume the rebuild kits cost $25 each. That's $600 in labor!!!! HOLY COW!!!!!

Dude, these old bikes require frequent maintenance and repair. Until you get it back into tip-top shape, you're going to be spending an AWFUL amount of money going with mechanics like that.

At those prices you should either getcher self a new(er) bike, or seriously start reading up, asking for help here, and rolling up your sleeves. $700 could have easily bought a lifetime's supply of metric tools to work on it too. Damn.

Good luck, man. And don't be afriad to ask for help around here. We love to help. Heck, even just reading the FAQs is a serious education!

dustyc · « **Reply #19 on:** August 11, 2007, 12:33:03 PM »

Great minds think alike eh? Man, my rear end hurts in sympathy.

S-Dog. That guy saw you coming man. If you can get him to make it right, that's great, but that's 50/50 depending on what kind of guy he is and I think that he's already shown that. If you can't get him to make it right, think of it as a good lesson. I've had lessons that cost more, so it's not the end of the world.

Alot of cases like this are of people not knowing what to expect and they complain because they were cheap going in, but you paid a premium price and should have received premium service.

S-Dog · « **Reply #20 on:** August 11, 2007, 12:46:07 PM »

I fully understood that he was going to be a little more expensive(not as much as it seems that I was overcharged now). I had someone else fix it because the riding year is short and I want to get riding PLUS the deal I had with the PO was 1k minus fixing costs... Luckily its my longtime friend who sold me the bike and I pretty much got the bike for just these repair costs.

In all it looks like he is giving me the good ole shaftaroo... It is not backfiring now but has no decent power until about 3500rpm and even then it is less than it was 2 days ago. I will give him another call on Monday and see if he will make it right. I am not holding my breath and will probably end up having to tear into it next weekend or maybe even tomorrow.

I am guessing I could look at the plugs right now after about 350 miles after the "rebuild" and see if there is any funny coloring. If cylinder 1 is different from the others I prolly have something to work with.

S-Dog · « **Reply #21 on:** August 12, 2007, 05:39:45 AM »

Will the plugs tell me where to start looking?

jdpas29 · « **Reply #22 on:** August 12, 2007, 05:59:37 AM »

i'm not sure if you've done it yet or not... but you need to do all the parts of a tune up excluding the carbs and see how it runs.

S-Dog · « **Reply #23 on:** August 12, 2007, 06:10:26 AM »

S-Dog · « **Reply #24 on:** August 12, 2007, 01:39:59 PM »

I took out 3 of the 4 plugs to look at what kind of condition they were in. plug 1 is wet and sooty. plug 3 look perfect(medium grey, looks right), and plug 4 its blackish but not horrible. I also found that the mechanic put in NKG dr8ea plugs in it. From what I have read this is probably the wrong plug to run. I think I should swap them out with d7ea plugs or similar. Does that sound right?

I also looked at the boot that connects the head to the carbs and it is in great condition.

I found where the leaks(yes leaks) are coming from... It looks like the carb bowl gasket for cyl 1(also the wet plug) and the T that connect the gas between carbs 1&2 and 3&4.

News:

Author Topic: problem child (possible breakthrough) (Read 6786 times)

gaustin