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Hey guys,
Took my 82' 750k in for a carb tune-up and before they even started they had to put a little work into get the spark an compression back up to snuff. The compression in cylinder 2 is also not as good as the other 3. They say there's a leak and the piston o-rings may need to be replaced at some point an they can't guarantee cleaning the carbs will get it running as good as I am hoping it will. They guessed that if I wanted to get the engine into good shape I'd eventually be looking at $1500 down the road. I paid that much for the bike running and safetied.
I assumed I would have to end up paying $2-3k eventually to get it into decent mechanical shape but don't want to do it all at once. I'm hoping the carb cleaning and sync will make it better for bumming around on for now before I do any cosmetic and body work to it. The thing that confuses me is it only has 17k km on it but then again maybe that was fudged some how. Is it worth it to keep this as a project bike or do you think I could find something in better shape as a starting point?
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Well miles don't mean much. if an engine was beat on badly, it could have bad rings. On the other hand, if it just sat, the rings might just need a good thrashing to loosen up.
Did they was what the actual compression readings were? And how much lower was #2? I mean, if you have 140-150 on 1,3, and 4 but 120 on #2, well that is ok. If #2 was like 60, then you could have an issue.
I would just get the carbs cleaned and synced and then get things tuned. You might find it is just fine after running for a while.
The ride IS the adventure. The destination is just to get gas!
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Thanks for the input, I started to feel stupid for buying the bike after hearing the shop talk about it today :(
I'll ask what the compression readings were. He says the engine is "tired" which is slightly ambiguous but I get that an engine that old won't ever be mint unless it's rebuilt completely. I basically want the bike to be a nice project to make it look beautiful and be good enough to ride on the weekends. It's not like it's a daily driver. On Thursday, October 2, 2014, Re-run [via Honda CB750'S] < [hidden email]> wrote:
Well miles don't mean much. if an engine was beat on badly, it could have bad rings. On the other hand, if it just sat, the rings might just need a good thrashing to loosen up.
Did they was what the actual compression readings were? And how much lower was #2? I mean, if you have 140-150 on 1,3, and 4 but 120 on #2, well that is ok. If #2 was like 60, then you could have an issue.
I would just get the carbs cleaned and synced and then get things tuned. You might find it is just fine after running for a while.
The ride IS the adventure. The destination is just to get gas!
To unsubscribe from Got some unsettling news today. Is my bike worth keeping?, click here.
NAML
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Administrator
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Well, "tired" means nothing without compression figures. I would automatically suspect any shoo that uses words like that with nothing to back them up. You want hard numbers, not vague words. And if #2 is still over 100, it will probably be fine for some time.
The ride IS the adventure. The destination is just to get gas!
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What would I be looking at if it's below 100 or gets there eventually? Rebuilding that cylinder? On Thursday, October 2, 2014, Re-run [via Honda CB750'S] < [hidden email]> wrote:
Well, "tired" means nothing without compression figures. I would automatically suspect any shoo that uses words like that with nothing to back them up. You want hard numbers, not vague words. And if #2 is still over 100, it will probably be fine for some time.
The ride IS the adventure. The destination is just to get gas!
To unsubscribe from Got some unsettling news today. Is my bike worth keeping?, click here.
NAML
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Just got off the phone with the shop. I think he made it sound worse than it is, I don't think this shop has faith in old bikes and I'm going to take it somewhere else in the future. He said in the drop test there were some air leaks. This seems okay to me for the compression test though:
Dry
1 - 100
2 - 105
3 - 100
4 - 100
Wet
1 - 130
2 - 130
3 - 135
4 - 130
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Administrator
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Depends on why it is low. Easy way is to take half a teaspoon of marvel oil and put it into the cylinder hole. Test compression again. If the number stays low, it is the valves. If it goes up, it is the rings. The oil makes a temp seal long enough to test compression quickly.
I would get the exact numbers though before deciding anything else.
The ride IS the adventure. The destination is just to get gas!
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Administrator
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Ok, so he says #2 is lower but it shows the highest on the "dry" test?
I would still go someplace else, or just get yourself a compression tester.
Just get a tester that has a skinny line. Fat lines do not read right since they are made more for engines with higher displacement cylinders. A skinny line delivers a more accurate reading.
And it is odd that all 4 cylinders are that close on both tests.
I could be wrong but those numbers are suspect, at least to me.
The ride IS the adventure. The destination is just to get gas!
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Yeah I'm not going to take it there anymore. I think he's just saying it like this because he doesn't like working on old bikes. Those numbers though, they seem pretty decent for a 30 year old bike that hasn't been driven consistently. Like I don't think there's anything for me to worry about right now. With that in mind, I think once the carbs are cleaned it's going to run alot better than he's saying.
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Administrator
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Engines do NOT wear out and need rebuilt just because they are old. It actually takes use, or mechanical damage to cause an engine to be worn out to the point of needing rebuilt. And 17K is not that many miles for one of these engines. Also I have noticed that it is hard to find an accurate compression tester. I have tried many, and gotten several different readings from the same cylinders. However they were all pretty even across with the readings on the different cylinders, so since all of your cylinders are within 5% of each other, I would not be worried. And if you look in the factory service manual, it says that as long as the cylinders are within 10-15% of each other, they are good.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."
1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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That makes me feel a lot better. Thanks for your input everyone. Are the piston rings something I could do on my own? I've done some work on other types of engines but I've never cracked open a bike engine. On Thursday, October 2, 2014, TOOLS1 [via Honda CB750'S] < [hidden email]> wrote:
Engines do NOT wear out and need rebuilt just because they are old. It actually takes use, or mechanical damage to cause an engine to be worn out to the point of needing rebuilt. And 17K is not that many miles for one of these engines. Also I have noticed that it is hard to find an accurate compression tester. I have tried many, and gotten several different readings from the same cylinders. However they were all pretty even across with the readings on the different cylinders, so since all of your cylinders are within 5% of each other, I would not be worried. And if you look in the factory service manual, it says that as long as the cylinders are within 10-15% of each other, they are good.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
1976 CB 750-A X 2
1977 CB 750-A X 2
1977 CB 750-K X 2
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
To unsubscribe from Got some unsettling news today. Is my bike worth keeping?, click here.
NAML
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Administrator
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You could if you had to, but I would not worry about it if I were you.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."
1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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At what point would I know that the rings are completely shot? For instance, what would happen while riding? Loss of power? Is there danger to the engine if this happened?
- E.T.
"It's not who I am underneath, but what I do that defines me."
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Administrator
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You would gradually lose power while burning oil. That is generally how it goes when rings are bad.
The ride IS the adventure. The destination is just to get gas!
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Administrator
|
When you see blue smoke billowing out the exhaust.
However you seem to be really worried about this, so maybe you should just sell the bike real cheap, maybe to me.  TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."
1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Haha thanks guys. Sorry for the worrysome vibes, been a little stressed lately at work and this added to it :D
You guys are the best! On Thursday, October 2, 2014, TOOLS1 [via Honda CB750'S] < [hidden email]> wrote:
When you see blue smoke billowing out the exhaust.
However you seem to be really worried about this, so maybe you should just sell the bike real cheap, maybe to me.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
1976 CB 750-A X 2
1977 CB 750-A X 2
1977 CB 750-K X 2
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
To unsubscribe from Got some unsettling news today. Is my bike worth keeping?, click here.
NAML
- E.T.
"It's not who I am underneath, but what I do that defines me."
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The numbers look good.
I'd be more worried about the shop.
Seems like they're trying to set your expectations low for how she will run after they attempt to clean the carbs. It can take a lot of time to disassemble, clean, and reassemble those carbs. It's not that hard, DIY'ers do it all the time. It does take a lot of time and often getting things to line up upon reassembly is trial an error, so the carbs go and off the bike more than once.
How much are they charging you? I would expect that someone, who knows what they're getting into, to charge at least $400 to $600 in parts and labor to rebuild a set of DOHC carbs.
89 VN 750A - Given to son-in-law
79 CB 750K-sold 3 May 21
78 CB 750K
77 CB 750K
77 GL 1000 x 2
77 CB 550F
Holton, KS, US
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That's what they're charging me yes. It's pricey but they have a good reputation in the community. I actually spoke to the shop today and got another gentleman on the phone than before, he really explained things a lot better to me and told me he's worked on hundreds of CBs over the years. He said yes they can become aimed sink but after the work they've done the bike should run very nicely compared to when I brought it in. Made me feel a lot better. Either way, bike will be ready early next week and we'll see what happens. I'm most likely going to take it somewhere else and unless anything else goes wrong that I can't do myself I won't need to do anything major mechanically for awhile. On Friday, October 3, 2014, rich [via Honda CB750'S] < [hidden email]> wrote:
The numbers look good.
I'd be more worried about the shop.
Seems like they're trying to set your expectations low for how she will run after they attempt to clean the carbs. It can take a lot of time to disassemble, clean, and reassemble those carbs. It's not that hard, DIY'ers do it all the time. It does take a lot of time and often getting things to line up upon reassembly is trial an error, so the carbs go and off the bike more than once.
How much are they charging you? I would expect that someone, who knows what they're getting into, to charge at least $400 to $600 in parts and labor to rebuild a set of DOHC carbs.
89 VN 750A
79 CB 750K
78 CB 750K
77 CB 750K
77 GL 1000 x 2
77 CB 550F
Holton, KS, US
To unsubscribe from Got some unsettling news today. Is my bike worth keeping?, click here.
NAML
- E.T.
"It's not who I am underneath, but what I do that defines me."
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