Small, one cylinder motorbike engines--how long before rebuild required?

[heybruce]

How long are small motorbike engines good for before they require a rebuild?  I know the answer is "It depends...." but can someone give me an idea?

 

I've only owned one motorbike, and I've had it for eleven years.  It's a 150 cc Suzuki Raider, it's been used almost entirely for  moderately aggressive city riding, and I've kept up on maintenance but have my doubts about the competence of the mechanics at the dealership.  It now has 44K kilometers and doesn't have the pep or fuel economy it once did.  I've had a tune-up and everything runs fine, just less power and fuel economy is much worse than when new.  I know 44K is nothing for a modern car engine, but don't know about these little one cylinder engines.  Is it time for an engine rebuild?

 

My lady friend wants me to get rid of the Raider and buy something newer and more fashionable, but I like my little six speed clutch bike.  I'm willing to pay for an engine rebuild, but don't want to do it if it isn't necessary.

[CMKiwi]

44k is very low for a bike thats 11 years old.  If as you say you have kept up with the maintanence ie oil and filter changes, plus checked plugs and timing etc then it should be all ok.

 

If the bike is starting to blow smoke, the rings may need changing.  A lack or drop of power could be many things...dirty air filter, blocked fuel filter, worn rings to name a few.  If your bike has a carburetor maybe the jets need cleaning and or replacing.  Like most things...they do slow down with age!

 

You mentioned that you are not sure about the competence of your current mechanic... well Id ask around and change the mechanic to start with.  Then detail your concerns to the new mechanic and ask him/her what they can do.  A lot of the time it is trial and error in Thailand, once you've secured a good mechanic a lot of problems disappear.

 

Naturally economics also come into the equation....why fix something (Apart for nostelgia purposes) when replacing it with new works out cheaper.

 

Sorry if this isnt much help....but maybe its a start

[papa al]

Keep the Laider.

Good Pattaya shop did my cbr150: rings, piston, bore for about B2500.

 

[AllanB]

7 hours ago, papa al said:

Keep the Laider.

Good Pattaya shop did my cbr150: rings, piston, bore for about B2500.

 

I agree, new stuff is boring. If you find a good mechanic you will have a nice bike for little money, B2500 is cheap. A few more years and you will have a classic.

 

I know Papa rags the crap of his bikes, so if his mechanic can get them back to normal, I would use him.

 

I am buying a new CRF, but absolutely plan on getting my old Honda Shadow back to full health, when (if) the rain stops.

 

Just because it is old doesn't mean it hasn't still "got it", well that's what I tell the girls anyway.

[VocalNeal]

Heybruce

 

Bung some fuel conditioner/carb cleaner from Tesco in the tank and give it a run through. Change the spark plug and see what happens. 

 

44k is nothing. if the oil has been changed according to plan. 

 

11 years old? Might be worth a new carburetor with ethanol in fuel and all.

 

 

 

Edited October 19, 2017 by VocalNeal

[heybruce]

Thanks for all the replies. 

 

I stopped going to the Suzuki dealership about a year ago and took the bike to a Thai mechanic recommended by friends.  He's the kind of mechanic that learned on the job through decades of working on motorbikes; since the old Suzuki has the old design (carburetor, kick starter, etc.) he seems like a good bet.

 

He has replaced all filters and the spark plug and disassembled and cleaned the carburetor, and the bike runs much better now; but I have the drop in power and fuel economy described above.  I've also run a fuel cleaner through a couple of tanks of gas, that also seems to clear up temporary problems with starting and periods of rough engine running, but not the power and fuel issues.  The next time I take the bike in for maintenance I will ask that the tank be emptied and cleaned--the bike runs roughest when the fuel tank is low, which leads me to think their may be some contamination that accumulated in the tank and floats at the top of the fuel.

 

The mechanic says it needs a new carburetor and that an engine rebuild might be necessary but I'm not sure if he means now or eventually.  The language barrier keeps me from getting details.  His desire to save money is part of the problem, he thinks Suzuki charges too much for a new carburetor but can't find a good condition used carburetor.  Part of the reason for my question is to determine if I should ask for a new carburetor and engine rebuild at the same time, or just the new carburetor.

 

I don't know what a carburetor would cost, I can't find the information online and I'm afraid if I go through the local Suzuki dealership they would add a big surcharge.  An engine rebuild would cost less than a twentieth of what a new bike would cost, so economically it makes sense to use the bike a like for as long as possible.

[thaiguzzi]

I believe they have 4V heads and DOHC? Valve shim adjustments never checked in 44k kms?

[canthai55]

If you want to know for sure perform a cylinder leakdown test. Can't / Won't invest, or know anyone who can do it for you ? Wet and dry compression test can also provide results.

[heybruce]

I think the valves were checked and adjusted during the last engine check, but will verify.

 

I'll look into the cylinder leak test before making a decision on the rebuild.

 

It seems that 44k is not that much on this type of engine, so I suspect I have some kind of fuel/carburetor problem.

[AllanB]

1 hour ago, heybruce said:

I think the valves were checked and adjusted during the last engine check, but will verify.

 

I'll look into the cylinder leak test before making a decision on the rebuild.

 

It seems that 44k is not that much on this type of engine, so I suspect I have some kind of fuel/carburetor problem.

Not necessarily, some people manage to wear an engine out in a few thousand kms, you said that it had been ridden hard and this bike is air cooled, in a very hot country... 

 

It is one of the most powerful bikes in it's category, hence the oil cooler, but that still means more wear when it is pushed. Add to that it is not Jap built, perhaps built to a price, so it's a bit of an unknown.

 

A simple compression test will show a lot, look at the plug for carb settings. then If not up to spec new rings, or rebore if necessary, head recon and carb recon. How hard can it be, pointless having a low performing high performance bike?

[canthai55]

The days of reading fuel mixture by reading the color of spark plugs ended with the advent of unleaded fuel. If you have a lighted magnifier you may be able to see the very top of the ceramic insulator where it passes thru the steel hex. But not enuf to give a reliable indicator. Best you can hope for without installing a wide band O2 sensor is to adjust the carb - provided it is not worn out - to factory specs. If equipped, adjust the needle - if equipped - which controls fuel mixture from 1/4 to 3/4 throttle - up until the bike bogs. Then adjust it one down. About all you can do. Stand alone O2 sensors are available.

[papa al]

papa roved his old Laider.

Too roud tho.

 

[AllanB]

2 hours ago, canthai55 said:

The days of reading fuel mixture by reading the color of spark plugs ended with the advent of unleaded fuel. If you have a lighted magnifier you may be able to see the very top of the ceramic insulator where it passes thru the steel hex. But not enuf to give a reliable indicator. Best you can hope for without installing a wide band O2 sensor is to adjust the carb - provided it is not worn out - to factory specs. If equipped, adjust the needle - if equipped - which controls fuel mixture from 1/4 to 3/4 throttle - up until the bike bogs. Then adjust it one down. About all you can do. Stand alone O2 sensors are available.

I think you have been misinformed, why would the absence of lead make any difference to plug deposits?

 

Lead disappeared from fuel many decades ago and people are still advocating this method today.

https://www.tuningmatters.com/how-tos/beginners-guides/check-spark-plug-correct-carburetor-setting/

 

I would have thought a stand alone O2 sensor was a bit of an overkill, you could get the whole engine refurbished for the cost, that is assuming you could find one in Thailand, which I doubt.

Edited October 21, 2017 by AllanB

[johng]

On 21/10/2017 at 12:52 AM, papa al said:

papa roved his old Laider.

Too roud tho.

 

shouldn't have shoved a  metal spike up the muffler and hit with large hammer then

 

to the original poster maybe the clutch is slipping  if you

( or someone) put the "wrong" oil in the transmission it can be too slippery.   oil needs to be API SG.. no higher than G   or JASO MA

SAE 40

[heybruce]

10 hours ago, johng said:

shouldn't have shoved a  metal spike up the muffler and hit with large hammer then

 

to the original poster maybe the clutch is slipping  if you

( or someone) put the "wrong" oil in the transmission it can be too slippery.   oil needs to be API SG.. no higher than G   or JASO MA

SAE 40

I'm pretty sure I'd recognize a slipping clutch, I've experienced them with cars. 

 

My fuel economy is now 16 km/liter, about half of when the bike was new.  I'm still not sure if I need a new carburetor, an engine rebuild, or both.

[AllanB]

Don't you have a local mechanic you can trust, he can start with a simple compression test and check the plug and oil, plus filters. It is more likely you can refurb the carb, a good clean and new set of jets.

 

You don't want to complicate this or buy anything you may not need. Keep it simple.

 

You don'y necessarily need a heart transplant, if it just wind.

Edited October 31, 2017 by AllanB

[heybruce]

50 minutes ago, AllanB said:

Don't you have a local mechanic you can trust, he can start with a simple compression test and check the plug and oil, plus filters. It is more likely you can refurb the carb, a good clean and new set of jets.

 

You don't want to complicate this or buy anything you may not need. Keep it simple.

 

You don'y necessarily need a heart transplant, if it just wind.

I have to rely on the recommendation of friends, who guided me to an experienced jack-of-all-trades mechanic.  Unfortunately I don't think he has anything beyond basic tools.  He did all the basic tune-up things, plus disassembled, cleaned and re-assembled the carburetor.  He said I still have a carburetor problem but the language barrier prevented me from getting details.  He also mentioned a rebuild as an option, though I'm not sure if it's urgent. 

 

I've lost all trust and faith in the local Suzuki dealer, which seems much more interested in selling bikes than hiring qualified mechanics for its shop.