Bike Engine Rebuilt, Now Kick-Start Doesn't 'connect'

[ClareQuilty]

Alas I have to report continued troubles with the old Yamaha Fresh. I took it back to the mechanic who had rebuilt it, and he did quite a lot of adjusting, at no charge. The bike ran slightly differently when I left, but the same problems returned just as bad - after the bike is warmed up a little, it begins to jerk and buck, and will even occasionally die, including while driving at speed, though mostly when one is beginning to slow down a bit from higher speeds (don't get me wrong, not high speeds, its just a 60 km/hour kind of runabout).

I've no idea what it could be. Seems to be bad trouble in side the engine, varous bad noises coming out. But, it still runs, and it will run normally at times.. at any rate when first started until warm.

Guess I should've passed on buying this one and found another old two-stroke Don't seem to have any luck with these old four-strokes.

[Turkleton]

I've no idea what it could be. Seems to be bad trouble in side the engine, varous bad noises coming out. But, it still runs, and it will run normally at times

Some people, including me, made suggestions to solve your problem. But no feedback from your side...

Anyway, do you think, it's a good idea to ride the bike, even it is noisy and runs crappy when warm?

What do you expect? A self-healing?

Guess I should've passed on buying this one and found another old two-stroke Don't seem to have any luck with these old four-strokes.

Defintely, this is the solution. Switch a old 4-stroke to an older 2-stroke. OMG

This has nothing to be with "luck", but with incompetent somchai's and ridiculously "2000 Baht engine rebuilds" ()

With a well-done engine-rebuild, your bike's engine would run "like new"

Stop whining and look for another, less incompetent somchai "mechanic". (If available)

Than open the engine and look what the problems are!

Unfortunately the crystal-ball is broken and "black magic" won't help.....

[VocalNeal]

Oops thought it is 2-T but it isn't. I was thinking spark plug but 4 strokes are more forgiving but it might be worth checking to see if is the correct one. I think it is the same as a Crypton so NGK CR7HSA.

Otherwise it could be a sticky valve. As has been said put a little oil in the fuel tank and run it through.

Edited December 8, 2012 by VocalNeal

[BirdsandBooze]

There are many possibilities and if Somchai is worth his salt he'll do what most people do and go through the process of elimination to find the fault. If your timing is out you can get all sorts of horrendous noises coming from the engine. I'd also check to see if your 'mechanic' fitted the correct spark splug; if it's too hot you will get pre ignition accompanied by knocking; try a colder plug. It could also be your voltager regulator breaking down when hot. Somchai should know these things and take the appropriate action to remedy the fault.

[Turkleton]

^^

I agree, but it seems, after reading the OP's posts, he is only interested in a "Small-Baht solution" (aka Black-Magic).

Any suggestions, that would cost more than a "change the spark-plug", seems to be ignored by the OP...maybe I am wrong....maybe not!

At least, he bought an old and crappy bike, brought it to an incompetent somchai, who did a crappy "2K engine-rebuilt", after that something "didn't connect" and somchai made a few "adjustments", because of the crappy running engine....

What did you expect: You get what you paid for....Som nam na...

Edited December 8, 2012 by Turkleton

[yankee99]

sometimes i am not sure tv gives the best advice although some is good. Proper troubleshooting would be better then guessing and parts replacing. Get a compression test and check for vacum leaks. Then please post the results.

[Turkleton]

Proper troubleshooting would be better then guessing and parts replacing.

Absolutely correct!

But this assumes a competent mechanic and not the "usual somchai" next door...

[BSJ]

This is extraordinary! Maybe this person that did the rebuild is in fact an imposter! Not a motor mechanic at all. Check his credentials and ensure that he has been to a trade school. It maybe he normally only fixes tyres and supplies benzene in old whisky bottles.

And demand your money back.

[noob7]

There are many possibilities and if Somchai is worth his salt he'll do what most people do and go through the process of elimination to find the fault. If your timing is out you can get all sorts of horrendous noises coming from the engine. I'd also check to see if your 'mechanic' fitted the correct spark splug; if it's too hot you will get pre ignition accompanied by knocking; try a colder plug. It could also be your voltager regulator breaking down when hot. Somchai should know these things and take the appropriate action to remedy the fault.

Most of 'em not even knowing, that for the Honda wave/dream, in the owner manual are 2 types of spark plugs named!

The '6', as standard and for the 'slower' usage, the '7' for the people, speeding a bit more.

Don't hold your breath, as long it comes to 'unneeded' details!

[ClareQuilty]

Oops thought it is 2-T but it isn't. I was thinking spark plug but 4 strokes are more forgiving but it might be worth checking to see if is the correct one. I think it is the same as a Crypton so NGK CR7HSA.

Otherwise it could be a sticky valve. As has been said put a little oil in the fuel tank and run it through.

Yeah it is just a little 100 cc four stroke - which is why the engine rebuild was so expensive. I guess you could be right about the valve.. or could be timing..

Turkleton, how can you criticize an engine rebuild for being too cheap when it cost 2,000 baht? A two stroke rebuild usually costs me 1000,or in rare cases 1500. Why would a little 100cc motor cost more than two grand? there';s very little to these small bikes, so I'm not sure what prices you imagine would be 'correct'. The brand new piston out of the box costs like 380 baht or so from the parts supplier..

Anyway, I've given the bike back to the mechanic (please refrain from the offensive quasi-racist 'Somchai' baiting), as I'm away for a week, so he'll have a chance to work with it and drive it around a while. I've a lot of confidence he'll try his best to figure it out and probably at little or no charge, as to both he and I 2,000 baht (my original payment, plus another 480 for the clutch) is a big investment.

Edited December 9, 2012 by ClareQuilty

[Turkleton]

The brand new piston out of the box costs like 380 baht or so from the parts supplier..

Oversize piston? (sure he really replaced the piston?)

And what's about the cylinder-bore, is it rebored or just honed....?

The cylinder-head?

The gaskets?

The oil?

The valves?

The valve seats?

The valve-seals?

The timing-chain?

The chain tensioner?

The "work"

and at least.....the skills of your "mechanic"? (something didn't connect, some adjustments, engine runs noisy, when warm....)

wake up....

[Lickey]

Alas I have to report continued troubles with the old Yamaha Fresh. I took it back to the mechanic who had rebuilt it, and he did quite a lot of adjusting, at no charge. The bike ran slightly differently when I left, but the same problems returned just as bad - after the bike is warmed up a little, it begins to jerk and buck, and will even occasionally die, including while driving at speed, though mostly when one is beginning to slow down a bit from higher speeds (don't get me wrong, not high speeds, its just a 60 km/hour kind of runabout).

I've no idea what it could be. Seems to be bad trouble in side the engine, varous bad noises coming out. But, it still runs, and it will run normally at times.. at any rate when first started until warm.

Guess I should've passed on buying this one and found another old two-stroke Don't seem to have any luck with these old four-strokes.

Just caught up with your posts CQ, What you are describing sounds like a gummed up main jet in the carb, this will cause "pinking" pre-detonation of fuel and bang and popping from the exaust on closed throttle when slowing down,

I see you are away for a week or so, but try to contact mechanic and tell him to overhaul/clean carb..

[BSJ]

Next time you buy a bike, change your mechanix! Don't think about it, just do it!!!

[ClareQuilty]

Just caught up with your posts CQ, What you are describing sounds like a gummed up main jet in the carb, this will cause "pinking" pre-detonation of fuel and bang and popping from the exaust on closed throttle when slowing down,

I see you are away for a week or so, but try to contact mechanic and tell him to overhaul/clean carb..

Thanks Lickey. It isn't a bang from the exhaust, or pinging, more like a death rattle from within the engine. At first it made me think it was totally ruined, but after the first few times, it always ran ok again for the first few minutes after a cold start the next day. Whatever it is, the sounds are from the engine itself, right under my feet, not the exhaust or out the back. And as it makes the noises, it loses power and then jerks back on again.. but eventually after a few minutes of this it dies out completely for a while.

Anyway as you say I'm out of town, and he's got the bike back for a full week.. we'll see what he makes of it. Hope he doens't charge anything much, because by now I've far more in the bike than its worth (approaching the 10k mark!).

Edited December 12, 2012 by ClareQuilty

[yankee99]

Alas I have to report continued troubles with the old Yamaha Fresh. I took it back to the mechanic who had rebuilt it, and he did quite a lot of adjusting, at no charge. The bike ran slightly differently when I left, but the same problems returned just as bad - after the bike is warmed up a little, it begins to jerk and buck, and will even occasionally die, including while driving at speed, though mostly when one is beginning to slow down a bit from higher speeds (don't get me wrong, not high speeds, its just a 60 km/hour kind of runabout).

I've no idea what it could be. Seems to be bad trouble in side the engine, varous bad noises coming out. But, it still runs, and it will run normally at times.. at any rate when first started until warm.

Guess I should've passed on buying this one and found another old two-stroke Don't seem to have any luck with these old four-strokes.

Just caught up with your posts CQ, What you are describing sounds like a gummed up main jet in the carb, this will cause "pinking" pre-detonation of fuel and bang and popping from the exaust on closed throttle when slowing down,

I see you are away for a week or so, but try to contact mechanic and tell him to overhaul/clean carb..

Sad to say your advice is no better then these mechanics that just guess and do unneeded work. I am sure if we just clean and replace everything the problem might get solved/

[Lickey]

QC, thats a bit more info for us mechanics to digest,

Although it might have something to do with the engine being warm, i wonder if your mechanic checked the clutch drive cogs ect, from what you describe it could be grating teeth in the drive line somewhere, Alloy castings expand a lot when warm,

Also it would not hurt to check the carb, when its warming up on choke its getting a rich mixture, when the choke is off, it could be getting a lean mixture and overheat, there is also the possibillity of a piece of crap in the float bowl that gets sucked up to the main jet now and then.

Does it have a oil pressured or sprung loaded cam chain tensioner? with the oil pressurred types if the pressurres is low, chain will rattle, spring types are normally ok, unless the spring breaks, this would be very noisy all the time perhaps below 2000rpm.

Theres some new ideas for you, you dont have to take heed, as said in the previous post i know nothing about engines!!!

Edited December 13, 2012 by Lickey

[BirdsandBooze]

What was the bike running like before the 'rebuild'? It sounds like your spanner man has made the bike worse with his fiddling. Maybe you could ask one of those retired foreign gentlemen or a fellow teacher in your locality if they know of a recommended mechanic, because I can't see your present one resolving the issues and you'll continue throwing good money after bad.

Edited December 14, 2012 by BirdsandBooze

[BSJ]

QC's previous mechanic was a wize! She never posted on here until she decided to go to a new mechanic!

[ClareQuilty]

What was the bike running like before the 'rebuild'? It sounds like your spanner man has made the bike worse with his fiddling. Maybe you could ask one of those retired foreign gentlemen or a fellow teacher in your locality if they know of a recommended mechanic, because I can't see your present one resolving the issues and you'll continue throwing good money after bad.

It was running ok but smoked terribly, however it was already developing a kind of bucking or jerking phenomenon at times. So far he hasn't really charged much for subsequent visits - I think he feels an obligation to fix whatever he may have done wrong.

Anyway its the same mechanic I've always used for all my rebuilds. Maybe he's only good at two strokes. I'll try another one next time, if there's a next time.

[ClareQuilty]

Ah, alas I just picked up the bike today, and the guy said he could do no more for it. However he had diagnosed the problem - it is the 'lower end' or 'bottom end' of the motor. I think they call it the crankshaft or crankcase, or possibly the wrist-pin. Its the thing that transfers the up-and-down motion of the piston to the rotating motion of the drive-shaft.

He said this would be 2,000 baht to replace, which I thought was far too much to spring for (throwing good money after bad as they say). He did say he thought the bike could still be used as-is, but I think it is pretty marginal and perhaps quite unsafe. Not sure what to do with a bike like this.. are there salvagers who might pay a few baht for something like that?

[BirdsandBooze]

Ah, alas I just picked up the bike today, and the guy said he could do no more for it. However he had diagnosed the problem - it is the 'lower end' or 'bottom end' of the motor. I think they call it the crankshaft or crankcase, or possibly the wrist-pin. Its the thing that transfers the up-and-down motion of the piston to the rotating motion of the drive-shaft.

He said this would be 2,000 baht to replace, which I thought was far too much to spring for (throwing good money after bad as they say). He did say he thought the bike could still be used as-is, but I think it is pretty marginal and perhaps quite unsafe. Not sure what to do with a bike like this.. are there salvagers who might pay a few baht for something like that?

Did he strip the engine down to diagnose the noise? He might just be guessing that the big end bearing is worn. The only things I can think of that would cause this so soon after a rebuild are lack of oil or he raised the compression ratio by using a high comp piston or a thinner head gasket. Why not visit a few back street mechanics and see if they'll buy it off you for spares.

[ClareQuilty]

The rebuild didn't touch the lower end of the engine - just the piston/rings, etc. I guess the previous owner ran the bike without oil, which not only wore down the rings, causing it to smoke heavily (though it still ran well) - the reason I took it to be rebuilt in the first place. This same running without oil apparently damaged the bearing/ping/crankshaft, whatever that is. I've no idea if he took it apart while he had it to make this diagnosis, but I doubt it - there was again no charge for the attempt.

[BirdsandBooze]

If the bottom end was already worn a top end rebuild would have restored compression which would have put the weak components under stress. Have you got any storage facilities? If you can afford to keep it, it might be an idea to dismantle it and keep the useable parts as spares in case you get a similar model. As you've indicated that you are on a tight budget I don't think it's worth putting any more money into it. Sell or keep for spares.

[ClareQuilty]

So far I've been loaning the bike to a fellow who mostly uses it for quite short trips, and it is working for that purpose. But for anything above about 5-6 kilometers, it starts knocking again and that's that - has to rest for 10 minutes or so before going on. Guess its a lost cause.

[Lickey]

CQ, next time you buy an old bike, start it, let it warm up a bit, rev it a little to clear the engine ect, then put the front wheel against a wall, rev it a bit in gear[or auto] and listen to the engine, Has the note changed? is there knocking noises under load? if so avoid it !!!

[BSJ]

Don't despair Clare when your Yamaha ain't firing there,

give it to Jack who will turn it back into something of use to us all.

[ClareQuilty]

CQ, next time you buy an old bike, start it, let it warm up a bit, rev it a little to clear the engine ect, then put the front wheel against a wall, rev it a bit in gear[or auto] and listen to the engine, Has the note changed? is there knocking noises under load? if so avoid it !!!

Thanks for the tip, Lickey! That's a great piece of advice.