Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - Thoppa

Pages: 1 [2] 3 4 ... 11
General Discussion / Re: Maxsym 400i
« on: June 05, 2021, 05:34:26 AM »

Welcome to the forum!

What are you planning to use the scooter for - urban rides? commuting? long distances? How much does gas cost where you are? I'm asking because I'm a fan of the 300s - an ideal compromise imo, unless gas is very cheap where you are.

all the best,

General Discussion / Re: Changing cylinders - anyone done it?
« on: June 04, 2021, 08:12:10 PM »
One month later... and still no leaks or problems of any kind. :-)

The ring replacement has restored engine power so the top speed is very similar to what it used to be as a low mileage machine. The engine is noticeably smoother and quieter. So far, she is not using much, if any, oil so I guess no top up will be needed between changes. The fuel economy is almost back to normal too - she was as low as 28km/l before the new rings, and now is a little over 30km/l so far, instead of the long-term average of 32km/l. I've been giving her more WOT than I used to - perhaps the camshaft has affected the bottom end power so I'm more inclined to give her lots of gas. Not sure.

Anyway, the ring replacement is a success - it's done a good job of renovating the worn engine. I wonder for how long...


It's the lack of a mechanical drawings for the forks, in the service manuals or the parts fische, that I find annoying. I was just left to guess and try, and you are in the same situation. When I contacted the dealer, they didn't even know if seals were available - they wanted to sell me a complete fork "cushion". It's not that expensive but far more than just seals.

The only other issue I have with the 250/300 scooters is the lack of an oil pressure sensor.

However, the rest has been great and I'll likely buy another SYM to replace this one.


My SYM doesn't have a circlip inside the top of the leg - just a plastic cap sealed into the stanchion - which seems to be what you have too - no clear method of disassembly - and that's why I looked for another way to do it.

The upper half of the fork leg, the stanchion, has a circlip at the top on the outside - that's to ensure the fork leg mounts correctly into the steering clamp. But I couldn't find a circlip or anything inside the top. It seems they haven't followed other designs I'm familiar with.

Most cheap motorcycle forks use a bolt at the bottom to hold the damping tube/rod in place. It can be hard to remove - needs a shock torque, for example, from an impact driver. To separate the upper and lower parts of the fork (the lower leg from the upper stanchion), you have to aggressively pull the two apart with repeated force. But with the SYM, you just undo the bolt at the bottom and it freely disassembles. I actually found this disassembly easier to do than a motorcycle fork, and it's easier to change the seals. If I remember correctly, I removed the lower drain/assembly bolt with the fork upside down, using an impact driver. Then turned it right way up to drain the oil out of the hole where the bolt was. I seem to remember that the two halves are ready to fall apart so be careful when you turn it right way up - the two halves can slide apart just cos of their weight. After draining, slide the two halves apart, and remove the dust cap, circular retaining clip (check the clip isn't rusting - the rust can cause grit that damages the seal), then remove the old seal (and note the washer below it). Then I fitted new seals, reassembled, and then turned the fork upside down again to partly fill the fork with ATF through the hole where the lower drain/assembly bolt goes - do that slowly cos it won't flow fast through the hole. Then bolted it... and it's finished :-)

My SYM has an 8mm hex head on the drain/assembly bolt and I used 120ml of ATF in each leg. I also fitted gaitors after the change so the seals will stay cleaner for longer and I don't have to do that job again. And so far, about 18 months, so good. Here's my post about it:

BTW, if it is a small leak, you may not need new seals - just cleaning the dirt out can be enough if the seal is in good condition. There are tools to do this such as:


Yes, it's possible to repair the front fork - at least it is on my SYM Citycom and I assume they have similar designs.

As you've found out, it's not quite the same design as a motorcyle - the top is sealed so it cannot be opened up that way. The whole top half of the fork is one unit and the lower half is another, and they are are held together by a hex bolt at the bottom of the lower leg. Turn the fork upside down and look down the centre hole to find the hex bolt. Once you've got that bolt out, the rest is more like a motorcycle fork.

You can replace the seals and oil but nothing else. If you can find out how much oil is in each leg that's best, but if not, try to collect all the oil that comes out and measure that. If you've got a leak, then of course, this is less than standard.

I use ATF fluid instead of motorcycle oil - it has all the same properties such as anti-foam agent etc but it usually costs much less.

General Discussion / Re: CruiSYM 300
« on: May 28, 2021, 11:19:36 PM »
An electrical gremlin :-) Like Tromper says, maybe it's just not happy until it's feeling used.

General Discussion / Re: CruiSYM 300
« on: May 28, 2021, 04:50:41 AM »

That is an odd one.

I don't think there is a pressure sensor for the gearbox/drive oil - as I understand it, they are reduction gears in a bath of sticky thick oil, so it doesn't have a pump and so there's no reason to monitor pressure. Besides pressure, the oil level is not at risk from component failure either, unless the bolts (infusion and drain) come out, so I doubt if there is any level sensor either. Here's a schematic of the transmission - no electrical parts:

So that's why I'm curious - why is the light coming on after a gearbox oil change.

The yellow engine light is described as an "EFi trouble warning light" in the manuals - for example, mine used to come on when I was experimenting with the solenoid for the exhaust-air-injection emissions gear. If the solenoid wasn't connected, the light came on. I think there is a diagnostic code to identify the broad reason why the light has come on. As you say, it may be an inconsequential warning but perhaps it's worth investigating?

I looked up how to do this without the SYM dealer's disgnostic scanner - it starts on page 87 of the Citycom service manual. There's a connector to find, and then by connecting the ends of this with a paper clip (as the manual suggests) the system will flash the light in a kind of code of long / short flashes.  Unfortunately, that part of the manual is very poorly translated so it is quite hard to understand. Maye pop to a dealer?

General Discussion / Re: CruiSYM 300
« on: May 27, 2021, 12:17:45 AM »
I refitted the wheel, after cleaning and oiling everything that needed it. I started the bike up and, once again the engine warning light came on. Each time I started up, on came the warning light. After a good run around today150km it finally went out. Why this happens I do not know. It comes on each time I change the fiinal drive oil. I know there is nothing wrong so just ignore it, until it gives up!.

I'm curious - which warning light comes on? Is it the yellow engine light?

General Discussion / SYM, my Speedy Young Motor
« on: May 05, 2021, 10:34:14 PM »
How fast does she go mister? was a question I sometimes got asked on my Yamaha YZF many years ago, but it is not a question I expect to get asked on the SYM. But, just in case someone does ask, I need to be prepared right? :-)

So, I took out for a spin, got her warned up and then gave her WOT from a standing start onto {edited} for 2 miles, with no wind. So, I can say 130kmh on the GPS, that's 140kmh indicated, with maybe a little more with a new belt etc. She still has the K&N air filter but is running the standard exhaust - when she was fully tuned with a straight through exhaust she did 148kmh indicated, 135 on GPS. The calculation anomaly for the maths is likely tire diameter.

I also noticed that the "knock" noise the engine used to make when cold has gone, and the engine feels smooth or at least smoother, at all engine speeds too. I can't tell if the 250 camshaft has made any difference.

The next stage is to run her for month and see if she has stopped using oil, measure the compression pressure, and calculate fuel economy. 

General Discussion / Re: Changing cylinders - anyone done it?
« on: May 04, 2021, 03:54:29 AM »
And it sounds awesome with no exhaust!

EDIT - I though you meant that as a joke but I realised I might not have explained what I was doing clearly - a lack of pics cos this site does not make pics easy. So, I was pulling on the cam chain to rotate the crank and piston to tdc with the head off. It's not possible to pull on the chain with the head fitted - insufficient access. When the crank marking is as close to aligned in its inspection window as possible, and that is not as easy as it sounds, I fitted the head down the mounting bolts while pulling the chain and guides through the slot in the side of the head. With the the head in place and bolted down, the cam chain can be worked around the cam chain sprocket (a little tricky due to the limited access) and then the sprocket is bolted onto the end of the camshaft - so the camshaft, the sprocket, and the crank are all at their tdc markings. When you torque the bolts that hold the sprocket to the end of the camshaft, the sprocket will turn and then so does everything else. That's when it makes sense to not have the spark plug fitted. The last thing is to add the camchain tensioner, and then the head cover, then the engine goes back in the frame and then reconnect cooling pipes, rear brake, throttle body, fuel, airbox, electricals, exhaust, rear suspension, etc.

It's mostly following the servive manual but, as I worked out from the first failure, also spending time thinking about what the manual isn't saying so stuff like the crank marking and camchain tensioner don't create problems.

Anyway, still no leaks and she's running well. I read up on breaking in piston rings and the "no idle and varying throttle and engine speed" doesn't need that long apparently. So I'm going to take her for a blast tomorrow :-)

General Discussion / Re: Changing cylinders - anyone done it?
« on: May 03, 2021, 01:11:37 AM »
Thanks Syd and Tromper - I am feeling super good - the adventure seems to have a successful end... and no sign of oil or other leaks so far either! Cursing and skin loss are key!

The skin loss was from pulling the cam chain to rotate the crank so I could get TDC - it's actually a lot of effort in places and then suddenly turns very easily and spins past TDC. Quite troublesome! There was also a lot of cursing while trying to get the piston into the cylinder without damaging the rings. Both of those jobs took a lot of time to get right.

Second time round I also realised there's no need to remove the bodywork - just loosen screws so panels can move and that gives enough room to access electrical cables and connectors. I also tied the handlebars into a centre position so I could lift the body away like a wheelbarrow and the front wheel wouldn't wobble. Lifting the "wheelbarrow" up and over the back wheel seemed like a lot of physical effort but manageable even though I'm out-of-shape and the wrong end of middle aged.

Another tricky bit was realigning the frame with the engine and then getting the long mounting bolt to pass through - it still had to be lightly hammered through even when aligned.

Anyway, now I'm watching for leaks and if none, then I'll run her in for a couple weeks ... I'm looking forward to giving her some beans and see if that 250 camshaft has made an obvious difference. It has the same size and same lift as the 263 but I guess more duration for top end power and less bottom end.

Beer time I think. :-)

General Discussion / Re: Changing cylinders - anyone done it?
« on: May 02, 2021, 02:04:35 AM »
Smile, take full credit, & party 'til dawn to celebrate.

Congrats, & well done.

Hey Tromper, so now I'm celebrating - seems to have worked second time, with a new piston pin and new camshaft (from the 250) and lots of prayer and cursing and lost skin.

The difference this time was using the crankshaft timing mark to get as close to TDC as possible so I was sure the timing was as close to correct as could get it. I hope dead on. I also disassembled the camshaft chain tensioner by removing the spring before removing the tensioner from the cylinder. Then I could reset the ratchet on the plunger so when it was reinstalled, the plunger wasn't applying any tension to the chain. Then after that, fitting the sping and hearing the ratchet click through to apply the tension.

And so far so good - she idles sweetly from the get go, actually smoother than I can even remember. I ran her to get her hot enough for the fan to turn on ... and no issues.  I'll leave her overnight and see if there any leaks in the morning :-)

General Discussion / Re: 200 cc sym engine won't start
« on: May 01, 2021, 07:42:21 PM »
If you unplugged everything and then plugged everything back in and it started, I would guess it is a connection problem. I would ty unplugging and plugging back in one thing at a time to see if I can find which plug/connection is causing the issue.

Besides that, some stuff to check -
battery voltage
voltage at the starter solenoid
functioning starter solenoid
engine cranks but doesn't run
spark plug / coil and wiring / spark strength
fuel level
fuel pump relay
fuel hoses and vacuum tube
blocked fuel strainer
blocked / damaged evaporative emission control system
ECU cables
AC generator cables
loose connections

General Discussion / Re: 200 cc sym engine won't start
« on: May 01, 2021, 06:29:57 AM »

I'm not familiar with the machine but if an engine won't start, there are check lists you can follow to see what has gone wrong. If you know exactly what engine, you can download a manual - such as this for the SYM Joyride 200.

You cannot eliminate all emissions from a combustion engine. Best at the moment is Euro 5 or electric which transfers the emissions to the power station.

All the best,

General Discussion / Re: Changing cylinders - anyone done it?
« on: April 04, 2021, 08:42:30 PM »
Well, it seems new rings have not made a difference.

I tried running her in for a day - very light loads, no static rpm for long, and no high rpm, and then today I did some more and a compression test. It is actually a bit lower than before. Although the cooling system is keeping temperatures in check, the engine is kicking out lots of heat, and I think the oil must be close to burning. One thing I dislike about these SYM is the lack of oil pressure warning/gauge etc.

Anyway, for sure it is not repaired and still has the feeling it could clunk out mid journey. I noticed in my pics a small longitudinal mark on the cylinder wall - it is visible in the top left of cylinder bore in the the pic above. It is more of a scuff - my fingers didn't feel any scratches. But whatever, I had previously thought the cylinder was without any such issue, but now it seems it is not so it is damaged to some degree. I'm pretty sure my attempt to use new rings was not enough and I will need to go with a new piston, rings, and cylinder repair if I try again. Now I've done it once, I know how to strip and rebuild so it should be somewhat more straightforward next time. I may even catch all the coolant next time :-)

I measured the outside barrel of the cylinder and it was 78.89mm and the hole in the engine block was 79.36mm. So I'll see if I can find someone selling a 278cc cylinder to measure it and work out if it will fit.

I have no time left for this now so the Citycom will be off the road until the summer. If the Z+ 300 becomes available soon, I'll buy that and perhaps not bother repairing the CC.

EDIT - I continued to try to break in the new rings but the heat turned out to be too much. It has eventually caused the camshaft to fail and the end of the shaft has sheared off. As some mechanic websites tell me, too much heat can cause the head to swell in the middle, and this shape change is enough to cause the shaft to bind so it doesn't want to turn, and then it breaks. So the engine now needs a new camshaft and bearings on top of the other parts, and the head would need to be stripped and rebuilt.

On the plus side, while stripping the engine a little to check out what had gone wrong (still in the frame), I did manage to catch all the coolant. The trick is simple - first drain the coolant from the drain screw and the remove the highest hose that connects to the thermostat - a second surge of coolant from the drain plug gives up all the coolant in the system.

Anyway, I might not bother with the repairs - too much time and money and I'm not confident it would work either. So, my Citycom is probably finished, just shy of 80,000kms. I reckon I could have got to 85,000kms and by then she'd have been such a heavy smoker that there would have been a "natural" end. Rest In Pieces Citycom. :-)

ANOTHER EDIT: I've been thinking about what the manual doesn't say about refitting the parts - it doesn't mention careful alignment of the crank position. So although I thought I had aligned the timing, I now wonder whether I aligned the camshaft with the crankshaft exactly right? I didn't check the timing mark on the crank, trusting instead that a piston that looks like it is at top dead centre IS at top dead centre.

But if the piston was not, and preferably at the compression not overlap tdc, I might have changed the timing by a few degrees when I fitted the camshaft gear drive sprocket onto the end of the camshaft. It's certainly possible this is what I did wrong. I know for sure I did everything else right - it was all correct on disassembly. And this timing error would explain why the engine would run but was running too hot.

So maybe it is worth trying a second time, and this time making sure everything is exactly right and not making assumptions. A new camshaft is available and US$45. I could try next month.... :-)

Pages: 1 [2] 3 4 ... 11