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Post by arcanus25 on Jan 6, 2010 14:59:02 GMT -5
My scoot kept dying shortly after I started it up (few miles of driving) whenever I slowed down at an intersection. It only had 750 miles on it. This problem would go away as it warmed up. It always started right back up and would be fine unless I had just come off high RPMs.
Jump to 1100 miles on the scooter and this problem kept getting worse. It even got very dangerous as it would die when I came off the throttle as I was entering a turn/highway ramp (even though I was sometimes going 20-30 MPH and had 3000+ rpms). Sometimes it would start on the fly and other times it would take awhile to start up again and I would have to roll to the side to not get run over. Now I could drive it for 70 miles and it would still die EVERY time I slowed to idle. It was always a little hard to start in the cold but that got worse too. I am new to the scooter world and have only just now (at 2200 miles) discovered this amazing forum. My recourse was to take it to the shop.
They said it needed a valve adjustment which they did. It came back purring like a kitten. I was jubilant. It still had some hard starting issues but nothing like it was and it never dies. BUT starting 200 miles later it began to die occasionally when slowing to idle in the first few miles. AGAIN it just got worse and worse, mirroring what happened before. I took it back under warranty to the shop and they said they had to fix the same problem, SPECIFICALLY it was the ROCKER BAR. They said they would not fix it again under warranty since it took them 4 hours to do and next time they may just replace the rocker bar.
Well, it came back purring again so this seems to be the big issue. But over the last 500 miles it has deteriorated again. I am not interested in paying them another 260 dollars to fix this problem. Thanks to this forum I will attempt it on my own for the first time. My big question is there any way to make the adjustment more PERMANENT? It seems like a huge hassle to adjust every 500 miles (i do that much every 2 weeks). It may be a silly question since this is inside the engine, but would Loctite on the adjustment screw be feasible?
Thanks for all your input!
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Post by Bluefront on Jan 6, 2010 15:16:02 GMT -5
If a valve getting tight is really your problem, I doubt loctite would fix anything. You're not dealing with something loosening up, like the adjuster nut. The problem is something that is wearing excessively......IMO of course. Sometimes a valve will "wear" into the valve seat, causing the gap to close up.
You might be more specific on the brand and model of the scoot. Perhaps someone with specific knowledge of this issue will chime in. Is that a Roketa model #?
Good luck.
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Post by fuloydo on Jan 6, 2010 15:17:50 GMT -5
It sounds like whoever did your adjustment last time didn't tighten things back down properly. I adjusted mine early last summer and have put over 3,000 miles on it since without having to re-do. I'm to lazy to search for it but I think I recall reading here somewhere that it should be done about every 5,000 miles give or take.
Definately do it yourself, though. The only hard part is dealing with all the plastic. Once you've got the motor exposed the actual adjustment is a snap and I say that as someone who does not consider himself a mechanic.
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Post by arcanus25 on Jan 6, 2010 15:18:56 GMT -5
The model and such is in the title. But it is the Roketa MC-54-250B.. JR confirms for me it is a Linhai engine based on photos I sent, but since the plate says 244.3cc it probably has a smaller piston then normal. I will be confirming this when I adjust the valve (i hope).
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Post by dasurfguy101 on Jan 6, 2010 15:40:43 GMT -5
i wouldnt lock tite them.my opinion.scoots are maintenance,constantly.i go over mine every day.and about every two weeks check the valves,change oil,etc.but once again they arent built tuf and consatntly need the tlc.but on the plus side if u do this they will run for a long time.not saying there wont be any other issues but it definatly helps.have you replaced the fuel lines,filter?theres a post somwhere about the fuelissues with i being new i would for sure(1) clean carb,(2)replace fuel lines and filter,(3) add sum fuel injection cleaner to the next half dozen tanks or so.this will help future problems.check all grounds make sure they are metal to metal an tight.hello assembled where?lol.this too will help with future issues.i have to agree with the job not properly tightened.and with the seating of the valves.adjust yourself then you know.just my thoughts on it tho..safe riding.
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Post by JR on Jan 6, 2010 16:02:56 GMT -5
Arcanus I Pm'd you back don't worry about the piston as it has nothing to do with the valve adjustment. The linhai comes with up to 4 different piston sizes and if it has an actual displacement of 244cc then I'll tell you now it has a 68mm piston in it! Another dawg Smorkle just put a big bore kit on his and his was 68mm also!
Now the rocker arm thing IMO is a put off by the mechanic because if it is a rocker arm problem and it's still under warranty then they damn sure need to replace it! I know you don't like the labor but at this time I can't think of anything about a rocker arm that would cause the valves to tighten up except if it's bent!
So if it is the rocker arm why didn't the mechanic just say Hey I got to get a rocker arm and replace it and solve the problem instead of just charging you to adjust the valves and sending you on your way with a known problem??
If it was me I would be bending someone as in the guy who sold to me ears I can tell you that!!
If the jam nut is bad or stripped after thinking about it the valve would loosen up and rattle like hell and for sure run like crap! All of your symptoms are the classic vavle adjustment thing but again don't worry about the piston size it has nothing to do with the valves!
The link I sent you is the step by step way to do it and you just need to take your time if you are going to do it and it'll be fine!
But as I said I would get to the bottom of the rocker arm thing! JRR
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Post by arcanus25 on Jan 6, 2010 17:34:53 GMT -5
Yeah this mechanic is crap, hence why I don't want to go back there and they are the only ones who really know/work on Roketas in Austin, TX. I bought this bike from someone on craigslist, so no normal warranty. The mechanic did the adjustment for 260 the first time and THAT work came with a 1 month warranty. The second fix is when they mentioned the rocker arm. Never want to go back to them again.
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Post by earlwb on Jan 6, 2010 18:08:26 GMT -5
I do not remember anyone having valve stretching problems on a Linhai engine. It did happen on the GY6 engines a couple of years ago. In this case the valves had a tendency to grow longer over time. So you had to readjust the valves from time to time. In that case it means one had to replace the valves to fix the problem.
I don't know what your situation really is, but you should adjust the valves yourself and use a little blue locktite on the lock nuts. Then after adjusting the valve gaps, let the engine sit for several hours to allow for the locktite to setup good. now after that if the engine runs good, then great. But later if the engine starts acting funny check the valve gaps again. Then you should be in a better position to determine what the reason is.
basically if the valve gap closes up fast, then it may be a valve stretch problem or a valve seat problem. if the valve gap opens up over time, then the rocker arms are getting bent back out of the way.
Now one should not rule out things like a intake leak or vacuum leak or something causing the engine to run too lean. check the ignition coil and make sure the two wires on the back are crimped good and lightly connected to the coil. also check the spark plug wire and make sure it is not loose on the spark plug cap. I have seen a lot of people with loose spark plug wires. the spark plug wire actually screws into the coil and the spark plug boot. You can snip a little off if it is loose.
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Post by arcanus25 on Jan 12, 2010 16:04:54 GMT -5
OK. Got the Valves adjusted. Both were totally closed. I tightened the lock bolts. Hopefully enough. I did notice a little play in the rocker arm especially on the top (intake) valve. Is this normal or did I not tighten it enough? There IS now a clatter coming from the bike. I made so many changes at once I may have done a number of things. Here is that thread: scootdawg.proboards.com/index.cgi?board=200cc&action=display&thread=28395One thing that was strange. AFTER I did the valve adjustment and heard it running (and the clatter that I thought maybe was from not having plastics on it and the engine just sounded different to me) I changed the coolant fluid. So I warmed up the engine many time and ran the engine (on the center stand) for about 20-30 minutes all in. Out of curiosity this morning I dug back into the valves. The intake (top) was still at the correct gap. The exhaust (bottom) was CLOSED again!! I couldn't even get the .002 in it. Seems VERY quick for it to close down. Re-adjusted it and tightened that bolt down a lot. It is running well now. I am about to go on a 70 mile trip. We will see how it goes. Anyone have a clue why it would close up so fast and what this clatter may be? |
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Post by widehide on Jan 12, 2010 16:39:50 GMT -5
was the engine cold when you rechecked it, The adjustment must be done on a cold engine. good luck on the long ride, I just finished a 40 mile cruise, it sure felt good to get out, the VOG260 is running great.
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Post by arcanus25 on Jan 12, 2010 18:52:00 GMT -5
Yeah it was totally cold the second time. I did add some oil on my long ride due to what came out when opening the lower valve cover.
The ride went well. It felt good. No noticeable change in power for the better or worse.
The clatter is still going. It increases with rpm and gets at its highest while accelerating...
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Post by dabucs on Jan 12, 2010 19:00:02 GMT -5
I'd check the exhaust valve on the bottom again.. When I did my adjustment I used needle nose plyers to hold the stem as I tightened the nut on the valve. I got the clatter because I couldnt keep the stem from moving using them. That is why I ended up buying a valve adjust tool, that I had seen posted here in the forums before. I used that to then adjust the valve.. Worked great, as I did not turn the stem while tightening the nut, and then no more valve clatter. *Edit: This post has the tool I got with the part number. Its at the bottom of the post. scootdawg.proboards.com/index.cgi?board=250ccengineandtrannsmission&action=display&thread=21566 |
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Post by arcanus25 on Jan 12, 2010 22:26:56 GMT -5
Dabucs... Why would how you hold the stem matter? I actually had another person holding it and saw no movement while I tightened. Even if it wasn't held right it would just close the game, wouldn't it?
I was able to move the feeler guage in and out of the valve after I finished tightening.
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Post by dabucs on Jan 13, 2010 0:15:01 GMT -5
That probably would be better answered by someone else, I'm not really mechanically inclined. I know that when I didn't get the stem steady with a good grip and turned the nut, that it would also turn the stem, thus not properly setting the valve.
It may not appear that the stem moved via how you were keeping it in place. But if it wasn't latched right it will move.
When I didn't get it right, the bike ran great but I had the clatter coming from the valves. Bike was fast responsive, but for the clatter, and the noise would increase when giving throttle.
Got the tool, checked the gap again and it had closed. Adjusted it again, it then ran great with no clatter
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Post by widehide on Jan 13, 2010 12:06:32 GMT -5
Here is my trick, I leave the feeler gauge in the gap while I hold the stem and tighten the nut. That way if the stem try's to turn closed it will only go as far as the gauge which stops it.
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Post by smorkle on Jan 29, 2010 19:40:35 GMT -5
Another dawg Smorkle just put a big bore kit on his and his was 68mm also! I heard someone mention my name so I just thought I'd pop in and say hi! I have nothing interesting or informative to add to the discussion, but I did in fact have a 68mm piston, 244cc Linhai style engine. toodleoo! |
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Post by flyangler on Jan 29, 2010 20:33:39 GMT -5
umm, a 244 Linhai ?
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Post by smorkle on Jan 30, 2010 17:04:05 GMT -5
Yeah. When I put the big bore kit in my engine measured all the old stuff and put the measurements into This Calculator and came up with almost exactly what the plate under the seat said for cc's on my bike. 244.3cc. Piston= 68mm Stroke= 67mm CC= 244cc I've read all the hype about 257cc Linhai on here and I'm not disputing that there are some out there that are 257cc that are actually labeled 244, but MY engine IS the linhai style and WAS 244cc. Now with the big bore kit in it it's a 290cc. I don't wanna get this argument going again, just stating that these are the findings I have on my own scoot. Big Bore Discussion here. |
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Post by cptk on Feb 13, 2010 21:12:00 GMT -5
Arcanus25,
I now have 11,500 mi. on my 250b linhai. (yeah) My exhaust valve was closing every 1500-2000mi. up to about 8,000...? Scince then I have not had to make an adjustment. Not that I havent checked it, but no adj. needed. Maybe it took awhile to seat or whatever, but that has been my experience. These big dawgs know too....Listen to what they say. Me I'm just a pup, but thats my story n' I'm stickin to it....
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