|
|
Post by wiscootsin on Jun 3, 2021 13:06:12 GMT -5
Bought my first scooter that had been worked on in a shop by the seller in order to get it running to sell. They made some mistakes, but, i suppose the generic "pro motor sports" shop mostly works on snowmobiles and not 35 year old scooters. Anyway, If i run near WOT at around 35 and above for more than half mile it bogs down and dies. After letting it sit a minute or two it will start again. I'm guessing this is a soft seize situation.
It's stock and mint right now. The OEM carb has no air/fuel mixture screw.
carb has a stock 82 mainjet. I checked, and the needle height is at the 2nd of 5 notches. 2nd lowest.
I'm thinking I will raise the needle height and see if i have an 84 jet to put in. If that's dumb, or if i should only do one at a time, let me know. I haven't troubleshooted a soft seize before, just a full on donezo seize. lol
|
|
|
|
Post by wiscootsin on Jun 3, 2021 13:49:32 GMT -5
Also just realized the auto bystarter passage in the carb bowl is closed.
I should probably buy a decent quality carb with adjustable air/fuel mix.
|
|
|
|
Post by geoffh on Jun 3, 2021 14:06:51 GMT -5
Post a picture of the carb it,s unusual not to have that adj screw it could be hiding under grime or hidden by a plug.Are you sure the autolube is working?
Geoff
|
|
|
|
Post by wiscootsin on Jun 3, 2021 14:48:49 GMT -5
Post a picture of the carb it,s unusual not to have that adj screw it could be hiding under grime or hidden by a plug.Are you sure the autolube is working? Geoff I know it is odd that it doesn't have one, but it doesnt. The carb has an air pilot jet though. Here is the diagram from the service manual.
I am wondering about the autolube. The shop didn't clean everything the way you would need to clean something that sat for 30 years. I may need to disassemble the whole thing to check.
|
|
|
|
Post by wiscootsin on Jun 3, 2021 14:54:08 GMT -5
I put a 70:1 premix in the tank in case the autolube isnt working at full capacity.
I raised the needle height to the middle (3 of 5) and put an 85 mainjet in it. After a half mile run up a slight slope it tried to die as i stopped, but i was able to keep it going by throttling a bit. On the half mile down a slope it stayed on fine and didn't cut out.
It doesn't seem to have any problems if it's kept at 30mph or below, which can be done at half throttle. I drove it 10 miles the other day without issue when I did that. So many variables. I just really don't want to break this thing, parts are hard to come by.
|
|
|
|
Post by wiscootsin on Jun 3, 2021 16:24:39 GMT -5
I just pulled the autolube tube that feeds into the carb off. I took off the airfan engine shroud and manually turned the engine to see if any oil would come out of the tube. I turned it a lot and no oil ever came out. I think that's a basic way of testing it's functionality?
So i'm thinking the autolube is the issue. Guess i'll put a higher premix ratio in and see if that gets it running better. Hopefully that first 50 miles at 70:1 didnt cause damage. When i compression tested it cold this morning it was at 130psi, which seems ok but i'm not totally sure what this vertical minarelli should be at. I couldn't find it in the service manual but maybe i didnt search it out enough.
|
|
df41590
Scoot Enthusiast
Posts: 285
|
Post by df41590 on Jun 3, 2021 17:57:10 GMT -5
I just pulled the autolube tube that feeds into the carb off. I took off the airfan engine shroud and manually turned the engine to see if any oil would come out of the tube. I turned it a lot and no oil ever came out. I think that's a basic way of testing it's functionality? So i'm thinking the autolube is the issue. Guess i'll put a higher premix ratio in and see if that gets it running better. Hopefully that first 50 miles at 70:1 didnt cause damage. When i compression tested it cold this morning it was at 130psi, which seems ok but i'm not totally sure what this vertical minarelli should be at. I couldn't find it in the service manual but maybe i didnt search it out enough. Not 100% sure, but don't think turning it by hand will be enough to get flow. Do you have an electric drill to turn it with? If not fill w/ 50:1 and let it idle with the oil feed to the carb off. According to the ETon service manual supposed to be 3-4 drops/min at 1700rpm, 5-9 @ 4k rpm, and 8-12 @ 7k rpm; don't know if this would apply to the verticals but think it'd be close. 130psi should be plenty. |
|
|
|
Post by aeroxbud on Jun 3, 2021 18:46:52 GMT -5
Like said above, it you take the pump off. You can remove the drive wheel. Then use a drill run a drill in reverse oil should come out quite fast then.I
If in doubt, I would take of the stator and check the worm drive. These are plastic and can wear out.
|
|
|
|
Post by wiscootsin on Jun 3, 2021 19:44:08 GMT -5
Good to know, thanks. I'll test it more thoroughly.
On the 80s hondas turning would be enough to see some kind of motion inside the tiny oil line, not enough for drops. Thats what I was looking for.
When I pulled the oil line no oil whatsoever came out so thats why I'm leaning that direction.
|
|
|
|
Post by wiscootsin on Jun 3, 2021 20:44:04 GMT -5
just tested it and got some oil dribbles to come out. I suppose I could make sure the oil inlet on the carb is free. I shouldn't assume the $80 carb clean sorted that out, if they didn't handle the bystarter circuit in the carb bowl.
|
|
|
|
Post by wiscootsin on Jul 27, 2021 10:45:07 GMT -5
i measured the auto-bystarter and it was extended 1mm above spec. I made a gasket that added about .5mm and now it starts up fine. It still started to lean out and stop at extended full throttle but not as bad as before. I'll add another gasket and i think it should work fine.
Ordered a front basket for it from Japan.
|
|
|
|
Post by geoffh on Jul 27, 2021 14:57:59 GMT -5
A few posts back you say you use 70:1 premix ?? 50:1 is ultra safe my maths is poor so someone more learned will chip in,but if your at 70:1 and still have auto lube your reducing the cooling effect of the petrol.
Geoff
|
|
|
|
Post by wiscootsin on Jul 27, 2021 16:30:47 GMT -5
A few posts back you say you use 70:1 premix ?? 50:1 is ultra safe my maths is poor so someone more learned will chip in,but if your at 70:1 and still have auto lube your reducing the cooling effect of the petrol. Geoff yeah i put that in as precautionary since it is a 35 year old scooter with 300 miles on it. I tested the autolube and it works to spec. I don't have premix in it anymore. |
|
|
|
Post by wiscootsin on Sept 9, 2021 16:33:35 GMT -5
I noticed this scooter was leaking gas very slowly. When I checked the fuel petcock was leaking and there was also a hose line leaking at a connection.
I replaced the OEM yamaha vacuum petcock with built in filter with a generic one and fixed the line. The three times I've started it since it has started up immediately.
I haven't had a chance to test it yet on a long WOT run, but i'm guessing the issue I've been chasing was just a result of a small fuel leak that was so small it went unnoticed (and i believe it got worse over the last few months). I will update when I fully confirm.
|
|
|
|
Post by geoffh on Sept 10, 2021 8:34:23 GMT -5
Just my  a small fuel leak wouldn't cause your problem,if you suspect a soft seize has occurred I would strip the top end down and inspect the piston etc. Geoff |
|
a small fuel leak wouldn't cause your problem,if you suspect a soft seize has occurred I would strip the top end down and inspect the piston etc.