Roketa Cayman 150cc has starting troubles. By jackhasalhoff (Read 1,690 times)

[jackhasalhoff]

Hey, new here, and wondering if I can get some help.

So my scooter has been having some starting issues, like sometimes it starts perfectly fine, other times it just doesn't at all no matter how hard I try.

Just adjusted valves to .004" both intake and exhaust, and changed oil.

It's just really weird that it starts fine sometimes, but doesn't start at all other times.

I have noticed that when it's been in the sun for a bit (100 degree plus weather at times) it usually doesn't start, but if it's been cool it's ok.

Thinking that's the problem, but would like some outside opinions about the issue, thanks in advanced.

[sprocket]

Sounds like you could have a vapor lock in the fuel system..loosen the gas cap and see if starts all the time...

Some compnents like the igniion coil, the Cdi and the pickup coil can be effected by high temperatures as well..they work at night, but not in the sun kinda thing...

[Bashan]

Sprocket is right on aboot the electrical/temp phenomenon. We've seen that happen many times on the forum. When it won't start check the spark and see if you're getting anything. Also, .004" should be OK but some of these engines are kinda hinky about that. Many folks set their exhaust to .005" so that it doesn't hang open in the heat. If you have a good spark you might try that. Rich

[jackhasalhoff]

I tried undoing the gas cap and that seemed to help a little bit, but it still won't start 100% of the time.

Also, one of the times I did get it to start I drove it around a bit to see if it would start again after that.
Ran perfect, but soon as I parked I smelt something burning, pretty bad stench too.

Would that have to deal with the spark, or is it something else?

[Bashan]

The smell complicates things, especially at dinner parties.....ba-dump! A few things come to mind now:

• If the bike is new the smell could be the straps holding the muffler if it's a canister.....unrelated to problem and will eventually stop.
  
• Could be the pollution PAIR canister melting and might be related....inspect.
  
• Could be the coil getting hot and and could definitely be related....swap it out.
  
• Could be the plug wire and could definitely be related....inspect it.
• Could be the trigger coil heating up...definite suspect but won't smell....test voltage.
  
• Let us know if you need help with any of that...Rich

[jackhasalhoff]

Actually, I really only have basic knowledge and all that seems fairly complicated...
That and in my town no one services chinese scooters, so any help would be wondrous and appreciated.

[Bashan]

About halfway down this tutorial is the trigger coil test. You'll need a multimeter and try to do it when the bike isn't starting. Rich

[sprocket]

Talk to a small engines guy where you live...they often won't work on these, but may point you the right direction. These engines are very much like older skidoos, outboards, riding mowers etc...

On the smell thing... Kinda of a sweet smell?

[jackhasalhoff]

Apparently the burning was another vehicle.
And now that I have been taking off the gas cap, it has been starting 100%, I'm already working on that coil test, but how would I fix vapor lock?

Are the fuel lines bad? Or is it the pump?

[sprocket]

Likely the fuel cap..replace it or drill a 1/16 inch hole through the cap...Sometimes you can bend the tabs on the cap... will loosen it just slightly...and stop the problem

[tvnacman]

When the starting problem is happening , does it crank strong ? Batteries are affected by heat and cold .
Try to kick start it a few times .

John

[Kaveman]

Are you getting ok spark when using the starter ? Solienoid ?
My previous scooter was an 05 Cayman .
will c.

[bcgreatness]

test your carbs auto enricher ( pretty much an electronic auto choke ) it might be jammed or just not working. sounds like it is stuck open. the way it works is when the engine is cold, it opens up to allow extra fuel to the carb so that it starts easier, when it senses a rise in temp, it closes back down to cut off the extra fuel to the carb, so you dont run rich. so if your in 100 degree temp trying to start it, you wouldnt need that extra fuel to start but so maybe its in a sense its getting too much fuel at times. what i did was an auto enricher bypass. if you live in a high altitude region or a state that gets snow in the winter, then i would NOT do the bypass. only works good if your some what close or at sea level, and it does not get too cold year-round. with that said, ignore everything i just typed, and re-adjust your valves to .004 / .005 lol if the scoot is new or still in the break in period, then 4 4 would be fine at first. hope that helps ya! happy scootin'

[jackhasalhoff]

Ok so I figured out the problem, but where would I be able to buy a new exhaust cylinder?
The exhaust bolt broke off inside and it's being way too difficult to get out, so I was recommended a new cylinder, but where do I find that?

[Alleyoop]

Where did the STUD break, is it sticking out a little or is it flush with the Head, or broke recessed inside the head.
Reason I ask is, it happens to many when they put in a new exhaust gasket because they CRANK on the nut to much and break the stud.

But you can buy a BACKOUT little set and drill the center of the stud and then use the backout drill bit to unscrew it. Or if you think you can not handle that find a garage that wroks on cars and they usually will be able to do it for you. They run into that kind of thing with the Header bolts all the time.
Alleyoop