** Carb Grabbing at Start **

[vintage97302]

First, I have looked through the topics on here searching for this exact issue and was unable to locate an answer, so here goes: My bike has been done for less than a week now. I am running the typical 80/66cc Grubee Skyhawk. I replaced the Chinese spark plug that came with the kit with a NGK one.

My problem is that the first time that I try to start the bike ( only when it is a cold start ie starting it the next day ) I have the choke set right, the gas is on...I get good peddling speed, let go of the clutch and give it some gas...it begins to chug, now not that the motor is having problems kind of chug, but that the clutch is grabbing. Then it dies and I end up wearing myself out repeating this process over and over again until finally it lights up and goes.

After I can finally get it to go and I ride it for 5 - 10 min I can shut it off, leave it for even 30 min, jump back on it, peddle for a few feet, pop the clutch and it starts right up, No clutch grabbing. I am not sure why when the engine is real cold that the clutch seems to grab...Anyone have any suggestions or advice??

Thanks, Eric

 

[motorpsycho]

it's because you're trying to start a cold engine. letting it sit for 30 minutes does not let the engine cool all the way back down, there will still be some heat in it which will help it re-start much easier.

it's not that the clutch is grabbing when cold, it's that it's harder for the engine to ignite the cold air-fuel mixture with a cold cylinder and piston.
you will see this problem go away when the outside temps get alot warmer.

 

[vintage97302]

it's because you're trying to start a cold engine. letting it sit for 30 minutes does not let the engine cool all the way back down, there will still be some heat in it which will help it re-start much easier.

it's not that the clutch is grabbing when cold, it's that it's harder for the engine to ignite the cold air-fuel mixture with a cold cylinder and piston.
you will see this problem go away when the outside temps get alot warmer.

Thanks for the 411. I live in Oregon and right now we don't get many days where the temp reaches over 55 degrees. I just always thought that it should be able to just start every time. Just the perils of being a newbie.

 

[MikeJ]

Some guys (myself included) have preheated their engine cylinders with hair dryers. It takes a few minutes; probably less than the time and effort you have been putting into starting. If you try this, let us know if this works for you. Do not use open flames like propane torches.

 

[vintage97302]

Wow, hair dryers. I never would have even thought of that. I thought that the problem might be more serious than that the engine is just cold. Thanks for the advice and tip. Too bad they couldn't make it so we could plug the engine in, like a head bolt heater *lol*

 

[MikeJ]

Well, if you want to get fancy.... Check with the local auto parts store and ask for a car battery warmer. I had to use them to start a diesel engine on cold mornings. It is literally an electric blanket for car batteries. You plug it in overnight. Wrap that around your cylinder head. It could be used for other warming purposes as well, I suppose.

 

[vintage97302]

I rode the bike today for over an hour today. It did the grabbing/pulling thing, took it as it is cold...it just catches then wants to fire up...then, it does great. I let it cool for about 15 min...got on it, did the same exact thing. Someone also told me that my problem also it the 16:1 break in oil to gas ratio as right now there is too much oil in the gas. I have no idea. It bothered me when it did the same thing 15 min after having ran for an hour. I can tell you it is starting to get REAL annoying.

 

[motorpsycho]

it kind of sounds like you are trying to describe a surge. when you say "grabbing /pulling" do you mean that the engine pulls and then the clutch slips (engine revs high wihtout pulling the bike) ?
or are you trying to say that when you ride, the bike feels like it's pulling back & forth...surging?
16:1 is too much oil, if you are on the break in, you can knock it down to 20:1. it will still be rich, but it will run better.
I have found that after break in, 32:1 seems to be a good ratio for me.
I have even ran one of my bikes ta 40:1 a few times and it has a tiny bit more power....nothing major tho.
32:1 is a safe gas / oil ratio in my opinion.

 

[Skyliner70cc]

32:1 is what you need at breakin and afterwards. No need for super oil rich mixture which makes starting that much difficult.

 

[vintage97302]

When I say that it is " grabbing or pulling " it is when I get it going I pop the clutch and it just seems like the clutch isn't making the engine turn over it just goes " chug, chug, chug "...like it is trying to engage. I peddle it again pop the clutch again and gradually give it gas and it catches up to speed then fires up.

The oil to gas ratio that I am using is the 16:1 ratio. I get so darn confused what the actual ratio should be. I read other topics on this forum and the other MB forum and everyone has a different opinion on what that ratio should be: Some say that I need the 16:1 for the first gallon as I am trying to break in the engine with as little ignition combustion as possible and also with that high oil mixture, it seats the gaskets; Then some say that you never go above 20:1 and that if you do, you can blow your engine...

This ratio topic is kind of an odd one...like what to do with the " white wire " that comes out of the engine. All I know, concerning this issue, is that I want to peddle a few feet, pop the clutch and have the sucker fire...THE FIRST TIME. I see videos all the time where this happens.

Thanks guys for all of your advice and tips...they are helping me greatly.

--Eric--