stuttering

[darbyman]

hey all
just done my new build and am having some problems
when i first start it up and ride it , the bike is very stuttery like its juddering. and it does this constantly even after its warmed up, i dont know what to do. its that feeling when your at really low rpm and the bike just doesn't have that right amount of power and it judders. Please suggestions???

 

[Toadmund]

I read someones suggestion that it's because it's a one cylinder and at low RPM's it's too slow under load to balance itself out.

Although since going from an NT carb to an RT carb the problem seems less and I have better low RPM running.
So, it could also be how it gulps fuel, then burns it at low RPM's under load that cause it to buck.

 

[rustycase]

What does your plug look like?
rc

 

[darbyman]

I'm running it in , I'm using a new motor and a carb and everything off another kit, it has a bigger jet, the exhurst has the hole drilled in it mod and its got a preety restrictive airfilter, and the standard **** spark plug which atm is blak and oily because I'm running 20:1 with race oil

 

[darbyman]

So could that have Annything to do with the float level toad?

 

[Toadmund]

I guess it really is what your definition of 'very stuttery like its juddering' means.
Do you mean 'bucking' like first gear in a standard transmission car when going too slow?
Perhaps you should take care of the problems you mentioned and when you do make sure you are up to speed before you pop the clutch, if you are going too slow the bucking and very stuttery like its juddering stuff is going to happen.

Does this happen at all speeds, or just at slow speed?

 

[rustycase]

Well, would you think about 30:1, a proper jet, and a B6es ?
a stock air cleaner is fine for these motors.
rc

 

[darbyman]

ok i put a new br5hs spark plug in, and rode it a little more , i think it just need to run in , its getting better and yah the stuttering 'bucking' is up until about half throtel . say about 21km/h, also it uses more that 2.5 litlers of fuel in 50 ks is this normal?

 

[rustycase]

You could try lowering the needle in the slide, one notch from where it is...

 

[Bikeguy Joe]

Sounds like it's four stroking.
The above advice from RC should help.

 

[crassius]

I've had some engines that didn't get 20 miles out of the first tank - they all straightened out as they ran in.

 

[darbyman]

ok found out it has too much oil in the mix, ran 32:1 and it was perfect but im still running it in so ill continue to run 20:1 , cheers for the responses

 

[darbyman]

what actually is the run it period length, like i have only done 50ks so far, how long till its fully run in

 

[Toadmund]

Some say 2 tanks, some say 2 gallons, so I guess 3 tanks is about right I guess, that was a while ago for me.
Use NON-synthetic for break in, don't baby it during break in, vary the throttle a lot, up and down, but don't WOT for too long, just short bursts.
Consider break in to be 2 gallons, or about 8 litres just to be sure then consider break in done.

Rest motor after half hour, let cool, Check your head bolts torque.

I followed this proceedure for two tanks last year and I have a nice strong engine that reaches near or higher than average top speeds.

Consider break in 2 tanks of non-synth, then go 2 more tanks with non-synth, then go with synthetic, the best that money can buy.

I use Echo powerblend, top rated, when that runs out I am going to try Opti2 which I have packets of.

Confused by this post?
So am I, get a second opinion.

 

[crassius]

you won't see much diff in how the motor runs no matter how it is broken in - proper break in makes the diff between a 2 year motor & a 4 year motor

 

[Reggie boy]

I just started running my new zete 100 firestorm with a sick bike parts heavy duty shift kit .I have an engine bucking problem . How do I resolve this problem ?