I just recently had my engine completely rebuild from the bottom up, my bike is running good, well sorta. The idle fluctuated quite a bit, the engine builder stated to use 20:1 for 2-3 tanks to break the engine in, which I'm on my 2nd tank, its smoking like a bastard which I think is normal bc i am running rich, but the idle fluctuates quite a bit, I have to constantly adjust it while riding is this normal for the break in phase of a new engine?
Idle fluctuation, help
- Thread starter jasindude1
- Start date
That is poor advice to run 20:1 at all without telling you to increase the size of the jetting in the carb.
That builder wants a swift kick up the quoit!
Adding extra oil to a mix leans out the amount of fuel in the mix and a change of jetting is required.
Revert Back to 32:1 or whatever ratio you were using before the rebuild.
You may be running rich on oil but in fact you are running dangerously lean on fuel and may be doing irreparable damage to the engine.
Do you feel comfortable in naming the builder so that I can personally direct all work away from him!
He knows nothing about the jetting requirements needed when changing oil ratios, therefore should not be in the building business!
Now that I am off my soap box, did the builder do or tell you that you should leak test the engine before it was started to confirm that there were no air leaks?
That builder wants a swift kick up the quoit!
Adding extra oil to a mix leans out the amount of fuel in the mix and a change of jetting is required.
Revert Back to 32:1 or whatever ratio you were using before the rebuild.
You may be running rich on oil but in fact you are running dangerously lean on fuel and may be doing irreparable damage to the engine.
Do you feel comfortable in naming the builder so that I can personally direct all work away from him!
He knows nothing about the jetting requirements needed when changing oil ratios, therefore should not be in the building business!
Now that I am off my soap box, did the builder do or tell you that you should leak test the engine before it was started to confirm that there were no air leaks?
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I usually run a 25:1 mix anyways so I didn't think the 20:1 was too bad just a little more oil while the engine breaks in. Ok, I see what your saying what would be a good jet size for the 20:1,? I live in 5000+ elevation I think I'm gonna pull the carb this morning and verify. Also just to play devils advocate isn't 20:1 what the pump mixes on factory bike? So isn't the stock jetting made to handle the thicker mix? Not trying to start anything bc I'm sure you know much more than me just simply asking a question 
Revert back to your preferred ratio of 25:1 and stick with it.
The oil injection delivers about 20:1 ratio, but it is injected into the inlet, not drawn through any jets!
Changing a pre mix ratio requires jetting changes!
A pre mix ratio of 25:1 will provide adequate oil for break in, no more oil is necessary, it just complicates matters!
The oil injection delivers about 20:1 ratio, but it is injected into the inlet, not drawn through any jets!
Changing a pre mix ratio requires jetting changes!
A pre mix ratio of 25:1 will provide adequate oil for break in, no more oil is necessary, it just complicates matters!
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I'm just curious where you got the information and made the decision to run 20:1 or 25:1 ?
and was that change in ratios without rejetting responsible for the rebuild ?
thats not common in given or searched for info, not suggested on any bottle of modern oil, nor currently used and proven mix ratios thoughout the ATV or MX racing communites.
99.99999% of jetting info on here, or searches, will be based on 32:1, or even 40:1 for liquid cooled machines.
richer than required fuel/oil ratios are an old wives tale from prehistoric times when the oils available
JUST PLAIN SUCKED, hence the need for more, as they only had about 1/10th the lubricating properties of todays highly evolved synthetic/blend oils.
forget about what ratio the pump injected, the stock blaster nor any of it's stock parts were designed for any type of performance what-so-ever, and that includes it's oil injection system ratio.
not that it doesn't work, it's just not a performance enhancer.
it's sole purpose was so any moron with at least 3rd world caveman intelligence could just add oil to a tank, and not have to do even 2nd grade math when mixing the fuel/oil mix.
hence the idiot light on the dash to remind said moron to do daily routine maintainence and check his oil level.
have a nice ride wasting oil and $ that simply is not required
and was that change in ratios without rejetting responsible for the rebuild ?
thats not common in given or searched for info, not suggested on any bottle of modern oil, nor currently used and proven mix ratios thoughout the ATV or MX racing communites.
99.99999% of jetting info on here, or searches, will be based on 32:1, or even 40:1 for liquid cooled machines.
richer than required fuel/oil ratios are an old wives tale from prehistoric times when the oils available
JUST PLAIN SUCKED, hence the need for more, as they only had about 1/10th the lubricating properties of todays highly evolved synthetic/blend oils.
forget about what ratio the pump injected, the stock blaster nor any of it's stock parts were designed for any type of performance what-so-ever, and that includes it's oil injection system ratio.
not that it doesn't work, it's just not a performance enhancer.
it's sole purpose was so any moron with at least 3rd world caveman intelligence could just add oil to a tank, and not have to do even 2nd grade math when mixing the fuel/oil mix.
hence the idiot light on the dash to remind said moron to do daily routine maintainence and check his oil level.
have a nice ride wasting oil and $ that simply is not required
Thats right, so with a 20:1 premix, you are getting less fuel to the engine, then if it was injected, IOW. With an air cooled engine your fuel is actually what helps cool your engine. It is a bad thing to be oil rich, but a good thing to be slightly fuel rich as long as you have a good oil ratio. Also at 5,000+ elevation you maybe ok with a stock jet, if you have no other mods
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