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Yamaha zeal 1991 fuel and
If your rings were shot and the engine was running you would see billows of blue smoke coming out the pipes, as well as oil. If not running, then your fuel would end up in your sump inflating the amount of oil in there. (this does happen on all bikes only ridden around town, get it out on the highway to burn off the excess fuel then recheck your oil level.)
I'm wondering if you left your fuel tap on overnight (if it has one) if so, then you will have fuel running back out either the carbs or the boot that goes from the carb to the engine. Oil will leak if your valve seals are shot. it is possible that it was only fuel that was stained with a bit of oil.
Yamaha FZX 250...
on Sep 17, 2011
I have a fzx 250
Sounds like lack of fuel to the engine. Has the bike been sitting for some time? You may want to pull the carburetor and give it a good cleaning payning particular attention to the jets. Don't use anything made of steel to clean your jets because you'll run the risk of enlarging and ruining them. I've had success using either wooden toothpicks (for large jets) or copper wire (small jets). Make sure you take your time and work very carefully when cleaning them; if you rush, you can end up with something broken off into a jet orifice and having to buy new ones.
Yamaha FZX 250...
on Jun 25, 2011
My 2008 Yamaha fz6 has a rough idle and it sputters until about 4000 rpm then it runs like a dream only have problems with low rpm and only when at operating temp?
Try the basics first. When was it given a Full service? (Spark plugs, air/oil/fuel filters and oil change. Have you got any warning lights on the dash? Has it been standing unused for a long time as sometimes a bad batch of fuel or old fuel can cause problems. Old fuel can go "Off" and leave a sticky varnish like coating clogging injectors and sticking valves.
Try this. When your fuel tank is down to about quarter full and the engine is cold add a bottle of injector cleaner to the tank. Start the bike and let it idle until it is up to working temperature. Don't 'rev it up' because at idle your getting a stronger mix of cleaner going through the injectors. Once she's warmed up take her out for a good long steady ride then fuel up on the way BACK home.
If this doesn't help you'll need to get a Good bike mechanic to look at it as it could be a worn engine part or an electronics issue.
on Nov 03, 2020
What should the cylinder compression be on a 1966 Yamaha 100cc twin jet motorcycle?
I remember these lightweight steeds that had an almost cult following in the UK, resulting in a large number of tuning parts becoming available at reasonable prices.
The noise of a gaggle of them pulling away from the lights all at once could and did break the windows of nearby houses.
The compression pressure of an exhaust tuned 2-stroke engine is necessarily quite low - because the cylinder capacity and the compression ratio "grows" at the rpm the reflected exhaust pressure wave effectively blocks the exhaust port and the engine power suddenly increases. Yamaha engines of that time were notoriously "sudden"...
I don't know the exact compression pressure but I would be happy if I did a test and achieved around 100 psi. My Suzuki of a similar design produced 105 psi on the kick starter. Much more pressure than that and there would be a danger of the fuel detonating in the cylinder when the engine "was on the port", usually resulting in a hole melted in a piston.
on Oct 16, 2020
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