40 Years old needing advice

2 Strokes seem to be LESS finicky about jetting.
Interestingly, modern 4-strokes are more particular about the jetting of the pilot/idle circuit than any other aspect. They are extremely tolerant of jetting errors on the main circuit, and will seem to run quite well at larger throttle openings from pretty darn lean to ridiculously rich. It's mostly at light throttle that they're fussy. Since their oil doesn't come with the fuel, being lean isn't anywhere near as dangerous to them.

Is that why they're so hard to start hot?

The fussiness over idle mixture is one of the major reasons, yes. Also, when a 2-stroke dumps a table spoon of fuel into the intake of a stalled engine, it goes into the relatively large crankcase, causes a fairly small percentage change in the air fuel ratio of the overall volume, and is nowhere near the spark plug.

A thumper, OTOH, puts that same tablespoon of fuel directly into the combustion chamber, a much smaller space, and right next to the plug. It makes a bigger difference.

Ended up buying the YZ 450F. Has Mega Bomb header, and scared me when I tested it:-) Going to sell the Mega Bomb and put the stock back on it. My first 4 stroke and it feels like it shakes the earth.

Good choice!!! Just be prepared for some arm pump, trying to hang on to the beast is fun.

The 03 and 04 have a harder initial hit than my 07 which I believe can be subdued by another flywheel which is relatively cheap, if you believe its too strong. Someone else on here should be able to elaborate on flywheels for that particular model. The 450 is a good choice because the big 4stroke is so easy to ride. Just take it slow because of the abundance of power.

The 03 and 04 have a harder initial hit than my 07 which I believe can be subdued by another flywheel which is relatively cheap, if you believe its too strong. Someone else on here should be able to elaborate on flywheels for that particular model. The 450 is a good choice because the big 4stroke is so easy to ride. Just take it slow because of the abundance of power.

I also replaced my 04 with the 07, and I am in love, the 04 was like a tractor on the bottom, you had to hang on for dear life, pulled so hard that it was almost annoying, my 07 is more like a good 2 stroke 2fiddy, and it turns better lap times.

Ended up buying the YZ 450F. Has Mega Bomb header, and scared me when I tested it:-) Going to sell the Mega Bomb and put the stock back on it. My first 4 stroke and it feels like it shakes the earth.

After a 30 year layoff from dirt I went with the same thing, 2004 YZ450F. I've had it a few weeks now and love it. Been riding big heavy street cruisers for the last 10 years or so and now I'm going to the dirt to spend more time with my youngest son still at home. These bikes are light years from what I remember riding. :ride::thumbsup:

i am 35yrs old, i to use to race and ride alot when i was younger, i got away from dirt and started rideing street bikes when i turned 16, this past x-mas i bought my 15 yr old son a dirt bike and thought id get one too so we could ride together, i got him a yz 125 and i got a yz250f ,after about a mounth i felt i needed a bigger bike, i got a 06 yz450f, 15 days latter it got away from me and i tore all 3 major muscles in my knee, (acl,mcl, meniscus) i am supossed to have surgery on my knee some time this winter, until then i wear a donjoy knee brace to work every day, if you are not planeing on raceing id suggest the yz250f, if you get the 450 becareful, its a beast, good luck and have fun

:thumbsup: wow this is crazy I am 41 my first bike in 1981 was a 76 yz175 rode family enduros in th cali desert with bar benders west mc. had a few bikes on and off over the years now my son has a 05 kx250f i had to get a bike 98yz400f

to take him to the places we used to ride.:ride:

Took the beast (450F) out yesterday. Wow, the suspension is the best I've ever ridden on!The thing is fast...too fast. What are the best fixes to slow it down so I can enjoy riding behind my daughter on tight trails on her ttr125 and yet still enjoy my ride around the track.

Is that why they're so hard to start hot?

Also many poeple hold the throttle while kicking. This naturally causes a slight rocking motion in your right wrist which causes the accelerator pump to discharge a slight amount of raw fuel. 450 4 strokes DON'T like raw fuel when hot.......

I have tought myself to hold the right handlebar, not the throttle when kicking, my bike always reliably lites off with 1 or 2 kicks (and I also have a slightly fat pilot jet currently in my bike)

What are the best fixes to slow it down so I can enjoy riding behind my daughter on tight trails on her ttr125 and yet still enjoy my ride around the track.

My daughter also has a TTR-125 LE and we ride together. I just keep the 450F in 1st or 2nd and it's fine. I'm thinking hard about a flywheel weight and will probably get one soon.

I like riding the YZ with her better than my old KDX. The KDX was a great bike, but, being a 2-stroke, I was constantly having to clean it out when putting around. The YZ's much happier at putting.

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