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162
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4/1/2008
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US
Edited Date/Time
1/27/2012 12:40am
So Boyesen says to lean the main jet after installing the rad valve. Why is that? I assumed the rad valve let's more air in the engine, so larger jets are needed. Can someone smarter than me explain why this is?
The Rad Valve increases the vacuum signal on the carb so more fuel is pulled into the engine, which causes a richer condition. You need to lean the jetting to compensate for this.
rear end on a Plymouth work? It just does.
rear end on a Plymouth work? It just does.
rear end on a Plymouth work? It just does.
Posi-Trac is a GM term. Mopar used the term Sure Grip. So to answer your question, it doesn't.
Just an FYI.
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My top end was rebuild a few months ago (new piston & rings) and it still pings - more now than before. It pings when I'm on the gas, especially in mid & upper RPMs. It is even worse when the weather warms up. I've lived with the pinging since I bought the bike 2 years ago, but after installing the RAD valve it's much worse.
I use 93 pump gas, haven't tried race gas and don't have easy access to it.
I want to try going one size larger on my main jet but I don't want to damage anything.
Just an FYI.[/quote:2vzah2ny]
So your gonna' tell me that you don't have no black cats, no roman candles, or screaming mimis? You're gonna stand there, owning a fireworks stand, and tell me you don't have no whistling bungholes, no spleen spliters, whisker biscuits, honkey lighters, hoosker doos, hoosker donts, cherry bombs, nipsy daisers, with or without the scooter stick, or one single whistling kitty chaser?
I'm almost afraid to try race gas. It's too much bike for me as it is.
Race gas is good. Pump gas is liquified garbage these days.
What about the 110 octane pump gas they sell near Road Atlanta? It's not advertised as race gas but is it safe to run in my bike?
What about the 110 octane pump gas they sell near Road Atlanta? It's not advertised as race gas but is it safe to run in my bike?[/quote:29xryqek]
I don't know about that - I haven't seen any 100+ pump gas in years. What kind of bike is it?
I'm sure it's plenty safe - race gas is just more consistent and is better in two strokes. Most bikes can run on pump gas safely, but they are more sensitive to jetting and if the gas is a little leaner than normal or the air is a little denser than normal or???, then they might ping some. With race gas, you pretty much jet it and forget it.
it is a kx 250.
Pinging isn't good - sometimes it's not jetting; sometimes it's an air leak in the rad valve manifold or even (heaven forbid) left side crank seal. I'd talk to some people who can ride it and listen to it, pull the plug and see if it's the right color, stuff like that.
My bike starts very easily.. usually on the 2nd or 3rd kick. I've never fouled a plug and it feels very crisp. I always turn the gas off after riding (usually a minute before to make sure most of the gas is out of the carb).
So...
I just took my carburetor off. My main is 155 and pilot is 142, both one step down from stock jetting (according to Clymer anyway).
[img:1b6q2d30]http://i162.photobucket.com/albums/t274/queen_of_spodes/mx/S6300747.jpg…]
[img:1b6q2d30]http://i162.photobucket.com/albums/t274/queen_of_spodes/mx/S6300749.jpg…]
[img:1b6q2d30]http://i162.photobucket.com/albums/t274/queen_of_spodes/mx/S6300750.jpg…]
So if it's pinging and my plug isn't tan, does that mean the crank seal is bad? The rad valve bolts are snug and it has a brand new gasket.
rear end on a Plymouth work? It just does.
Daaang!
I just read your last post. With the rad valve, and especially if you have an aftermarket pipe, you'd want to go up from stock on the jet sizes
Pit Row
Yes it has a FMF pipe and silencer. (and a flywheel weight according to the last owner)
Yes it has a FMF pipe and silencer. (and a flywheel weight according to the last owner)[/quote:2bpx4qb0]
Then you probably do need to lower the clip on the jet needle, and most likely go up at least one size on the main jet.
I would try the high octane pump gas first, and see if that helps you out. It's got better knock/ping resistance, and probably a different density than the premium 92/93 gas. If that doesn't help you then I would change the jetting as mentioned above.
Looking at the plug, it doesn't look likely that you have a leaking crank seal.
Higher octane gas sounds like the ticket to me, though. 2 strokes don't seem to do well on pump gas that has a lot of ethanol, like a lot of blends do these days.
do you let that thing idle much and put around quite a bit?
you have so many quirks going on there you better slow down and think this through. let's see a good pic of plug first before we start changing the jetting.
how do you even know it's detonating, could your chain be slapping the swingarm causing that noise?
do you let that thing idle much and put around quite a bit?
how do you even know it's detonating, could your chain be slapping the swingarm causing that noise?[/quote:2j4qhy2g]
That's the best my camera can do. Sorry.
I don't idle much at all. Sometimes I put around but clear it out every few minutes. Most of the time I ride like DV12 & Trey Canard gooning, but not on purpose. lol.
So, when I accelerate on the track the engine makes loud pinging (like big needles clicking together) noises. If I let off the throttle the pinging stops. If I only open it up halfway there is slightly less of the pinging. If the weather is warm I really notice it. When it's in the 40s and 50s it doesn't ping much at all.
Most octane booster are nothing more than overpriced Toluene. The problem with Toluene is that when you add enough to make the bike quit pinging, you lose throttle response.
I'd suggest that she start running 1/2 pump premium and 1/2 VP C12
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