Engine Running Too Hot . . .Melting Rubber Connector

Uptown_Blaster

New Member
Mar 15, 2010
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Philadelphia
I recently seized the crank on my blaster so I purchased a bottom end from another blaster and replaced the whole bottom end. My bike ran just fine before I replaced the bottom end.
I put on a new bottom end but I also got my hand on a new FMF front pipe and fmf silencer . . . . I orginally had a dg silencer and a stock front pipe. NOW, the rubber connector that connects the front pipe to the silencer is literally ripping apart from the heat. The only thing holding it in place are the metal clampe. The front fmf pipe sits inside the silencer( there is no gap between them).

I obviously still have the same carb and top end and my bike ran fine before but now the whole dam bike is like an oven. Even the spark plug cap seems to be slightly melting onto the spark plug. The bike now bogs when at wot as well, it didnt do this before!! All I changed was the bottom end and the front pipe and silencer. The bike runs pretty good as long as I dont give it a lot of gas. I cleaned the carb several times too

Could this be a jetting issue?? I know absolutely nothing about jetting or even how to find out what size they are.
Any Help??
 
Your jetting is wrong man. You have to increase your main a couple sizes to go from a stock pipe to an FMF.

You prolly siezed your bottom end cause you were too lean, and Ill bet youre on your way to siezing it again.

There are threads on here that tell you how to jet. Youre going to have to learn, or youre going to fry your engine again.

Basically the gist of it is, you remove your carb, pull the bowl off it, and take out the main jet, and replace it with a bigger one.

I believe stock jet is a 230? You should be running like a 270 or higher IIRC. (To be honest, I dont know jetting on a Mikuni carb so well, someone else is gonna have to chime in on this advice)

But yeah, you honestly should start by NOT riding your bike. Also, you can pull the spark plug out and take a picture of it. My guess is youre running lean and you are lucky you havent fragged your engine yet.

See if you can figure out how to get that carb off and see what main jet you have. Also pull your plug and see how it looks.

Pics really help us help you.
 
figure out how to do a leakdown test first. Then find someone thats really good at jetting or buy an EGT. jetting mistakes are expensive and an EGT costs about as much as the new top end you will buy if you get the jetting wrong.
 
figure out how to do a leakdown test first. Then find someone thats really good at jetting or buy an EGT. jetting mistakes are expensive and an EGT costs about as much as the new top end you will buy if you get the jetting wrong.

What is a EGT? Can't I buy a jet kit with several different sizes instead of juat one main jet size.
 
Get your jets from rockymountainatv.com or jetsrus.com

Mikuni jets are like 2-3 dollars a piece. Theyre cheap. You can buy the 5 you need for 15 dollars easy. Jet kits are a waste IMO. They give you crap you may or may not need. Just take yours out and see what you need.

Guys with pipes and stock mikunis, give this guy some idea on where to start with his jetting.

Im going to go with start with a 270 and range it up to a 320 (I doubt youll need as rich as a 320, but 270 should be a good starting point I think)
 
I found out I have a stock 230 main jet so I am def going to get a a 270 and prob a 280 and a 290 and check to see if I see an improvment. My next question is what is the significance of the needle. I have done some searches and saw some people talking about lifting or adjusting the needle in the carb to a third notch?? I have a removed the tors and I see nothing that is adjustable in the slide where the needle is held.

Thanks
 
first of all, check the compression and do a leakdown test to verify that the engine is still in good condition.

you have to pull a little retainer down in the slide, and then the needle will come up out of it, and there are notches on it