Exhuast is melting air filter box

We checked the carb boots for leaks and nothing there. I'll try again to see if there's any leaks though. When you say hot start how do you check for a leak with it? The kid that owned it before me cut the air filter box down in the back. Would that cause the problem?

Well first of all when its running try pulling the hot start lever and see if it changes rpms

As for plugging it remove hot start fitting from carb.chech the o ring on the plunger and also try plugging the air passage and then run it to see if pipe still gets hot that fast. I have to say don't dump off the bike keep looking for what is causing it to run lean you will eventually figure it out

The hot start air passage is entirely internal to the carb.  How exactly do you propose to plug it?

Well I'm no rocket scientist but I could figure out you need to use something as a plunger

Its pretty simple to replicate a plunger

The best thing to use is an actual plunger with a good seal on it.  Don't complicate simple things.

Ya I guess you are right. Electrical tape on a screwdriver is getting a bit too complicated...

I have ordered all new seals for the water pump and hot start. I'm also welding a small crack on the mid pipe where it connects to the muffler and repacking the muffler to see if that helps. Thanks everyone for all the great help!

Keep us updated

So we replaced the water pump rings and the hot start seal. We tested the hot start and it seems to work fine. We started the bike and when I pull the hot start it drops rpm's significantly. It definitely helped to keep the bike from running so hot but unless I'm riding it, the mid pipe still seems to be getting very hot, almost red hot. The dealer told me they run hot so is that just how they are? What is the difference in the Yamaha trail bikes that keep them from running so hot?

They do run hot and it is normal for header to glow after idling for a couple minutes but the mid pipe definitely should not glow red.

Have you checked the spark plug after letting it idle and the midpipe gets hot to see what the Afr is like

The spark plug won't tell you that.

Lean or rich

Nope.

Wat do you mean?

Does plug check not work on idle? Explain

Spark plug is fine but it's still idling high. I have heard you can adjust the pilot by lowering or raising a couple notches. Is that worth a try? 

Look up on here how to jet pilot circuit.... The clip positions I assume you are talking about are on the needle and the needle generally affects 1/8 to 7/8 throttle, not idle.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now