cause of overheating


21 replies to this topic
  • RJC

Posted May 23, 2005 - 02:36 PM

#1

This seems strange to me. I changed the main jet and pilot on the carb. put needle in 3rd position. Bike was initially hard to start. but when it did start took it for a spin around the neighborhood. Stopped and the coolant was boiling. Pipes near cylinder were bright blue. Doesn't seem logical just a jet change could be related to the dramatic overheating. Any ideas? Bike was running fine before.

  • BWB63

Posted May 23, 2005 - 02:49 PM

#2

Did you change the intake manifold (called an insulator, rubber intake boot between the carburetor and engine) It must be change to the HRC one or modified (easy to do) to be like the HRC one. Rubber and plastic plugs have to be taken out of the air box. They are right, above the air filter, below the seat. Then you have to open up the exhaust, drill out the stock tip with a 2" hole saw or buy an HRC tip or a slip on muffler.

  • don87xr600

Posted May 23, 2005 - 05:49 PM

#3

Did you put smaller jets in, if so this could cause overheating.

  • frankstr

Posted May 23, 2005 - 06:37 PM

#4

What jets were in it, and what jets did you install....... :)

  • RJC

Posted May 23, 2005 - 06:38 PM

#5

Did you change the intake manifold (called an insulator, rubber intake boot between the carburetor and engine) It must be change to the HRC one or modified (easy to do) to be like the HRC one. Rubber and plastic plugs have to be taken out of the air box. They are right, above the air filter, below the seat. Then you have to open up the exhaust, drill out the stock tip with a 2" hole saw or buy an HRC tip or a slip on muffler.

I don't see the plugs in the airbox. Here's some pics. Maybe you can tell me what I'm not seeing here. And a shot of the exhaust. 2nd pic is airbox from inside fender
Posted Image
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  • frogman

Posted May 23, 2005 - 06:46 PM

#6

What size main jet did you put in it???????

  • RJC

Posted May 23, 2005 - 06:51 PM

#7

What jets were in it, and what jets did you install....... :)


The HRC carb insulator is in there. I swapped out 178/65s jets and put in 175/68s jets. cleaned the carb, set float to spec, needle set-#641 and clip in 3rd position. New gaskets, diaphragm checked OK. With the old jet setup, the bike started on 2nd kick every time but was sluggish. Now, the bike is harder to get started but it wants to fly in almost every gear. And there is now less popping on decel. I don't quite know where to go from here. :D

  • Max Power

Posted May 23, 2005 - 07:21 PM

#8

I want to see a pic of the plug and did you change the intake manifold?


And clean that chain. :)

  • frogman

Posted May 23, 2005 - 07:40 PM

#9

Just buy an Edelbrock and live happily ever after, you going to get one anyway, just "do it"!

  • don87xr600

Posted May 23, 2005 - 09:24 PM

#10

Put the 178 back in.

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  • RJC

Posted May 23, 2005 - 09:33 PM

#11

Put the 178 back in.

I'm thinkin' about it. Amazing how these little piss whistles can make a difference in something you come to rely on 100%. :)

  • frogman

Posted May 24, 2005 - 02:17 AM

#12

The HRC carb insulator is in there. I swapped out 178/65s jets and put in 175/68s jets. :)



The HRC intake manifold has no "insulator" the steel piece in there has to go, its really not an insulator, its really just a plug.

Get the Honda intake manifold without the steel device or cut that one out. Theres no use going any further with the jetting till you do.

Why did you put in a smaller main jet if your goal was to open up the airflow? Remember more airflow needs more fuel.

I'd still get an Edelbrock or a Mikuni pumper if you're serious about riding the bike a lot without a lot of problems with starting, stalling and popping.

  • RJC

Posted May 24, 2005 - 10:01 AM

#13

The HRC intake manifold has no "insulator" the steel piece in there has to go, its really not an insulator, its really just a plug.

Get the Honda intake manifold without the steel device or cut that one out. Theres no use going any further with the jetting till you do.

Why did you put in a smaller main jet if your goal was to open up the airflow? Remember more airflow needs more fuel.

I'd still get an Edelbrock or a Mikuni pumper if you're serious about riding the bike a lot without a lot of problems with starting, stalling and popping.

If you mean the rubber collar that goes from the front of the carb to the cylinder intake, I have that in. My air box doesnt seem to have the inserts to remove (take a look at the pics) so I was going to get a Barnums Pro screen for the left panel. Also, if I left the 175 jet in and put the 65s back in would it make the bike run cooler?

  • qadsan

Posted May 24, 2005 - 10:35 AM

#14

RJC,

The plugs being talked about are just above the air filter. If you look at this picture you'll see two rectangualr cutouts just above the air filter and to the sides of the zeuss socket. Those sockets used to have plugs in them.

Posted Image

Here's a picture of one of the plugs being removed.
Posted Image

  • 1biglung

Posted May 24, 2005 - 10:45 AM

#15

Another thing to look at is make sure you don't have a vacuum leak between the carb and the head. This could create a serious lean condition.
Easy way to check is while running hit the connections with some carb spray. If the idle goes up you have a leak.
Its real easy to knock something loose while playing around.

Good Luck

  • don87xr600

Posted May 24, 2005 - 01:57 PM

#16

If you mean the rubber collar that goes from the front of the carb to the cylinder intake, I have that in. My air box doesnt seem to have the inserts to remove (take a look at the pics) so I was going to get a Barnums Pro screen for the left panel. Also, if I left the 175 jet in and put the 65s back in would it make the bike run cooler?

No you can't make it run cooler by putting smaller jets in.

  • RJC

Posted May 24, 2005 - 06:54 PM

#17

I want to see a pic of the plug...

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Here it is. too rich right? Bike is uncorked, and all mods, 175 main/68s pilot. air filter clean.

  • Max Power

Posted May 24, 2005 - 07:51 PM

#18

Oh man..... I say you are LEAN. What plug are you running?

Here is my plug that I changed out at the beginning of the season.It has about 200 hours on it.

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And I run my bike lean. 160 main, needle in the first clip. Stock slow jet. But most of my riding is done at a density altitude from 4000 to 10000 feet.

  • RJC

Posted May 24, 2005 - 10:01 PM

#19

The plug in the photo is standard K22PR-U11. It wasn't really oily. Just kind of black residue that was like burned on to the plug. That's lean?

  • frogman

Posted May 25, 2005 - 12:42 AM

#20

Wow, he actually went an took a picture of the plug!
Now thats a man that wants his bike to run!

See that brown color, thats good, just that the plug is old.
Get a new one.

You need to take off the "Rubber collar" that goes from the front of the carb to the intake on the engine, take that off and look thru it, if theres a metal plate inside reducing the inner diameter than that intake is stock and needs to be replaced with the HRC unit.





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