OK got the 351 BB installed with the TM36-68 carb. Got the bike started up and it fires to life right off. Im keeping it running between 3-5,000 rpm for the first heat cycle. While running I notice the stock 300 headpipe glow bright red. I suspected a lean condition so I worked the choke to give it more fuel and the pipe went back to normal and I managed to finish the first heat cycle. The tm36-68 pumper has the following: Pilot: 17.5, Main: 125, Needle jet: P4, Jet needle: 9DZH6-50. I was suppose to get the 130 but the 125 was installed.

If you noticed I have a 9DZH6-50 and not the 9EBY01-50. Does this matter? Also how do you adjust the needle position on the TM36-68? Do you simply remove the small cover on the top to access the needle? Another question for those that have done the 351 with the tm36. Does one of your fuel lines contact the return throttle cable stay?

Sorry for all the questions.

 

too much fuel maybe?

I know when I had the stock setup, before I got a DynoJet kit installed, that the header would glow cherry red when sitting with the choke pulled on idle,

I asked afterwards, to the guy who installed the kit, and he said the carb was dumping to much fuel, and thats why the header would glow cherry red,

after the Dynojet kit install, I still have to pull the choke to start it, put it warms up quicker now and stays running, without needing to have the choke pulled.

I'm sure others have done the 351 BB kit, and help,

I would contact who you bought the kit from and ask also.

I would also say that if you think you have the wrong jet needle, that would certainly be a problem.

my guess would be too much fuel, but then again, that is just my opinion, I am not a expert. I may have it backwards, maybe the motor is not getting enough fuel.....

 

I had the same problem my first time around with the 351. It ended up being that I was running too rich and I was dumping fuel into the header where it was burning up and causing the header to get really hot. I didn't notice it until nighttime. I was using the stock carb however.

 

Definitely running lean with a 25 main jet. Also when the choke is worked when the bike is running the pipe returns to normal.

 

Yes, you can adjust the needle position by just popping out the two top cover screws and removing the allen head plate screw that retains the needle. Be careful not to lose the washer on the needle or forget the orientation of where it went. I do this frequently when going from my home area of 1700' to places that go from 4000' to 9000'. I run a 127.5 main normally unless I'm going to be at 9000' to 13000' with some regularity...then I go to a 125. However, I run a KLX300 cylinder instead of a 351, though I do run a topless airbox and a full Muzzy exhaust.

I'll be interested to see your results with the needle you list in your post. Not saying it can't work, just let us know how it performs.

 

Do you know the difference between the two jets?

 

I noticed on my wife's bike (2006 Yamaha XT 225) if you leave the choke on too long the pipe starts to get red. On my bike I can shut off the choke in like 15 seconds and the bike will idle fine.

 

Not a big deal.



All single wall exhaust head pipes will glow if left sitting and running. Why, you may ask?

"The temperature inside the exhaust manifold can range from 600-1200 degrees Celsius"
- Exhaust Gas Temperature Monitor For An Internal Combustion Engine - University of Victoria

That's roughly 1100°-2000°F for those using English measure.

When does steel glow and what colors you may also ask?


400°C 752°F - Red heat, visible in the dark
474°C 885°F - Red heat, visible in the twilight
525°C 975°F - Red heat, visible in the daylight
581°C 1077°F - Red heat, visible in the sunlight
700°C 1292°F - Dark red
800°C 1472°F - Dull cherry-red
900°C 1652°F - Cherry-red
1000°C 1832°F - Bright cherry-red
1100°C 2012°F - Orange-red

You can't defeat chemistry and physics, even with perfect jetting if the bike sits, the exhaust will glow. Even when the bike is moving the exhaust temps inside are in those heat ranges. The pipe doesn't glow due to the cooling air. So if you don't want it to glow - Ride it!

I once let my SR500 warm up, it was 27°F and I let it idle for about 5 minutes or so. The pipe was glowing cherry red - bright cherry red - about 8" up the pipe. The head pipe was well blued. I rode it away, the glow was gone in about 1/2 block. No problems with the bike, just the way it was with the single wall head pipe.

It is normal. Just ask Ford and Cosworth...

 

Two jets or needles?

 

Needles. The carb they sent me has the 9DZH6-50 needle but I see others are using the 9EBY01-50.