Exhaust Crossover Removal

[Pardee]

Has anyone else removed the exhaust crossover from their TX750?

Curious to see how it reduces heat on the top end of the engine.

[argo1974]

Yes, it will reduce top end temps so the engine is less prone to detonation and oil leakage from cylinder head/head cover area. Also oil temps will go down but not as significant as Yamaha already works with "reduced oil flow to top end" concept. The idea behind this concept is to direct as less oil flow to top end as possible - only to ensure adequate lubrication, not cooling the head internally. Engine oil would have less temperature load and its volume could be kept smaller, while longer oil change intervals can be adapted.

You can set the carbs little leaner as well to reduce fuel consumption after that mod.
Expect also less torque below 2000-2500 rpm and different sound.

You can also keep the crossover pipe for design reasons by filling the middle section with weld on both ends and cutting the middle section to form cooling fins (keep few bridges to prevent cracking/singing).

[Pardee]

I will definitely try welding / capping the center section.

That never crossed my mind.

Thanks Argo.

[CalsXS2]

Aug 1, 2014 7:49:55 GMT -5 argo1974 said:

Yes, it will reduce top end temps so the engine is less prone to detonation and oil leakage from cylinder head/head cover area. Also oil temps will go down but not as significant as Yamaha already works with "reduced oil flow to top end" concept. The idea behind this concept is to direct as less oil flow to top end as possible - only to ensure adequate lubrication, not cooling the head internally. Engine oil would have less temperature load and its volume could be kept smaller, while longer oil change intervals can be adapted.

You can set the carbs little leaner as well to reduce fuel consumption after that mod.
Expect also less torque below 2000-2500 rpm and different sound.

You can also keep the crossover pipe for design reasons by filling the middle section with weld on both ends and cutting the middle section to form cooling fins (keep few bridges to prevent cracking/singing).

Did you do this to your bike. Got any pics. Thanks

[vanislejay]

Any other pics of this mod or a link with more pics or details? Is it a fab job or what parts are used for this?

What about installing a crossover further away from the motor like a most other bikes? Would this get the heat elimination benefit without the loss of torque?

[Pardee]

When I have time, I'm going to weld mine.

I will take some pictures.

[vanislejay]

So I guess that's not your bike in the photo?

Is the heat reduction from eliminating the heat sitting in the crossover (I assume this is correct), or from heat blowback into the cylinder while scavenging?

[argo1974]

I'm following different philosophy while building my current TX engine, so I left the crossover alone. But I've tested in the past how "it feels" without crossover. Back then, cutting out the entire center section and filling the holes with weld from outside was pretty common in Europe due to higher speeds on roads causing also more heat (picture found in internet):



There are several TX's around in Germany with crossover pipe cut and welded from bottom/back side so it looks pretty stock. But why not to weld it shut through exhaust passages on both sides L and R and just design the center section as cooling fins?