Intake manifolds less than 41mm

[Mincehead]

Yep rotary burr does the job, then finished with fine emery wheel.Obviously with tools small enough to carry out the job, in my case with an air powered die grinder.
It`s important not to have any steps that`ll create eddies/vortex`s in the flow/velocity of the intake mixture.

http://en.wikipedia.org/wiki/Eddy_(fluid_dynamics)

http://en.wikipedia.org/wiki/Vortex

[Redog1]

OK thanks.
I'll give it a go.

Cheers

[Redog1]

Yep rotary burr does the job, then finished with fine emery wheel.Obviously with tools small enough to carry out the job, in my case with an air powered die grinder.
It`s important not to have any steps that`ll create eddies/vortex`s in the flow/velocity of the intake mixture.

Hay, I was surprised how badly the intake manifold mates with the cylinder head. Instead of a nice smooth seamless transition, there are a couple of 2mm protrusions on one side. Would have to take the head off to grind them away. Don't like the idea of stuffing rag into the intake port to catch the debris.

Anyhow, job nearly finished. My die grinder is excellent, but my compressor is lousy. Have to give it long brakes to catch it breath.

Cheers

[Mincehead]

A good fitting piece of sponge works well, especially if you oil it lightly first.Then you can use a pair of long nose pliers to pull it out.
All the aluminium grindings just stick to the sponge surface and in the cells, open cell types are best like that used for filters in fish tank power filters etc.
I`ve always got plenty of it around as I`m an aquarist too.
Any fine particles will stick to the side of the inlet due to the light film of oil, you can then use a small piece of dry, lint free rag in the long nosed pliers to wipe it up and out of the inlet port, done carefully it`ll be fine.

[Redog1]

Ok
I'll give it a go on the weekend.
Are you surprised how poorly these components mate up?
Or is my bike just a Friday bike?

Cheers

[Kayla]

Ok
I'll give it a go on the weekend.
Are you surprised how poorly these components mate up?
Or is my bike just a Friday bike?

Cheers

It's just general production tolerances, isn't it? I did a TZR250 a few years ago and just cleaning the ports and matching stuff up makes a difference (but not actually tuning it), and it's strangely satisfying

[Mincehead]

Yep, just poor QA and tolerences from the way things are mass produced.Now if it had been a motor from a Bimota, everything is hand fettled to a high quality.

[Quan-Time]

Factory fitting is quite poor. I noticed a bit of flow increase with some light work.

As for the 38 VS 41mm bore size. Jetted correctly, the 41s will always be better on any given TRX setup. They start to shine when you fit exhaust and cams, or possibly a bore kit. Please let it be said on record, that the TDM900 has 38mm throats too.

There is a huge technical reason why 41 works BETTER, but 45s would kill power, but on a worked engine, 45s could be better again (45s would suck on stock exhaust / cam / bore). If any wants to know, i can probably do one of my huge ass spiels about it.

I just had a old Japanese head on a P4 race bike to flow. Not bad for a hemispherical 2v engine.
Someone would have to nudge me with a PM if you want details.

[Redog1]

Factory fitting is quite poor. I noticed a bit of flow increase with some light work.

As for the 38 VS 41mm bore size. Jetted correctly, the 41s will always be better on any given TRX setup. They start to shine when you fit exhaust and cams, or possibly a bore kit. Please let it be said on record, that the TDM900 has 38mm throats too.

There is a huge technical reason why 41 works BETTER, but 45s would kill power, but on a worked engine, 45s could be better again (45s would suck on stock exhaust / cam / bore). If any wants to know, i can probably do one of my huge ass spiels about it.

I just had a old Japanese head on a P4 race bike to flow. Not bad for a hemispherical 2v engine.
Someone would have to nudge me with a PM if you want details.

================================================================

Thanks for the reply.
I guess I can't understand why it would be beneficial for the air to slow down through the carby. Which it must do if the carby venturi is larger than the intake manifold.

Cheers,