My pipe doesn't seem to have any inserts. That can't be good - right?

Considering the general lack of availability, does anyone have any pictures and dimensions they could share?

Thanks!

I am not sure of the intake duct dimensions of a CT3 cylinder, but the CT cylinders I have use the DT100 reed block, which is also common to the TY175, and the intake duct is smaller than the later DT175, which uses the same reed block as RD250/350.

Its possible to modify the smaller intake ducts to take an RD reed block, and this makes quite a difference, and doesn't cost much if you can alter the duct yourself. Even bigger improvement can be had from a V/Force reed block, but these require more extensive mods to fit.

"My pipe doesn't seem to have any inserts. That can't be good - right?

Considering the general lack of availability, does anyone have any pictures and dimensions they could share?

Thanks!"

I'm pretty sure  ENDURONUT  produced a dimensional drawing of the baffle, maybe drop him a message if that's what you were referring too

Well i got the bike up to full power last and final bit was the exhaust flange gasket (the packing string)only £3 ....it was missing i didnt even know it shouldbe there....so the learning points were carbon on spark arrestor inside exhaust and no gasket in flange(air leak)thanks for the help and hopefully people can read this later and save some pain haha.
 

Yep, them exhausts have caught a lot of people out that's for sure.
First port of call for serious lack of performance. Well, that & a few other things.

Something to keep in mind is to look for complete pipes with the insert.  You buy the whole pipe and ask the seller to remove and ship you only the insert to save money on shipping costs.  They can sell what's left or toss it, their choice. 

Use Gr8uncleal's strategy as well and keep an eye out for "parts lots".  Sometimes you get lucky and sometimes you can buy the lot and just ask the seller to ship what you want and they can toss the rest or sell it again.

I've seen complete pipes with insert sometimes sell for a fraction of what an insert goes for by itself... and I have used the above strategy successfully.  Some sellers won't remove the insert even if you buy the complete pipe, so ask first. 

You can check part numbers, but I'm pretty sure 69-73 AT/CT used the same insert. 

Here's one of the threads where Enduronut posted the drawings of the insert(s) with dimensions.  Unfortunately, the drawings are missing. 

yamaha-enduros.com/index.php/forums/gene...st-silencer?start=10

I’ve been following this thread as mine acts the same. However mine has 450 original miles. However it was running great 2 to 3 weeks ago. Rode it Monday.... revs out fine just after warm up. Then by 3rd gear and up... low revs &40 mph max. Changed plug. No change. Fuel flow seems fine, bout changed inline filter anyway. Same thing. Removed and cleaned out carb. No change. Air filter was new about 100 miles prior.

Video is great to help but not easy to do while riding & to get a good audio.
450 miles from new sound great. Where'd you find a Gem like that.
I could say exhaust but unlikely at that mileage unless loose lumps are floating around & blocked it from the inside end of the baffle. Na forget that thought although could pull baffle & go ride if you can stand the noise.
Low revs @ 40mph max!!.
Revs should be the same now as they've always been at 40mph in 5th gear.
Maybe i'm mis-understanding your meaning.

Try loosening the gas cap to see if maybe it's vent hole is plugged.