F2 thruster exhaust pipe

Wevil Kenevil

Wevil Kenevil

Well-Known Member
I recently got an f2 pipe and feel that there are a few things I can share that may be helpful in determining " where and if" you are thinking about getting one.

In a nutshell you get the power upgrade but at a cost in noise and oil blow by.

There is remedy for this. 2 actually...
1 being cutting a small pie wedge into the pipe and bend it over and weld it closed...

OR if you don't have a welder and you can fit it on the end of the pipe, an aftermarket muffler.

They are 20 bucks on Amazon and you can cut them to whatever size is suitable.

On my bike it rides so close its literally pointing at the back rim spewing little bits of oil on it. As to be expected with ANY pipe on any two stroke motor.

Making it a danger to anyone using rim friction style brakes.

TAKE THIS WARNING SERIOUSLY. Think about it... Makes you go faster but depletes your stopping ability on half your bike.

I use disk and have been checking it regularly before I ride and haven't seen and blow by on my disk.

Now the flange, it's not very thick and was warped from the humongous weld they attached the pipe with. I just filed it down so an hex head will sit flat on the flange and flattened the flange so it sets flat.

Now the burn factor, don't think "I will just ride with my leg held out like this", and go ride.

This pipe is short and HOT AND without pipe wrap on it YOU WILL BURN YOURSELF. Just trust me on this.

Another thing is installing it...

It loops back so tightly that getting the bolt in and threaded properly is something to be aware of.

I just cut the tip off an Allen wrench to be able to bolt it on as there is no straight shot to it.

AND DONT BUY KNOCK OFFS OR CLONES... they are hap hazardly welded and are not cut to length to be in tune with a bike. I've seen several that were knock offs and they are junk.

Don't get me wrong, I like the pipe. It just comes with a cost.

That's about all I have to share with my experience with it.

I hope it's helpful and if you have any questions message me or leave a post and I'll answer whatever I can.

Peace y'all!
 
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To alleviate the pipe being pointed at the back tire I cut a small "wedge" out of the stinger pipe and bent the pipe down and away and it works great.

I also had to do this for space for a muffler tip for the pipe.

The pipe is good BUT... I'm not so sure it would be a wise investment for somebody that doesn't have a welder or isn't good at fabricating parts. On the ld100 cylinder it's a tight squeeze and a sumbish to mount.
 
That is close enough to almost warrant taking a little bit off of the fins so they don't rub the pipe
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Wevil Kenevil said:
That is close enough to almost warrant taking a little bit off of the fins so they don't rub the pipe
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Click to expand...

Thank you Tony, I appreciate the thumbs up as this is a little more in-depth and daunting than I had originally anticipated.

Just to add clarity to my post for new builders...

This only occurs with the LD100 50 MM cylinder AND billet Hi Compression head .
I imagine almost the same for YD100 one piece cylinder as both the LD and YD are both @1/3 bigger in both diameter and in height.

But this does not apply to all 50 mm cylinders as there are the smaller 46 mm cylinders that have been bored out to 50 mm leaving the sidewalls of the cylinder extremely thin and vulnerable to being blown out. And I think the reason for this phenomenon is because of a surplus of the smaller motors and people wanting a larger cylinder..

You can check this by examining/ measuring the distance of the center of the bolt holes on the top of the cylinder .

The LD cylinder is 70mm from center point to center point of the bolt holes on the top of the cylinder ***DIAGNALLY*** NOT RUNNING FROM SIDE TO SIDE OR FRONT TO BACK I will definitely take a measurement and come back and post the measurements that I found in the differences between the two.

Being fairly new TO building bikes from scratch from ground up myself I was unaware that there was a difference so I kind of lucked out the way it worked out for me.

It might not be the same for you depending on the configuration of the frame and the parts that you're adding to the motor itself.

I would suggest to everyone to quadruple measure everything just to make sure you don't order useless parts for your build or miscalculated clearance or tolerance for another part ect...

Most if not all of the cylinders or cylinder- piston- and head upgrade kits on ebay FAIL to show the exhaust port which is EXTREMELY THIN WALLED (3.2mm), LEAVING VERY LITTLE FOR THE MUFFLER FLANGE TO MATE TO TO GET A GOOD SEAL.

Wrench said something about the pre-built kits coming with an exhaust pipe that matches that but I have yet to find one for sale outside of a whole kit but I'm still looking.

I just took a chainsaw file and hogged out the hole on the f2 thrust pipe to more closely match the aperture of the exhaust port. But all that did really was just give me less flange area for the exhaust to attach and seal but it seems to be holding for now.
 
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F2 thrust pipe?
i love the thrust F2, it will need to be ported on the end that bolted to the cylinder (Dremel it out).... besides that it's great :) i love the noise!!

for keeping spurting oil off the rim i zip tied a curved radiator rubber hose to the pipe ;)
 
Testname111 said:
F2 thrust pipe?
i love the thrust F2, it will need to be ported on the end that bolted to the cylinder (Dremel it out).... besides that it's great :) i love the noise!!

for keeping spurting oil off the rim i zip tied a curved radiator rubber hose to the pipe ;)
Click to expand...


Good idea!!! I had to cut a small wedge out of the tail end pipe and bend it down and away from the bike and weld it because it rubs on the back wheel. Now it points down more to the ground and doesnt give me an oil slick harrry back wheel..
 
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