Tanaka pipe problems.

Jemma Hawtrey

New Member
Dec 29, 2007
288
2
0
Essex, UK
I got hold of the tuned pipe finally and its fairly well built and of good quality.

However I am having some problems. the first of which being that the manifold part is about 3 inches longer than expected so all in all the exhaust in total is long enough that it is sticking out inline with the handlebars on that side... not really what I want.

My first question is can I shorten the manifold length without any problems?

The second problem is that when the bike hits 31mph it spits the pipe out of the manifold at one end and the silencer at the other. I am guessing that means the pipe 'comes on' at that speed. What can I use to seal it so I dont have an unguided missile attached to the back of a bike. I have tried an interferance fit and superglued the joint to no avail...

I am going to try and have a word with a local exhaust fitter so I can get the manifold pipe bent 90 degrees and might even get them to fit it up for me if their price is good.

Jemma xx
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
6,621
432
83
Los Angeles, CA.
If you engine is a 4-stroke, the length of the pipe shouldn't matter that much...
If the pipe keeps coming apart like that, it could mean too much back pressure?
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
236
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up north now
Jemma- If you change the length of the pipe ahead of the chamber, you'll change the RPM that it comes on the pipe. Shortening makes it (manifold) makes it get up on the pipe at a higher RPM. For optimal power, you'll need to find the RPM at which your engine makes the best torque and then set the pipe to come on there, for highest speed, find your peak horsepower RPM and set the pipe to come on there. Either way you will experience a large gain over a small range of RPM. You will more than likely have to play with the jetting a little so you don't burn your engine up, you will have to go richer for sure!

Also, could you just drill a couple of small holes and use some self tapping sheet metal screws or rivets to hold it all together? Three set at 120 degrees apart should be strongest.
 

Jemma Hawtrey

New Member
Dec 29, 2007
288
2
0
Essex, UK
Hi Joe,

I was hoping that it was the opposite - shortening would drop the RPMs because if it comes on the pipe at 31mph headwinds of any strength would make the thing useless unless I get a longer manifold built.

There is not a single company in my town who can or will help me adjust the shape or length of the manifold - even 'engineering firms' cant or wont. Is it me or are are people getting less helpful as the years go on? :(

I did think about drilling and tapped screws but there is very little room to do that and I dont want to block things up any...

I'll think of something..

Jemma xx
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
236
63
up north now
Do ou have a photo of the pipe? I could brainstorm more if I could see the pipe.
If you use small. 1/8" rivets, very little will be inside the pipe to block flow.
 

Ilikeabikea

Moderator
Staff member
Jan 27, 2008
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Ptown, Texas
Jemma, could you put a self tapping screw in. Then take it back out and grind the end off the screw where it would just barely go through and then put it back in with some JB Weld. That should hold it..........