It turns out that I have to modify one exhaust tube after all. The engine was not level when I took the picture below and once I leveled it off the tube shown below hit the engine subframe and I will need to reroute the tube back and to the left about 1" to give me the desired clearances/engine position. Still examining it to see how I have to make the cuts to make this as painless as possible...

I studied the plans to see how the exhaust is routed and it basically just states that it should be located on the passenger side of the vehicle. Looking at the pictures in the plan set *real* closely it would appear that the exhaust pipe comes from the 4-to-1 collector and then snakes between the intermediate shaft and the lower rear tube of the engine subframe. I also looked at Alex Smith's Vortex website and from what I can determine it looks like he might have done the same thing.

I have been perusing through eBay at nights to see if I can pick up an extra exhaust system. I figure that if I can get one cheap enough then between the two sets I should be able to cut/assemble/weld up one that will fit more-better into the area that I have to work with. It should be easier than to try to fabricate up some of the parts from scratch even though I do have a hydraulic tubing bender.

I contacted a company that would custom make one to my dimensions and they said that it would cost approximately $325.00 plus $65.00 for the sending unit - ouch!

I ended up finding this fuel cell on eBay (where else?). It is an aluminum fuel cell manufactured by RCI, it also came with the 90-ohm sending unit and has the capacity of 12 gallons and it's size is 18 " W, 12 " D, 12" H, so will fit pretty well. The top of it has the sending unit, a #8 outlet, #8 vent and #8 rollover valve as well as the filler. The trade off was a couple of gallons storage for a savings of about $240... I can live with that!

Here are some pictures:

I may have to make up a mounting bracket and possibly rebuild it but it is a good start!

Today I built the front engine mount, it is a bit more involved than making the rear mount. The first order of business is to ensure that the engine is level, this will depend on the motor that you are using. If possible seeing the motor in the original bike chassis is preferred as inline 4 cylinder engines typically want the cylinders at a predetermined angle. One thing that may help out is that the oil pan is typically level with the ground, worse case is to remove it and level the engine off in the engine subframe.

In my case since I am using a V-4 engine I had no room to put a cross member behind the headers and instead had to make a front engine mount that more resembles a trailer hitch that would go onto a car. I cut 2 pieces of 3" x 3/16" plate about 8" long and drilled a 1/2" hole where they would bolt onto the engine. Next I tapered and radiused the ends a bit, but on the drivers side I had to remove a bit of material to clear some oil lines. I then bolted these plates onto the motor and leveled them off.

I then made the mounting plates that would be bolted to the engine subframe and put 2" long 7/16" wide slots for adjustment and put them into position. Next I cut out the uprights that go between the mounts and the 3/16" plate cut them, and allowed for a little extra clearance and tack-welded them into position.

I measured the distance between the plates and cut another piece of tubing to fit snugly between the 3/16" plates, leveled it off and squared it, then tack welded it in place. The engine is offset towards the passenger side to help position the drive sprocket so that it would not interfere with the pulley on the intermediate shaft. Here is a rough idea of dimensions:

Lastly I removed the front mount and clamped it to my welding table so that it would not warp and affect the distance between the mounting bolts - you don't want the total distance between them to shrink or stretch!!! Welded the whole thing up and cut off any excess 3/16" plate and radiused all the corners.

Here are some shots of the completed front engine mount.

Here are some shots to show you how it fits onto the front of the engine.

This is pretty time consuming getting all of the angles and mating surfaces as close to perfect as possible. It certainly helps having a metal cutting band saw as well as a 12" bench sanding disc. What you do is to cut the tubing a bit oversize then using the sanding disc slowly and cautiously grind the mating surfaces, you do not want to grind too much at one time - so it is grind a little - test fit, grind a little - test fit and so on until you get absolutely as good a fit up as possible. All of this has to be done with the entire exhaust system on the engine and with the motor mounts in place, otherwise you have a very good chance that it will not fit properly (and have to do it over again...)

I took one of the front slip tubes from the spare exhaust that I have as it appeared to have approximately the bends/angle that I was looking for, another part had a tight bend that I am using to come off of the manifold, and a short piece that goes into the manifold. Ultimately I have to change the angle coming out of the manifold so that it goes to the side by about 1" and bring the pipe closer to the engine by about 1-1/2" so that it parallels the pipe from the adjacent cylinder. Unfortunately I could not just rebend the original pipe as it is too close to the adjacent exhaust pipe.

Last night I think that I finally got the 3 new pieces of tubing cut and fit about as close as I can/dare to, and in the next couple of nights I will tack weld the parts together using my MIG welder and then TIG weld the parts together. When done I will show pictures of the new exhaust tube, below is a picture of the original with an arrow pointing to the offending exhaust pipe:.

So I took a torch to one of the pipes on the opposite side that I wanted it to bend, figuring that it would be better to stretch the metal than compress it - and possibly cause crimping. It worked pretty good, so much so that I cut the offending tubing, heated it to bend it both to the left by almost 1" for clearance and back toward the engine, I also used one piece that had a tighter bend to connect to the manifold.

It worked pretty well, I got one relatively small crimp - but certainly not too bad. As a friend used to say "It's good enough for who it's for!".

Now I only have a single cut to weld - instead of the previous 3. Got the part tack welded with the exhaust bolted to the engine and then removed it so that tomorrow I can TIG weld it up.

I got an email from Bryce Kindla who stumbled across my web blog, it so happens that he is using a Honda VFR750 in a dune buggy (and doing a *really* nice job at it) and already performed a modification to the collector. He sent me some pictures with details on how he did it. He did a great job and I think that I will be using a similar technique. Here is a picture of his modification where he kicked up the outlet to 45 degrees.

In addition the above picture also shows that he is using a relatively short spark arrester which is tuneable to the engine using baffle plates. He purchased it at Dan's Performance Parts they sell a variety of them from 10" to 18" long, SuperTrapp is a well known manufacturer as well.

Pretty quickly I noticed a *major* blunder/oversight on my part, I never looked under the vehicle to see how much clearance the exhaust had... Well it appears that the collector stuck out below the vehicle about 2-1/2", with the vehicle clearance being less than 6" it's a problem. (I knew that the V-4 exhaust was going to throw a monkey-wrench into the project!)

The whole problem extends from the way that the stock exhaust 'stacks' 2 of the pipes that go into the collector vertically, thus the bottom pipe is too low for my application. I could raise the engine and remake the mounts but with a 3-wheeler you really want to keep the static weight low so that did not seem like a viable option.

So as a start they took a length of standard 2" OD exhaust tubing and expanded the end to 3" OD (it's amazing with the right tools to see how much they can stretch metal...) I will be squashing it to make it oval and the front 2 pipes will plumb into it. The rear 2 pipes will combine together and then redirect into the side of the new collector,. As a side bonus the collector will be in a more optimal position on the passenger side of the vehicle and making plumbing the outlet into a muffler far easier and not so much of a tangled mess. Good-bye tuned exhaust system!!

I started out with a 2" pipe and had the muffler shop expand one end to 3", I then ovaled it and pinched the middle so that the front slip-tube connections could go into it.

I needed the output from the collector to be located on the passenger side so swapping pipes around I was able to redirect the front pipes towards this side. Modifying the rear pipes so that they came out on the drivers side, combining into a single pipe, then swooping around to join back into the main collector. All this while maintaining clearance to the oil pan.

Here are a couple of 'before' and 'after' pictures:

The #530 chain has less rotational mass, and it is used by racers worldwide. It has been reported that the less rotational mass also helps bump up the horsepower at the rear wheel as a result as well.

Today's O-ring and X-ring chains can be at least as strong, if not stronger than the original #630 chain, and. I have seen #530 chains as high as 10,600lbs! You still have to be careful in chain selection though and be sure not to cheap out and get the highest quality (ie: tensile strength) available.

There is an excellent discussion about General Chain & Sprockets FAQ that you might want to check out.