Spec II Exhausts

1985 RZ350

Installing New Spec II Exhausts

Once I had my RZ350 up and running I used it for about two years before getting the tuning bug again. It ran well but didn't have the power band snap of a two stroke, or really even sounds like one. After a fair bit of research my choice for an exhaust came down to either Spec II F1s or JL Lomas pipes. Since the dollar was tanking the already expensive Czech produced JLs became more and more costly, and I like the idea of supporting a Californian company so I chose the F1s.


The kit comes with all the parts shown above. Exhaust flanges are separate from the main body as are the end cans. The flanges are bolted to the motor and the pipes are held to them with two springs. End cans come unpacked, but the material used to wrap the pipes is recommended as the packing.


The first step in the entire process is to paint the exhausts as they come as raw steel. The can of hi-temp "black" that comes with them is actually a very dark brown and had I known this prior to spraying I would have gone out and bought something else. Before spraying rub the entire exhausts down with a degreaser such as lacquer thinner to get rid of any residual coating, and then spray away! The end baffles are marked to fit with the aluminum baffle covers, so if you spray the baffles make sure you note the orientation one way or another.

Put the bike on the center stand. Before mounting the new exhaust flanges run some RVT hi-temp compound around the area where the exhaust will slide in to the flange. Then install both flanges with a new fiber gasket (the one shaped like the flange) and a new circular sealing gasket. Please note that although the picture shows the flanges above with the spring clips on the inside, I later reversed these as I felt the pipes wobbled a bit too much. In my final install the spring clips were both on the outside.

The picture above shows the right pipe in place and it can easily be identified as it is the one without the extra metal fabrication used for a center stand stop. Place the pipe into the flange and ease it backwards until the rear support bracket aligns with the footpeg mounting bolt. Push the bolt through and loosely install the washer and nut. Come round to the front and stretch the springs between the two eyes on the flange and exhaust. I highly recommend the a spring puller tool as shown above. Once in place wipe off any extra RVT and secure the rear footpeg nut. Do the same for the other side.

Now that both pipes are in place, you can pack the silencers. The instructions from Spec II said to cut up the material that the pipes were packed in. I made two lengths of exactly the same length and the height of the internal baffle of the cans as shown above.

Tightly wrap the fiberglass packing around the internal baffle and slide it in to the aluminum tube. Be sure to note where Spec II has marked the baffle and the end can as they sometimes will only align one way.

Fit and lighten the eight small Allen head bolts to retain the baffle cover. These do not need to be tight and can distort the tube if tightened too much.

Mount each can to the pipes and tighten the small nut to retain them. I switched my stock nut out for a stainless steel Allen head bolt and nylock nut so that it wouldn't rust in the future.

The final step is to check each pipe for clearance. I had a problem that when my side stand was up it would rub against the left side pipe, so I had to dismantle the side stand and add a thin washer so it wobbled less. Leave the bike for 24 hours to allow the RVT to set. I still find my pipes wobble a bit but it doesn't seem to affect anything.

Lastly make sure to follow the carb modification page (or simply rejet the main) and consider adjusting the oil pump for more oil flow as recommended by Spec II. Standard carbs will be too lean which can have disastrous affects on a motor and result in holing a piston.

Also install new plugs before firing it up and carefully monitor their color by removing them periodically. They should have a nice chocolate brown color to the ceramic part around the electrode, starting from up in the recess.

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