Thread: How to fit a Hotbodies Undertail

G'day again folks. Welcome to shop class. So, you want an undertail but don't trust dodgy instructions? I reckon that I can help you there. This is for a Hotbodies model but will work on most popular models. Let's roll.

What you need for the job.

7/32 drill bit,
A smaller bit for a pilot,
A dremel or equiv with two cutting wheels,
A grinder,
A socket set,
Hex keys,
Elec connectors and tape,
Magic tape,
A grease pencil,
No2 X-tip screwdriver, and
A couple of odd bits and pieces.






Let’s get on with it.

• Prep is the key to any decent job. Take your undertail out and inspect it for anything untoward. Check the colour match. Check for workmanship. If all is good. Move on.
• Label the lines.

• • Black = Ground/Earth
  • Red = Brake
  • Orange = Indicators
  • Blue = Running lights.

Test the components. Grab a 9V battery. Black to the neg and work your way around on both sides.

• Quick note. At this stage you might want to think about the numberplate light. There isn’t one included so grab a suitable small one that will get you out of trouble. It will need to be small, like an LED. Don’t mount it yet, we will get to that. You may wish to compliment the built in indicators by installing minis. This is an easy fix and we will get to this as well. Might be worth ordering some at the same time you order the undertail. On the upside, that person who can do these will probably be able to supply a suitable numberplate light.
• So, you have all the bits. Probably not. Lol. Put the bike on a race stand. Level standing will prevent various parts from being crooked.
• Remove the rear section. Put all the bolts and plastic rivets in a container. If you have any doubt about what goes where, bag them and label them clearly. There isn’t a lot to know here. Take your time. Remove all the crap from under the hump area. Remove the rider seat and the battery. Clear it all away. Place it carefully where it won’t get stood on. Put the rear section on an old sheet. Paint work damages easily and will drive you nuts forever.

The original undertail panel is now hanging by its lonesome from the subframe. Leave it in place. It is time to mark the panel. Take your time. Think it thorough and get it right. A clean job is the best job. In the example, a fool at a local bike shop already had a go at hacking the tray. See shit job above. Lucky for me, he didn’t work into any area that mattered and I will be able to clean that right up. With the grease pencil mark around. The critical parts are the upper fastener holes to the subframe. If you hack these off, you are done for the day. Screwed up. The instructions are not clear about the line to cut. Mark your line behind the upper fastener holes and run parallel to the subframe. This is where I spear off from what Hotbodies will tell you.



Remove the tray. There is nothing to be gained from cutting it on the bike. It is a hell of a lot easier to cut it separated. Not only that, why risk your electrics and other bits with running a cutting wheel near anything. Your finished job will be better anyway.

• Cutting time. This is the major operation of the job. Fetch the dremel. Work your way around and line the whole lower mess. In the rear, cut along the line in the rear where the tray drops away. This is make a mailbox shape with the subframe. See pic. No matter how you try, this will not be a one cut deal. A few cuts will be needed. A bit here and a bit there. Plastic gets hot and will flick in your face. This can be reduced by running score lines. Run the dremel for a continous length and then back to the start and go again. It will generally take three to four strokes to cut through. If you try and do it in one hit, all you will get is a shitty melted mess. Keep the heat down by moving. Every now and then, place the tray back in and check that you are still correct and that the job is symmetrical.

Once you have done the major cuts and the shape is right it is time to clean it up. Grab your grinder. With a nice sweeping motion clean it off and pick the scrapes away. This includes the lip on the lower edge, that has no further purpose. Don’t get greedy. Bit by bit. Take it easy.

Test fit. If you have done a decent job it should look like this.

• Replace the forward tray bolts and secure them up. They won’t need to come out again. Time to replace your rear section. Place it on like normal. Loose fit will do. Make sure you have the rear loom available to you, not shoved down the right side of the subframe.

Lets fit that fancy undertail. This takes bugger all. Place your newly available sheet and place it over the rear tyre/or hugger. Don’t scratch your nice paint. Slide it in and put a couple of plastic rivets in to hold it in place. It will have to come out again in a little bit.

• Grab your trusty grease pencil. Look at the place where the numberplate will look the best. I happened to measure the one that I was doing, mainly to make sure it was straight. The measurement I had was 95mm. A little under three inches. With this one, it had a nice frame that he wanted to retain. I spaced it so it wouldn’t contact and also gave me a chance to damper it with rubber. I will never crack the bodywork now. Of course, my pencil wouldn’t go through the hole, so a scribe was used. Take the undertail out.

On the bench, grab your magic tape and position it over the potential drill mark. Use the pilot drill to position the plate brackets. Once the pilots are done, check the holes for a good central position. If this is good, a 7/32 will finish the job. Reassemble the plate. She is done.



What we did now was put the additional indicators onto right angles off the plate bolts. This of course meant that an additional hole was required for those wires. A neat drill hole behind the plate will fix this right up.

• Place the undertail back on. It should look nice now.
  
• Time to break out the test light. All you really need to know is that there is two black wires with a white stripe. The thinner stripe is the ground/earth. Get those nicely done. Clean, neat and insulated. Go as far as you can. Solder and heat shrink if you have the necessaries. Before you go that far, make sure you have it right by testing the running lights, brake and indicators.
• Go around and tighten everything up. Sweet looking by now. Stand back and admire your work.
  

• Find some giant piece of military hardware, take pics and post to the forum.

The End.

Apologies on the formatting. I don't seem to have the tools to fix it properly. I penned it in word because writing in that little box didn't float my boat.

Very nice walk-thru Glen !!

Very nice write up indeed!

Props Glen. Nice write up

This will be useful for future members. Nice work.

Good job excellent walk trough.

Hey i know that garage and that rear stand
and the owner sorry bud

and crap everywhere. At least I put all the blots ina tray. I was emptying my pockets before at the laptop. Score was a 1 cross tip, 1 small spanner, 7 hex keys, 5 bucks and a cell phone. lol. Situation normal.

Ruffy is on his way down from Sydney to hang out for a few days. I am going to fit some stuff for him while he is here. I would have preferred warmer weather for it. Oh yeah, there was a cutting disk too.

Most excellent write-up!! Thanks a lot Glen!!

What are the rules for modifying bikes there in the US?
I`m in Australia and have a 99R1 and an 06 Busa. I got hotbodies undertail for my R1 some time back but the pigs here give you 3 licence demerit points as well as a fine for anything non standard. I see custom bikes on US sites that are amazing but here you`d go to jail for riding it on the street.

We can sort you for something that won't get you in strife but get the job done nicely Wally.

I have ghe same undertail.
If you have any problems with the LED's burning out email Kevin.
mailto: kein@hotbodiesracing.com

I've had 2 relaced free of charge

Nice write up, and that is what I had to do as well, I did mine in May 06.

I have the same undertail and it looks badass to me. Everyone who sees it likes it. I think I am going to have to give kevin a shout. I think one of my LED's is going out. It is intermittent right now. A sign of things to come.

Sweet write up. I was never really clear about how they were installed. Thanks!!

Is this pretty much the same for the Mototeck undertail?

The general execution would be the same.

I am installing a hotbodies undertail and have a question on wiring the grounds.

There is two ground wires on the undertail, one for each side. It seems there is three grounds on the bike. One for each signal and one by the brake and running lights.

What is the best way to connect things?

Thanks

You can join all the grounds together if you feel like it and run them out of one proper earthing. its the + that matters.

Thats what I was thinking but wanted to double check.

Thank you for the quick response!!

This site rocks.

Anytime bro.

Just got it wired and I do notice the lighting sucks as others have stated.

Is there any options for better lighting?

Not with that undertail. The lights are glued in. You can up the bulbs perhaps. Thats why I have dropped them from the lineup. If something goes wrong, it has to be junked. Makes big guys unhappy and I got a soft head.