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Installing 4-Gauge Starter Cables and a Warrior Starter

Written by Randy Fox (Randysgym)   
Saturday, 15 September 2007
Warrior starter installed in Yamaha Road Star


The stock Road Star starter has a tough life even in the best of circumstances. You've probably thought so yourself at times--maybe when the weather turns cold and your battery is not as young as it use to be, or maybe every time you hit the starter button with your big-bore engine.

The starter is adequate for a stock engine with a new battery on a warm day. But if you repeatedly start your bike under more challenging circumstances, you might be asking for starter trouble.

This article covers two solutions which can be done separately, but should be done in order:

  1. Replace your stock starter wires with 4 gauge cable. This dramatically reduces the resistance caused by inadequately small wiring. The undersized, stock starter wires, and the associated resistance, can lead to premature starter failure.
  2. Swap out your stock starter for a Road Star Warrior starter. The Warrior starter has about 30% greater cranking power--even over the 1700 (102ci) models. Note: This option may not be necessary (but still desirable) if your pistons are stock, and you maintain your battery's charge.

Parts List

  • Starter Cable kit, available from Bulldogs Custom Cycle, Max Air Engineering, and probably some other suppliers, as well. Tip: Some riders have created their own cables by purchasing bulk cable from an auto parts store, and having terminal-ends fastened on. I opted for the Bulldogs kit because it is sealed against corrosion. I also felt that the time it would take to remove the stock cable, then measure, buy, and fastener-ize a homemade cable wasn't worth saving a few bucks.
  • 3.5", 4-gauge cable, with ends soldered on, available from most auto parts stores. Tip: the Starter Cable Kit from Max Air Engineering comes with this short piece, so you won't have to get it separately. The kit from Bulldogs does not include this piece. Tip: Without this short piece, with a Warrior starter the negative wire may get hot enough to melt solder! And you might burn out your starter, over time. Even if you aren't going to install a Warrior starter, you'll rob yourself of some of the benefit of this whole project without this little piece.
  • Warrior starter, complete with oil seal O-ring. Note: I opted for a nice, chrome starter from www.sxygramps.com.
  • Wire ties, medium length (6-inch or so). Qty: 1 or 2, (optional).
  • Warrior, 180 amp, type starter relay. Yamaha part#: 4BH-81940-02-00. Optional. See the Removing the Stock Starter Wires section for details.
  • Dielectric (silicone) grease, to protect the terminal ends of the cable from corrosion.


  • Wire cutters, or other tool to snip off wire ties
  • Pliers, for bending the terminal ends of the cables to suit your bike
  • Open end wrench (thin, 10mm, like the one in the R* tool kit), for removing/installing the cable from the starter terminal
  • Large phillips (X) screwdriver or small sockets, for removing battery terminals
  • Slotted (--) screwdriver or other tool, for prying open cable clamps
  • Socket wrench with extension, for removing cables from the relay-block.
  • Rat-tail file or rasp, for enlarging the entry hole in the battery box --optional
  • Motorcycle lift --optional, though highly recommended

Removing the Stock Starter Wires

Remove the left side-cover. Disconnect the negative (right side) battery lead (the terminal wire), then disconnect the positive (left side) battery lead.

Tip: You may wish to completely remove the battery, which will make it much easier to work the new cable through the battery box. I didn't do this because of the hassle, but slightly wish I had.

Yamaha Road Star left side cover layout

Next, trace the disconnected battery cable. You will see that it goes down to the left side-cover area, and terminates at a small terminal-block. This is the starter relay. Pull the rubber boot away from the terminal, and use a socket wrench to remove the exposed bolt.

Now pull this cable out of the bike. You will see that it’s very short (6"-9").

Pull off the rubber boots from the stock cable, and clean them inside and out--especially inside--with silicone or other type of rubber treatment. Just be sure that your rubber cleaner leaves the surface greasy to make it easier to work onto the new, fatter cable.

Yamaha Road Star boot

I put the rubber boots on the new, fatter cables by doing the following:

  • Turn the boots wrong side out.
  • Wriggle them on to the cable ends backwards.
  • Work the boot back over itself. This will make it faced forwards--right side out. See the photo above, showing one boot being installed inside out.
It took a lot of very hard work, using some old surgical forceps I have, to get the boots on. I'm very happy they're on, but if I were to do it again, I would just slit the tail-end of the boot a little, to fit the fatter cable easier. If you do slit the boot’s tail-end, just be very careful that you don’t tear it more as you slip it over the terminal-end.

Before you install the new, short cable, first inspect the terminal-post to be sure it is free of corrosion and dirt; clean as needed.

Then simply snake the cable through the same route as the stock one you just removed. The fit in to the battery box can be very tight, so you may wish to use a rat-tail file or rasp to enlarge the cable's entry slot. Note: This is where 'removing the battery' comes in handy. I took the picture below after completely removing the battery box, at a later time.


Yamaha Road Star battery box marked


Then bolt the cable to the relay terminal-post, smear on some dielectric grease, and slide the boot over the bolt. Do not use thread-lock, as you want to ensure a good electrical connection. Do not connect the cable to the battery yet.

Tip: There are mechanics that recommend that you also replace your starter relay. I've read some reports that the stock Road Star relay is rated at 100 amps, and the Warrior (and later model Road Star) relay is rated at 180 amps. In addition, I've read that the stock starter cranks at 80 amps or so, and the Warrior starter cranks at about 115 amps. I have not heard or read of a relay failure. However, if you decide to also replace the relay with one from a Warrior, be careful. You may need to swap your starter cables at the relay terminal posts. In this case, check your new relay to see which terminal has a silver tab-washer on top of the brass post. The battery-cable bolts onto this side.

Author's Update (09-Jun-2009): I have just replaced my starter relay with a Warrior, 180 amp, type. I think my stock relay is still OK, but I did a test that prompted my upgrade. I aimed a non-contact thermometer (the type with the laser pointer) at various parts of the starting system, and noted that the relay was getting much hotter than the rest of the starting system during starter cranking. The relay is easily replaced by just unscrewing the two cable screws, and lifting the relay straight up off it's plastic tabs.


Yamaha Road Star stock wiring block


Next, pull back the left boot from the relay terminal-post, and remove the bolt (see photo above). By doing so, you free one end of the starter cable. Next, we will free the other end.


Yamaha Road Star starter placement


To do this, locate the starter motor. See photo above.

Disconnect the cable from the starter by first pulling back the rubber boot. Refer to the opening photo in this article to see the starter and boot. This will expose the cable mounting post and nuts. Then hold the lower nut using an open-end wrench, and remove the upper nut using a socket, box, or open-end wrench. Note: My cable was on very tight.

Now open the two, black plastic, cable harness clamps located on the left-frame, near the starter area. To open them, I just used a small, slotted screwdriver and pried them open at the seam.


Yamaha Road Star stock cable marked


The red line in the photo above highlights the path of the starter cable. Note: My engine was out at the time. It is not necessary to remove your engine for this project.

Cut the wire-ties along the left side of the lower frame--under the engine. See photo above.

Starting at the front, pull the cable from the frame. Pull it back to a point just past the rear horn.

Now, before you pull the rest of the cable free, make note--or take a photo--of where the cable routes between and around other wires and obstacles in the left side-cover area.

You can now un-snake the cable from the surrounding wires in the left side-cover area. Free it back to where it disappears down between the transfer case and engine case.


Yamaha Road Star stock wiring harness marked


The cable portion still hidden within the bike is only attached via a long, ribbed, plastic harness/jacket/sleeve (see photo above). At this point you can pull the cable out of this sleeve from the top or from the bottom. I did this when my engine was removed, so it was a non-issue for me.

Tip: The new cable is too fat to fit back in to the sleeve, so don't worry about trying to devise a method to do so.

After removing the cable from the bike, pull the rubber boots off and clean them inside and out, just as you did for the battery cable.

Next, remove the short, negative cable. It is connected to the frame via the single bolt that holds the oil fill tube in place, just forward and to the right of the battery.

Installing the New Cable

First, snake the starter-end of the new cable down between the transfer case and engine case, where the stock cable was just removed.

Route the relay-terminal end of the cable via the same routing as the stock one--to the relay terminal-post, in the left side-cover area. Refer to the picture(s) or notes you took. Also, see the TOP VIEW photo below.


Yamaha Road Star new cables from above


Inspect the relay terminal-post to be sure it is free of corrosion and dirt; clean as needed. Then slip the appropriate boot on the cable, and bolt it to the terminal-post. Smear on some dielectric grease, and pull the boot down over the bolt. Do not use thread-lock, as you want to ensure a good electrical connection.

Route the starter-end of the cable along the same route as the stock cable. It is a very tight fit under the engine, but it will snug in nicely, with a little effort. The tightest area will be near the side-stand; just take your time.

As you work the cable toward the starter area, be mindful of the cable length. You want to reach the starter with enough cable length, but not any extra. My cable fit very tight against the frame and engine, so I was not able to pull up extra length nor push excess back. I had to really watch that my cable length came out right.

Once the cable is routed beneath the engine, insert the cable into the two, black plastic, cable harness clamps located on the left-frame, near the starter area. Simply snap these clamps closed. The new, fatter cable should just fit.

Then install some wire-ties, if you feel it necessary. Since my cables fit very snugly, I did not wire-tie them.

Now install the new wire for the negative side of the battery. To do this, simply slip one end of the short cable under the bolt for the oil fill tube, and torque the bolt back down (7.2 ft-lbs. Not too tight).

Changing Starters

If you will not be installing a Warrior starter, skip to the next section.


Yamaha Road Star starter mount


Remove the two, allen-head bolts from the starter mount, where the starter mounts to the engine, near the front horn.

Then use both hands to pull the starter free from the engine housing by simply wiggling, turning, and pulling the starter toward the left of the bike. It will feel tight at first, as there is an O-ring seal in the end of the starter. Once the O-ring begins to slide out of its seat, the starter will easily slip out. Be careful, though; it can release suddenly.

Set your old starter aside.

Now lubricate the O-ring on the new starter with a bit of engine oil. Then using both hands again, slide the new starter into the engine housing. Wiggle the starter as you go, to help the starter gear engage with the engine gears.

As the O-ring nears its ‘home’, it will become tight again. You can stop pushing at this point. Then insert the two mounting bolts into the starter mount, and torque them to 7.2 ft-lbs (easy does it). The starter O-ring seal will be pushed ‘home’ as you tighten the mounting bolts.


Yamaha Road Star chrome warrior starter


Note: The Warrior starter will show a slight gap between the engine housing and the starter case. This is normal, and does not affect operation of the bike or starter. In the picture above, you can see that I have a custom, irridescent, powdercoat color on my engine. I apologize for any viewing confusion this may cause (he he).


Yamaha Road Star and warrior compared


Note: The Warrior starter has a shorter arbor shaft than the stock Road Star starter. Since this shaft does not engage anything within the engine housing, the shorter arbor shaft is fine. See photo above.

Finishing the Installation

If you have not installed a new starter, inspect the starter's terminal-post to be sure it is free of corrosion and dirt; clean as needed.

To connect the new cable to the starter do the following:

  • Be sure only one nut is on the starter's terminal-post.
  • If you're installing a Warrior starter, check the post. It should have a rubber O-ring, and two brown plastic (dielectric) washers at its base. The washers should place the lower nut high enough so it won't touch the starter case.
  • If you're installing a stock starter, check the post. It should have two brown plastic (dielectric) washers at its base. The washers should place the lower nut high enough so it won't touch the starter case.
  • Snug the lower nut down against the washer(s) at the base of the post. If you skip this, the post may come loose.
  • Slip the rubber boot onto the cable.
  • Put the cable end on to the post.
  • Install and tighten the upper nut, while holding the lower nut using an open-end wrench. Do not use thread-lock, as you want to ensure a good electrical connection. Instead, just be sure you've got the nuts good and tight (but not excessive).
  • Apply some dielectric grease to the post and nuts to inhibit corrosion. Note: Do not use excessive grease, as it can seep into the cable and discolor the look, if you are installing transparent coated cables.
  • Pull the boot down over the post and nuts.


See the completed installation in the photo below.


Yamaha Road Star new cable installed


If you removed the battery, reinstall it now.

After inspecting for corrosion, reconnect the positive (left side) battery cable. Remember to smear on some dielectric grease.

Then connect the negative (right-side) lead. Remember to smear on some dielectric grease.

Now turn on the ignition and hit the starter button. The starter should be noticeably more powerful--especially if you installed the Warrior starter.

If the starter won't engage at all, be sure your transmission is in neutral.

If it doesn't spin the engine with more authority, check your connections for a loose bolt or nut. Also try removing the bolts/nuts, cleaning the terminals and fasteners again, and then re-tightening them.

If, after thoroughly searching for a poor connection, you still have little, or no, starting power, you can suspect the starter or the battery. To test them, do the following:

  • Turn on the ignition.
  • If the lights don't shine brightly, the battery terminals may not have good connection.
  • Turn off the ignition.
  • Detach the new cable from the starter, and temporarily bolt one end of the stock cable to the starter post. (Be sure the stock cable ends are clean).
  • Be sure your transmission is in neutral.
  • While protecting yourself from electrical shock with thick rubber gloves or other insulation, touch the other end of the stock cable to the positive (left) side of the battery.
  • The starter should immediately spin.
  • If not, and yet the lights come on with the ignition, the starter may be bad.

You can also try this test again, using your stock starter--reinstalled.

Once everything checks out, just put the left side-cover back on and smile. You’ve done something very good for your bike.

Ride on.


Questions should be asked in our forum (Use discuss link below). The forum is very active and you stand a good chance of getting your questions answered there. If you would like to leave feedback for the author, or have additional information you think will benefit others, please use the comment section at the bottom of this page.

Discuss this article on the forums. (0 posts)

DISCLAIMER: This information and procedure is provided as a courtesy and is for informational purposes only.  Neither the publishers nor the authors accept any responsibility for the accuracy, applicability, or suitability of this procedure.  You assume all risks associated with the use of this information.  NEITHER THE PUBLISHERs NOR THE AUTHORs SHALL IN ANY EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, PUNITIVE, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OF ANY NATURE ARISING OUT OF OR IN ANY WAY CONNECTED WITH THE USE OR MISUSE OF THIS INFORMATION OR LACK OF INFORMATION.  Any type of modification or service work on your motorcycle should always be performed by a professional mechanic. If performed incorrectly, this procedure may endanger the safety of you and others on your motorcycle and possibly invalidate your manufacturer’s warranty.

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  Comments (10)
4 gauge starter wires
Written by Newf1, on 02-15-2017 07:55
great information , if you need any assistance on fixing anything on your (Roadie) this is the place to look ROAD STAR CLINIC.
OEM Part numbers please?
Written by Starjunkie, on 01-17-2014 10:24
Could I get the OEM yamaha part numbers for the solenoid and starter please? Thank you. Jeff
Worked great
Written by Jeephed, on 05-15-2013 20:05
I was having an issue with my starter where it would turn over once, wait a few seconds then turn over again and start the engine. I figured I would need to replace the starter. I started with the wires first since it was cheaper.  
Like night and day now, it rarely does the hesitation start any more.  
Great mod.  
One thing I had a problem with was the Warrior relay. I didn't know it was reverse wired to the batt.
Written by yamaleidy, on 08-28-2012 23:36
I don't even open my owners manual anymore,I come straight here. I am now ready to tackle this job. Thanks
Written by Lazydog, on 10-18-2009 21:54
great piece. I'm experiencing starter problem where it won't start but wires and motor get hot. What about the various relays. Don't they play a part??
Written by BrooklynBiker, on 05-01-2009 03:12
great improvement
Written by chromepony, on 03-15-2009 19:14
I just finished the cable install on my '00 R/S. I stayed w/the stock starter,but put a kit[(new brushes)$60] in it while I had it on the bench. Don't know if it's the cables or the fresh starter or (probably) the combination of the two,but the starter almost spins the motor out of the frame when I bump the button now. Time & money well spent.
Great, Great article
Written by TChaap, on 02-14-2008 18:59
This is just an outstanding article. This install is not rocket science but it sure does give a novice like me a lot of confidence to tackle something they want to fix. The details were super. Thanks for your time. 
No longer available?
Written by nazuma, on 11-11-2007 14:25
Can't seem to find the custom starter cable kit on the bulldog website. 
Recommend anything else? 
If not, what is the length? 
Great article
Written by flashback, on 10-13-2007 16:16
Randy, this is a great article, Iv'e only had my bike a short time but have always felt the starting circuit was a bit aneimic. It is something I have on my list but did not know if anything was available.. Thanks...

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