How to: Install A Harley-Davidson Sportster Hardtail Frame 1982 – 2003
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How to: Install A Harley-Davidson Sportster Hardtail Frame 1982 – 2003

October 10, 2019

Tyler: Hey,
it’s Tyler with Lowbrow Customs. Today we’re going to show you
how to install one of these hardtails which are for ’82 to
2003 Sportsters under this bike. This one’s a 1988. It’s quick and easy,
follow along with us and you can have this done in an
afternoon very easily. [music] The bike has it sits,
is pretty much ready how you should have
your bike prepared. It’s a hard talent. Basically removed everything,
all the main components. The last things are
the wheel and front end, you can leave them on at this point or you can have
those off and just have your frame and
motor preference. The first thing that we’re
going to do is pull the motor out of the frame so we can
measure and cut the frame. If you’ve got a front motor
mount, top motor mount, those can be unbolted
completely removed, and then the motor unbolts
at the front and rear and we’re going to pull it
completely out of the frame. We’ve got all of the
hardware removed, all the motor mount plates removed. This motor is just sitting here on the spacers and will
be on the cradle here. To pull this out of the frame, it’s
going to come out of the right side. We’re going to grab this and shift
it forward very slightly to release the rear, and then I’ll tip it
toward myself, throw it on the table. I may have a block of
wood ready to support the front so the motor
doesn’t fall over. That’s about it. Now that the motor’s out of the
frame, I’m going to show you where to pull measurements from to scribe
your frame, your stock frame. I’ll show you where to cut. The hardtail’s already slugged. These are machined
solid slugs here on the lower rails and
a piece of tubing on the top which allows you
to run internal wiring through your backbone if you desire. When you cut this,
what we’re going to do is we’re going to
mark it out and cut it and then go ahead
and grind the tubes to make sure they’re totally flat. What we’re going to
really aim for once it’s ground and everything’s
nice and square is about an eighth-inch gap between
the stock lower frame rail tubing and the
tubing of the hardtail. That gap, roughly an eighth
inch, when you weld, it’s going to
allow good penetration on the slug as well as both
tubes, so all three pieces can be a really
nice strong weld. You’ve got some leeway here. If you cut,
you grind a little too much or something and it’s
a quarter inch gap, that’s fine, it’s not going to be a strength or structural
issue whatsoever. Really, all these joints get
hidden with the motor and gas tank on, so you’ve got a little
leeway on these measurements. The first measurement
I’m going to pull here, I’ll show you how it
corresponds to the hardtail. This flat plate here
at the rear motor mount is the same
measurement as far as in relation to the motor
as the face of these bungs here on the rear motor mount. What I’m going to do is just
pull a measurement using a square, it’s just a common
square you can get anywhere. I’m going to go ahead and keep
the lower run parallel to the tube and just butt it right against
the corner of that block there. You can see pretty
clear it’s right at six inches to the end of this tube. What we need to do
on the stock frame, and it’s a little different
with the way the rails are in such a bend here,
but you’re going to butt the square against
the face of that bump. Pull this ruler so it’s parallel
to the lower frame rail, and then the easiest way to do this is just to
scribe a mark right into your paint. Right here at the sixth-inch mark, I just went ahead and
did a little scribe. You can go ahead and deepen that. I’ll go ahead and do the
same thing on the other side. For the upper mount,
we’re going to pull a dimension coming from the rear
of the top motor mount bracket right where it
meets the frame, and that’s going to be a nine-sixteenth
back on this top tube. For that, you can use just a standard
ruler, it’s a little machinist scale. I’m just going to go ahead and line
it up and the same thing, I’m just going to scribe it
at nine-sixteenths, move the ruler, deepen it. You do want to hold this parallel to the tube to get an
accurate measurement. I went ahead and inscribed
a little line there, nine-sixteenths,
I’ll mark that other side, and I will probably pull
the rear wheel off before we cut this just to
make it a little easier. All right, so the rear wheel’s
off, this thing’s ready to cut. We’re going to go ahead and cut
the rear section of the frame off. We’re using a Sawzall for the
job, this works great. You could also use a
grinder with the cut-off wheel, a hacksaw,
whatever you prefer. All right, let’s cut it. [drilling sound] There we go. I’m ready to slip the
hardtail in once we clean up and debug the
inside of these holes. We’re going to go ahead and drill
through the lower and upper frame rail to get some rosette welds once
that new hardtail is slipped in. The rear spacers are strapped
so there’s no way those can move, but the top piece
is a tube and the rosette weld will hold that in
place and offer a little stability while we go ahead
and weld around the tubes. Let’s do it. [music] [drilling sound] All right,
so we cross-drilled through both lower rails, which that’ll be used to rosette weld the slug to the
tube before we weld around there. Also, cross-drilled the
top the backbone and put a chamfer around the outside
edge of all of these tubes. That make sure you
get really good weld penetration between
both pieces of tubing and this bug,
and you just do that with anything, a grinder,
a flat disc, whatever. The other thing we did was clean
up inside of the tubing here. This was actually, being a bit of an
older frame, pretty rusty and crusty. You can use a die grinder
with a barrel sander like that and then
work around in there. Make sure you get in
for the full depth of the sleeves or a little
flap disc will work. The die grinder bit,
pretty much a little bird bit. Anything you can to
clean that up in there. Then you can test fit this. Because these are going in
at different angles, usually you’ve got to use a rubber
mallet to send this home, but if you’re just going to offset it,
you can test and see that that goes fully seated home on both
sides, and then tilt this. There you go, the backbone so
it all slides in so we know these holes are all open and
there’s no restriction there. To send this home, what you’re
going to want to do is use a rubber mallet, varying sizes, whatever
you need, the big one right here. Don’t beat on this with a metal
hammer or a ball-peen or anything. What we’re going to do is go ahead and line these up and
I’m going to probably smack right here
with a rubber mallet and get these started
sliding in there. There can be a little
bit of tension depending on the display of
the frame rails here. It’s usually I’d use
a mallet to tap it in. One thing we noticed on here is
when I go to line these lower slugs up, the stock frame
is just a hair wider, sprung a little wider than the hardtail,
so you do something simple like this clamp and just give
it a little bit of tension. Adjust it so these are
just the right width. There we go. It’s sliding right in. The reason the mallet comes
into play is because you’ve got conflicting angles on
this plane and this plane. Typically,
you’re going to need to give it a few whacks to get this seated. We’ve got the hardtail slid in place
through the rear wheel on it just to support it, and got together
our hardware and the tools needed. What we’re going to
do is I’m going to grab the engine,
get it into position getting an exact opposite of how
we pulled it out as far as tipping it in, getting the sump in between
the rails, and then sliding it back so the dowels engage the holes
here on the rear motor mount plate. It’s handy to have another set
of hands around, so while I’m holding the motor, Tim can get
the hardware started in place. We’re going to go ahead and
bolt the motor up to all the different stock points
and then to the rear here. That motor is going to serve as our
fixture for tack welding the frame. It’s going to ensure that we have
a proper fit with the engine. You don’t want to go ahead
and just weld this thing up because your motor
will probably not fit. All right. Tip it towards you and
then you got to lift up. Tim: There you go. Tyler: Yes. Tim: Yes, slowly. This should go back here. Tyler: Yes,
that means we go upwards. There we go. With the help of Tim,
the pry bar got the engine located there, and so now
I’m just holding it steady while he gets the hardware
started, and then we’ll go around and just bolt it all
up, tighten it up. The motor is back in the
frame and we went ahead and installed all of the
motor mounts and hardware. Don’t skip this step,
don’t try and save yourself two minutes by only
partially bolting stuff in. All hardware are on
the rear mounts, you got your top motor mount bolt to the frame,
you got your front plates, and then this upper
front mount as well. Again, it’s just this is all
the stock mounting hardware. This is shorter mounting
bolts, but the same idea, everything is bolted
up, torqued into place. You might have to rock your
motor a little getting these bolts all situated,
but it’s pretty straightforward. Again, do not get the hardtail
fit up and just weld or tack or anything, your engine serves
as the jig for this hardtail. This is imperative,
it’s the most important thing you can do to not screw
up your hardtail install. Bolt this in like we did. Now it’s sitting right
where it needs to be and the next step is going to be
putting some solid tack welds. We’re going to TIG weld this. In our case,
it’s going to be we can just leave this uncovered,
TIG welding doesn’t throw sparks. If you’re MIG welding,
you might want to cover your motor or whatever,
that’s up to you. We’re going to go ahead and throw
some nice heavy tacks probably a few are on the top and two
or three around the bottom. Then next up what we would
typically do is finish weld everything possible with
the bike as it sits, and then we will end up
pulling the motor back out of the frame for the final
finish welding and that’s it. That seem to be the job,
so we’ll get welding. [music] All right, there we go. That’s basically it for
this hardtail installation. We’re not going to
bother showing you on film, but we’re going
to pull the motor back out and then
weld to the areas we couldn’t get to with
the motor installed. If necessary,
you could flip it on its side. If you pull the front end
and the wheel off, it’s really easy,
you can turn it any way you want. Basically, you’re just going to
finish weld everything up there and you’re ready to move onto
the next phase of your project. If you liked this video,
you can click follow below and you’ll see all the latest
videos from Lowbrow Customs. We’re constantly
filming new how-tos, event coverage all
kinds of great stuff. You can pick up your own
hardtail at, and if there’s questions,
comments, anything you want to say,
say it in the comments below and we’ll be sure to read
them and respond to you. Thanks so much for watching. [music]

Only registered users can comment.

  1. Do you sell a hard tail for a 65 triumph frame? I have a bolt on one on there now but I just don't trust it. It seems to have too much flex. What's your opinion?

  2. Well done Guy's, this is the kind of video that could sway someone on the edge of installing a hardtail themselves to go for it. You make it look easy and stress free.

  3. Great video thx. To mark the frame for cutting, I scribe it the way you do, then wrap masking tape around the frame tubes with the edge of the masking tape right on the scribed line. This helps me to keep my cuts straight because you can see if you are cutting off on an angle. Just follow the edge of the masking tape with your cutting tool. PS: I loved watching the rear frame section drop on the table, haha. Nice effect for the video.

  4. Great video. What is the brand of that blue scissor jack and motorcycle lift? Looking to invest in both. I heard the Harbor Freight lift is pretty good.

  5. !0 easy steps to fuck up a good handling motor cycle. Hard tails are for idiots, why fuck up the suspension on a modern motor cycle? Because you think it's cool. When I pull up next to one of these novelty built bikes I just laugh at the dumb ass ridding it.
    Same thing for those running drag pipes.
    Stupid shit to promote.

  6. Great video. Seems pretty simple to do.. wish you guys would do a "How to rake a sportster frame" for those of us who cant afford a chopper

  7. Hand in Hammer makes a hard tail like this which comes with a bolt on jig which eliminates putting engine in twice. I know you have probably seen theirs, what makes your better?

  8. Okay, but… Question. Why? Why make your bike less fun to ride? I'm all for modding bikes and to each their own, but I have never and will never understand the appeal of hardtail bikes. It's the only mod I genuinely consider stupid.

  9. That's the worst thing about it . . you can accumulate a ton of tools more . . but you can still do exact the same with your old near half dozen makita power tools & Lincoln welder & cheap Chinese mill/lathe

  10. All these comments are the worst, no they don’t make it for 04 and up, no it won’t work on anything it’s not made for, and yeah this is hard work def easier with 2 people, and hardtails are just for fun, if you don’t understand that and think it’s stupid, then don’t watch these kinds of videos you fucking morons

  11. Sooooo many pansies in the comments! "Boo-hoo, why would you hardtail? Why get rid of suspension? Boo hoo, so uncomfortable!" If you cant handle a chop, why are you here?

  12. Like how they go step by step even how to remove the motor. No others channel has gone into every little detail like this. One of the better diy videos I have seen

  13. This comment section is further proof that male testosterone levels are at historical lows world wide. Men aren't sure what to do with themselves anymore. Why do ANYTHING other than breathe heavily out of your mouth since you have Uber eats and 500 channels?

  14. Je pense qu il vaut mieux changer directement le cadre pour un peu plus cher mais moins de risques

  15. hmmmm like that sound ' hardtail sportster ' n that likes pretty cool also, i myself have 95 sportster lowrider very slick looking if i may say so , great video easy to do now

  16. Why not buy a frame some people ask? Well first to register with state laws some states are complicated, frames are more expensive, and if you think that's simpler go for it. Oh yeah you can't do this your self, well too bad.

  17. what kinda japanese cruisers does this kit fit? what is the japanese clone to the sportster? as far as framewise

  18. yeah except they sell the iron head hard tail kit in pieces you have to wield their pieces together properly then weld it to your frame then weld on your own bolts for the axle adjusters…… and they charge 350 for that lol if Im gonna fabricate it myself ill buy the parts form a local shop for 50 bucks and fabricate it myself, otherwise ill buy from a company for 100 bucks less that is complete on ship including a caliper mount and bolts to run axle adjusters through pre wielded

  19. I got a 73 XLCH Motor in a Pre 1970 frame. HD didn't put any numbers on their frames before 1970. I know I had a hell of a time finding swing arm bearings for this thing. My cousin had a set for a 50's frame that worked. So do you have a hard tail for the Pre 70's frames?

  20. Tyler is the shit!!! Lowbrow is a one stop shop man, everything is top notch, quality is impressive, and tech's and customer service is kickass!!! Great people, and company!!!

  21. That hardtail gives a real jump in the clean looks of a build. I need to ride one to see how much you give up in terms of handling.

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