Suzuki K10 motorcycle forks

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bigbutterbean

Active Member
Jan 31, 2011
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Lebanon, PA
I bought a pair of these forks for my latest build, and I thought I would post a thread about the modifications I have done to fit these on my frame. Here is a link to the forks for anyone who is interested: http://www.ebay.com/itm/220986587363?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 The first thing you should be aware of is that this version of these forks come with a handlebar clamp for 3/4" bars, and most bicycle bars are 7/8. They sell a version with a 7/8 handlebar clamp, but it costs $20 more. So it is necessary to make the handlebar clamp wider to accept bicycle bars. I did this using a dremel. I started with a grinding bit, but changed to a cutoff wheel and reamed it out that way. It worked out well, and I now have a nice pair of cruiser bars mounted up. Another thing is that these forks have pretty soft damping, and the oil that comes in them is very light. I don't know what weight it was, but I emptied it from the fork into a measuring cup to see how much was in there, and it was about 2 ounces. To me that didn't seem like enough, so I added 4 ounces of 10w30 to each fork after emptying the oil that came in them. Another thing I did to stiffen them up a bit was turn the spring perches upside down. In layman's terms, the spring perches are these plastic washers that when installed from the factory seat into the top of the springs and I suppose keep the springs from digging into the bottom trees. Turning them around makes them not seat into the springs, allowing the springs to be compressed about 1" further than stock, stiffening them up nicely. They come with a 1" steerer tube, but you can't use a regular crown nut on the headset, because the top tree bolts to the steerer tube, and a crown nut would make the top tree sit at the wrong angle. Here is how I installed my headset. I first put the cone nut on, then a flat washer, then a threaded washer (sort of like the cone nut, but flat), and then I used a crown nut, but I cut the crown part off so it can be threaded down past the top of the steerer tube. The steere tube is also 6.5" in length, a bit longer than my head tube, but I saw no reason to cut it shorter. Considering the way I installed my headset and the fact that the top tree also bolts to the steerer tube, I saw no reason to cut it to length. The frame I am using is an American made Schwinn cantilever frame, I think I forgot to mention that. The only other modification I am making is to cut the dropouts. Because they are motorcycle forks and I guess motorcycle wheels have sealed bearings and therefore an axle can be slid through, the dropouts on these forks are completely round and enclosed, in other words they cant be picked up and slid onto the wheel like a regular bicycle fork. So I cut the dropouts so they can be slid over the axle. I used a dremel and a cutoff wheel to cut a small section off the dropouts, then a grinding bit to widen the space it left because at first it wasn't wide enough to put an axle through. It worked good, and there is still plenty left of the dropouts for the axle nuts to have good surface contact. Lastly, these forks are much wider than a bicycle fork, so a standard front axle most likely will not reach both dropouts and you'll need a longer axle. I took the axle out of a mountain bike wheel, and I'm in the process of fitting it up to my Worksman front wheel. There might be different ways to make some of these modifications, but this is what I've done and I hope this helps anyone considering the K10 forks. For $39 plus shipping, they are one heck of a deal and they are well worth the relatively small amount of modification needed to get them to work on a bicycle.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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You only need to modify one of the dropouts to be able to fit the axle into the forks. Leaving one dropout fully enclosed will make it even more bullet proof.
SB
 

bigbutterbean

Active Member
Jan 31, 2011
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Lebanon, PA
You only need to modify one of the dropouts to be able to fit the axle into the forks. Leaving one dropout fully enclosed will make it even more bullet proof.
SB
I'm not sure how other people wiggle the axle in, but with having to add spacers between the hub and the fork, cutting only one dropout is not going to work for me. it's gonna make it impossible to get the axle on at all.
 

MotoMagz

Well-Known Member
Aug 2, 2010
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You only need to modify one of the dropouts to be able to fit the axle into the forks. Leaving one dropout fully enclosed will make it even more bullet proof.
SB
I actually left both drop outs stock. No cutting just some fishing thing through.The hub is a xlfd with a 10mm axle as a replacement and 3-3mm spacers added to each side.It took a while but it can be done.
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
3
38
Lebanon, PA
I'm not exactly sure what you mean by a fork spacer? I detailed everything I had to do in my first post, so most likely not. I can't use that tank because its too close to my head.
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
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Lebanon, PA
I didn't need a spacer. I detailed in my original post how I modified my headset to work on the triple trees by cutting the crown part off a fork crown nut. Tomorrow I will snap a pic of the headset so you can see exactly what I did, but no I did not use a fork spacer. I used a standard bicycle headset underneath the top tree.
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
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38
Lebanon, PA
I got my front wheel on today, man was it a pain. I'm a little busy at the moment to post details, but I'll just say that adapting a Worksman wheel with a drum hub to these forks is not an easy task. I ended up only cutting one of the dropouts. I'll post details later tonight and some pics in the morning.
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
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Lebanon, PA
Ok, I'm back to post details of getting the wheel mounted. I have a Worksman front wheel with drum brakes, and it has pressed bearings, which means the bearings dont come out, but you still have a threaded axle and cones and all that jazz. As I mentioned before, I took a rear axle from a mountain bike, and it was just long enough to reach. The original axle for the wheel came with four lock nuts, but they didn't fit the mountain bike axle, so I used axle nuts, a spacer, a washer and one locknut I found laying around that luckily did fit the new axle. Getting the wheel centered on the new axle was pretty difficult, because the threads didn't reach far enough towards the center for me to position the cones where they needed to be. So what did I do? I forced one of the cones past where the threads stopped. I positioned the cone where I needed it on the other side, and then I used a pair of channel lock pliers to gently hold the axle still while I used an adjustable wrench to force the other cone past the threads. I was able to get both cones in the proper position for the wheel to be properly centered. On the side of the hub opposite the drum, I used two axle nuts as lock nuts/spacers. On the drum side, I used the spacer that came with the original axle between the cone and the drum cover, and outside the drum cover I used one axle nut, a flat metal washer, and a lock nut. This allowed me to get the wheel perfectly centered. I also came up with a creative way to hold the brake arm in place. On my previous bike, I had used a piece of aluminum bent around the fork and bolted through the stud hole in the brake arm. However, that piece of aluminum wasn't long enough to go around these forks as they are much thicker. I noticed that the K10 forks have holes to mount disc calipers, so I flattened the aluminum. I found a short screw that would thread into one of the caliper holes, and bolted one end of the aluminum to the caliper mount and the other end to the stud hole in the brake arm. It looks pretty clean compared to clamping around the fork.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
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northeastern Minnesota
http://motorbicycling.com/showthread.php?t=27983&highlight=suzuki+k-10+forks

This is a link to an earlier thread started by BarelyAWake on the K-10 forks. There's a lot of good information here. This was the first time many of us ever heard of these great forks.

I've used these same forks on three different builds. I've also used other suspension forks from the early Schwinn to moped forks (Tomos, Whizzer, Herculese) and have to say that in my opinion the K-10 forks are above and beyond anything I've experienced. The way they smooth out the road is fantastic and they look terrific. Where there's chrome it is good quality and the aluminum parts' finish is very nice. Double or triple the price and they are still a bargain, elevating the humble bicycle frames we start with one significant step closer to becoming light motorcycles.

There are a couple of negatives. They are heavy. For me that doesn't matter since my cruisers end up on the heavy side anyway. Add in a sidecar, canine passenger and the circus bear steering the rig and it gets even heavier, so I don't care about that. The other negative is in the hassles fitting a wheel to it. Best option might be a Suzuki K-10 wheel, which I have never found. Or do like BBB and the rest of us and fuss with it. The result is worth it.

Regarding the holes mentioned for mounting disc brakes. I don't think that's what the holes are for. You'll find the same thing on old moped forks which are for mounting the center vertical support for a front fender. It is mounted there so that the fender and ride up and down with the telescoping portion of the fork. That's what I used mine for. I secured the Worksman brake arm with a hose clamp which has worked fine.

I'm glad to see a renewed interest in the K-10s through this thread of BBB's. Anything which will make your ride safer and more enjoyable is a plus, for sure!
SB
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
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Lebanon, PA
I wasn't aware of BarelyAwake's earlir thread, so if this thread is redundant, I apologize. I just wanted to provide some detailed info on the modifications necessary to fit these forks up to a bicycle. Some of the modifications are a bit of a pain in the butt, but definitely still worth it. for $50 shipped for a pair of genuine motorcycle forks, no amount of modification could make me feel that it wasn't worth it, or that it wasn't a killer deal. I haven't even driven the bike yet as it is not even a rolling chassis, and I can already tell from the look as well as the feel when I squeeze the brake and push on the forks, I'm never going to want to use any other forks. Right now I have no future plans to build any more bikes because I don't have anywhere to keep them, but if I did, I'd be picking up several pairs just to have them.
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
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38
Lebanon, PA
Here are some pics of each fork, the metal strap I used to secure the brake arm, and my headset. I was only able to snap one pic of the headset before the batteries in my camera died, so I apologize if its not easy to see how it's set up.
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
I wasn't aware of BarelyAwake's earlir thread, so if this thread is redundant, I apologize. I just wanted to provide some detailed info on the modifications necessary to fit these forks up to a bicycle. Some of the modifications are a bit of a pain in the butt, but definitely still worth it. for $50 shipped for a pair of genuine motorcycle forks, no amount of modification could make me feel that it wasn't worth it, or that it wasn't a killer deal. I haven't even driven the bike yet as it is not even a rolling chassis, and I can already tell from the look as well as the feel when I squeeze the brake and push on the forks, I'm never going to want to use any other forks. Right now I have no future plans to build any more bikes because I don't have anywhere to keep them, but if I did, I'd be picking up several pairs just to have them.
BBB,
No need for an apology. It was an old thread so who was going to see it? It's good that you're sharing your experiences with the K-10 as it re introduces a great fork to a lot of people who would have remained unaware of it. Keep doing what you're doing.
SB
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
3
38
Lebanon, PA
BBB,
No need for an apology. It was an old thread so who was going to see it? It's good that you're sharing your experiences with the K-10 as it re introduces a great fork to a lot of people who would have remained unaware of it. Keep doing what you're doing.
SB
Thanks, SB! Whenever I buy a new part and I don't see a lot of info posted about it, I always try to post about it and give whatever details I can, so other people will know about how good it works or what needs done for it to work good on a bike. I'm glad I was able to make these forks work for me, and I'm also glad I was able to share some info on it, so for the next person considering these forks, they'll know exactly what they are getting into. All in all, I'd say there was a minimal amount of modification involved in getting these to work. Change out the oil, get the springs a little tighter, modify my headset, cut one of the dropouts, find a new axle. Apart from fussing with the axle, I could have had everything else done in a few hours or maybe a day at the most if I'd wanted to. I just don't work that fast, lol. Now I can't wait to get my 98cc Lifan in this frame.