In the grand tradition of magazine projects it’s taken a little longer to get this thing going then I had anticipated (see part 1).
I thought I’d planned it well, doing a mass of research on the web about what mods KLR users recommend, finding all the possible accessories available and then whittling it down to a list of the most important, while trying to keep it under the allotted $3,000 budget to boot. All this wasn’t actually that hard (just time consuming) and I even managed to strike a deal with Les Clarke at Dual Sport Plus to provide all the parts. It seemed like all was hunky dory. But then came a particularly hard and intensive few months at CMG with the launch of our new daily news site. We also had some delays getting the parts we needed from Dual Sport Plus, so the project that was supposed to start in January but didn’t start until May. Sigh. Well, the hurdles have now been hurdled, most of the parts have been garnered and I’m now into the fitting and appraising process. I’ve decided to split the process up into a few sections, starting with the motor mods, which I’ll go over here, stating what we’re doing and how much it costs. Hopefully by the end of it we’ll have a pretty good adventure tourer and all within our budget. Then we get to ride the damn thing!
THE ENGINE MODS The Plan
For all the readers out there that are not home mechanics or students of mechanical engineering I thought it might be useful to open each update with a little bit of theory as to why I’m modifying what I’m modifying.
Please note that I’m not going to go into a blow-by-blow account of fitting these parts, as this info is already covered elsewhere online (links provided), but I will highlight any issues I find along the way. What I want to achieve with the motor of the KLR is to try and boost performance without spending an arm and a leg (gotta watch that budget) or indeed sacrificing fuel economy too much in the process. An adventure tourer is for touring, after all, and there’s no point in making a motor that just sucks fuel. Okay, so what are the best performance mods and why? Hours of scanning the web tell me there is room to give a slight power boost and improved throttle response (the KLR motor is far from snappy) and all within a small budget to boot.
Of course, you can spend a fortune if you want with hotter cams, big bore kits and replacement carbs, but then you shouldn’t have bought a KLR in the first place. There’s always a point when it makes much more sense to spend more money on a more powerful bike, than try and make one out of one that just isn’t. You can’t make ice cream out of shit, you know. Well, unless you want shit ice-cream. I also want to fix any inherent weak points, and with the KLR motor that means the balance shaft adjuster, AKA the Doohickey. I’m also fitting a low-profile magnetic drain plug, as the original sits above the skid plate and so can be clipped if you graze a rock (seen it happen, and the resulting cracked case—very messy). The magnetic bit will catch any metal shavings floating around in the motor (hopefully not too many).
The Mods A) Air box mod & filter. Price = Mod is free (if you have the drill bits) and air filter costs $20 (estimate)
The idea of my chosen mods is to get more air and fuel into the motor. Now that sounds like a recipe for poor fuel economy, but since all motorcycles have to work within some pretty strict noise and emission regulations they tend to suffer from restricted airflows and overly lean mixtures, thus reducing performance.
I decided to do this by drilling some extra holes in the airbox, and fitting a freer-flowing filter than stock. One mod I saw on the web was to cut out an ‘L’ shape in the top of their KLR airbox to let it breathe more. It looked like a bit of work so I decided to just drill out several circles instead using 1 1/4″ and 1 3/4″ drills. It wasn’t exactly symmetrical but it’s hidden under the seat so beauty isn’t a requirement and I left a 1/4″ gap (ish) between the holes, which I think should retain some strength too. Oh, and I’m also going to remove the wire mesh found between the filter and the intake. Someone had recommended it and I don’t see why it’s needed, so why not? Some people may think that this mod means the bike is more vulnerable to water intake if dunked in water, but the holes are in the top of the box and above the regular snorkel, so if it got that deep, water will already have got in.
No, I think the main downside will be the ingress of dust, requiring more regular filter cleanings. I’m also expecting more intake noise but if it’s bad I do have a spare parts KLR so I can always convert it back to stock. The air filter is actually on back order with Dual Sport Plus, but I’ll add an update on that if required. So far I’m undecided about the exhaust pipe. An aftermarket unit offers better flow and reduced weight (the standard pipe appears to be filled with lead), but the drawbacks are increased noise and high cost. I’ll get back to you on this, but any advice on a pipe that might fit that criterion is much welcomed (comments below please). I do have a Cobra aftermarket pipe from a parts bike I own, so I may try that — and it’s free. B) Dynojet Carb Kit. Price = $53.95
But more air isn’t much good if you can’t match it with some extra fuel, and a quick and relatively cheap way to do that is to install a carburettor jet kit. This will not only increase flow rate, but also improve response at lower throttle openings (emissions regulations tend to adversely affect the low throttle openings).
The Dynojet kit comes with the jets to do a stage 1 or 2 conversion. Stage 1 is for pretty well stock machines, whereas Stage 2 is for bikes with modded airboxes. Both are suitable for use with an aftermarket pipe. The procedure seems to be the same for both stages, though needle height and main jet size are dependent on the which stage you perform (higher and bigger for stage 2 respectively). You must be careful to select the proper drill bit from the kit as there are two supplied, one to drill out the mixture screw plug, the other to drill out the slide lift hole; don’t mix them up, or as I found out, read the instructions carefully. The fuel mixture screw is set at about 1 3/4 turns at the factory, but this kit recommends 3 1/2 turns out (richer). That seems like a lot, but I will readjust if needed once the bike is running. I should mention my bike wouldn’t idle without the choke applied before I began working on it. It turned out that it had a blocked pilot jet so I threaded a piece of copper wire (extracted from an electrical cable and used because it’s soft and won’t damage the jet) through the jet to clean it.
Of course, it may not have helped that the air filter was pretty gummed up too! The standard main jet is a 148 (the higher the number the more fuel it passes) but the kit recommends anything from a 136 to 150 depending on the stage chosen and exhaust fitted. I find this a bit odd as you’d expect it to want to deliver more fuel and therefore go from 150 and up, though this could be due to differences in numbering between Dynojet and Kawasaki. Since I did the airbox mod I’ll try 150 and go down from there if needed. The final mod is to replace the non-grooved stock jet needle (which restricts the flow out of the main jet progressively with throttle application – full throttle meaning no restriction) with the new one that has five circlip grooves in the top. The location of the circlip on the needle determines the needle’s height (a higher needle offers less restriction to the fuel from the main jet), the exact position depending on which stage you’re opting for.
With all the mods carried out to stage 2 specs, the carb was reassembled and ready for on-road testing (if anything it’ll likely be on the rich side which is better than lean as that can cause engine damage). All in all, with the carb off, it’s about an hour’s job. By the way, you can apparently get a very quick and easy improvement in carburation by adding a 0.020″ shim under the standard needle and turning out the fuel mixture screw a bit. More info: Here’s the link to a guy that started doing much what I have here and dyno’d all the changes along the way: www.patmanracing.com/klrdyno.htm Since my mods are very similar to his then I should see a healthy boost in lower rpms (which is kinda where I’d like it most) though with a slight drop at the top. He also took out the snorkel from the airbox, which I may try if I want to lean it out a tad. C) Doohickey/balance shaft adjuster upgrade kit (includes Doohickey, coil springs, rotor holder, gaskets, puller, bolt). Price = $124.99, plus $13.99 for the torsion spring (optional).
As with any large capacity single cylinder machine unless you have a balancer system in place to counter the up and down fling of the piston you’re going to have a pretty vibratory ride (ever ride a KTM 640???).
The KLR uses two balancer shafts connected by a chain that is kept taught by an eccentrically mounted adjuster mechanism (aka Doohickey). Every now and then you need to loosen the adjuster to allow a spring to take up the chain slack, where upon you retighten the adjuster and Bob’s you auntie’s live-in lover! Trouble is the standard Doohickey is prone to breaking from over tightening of the adjuster (or just bad luck) and the spring can fail too. This can lead to the chain jumping and seizing up the motor. I even had a friend suffer a complete ignition failure when a part of his broken Doohickey took out his ignition pickup coil.
Thankfully there are a couple of aftermarket upgrades that are significantly stronger and can even be bought as a kit that comes with optional torsion spring, rotor holding tool, rotor puller and replacement rotor bolt (Kawasaki recommends replacement every time) and gaskets — which is what Dual Sport Plus sent me. Now interestingly there seems to be a big hooharhar in the KLR community over which Doohickey to buy. It used to be that it was just made by Eagle Mike but it appears that another company (Studebaker) have jumped in on the Doohickey train and there is now much furore over whether the Studebaker unit is any good. There certainly seems to be no physical difference other than the Eagle Mfgr is harder, but whether it is enough to cause a problem, who knows? All I know is that I was sent a Studebaker version, which looks a damn sight better than the original, so I’m fitting it. The job is pretty straight forward, though you’ll need a good long extension bar to get enough torque to get the rotor holding bolt out. I wouldn’t bother trying to do it without the complete kit, unless you have a friend with one that you can borrow, as it’s really a one off job.
With the covers (2) and rotor removed, the Doohickey was easily accessible. The original spring was still in one piece (they are reported to break easily) but the Doohickey was gouged and actually bent from over tightening in the past – just see the pics to see the differences between the original and its replacement!
To fit the torsion spring you need to drill a hole (bit provided) in the secondary cover to anchor one end of the spring, while the hook end attaches into the slot of the Doohickey itself. As with any spring this is a bit tricky but with the help of needle nosed pliers and a few attempts the job was done. Looks good too! All in all, with a good workshop and the right tools you should be able to do the job in a couple of hours. More info: Doohickey video: www.youtube.com/watch?v=26oSOrvv_e8 Doohickey text and pics: www.klr650.marknet.us/doohickey.html Installing a torsion spring: http://leftcoastklrs.com/Install_a_torsion_spring.htm D) Low profile magnetic drain plug. Price = $ 13.49
Do I really need to go into this? Not really, remove old, fit new. Job done.
The Damage I’m really looking forward to seeing how the performance mods liven up the motor, with all done relatively easily and at reasonable expense. To date my cost is $226.42, though that doesn’t include an exhaust pipe (if I decide to go there) and an estimate for the air filter. $2,773.58 left to spend! I’ll try and make the next update a little sooner. First I have to work out which is the next area to be updated. Thanks to .. Dual Sport Plus for supplying us with all the bits we needed to do the engine mods!