Thursday, June 30, 2011

Chain Lube & Drive Line

I've been pretty blessed with respect to drive train maintenance. Only once have I had to replace a set of sprockets and a chain. And, I really did that because I was taking a long trip (Trans-Am Trail - Oklahoma, New Mexico and Colorado) and didn't want to have to worry about the chain failing. The original equipment chain probably would have made it but I figured "better safe than sorry."

One the things the previous owner did, to ensure the chain wouldn't turn to junk, was to liberally apply (red) grease to the chain. He did a nice enough job because the chain is still in pristine condition but the grease attracted an awful lot of dirt and debris along the way. Over the winter I made a feeble attempt at cleaning it using rags and brake cleaner. That was good enough for the time being but last weekend, while I was changing tires, I decided to get it good and clean once and for all. This time I used about a pint of turpentine, in a shallow oil drain pan, and let the chain soak in it while I swapped tires. Using a little elbow grease and an old toothbrush did the trick. The chain now looks like it did when it left the factory. I opted to try some Liquid Wrench Chain Lube.So far it's been great. It goes on as a liquid and dries within sixty minutes. It does not sling off but you do need to be vigilant while applying the lube to the chain, as it will drip. The next time I apply it, I may remove the chain from the NX and suspend it so extra liquid lube can drip off into a catch pan. After its dry, putting the chain back on the bike should be easy and keep everything much cleaner.

I am kicking around the idea of changing the sprockets so I can get a little more top end speed. Stock gearing for the 1988 NX125 is 15/56 (3.73:1 final drive). The 1989-90 models came with 15/50 (3.33:1 final drive) gearing. I am thinking of switching to 14/48 (3.42:1 final drive) and an o-ring chain. I will stick with the 428 chain as I see no reason for an upgrade.
EDIT: a reader left a comment (thanks Ed) to let me know that the stock gearing, on his 1989 NX125, is 15/48. So, if I wanted to increase the top speed potential, I could always go with the factory gearing for the 1989-90 NX125.

Monday, June 27, 2011

Ring out the Old

I was really hoping to get a season's worth of riding on the original equipment tires that came on the NX. They're the ubiquitous Bridgestone Trail Wings, TW41 in the front and TW42 in the rear. Some folks refer to these tires as "Death Wings" due to their dearth of grip in off-pavement conditions.



When I owned a DR350SE, fellow owners hated them and would remove them, regardless of condition. I was fortunate, my DR350SE came with Dunlop D607s. They howled on pavement but I got good wear and gas mileage out of them. I eventually sourced a second wheel set for some Pirelli MT-21s and replaced the Dunlops with some Kenda K761s. I loved both; the MT-21s were great off-road and even on-road they were good (in the wet, too). The Kendas were pavement only, smooth and quiet.

I digress, I found the Trail Wings to be pretty good on the pavement and got good fuel mileage to boot (~94 mpg). However, at twenty-two years old, the carcass can begin to breakdown which would lead to catastrophic failure. While that's not necessarily bad in the dirt, it's going to be very bad on pavement, worse on pavement and in traffic. So, I opted to purchase some Shinko 705s from Motorcycle Superstore.

I ordered them on Tuesday, June 21, 2011 and received them two days later (!!). I don't care where M.S. is located, that's some fast handling & shipping. What's sad is that the Bridgestone's still look great, there aren't any cracks or splits and there's at least 1/4" of tread depth left. However, I'm not willing to take the risk (on having them fail massively). The Shinkos were $92 for both (on sale as of this writing) which included free shipping. They mounted up easily and the only issue I encountered was that the front Shinko (90/90/-21) is slightly wider at the tread shoulder than the original Bridgestone (2.75-21). This caused some interference issues with the front fender/fork brace. I had to reform it to clear the new tire.

I took them for a spin to scuff them in. I did not notice any difference in smoothness/vibration but they do ride much more quietly. I've seen several reviews, both on M.S.'s web site, on TransAlp.org and on AdvRider. Most agree they're a good value and wear slowly. I would hope they'll last a while and should based on the light weight NX. They have wide, deep sipes which should allow them to clear any mud quickly (although, I doubt I'll have the NX off-road any time soon) and prevent any hydro-planing. The rest of the week is supposed to be warm/hot and dry. So, I'll have ample opportunity to fully scuff them in before extended gravel riding on Saturday, July 2.

Friday, June 17, 2011

Change of Heart on the Top Case

As I previously mentioned, I've decided that I don't like the Givi Top Case on the rack I made for the NX. I specifically don't like the amount of weight that the base plate, top case and contents of the top case put on the turn signals. I may rethink this decision if I have the opportunity to modify the rack itself but I'm thinking I'll stick with what I have now; an original equipment rear rack off of an early Honda TransAlp.
Sorry, this is the best picture I could find, on the 'Net, without resorting to running outside to take a picture of the rack now on the NX. So, the laptop, in it's sleeve, is lashed to the rack with ROK Straps and my remaining items go in the Seal Line Shoulder (Messenger) Bag which is waterproof. I like the messenger bag concept because it allows the bag to rest on the rear portion of the seat while I'm riding. And, the bag comes with a waist strap to keep the bag positioned directly behind me. Lastly, the bag's color is orange which contrasts nicely with my hi-viz Olympia Bushwacker jacket. Earlier this week my brother-in-law was unceremoniously punted off his cruiser, while attempting a left turn into his chiropractor's office, by some nineteen year old idiot who wasn't paying attention. So, I'm a little sensitive about being visible right about now. So, far, the combination has worked well. I have some concerns about the jacket's ability to flow air with the bag sitting just behind the small of my back. Hot temperatures aren't too far off and I'd like to stay somewhat cool during my commute in the Dog Days of Summer.

Thursday, June 16, 2011

Tail like a Peacock

OK, so I have yet to ride the NX is the rain. However, I did ride it, this morning, through the wet. A storm system passed through Chicago-land just before I left for work. The roads were wet enough that water still pooled on the pavement and it had not yet begun to dry. I was pretty surprised by how wet everything was on the back of the bike. I have switched from the Givi Top Case ( I'll discuss why in a future post) to a simple rear rack and a SealLine waterproof shoulder bag. I use an Outdoor Research Dry Sack (25L) to protect the laptop which is strapped on the rear rack. Both the dry sack and the shoulder bag were wet and there was even a spot of the back of the seat that was damp, too. I have to think that the rear bodywork does not do a very good job of shielding the spray kicked up by the rear tire. I may look into adding some shielding now that I know this.

Additionally, the NX still rides on the original equipment tires; Bridgestone Trail Wings. I've heard of these tires referred to as "Death Wings" due to their lack of off-road grip. They seem to be pretty good on the pavement (for 22 year old tires) but they'll need to be replaced if only due to their age. In the mean time, if I can burn them up, I'll feel much better about replacing them.

Wednesday, June 15, 2011

Meet the New Parts ("the" solution?)

Not the same as the old parts, that's for sure. In an effort to eliminate some of the more basic issues that could be the root cause of 'the hesitation', I replaced as many carburetor rubber pieces as I could. It seems to have had a positive effect and cured (?) the issue. So far, so good.
Here's what I had planned to replace: (sorry my captions are too small to see/read) that irregular shaped gasket is for the float bowl. Inside of that is the gasket for the carburetor slide cap. Inside of that is an o-ring who's purpose escapes me (it wasn't used). Below the irregularly shaped gasket is the carburetor-to-intake o-ring. To the right of that (lower right) is the intake-to-cylinder head o-ring. In the upper right hand corner is the o-ring and washer for the air/fuel mixture screw. I had previously used Permatex Ultra-Blue to help seal the old float bowl gasket. I opted not to replace that gasket because I did not want to install the richer main jet (I wanted to see if the stock jetting would work appropriately). It turns out I will not need to use the richer (#102) main jet, the NX runs just fine with the stock jetting. At some point, I will replace the old float bowl gasket but there obviously isn't any urgent need. The image of the air/fuel mixture screw (below) shows the new parts on the screw, the old parts to the right and a small hook I made out of safety wire (in the middle). The hook was necessary to pull the old o-ring and washer out of the carburetor body.
Manifold-to-Cylinder Head O-Ring
Carb-to-Manifold O-Ring
Slide Cap "O-Gasket"
Air/Fuel Mixture Screw

Monday, June 13, 2011

Remedial Learning

For a moment, let's return to kindergarten and review one of the tenants of early childhood; sharing. Learn to Share.

Let's now fast forward to the current day and apply said tenant; Learn to Share the Road.

I had two incidents happen recently, one last last week and the other happened this morning. Last week's incident had parallels to this morning's incident; another motorist that seemed to think the the space I currently occupied was their's to take. I tend to take offense when you think my space is yours. Scenario; I am approaching the intersection of two four-lane undivided streets. There are  no turn lanes on either street. So, if you're turning left, traffic in your lane will be forced to stop until you can safely turn. I am in the left lane and have had my left turn signal on for the last sixty feet. I have another fifty to sixty feet to go before reaching the intersection. The traffic in the right lane has slowed for some reason and as I'm going past a large Mercedes-Benz (S Class, I believe), the driver decides to (classically) flip on the left turn signal AND change lanes without looking in his mirrors or checking over his left shoulder. At this point, I'm opposite his left rear passenger door. There's no time to apply the brakes to provide room for him. I hit the horn and veer to the far left side of my lane of traffic. He slows his advance into my lane but only enough to allow me to pass. He's now inches from my rear wheel and I'm beginning to apply the brakes so I can make the left turn. He zooms past me, still partially in my lane and manages to hit my right wrist with his rear view mirror. This knocks my hand off the grip and kind of into a "F You" arm gesture. I see him check his rear view mirror (to see if I was coming after him or to see if I'd been hurt/knocked over?) and continue on, not even applying the brakes to slow down (in other words, "full flight" mode). I wear gloves with some serious padding on the back of the hand and wrist. I completed the left turn, a little shaken, and continued on to the office.

This morning was similar; I was stopped at the intersection of two four lane non-divided streets. I was in the left lane about six vehicles back from the light (i.e. sixth in line). In the right lane are a couple of cars, a big semi full of hot blacktop, a silver Mercedes (not the same as above) and a white Honda CRV. The typical modus operandi, for vehicles like the Mercedes and the Honda, is to hope someone in the left lane is a little slow so they can cut in front and avoid being stuck behind the slow semi. The silver Mercedes pulled it off, jumping in front of the minivan in front of me. But, the speed of both lanes was reduced for some reason so there wasn't much spacing between vehicles. At about 40 mph, I'm nearly abreast of the Honda. Again, I'm watching for the glance in the mirrors or the look over the shoulder. Nothing. Older woman driver (lots of grey hair) yet not elderly. As I expected, here she comes, drifting into my lane. I honk the horn and she returns to her spot behind the semi. When she realizes what she's done she sucks in a large volume of air and releases it through her mouth. She's obviously perplexed and put-out by the fact that I am where I am. I shoot her a look over my right shoulder and give her the palms up gesture ("what are you doing?). She slows considerably as I maintain the speed limit (45 mph). As we approach the next light, she will not even come close to pulling up along side me, hanging back to avoid confrontation. Really? If you're that timid, then why drive like you own the road? Perhaps she'll a least check her mirrors for the rest of the day (but, I doubt it).

Monday, June 6, 2011

Obviously

I finally encountered some knowledgeable inmates over on Adventure Rider. Let me amend that because there are a lot of knowledgeable inmates there. I'm referring specifically to inmates that have experience with the NX. I retrospect, it seems that I might have an air leak, someplace, between the carburetor and the cylinder head.

Normally, the sure sign of an air leak is a slow but steady rise in rpm as the engine warms. Usually a shot of carburetor cleaner or starting fluid on the intake manifold will cause the rpm to increase dramatically (these are flammable fluids, you see). I've never tried this method to try to diagnose the issue because I've never suspected an air leak. The NX is twice as susceptible because it has two o-ring seals; one between the carburetor and the intake and the other between the intake and the cylinder head. What makes it more difficult is that the air leak, minor as it may be, would seal as the parts warmed (expanded). This pretty much explains why the issue was more prevalent when temperatures were cold (20º-50º F). Another clue would have been that the float bowl sealing gasket recently quit sealing. These are the parts, o-rings and sealing gaskets, that suffer the most from age. While mechanical components fair pretty well, these parts still tend to degrade even though they still look good and feel pliable.

So, I ordered a carburetor gasket set (which includes the carb-to-intake o-ring as well as the float bowl gasket) and the intake-to-cylinder head o-ring. If there is an air leak, however slight, this should seal it and resolve the leaking float bowl, too. I would still like to check the valve clearances as well as the compression. I ordered from Honda Parts House in Muskegon, Michigan. They seem have the best OE Honda prices I've found on the 'net and are relatively close to me (Chicago).

Thursday, June 2, 2011

Taking Steps

So, it was 57º F this morning and I decided to test out my theory that the carburetor is jetted too lean. I did this by applying a small amount of choke even after the engine had warmed up. It certainly ran better than it did without any choke at all. This leads me to believe that the 125cc engine is too small of a mass to keep the necessary heat for the engine to perform optimally. It also explains why it ran so poorly in much colder conditions. So, I ordered a #102 main jet from Carb Parts Warehouse (along with a pilot jet upgrade for the TransAlp). I already own a #105 main jet since it came with the carburetor off of the ACT200X. So, I can step up one or two main jet sizes in an effort to eliminate the hesitation I've experienced. What I find slightly odd is the fact that the same carburetor is used on various other Hondas, with different engine displacements, and the main and pilot jets are same. So, I guess it's not surprising that the jets may not quite right, in the case of the NX.