Project Husqvarna TE610 Part 3: Dual Sport Adventure Bike Nut and Bolt

,

 

te610 cam chain tensioner
Another common TE610 issue is accelerated timing chain wear, typically blamed on the chain tensioner, a spring-loaded ratcheting mechanism on the left rear of the engine behind the exhaust pipe.

Checking the cam chain condition by removing the tensioner and counting the number of notches it is extended should be a standard maintenance item, at least as often as the valves are checked. Installing the tensioner incorrectly is guaranteed to damage the timing chain, so be careful to follow the correct procedure. Many owners change to a manually adjusted tensioner and claim much reduced rates of chain wear compared to results with the stock tensioner. This engine is essentially brand new, so for now, this is on the list of things to think about later.

Once again, use the opportunity of disassembly to clean and inspect everything. While the swingarm was off to be welded, I found that one of the shock linkage bearing seals was improperly seated. I was able to remove and reinstall it satisfactorily. While I was in there, I relubricated the linkage bearings with Motul Tech Grease, a synthetic blend, lithium based grease that is water resistant and includes additives to resist oxidation and corrosion. It is rated for use at 302°F continuous and 428°F intermittently, which is much hotter than any part of this bike outside the combustion chamber and exhaust should ever get.
 

te610 arp bolts flange head stainless polished
Another big opportunity for improvement on the TE610 is fasteners. A handful of the OE bolts had gone missing from the bike when I bought it, a few have a well-established reputation for breaking in service, some were specified too short, and some were beginning to show thread damage just from being loosened and tightened during normal adjustments or service (even when threaded into aluminum). I replaced questionable fasteners with flange-head hex bolts from ARP, including going back and upgrading the subframe and chain roller bolts shown in Part 2.

The TE610's OE bolts are generally flange-head hex bolts, many with reduced hex sizes where M6 uses an 8mm wrench and M8 uses a 10mm wrench, the same as ARP's metric flange-head bolts. Twelve-point bolt heads can sustain greater torque without stripping, but a six-point socket is useless on them. In order to prevent a situation where I have a tool but can't use it, I chose hex heads. Since the Husky will see water and mud and not be cleaned and wiped down with WD-40 daily, I went with stainless steel rather than black oxide, so the bolts don't rust.

Typical stainless steel fasteners from your local hardware store have an ultimate tensile strength of about 101,000 psi and a yield strength (where the metal is permanently deformed) well below that. They basically shouldn't be used for structural applications unless weight is of so little concern that you can afford to use substantially oversize fasteners.

A grade 12.9 metric bolt has a minimum ultimate tensile strength of 174,000 psi and a minimum yield strength of 157,000 psi. However, most readily-available, flange-head, metric bolts are graded no higher than 10.9 and have a minimum ultimate tensile strength of 145,000 psi and a minimum yield strength of 130,000 psi.

In contrast, ARP's flange head bolts sold in five-packs are much stronger. Polished ARP “Stainless 300” bolts have a yield strength of 140,000 psi and ultimate tensile strength of 170,000 psi. ARP's 8740 chrome moly bolts, with a black oxide finish, are rated for a yield strength of 180,000 psi and an ultimate tensile strength of 200,000 psi.

If you happen to ride in salt, stainless steel will effectively resist corrosion of the fastener itself, but may tend to accelerate corrosion of any aluminum it's threaded into. Since this is California, I'm not super worried about that, but I still plan to hit any accessible threaded areas, such as the triple clamps holding the fork tubes, with WD-40 after washing. 

Miscellaneous Details
The TE610's shifter was loose, the grade 8.8 bolt showing damage on its threads. I chased the threads in the shifter and used a new ARP bolt and new wave washer. The socket head cap screw holding the top of the gas tank to the frame also had damaged threads. The threaded boss it screws into was still full of fine steel shot from the frame finishing process, but the threads in the frame seemed to be in much better shape than those on the bolt. Thorough cleaning and a new screw seem to have squared it away.

One of the exhaust heat shield bolts was missing and the holes in the aluminum shield itself were egged from rubbing on loose fasteners. I replaced the button-head hex screws, which were liable to not be tightened sufficiently due to the small hex cavity and soft stainless material, with more stainless flange head bolts from ARP.
 

te610 engine mount bolt missing
The upper engine mount bolt, which connects the cylinder head to the frame, was missing, and was replaced with ARP. Two shoulder washers that should have been between the right-side radiator mounting bushings and the frame were missing, never installed at the factory. As a result, one bushing was over-compressed and the fastener on the other one had never been able to be tightened, so was about to fall out. By their location, all three may have been “installed” by the same guy on the assembly line.

A screw holding a radiator side panel to the fuel tank had been replaced by the previous owner with whatever the local hardware store had, so I ordered a new screw and shoulder washer from the dealer. Several shoulder washers that passed through holes in the body plastic didn't really fit, but careful trimming of plastic around them made a big difference in alignment and ease of assembly.

At this point, the Husky is ready to ride. Nothing broken, nothing in the process of breaking, nothing inevitably going to break, nothing falling off. It hasn't taken significant reengineering, wherein a science project swallows piles of cash and ends with compromises. Instead, it's taken obsessive attention to detail, careful observation and a commitment to get things right. By far the most expensive and time-consuming part was the fabrication and welding done in Part 2. For the rest, doing as much as I could myself meant there was budget for good parts and materials when required.

I don't believe you can pay someone to go over a bike this thoroughly. The ability to take time and caring about the results enough to do whatever it takes to get it right are advantages a DIYer has over any professional. Next time, we'll move into personalization, dialing in the Husky's ergonomics with simple changes making a world of difference, and adding a few nice upgrades.

 

Sources

Automotive Racing Products

Baja Designs

MD Automotive

Motion Pro

Motul

Zenith Performance Fabrication

 

 

Follow the links to read more about Project TE610:

 

Part 1: Dual-Sport Adventure Bike Options

Part 2: Fundamental Fixes

CAD – Cardboard Aided Design

 

Leave a Reply

Your email address will not be published. Required fields are marked *

*
*