Aluminum threaded into aluminum can corrode and seize, possibly ruining a carb body upon removal. It looks like the aftermarket part has a good hard finish on it which should help, but the plastic part would likely never damage a carb body.
Good thoughts. The rubber boot didn't come with the fitting, I was in the carb rebuild kit from Motolab. I considered the aluminum/aluminum connection and put a thin coat of anti-seize on it just in case. If a crash caused the plastic part to break, I would suspect I'll have bigger problems than the enrichment circuit. Its pretty well protected inside the frame. The plastic part breaking would be better than the carb itself breaking for sure. I'm willing to risk it in this case.
The idea of replacing the plastic choke nut/screw/holder(/whatever) with a more durable version is not a new one and has been discussed also in this thread earlier, some two years ago (linky). It's good that ProCycle has come up with a commercial product to address this problem, although due to corrosion issues, brass might have been a better material choice. Cheers, Tseta
My mother was German. I spent 10+ of my formative years living and going to school in Germany. Regards, Derek
BST40 carbs use a cold start enrichment circuit instead of a choke. A choke is closed when an engine is cold and opened when it is warm, whereas a fuel enrichment circuit is opened when the engine is cold and closed when it is warm. A choke works by restricting the air flow, whereas an enrichment circuit works by adding extra fuel. A choke requires a fast idle cam or something akin to it (or you have to hold the throttle open manually), whereas an enrichment circuit adds a little extra air simultaneously with the extra fuel, so the fast idle is already built in. Regards, Derek
Why does activating the enrichment circuit make the starter work harder? My bike will crank well with the enrichment circuit closed, but sometimes when I open the enrichment circuit the cranking motor will stop dead in it's tracks.
Brass and aluminum, having differing galvanic potentials, will actually be more prone to corrosion next to each other than aluminum and aluminum. Obviously we've seen that this is not a big issue, with jets and such being made from brass. What I would be concerned with when screwing an aluminum part into an aluminum hole is galling, as I have seen extended fuel screws made of aluminum completely seize in the carb body, thereby rendering it useless. Regards, Derek
WOOF! Hi Meaty. I parked my '03 Adventure 3 years and 2 months ago (2010) when it ran out of rego, but had to move it recently, so I hooked up a jumpstart pack and presto!, it fired up and idled like a bought one on 3 year old fuel. I love this bike eh. I've been riding my Honda XR600 mostly though, as it has a new top end and needs bugger-all work done to it. How's yours these days?
The hard anodizing prevents corrosion. It also prevents galling of the threads because it has minor lubrication properties, as well as the extra hardness. It is a long proven technology and works remarkably well.
The Procycle cold start enrichment plunger retainer does not appear to be hard anodized. Regards, Derek
Still chasin' my tail... but they pay me to do it so that's good. My LC4 has a new tail: been dreaming of one for years (over 5) but at $700+ I couldn't justify it. The US importer was liquidating old stock and had one left, for $350 The carb is in pieces currently - about to ask Derek if he'll be around this week to see if I can buy some rebuild parts. Looking forward to trying it out! PS - you know you should drain the fuel - luckily you had drained the carb so there's no varnish in there eh?
Finally got the bike put back together. Man, the new carb parts really woke the Adv up. Thanks for everyone's help!
I would not increase cylinder filling without first verifying that doing so will not cause (or exacerbate) a detonation problem. Regards, Derek
