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Discussion in 'Thumpers' started by neepuk, Jan 10, 2009.
An '89 is old, yes. But it is one of the better years for TWs. It has the upgraded electrics, still has the kickstarter and I've heard the frames are built to a higher standard on the older ones. I can't verify that last, since I only have an old one.
The '89 does still have a drum brake in front (they all have drums in the rear; even the 2020) but it works well. In fact I've heard that the front disk doesn't actually stop any better than the drum.
It wouldn't be difficult to retrofit anyway, if one really wanted to.
One thing the later ones do have is automatic cam chain adjustment. Pre-2001 (basically the ones that still have a kick starter) has a manual adjustment that needs to be adjusted every 12,000 miles or something like that.
Can't speak to the frame differences, but I have a 2009 with disc brake and kick start. For such a budget bike, I continue to be amazed at how strong the front brake is. I can't comment on the cam chain adjuster as it hasn't entered by radar as of yet... But the front disc brake has been, and continues to impress as being pretty damn awesome! For me at least, it was worth picking up a later model with the front disc, and retrofitting the kick starter for a few more $$. For me it was the best of old and new, and the total cost difference wasn't that large... The rear brake seems to work just fine as well. Then again, my experience over the years has been that the demands on rear brakes are nowhere near as specific as those placed on the front... YMMV, of course...
Hi Randy, I guess I'm more old school. My TW is a 1994 with the drum brake up front. I like the fact that all I have to worry about is a front brake cable and not have to worry about smashing a master cyl. full of fluid or bending a disk when I take a nap in a rock pile, hahaha, Which I did with my DR650. Or ripping off some hydraulic lines. The drum brake has a large "o" ring around the housing that keeps water out and I can lock up the front brake on pavement if I really want to fall on my ass. hahahaha So it's all good.
I've never ridden the older drum brake equipped TW so I don't have a solid frame of reference for its performance. I did however, once own a Honda XR200R with drum brakes front and rear. And while it wasn't as cool as a disk, it worked just fine and I never had any issues with it. And there is a lot to be said of simplicity!
I guess my thought process was that since I'm not using the bike to really ride hard off-road, and will primarily use it to explore back roads, gravel, and the occasional mild trail, that the disk system stood little chance of being damaged. And perhaps the front disk might offer advantages on the asphalt, at least. Perhaps not, IDK... And maybe more importantly, I got one with a disk because that's what I found a decent deal on when I was looking to buy. Had I found a good enough deal on an older drum brake version, I likely wouldn't have let the front drum dissuade me from the purchase.
The advantage of a disk over a drum is IF the drum brake gets wet you lose most if not all braking power.
I like drums fine too and I just remember that when I am going through water deep enough to drown the drum brakes on a bike I am riding to drag the brake for a while to dry it out once out of the water.
Before I need it!
I agree with you Randy. Bending the disk on the DR650 was some kind of freak accident and would prolly never happen again. However I still don't like dealing with hyd. systems on a back country bike but it's pretty hard to find one that isn't today. So if a bike was what I wanted I wouldn't let disks stop me from buying it. However last year down in Death Valley I took a nap at prolly 5 miles per hr. onto a big rock pile. Glad I had my chest protector on, so it can happen even on some simple stuff at slow speeds. Dang rock just jumped up and bit the front tire. hehe
I had two TW's and I sold the one with the disk brake. It was 2003.
yup, i agree. and That o ring does a good job of keeping water out.
I searched here and on TW200 forum for Carburetor Vent mod; for water crossing. On the TW200 forum, there are threads, but the photos are gone. Does anyone here have photos and a writeup to share? There is also some discussion on the seat foam for intake snorkel. What does this forum of experts know?
No photos to share, but it's a pretty simple idea. The float bowl needs to be vented to atmosphere. The vent line typically runs down and terminates somewhere below the swing arm pivot area. In deep water crossing this location can be below the waterline, blocking the vent and creating bogging/stalling issues. The idea is to cut this tube just below the float bowl, then install a "T" fitting between the bowl and the end in it's normal location. This allows the bowl overflow to work as designed (needed if your float needle ever gets crud in it, or whatever... You want the excess fuel to drain down below the bike in a safe location rather than pouring into the cylinder or dribbling all over the bike elsewhere so the stock vent hose still needs to terminate in the usual location). But, then, to prevent the water crossing issue, put a second length of tubing on the "T" that you installed, and run it up to a higher location. Usually somewhere up under the tank near the steering head. When done in this way, the overflow function still works, AND, even if the lower hose is blocked, the float bowl is still vented to atmosphere so the bike continues to run normally.
Rereading that, I'm not sure how clear my description is... Sometimes a picture is worth a thousand words... Or in this case, maybe a simple diagram...
As you can see, the original tube, terminating in original location, still serves as a carb overflow drain, and the newly installed tube provides venting in the event the original is temporarily obstructed during a high water crossing.
And, because this is the internet, and shit tends to happen, let me make one more comment on this subject...
While I'm sure that most here are fully aware of what I'm about to say, I also realize that some may not be... There could be someone that comes along, reads the above and says, "Why bother with the "T"? I'll just stick on a longer tube and run it up high..."
And yep, that would work... Until you had a float needle stick and not shut off the fuel supply to the float bowl... Think about it... Liquids don't like flowing uphill. The tank is the highest point in the system. Liquids like flowing downhill. The float needle keeps this in check. As long as it functions properly. If the float needle valve seal fails to do what it does, fuel continues to flow into the float bowl until the bowl is full... Then, it has to go somewhere, because the fuel tank is still higher and pushing fuel with head pressure. Normally, it flows out the bowl overflow tube, then down the rubber tube to dribble on the ground below the bike. BUT, if you reroute that rubber tube higher than the bowl, where does the fuel go? It'll continue to rise until it flows up the jets and into the venturi. From there it'll flow into the airbox and/or the intake, potentially filling the crankcase with gasoline.
Leave the lower vent/drain tube intact though, and the fuel has an out... It'll simply flow out the overflow tube and down to beneath the bike.
So, in a nutshell, add the "T" and extra vent if you feel the need. But avoid the temptation of just routing the single tube higher than the float bowl...
Another simple diagram to illustrate what I mean...
Randy, Thank you! Your description and write up is clear as a bell.
Most people put a sintered bronze filter or aquarium stone on the upper tube end. Also consider using a street (Y) fitting instead of a T fitting. Less likely to form a liquid pocket.
Mikeped, great info. I’ll incorporate those recommendations.
Randy & Mikeped.......great info......glad your both here. Any more tech thoughts , keepim coming.
Not for nuthin' , but I was gonna be one of those big mouths. My kibitzing has a twist though; I ran my vent line up around my tank cushion on the RH side then looped it around to a "crankcase filter" that sits just higher than the carb.
My reasoning was that I shouldn't have a liquid lock as the fuel can run back into the float bowl and/or the overflow...or the fuel can run out of the filter.
I found out about troubles with a low-hanging vent on my DR in the Mojave River.
Since I altered how the vent line runs on my DR, I've also had much less trouble getting the bike started after falling over.
However, one can't go wrong with the method outlined above.
I think the other posts about this are wrong.
Its got nothing to do the the float bowl or its vent.
Its the vent for the vacuum operated slide.
Here is a picture of how I fixed my bike:
The stock hose comes out to the right of the choke knob and runs under the engine.
I added a T and ran another hose up under the gas tank.
If I go through deep water, water will drain right out of the hose.
Without the added hose, the water in the hose prevents the slide from responding to vacuum.
It may be closed when you have the butterfly throttle (cable controlled) open causing a very rich condition.
Why not run the hose up under the gas tank and not have to add anything?
If anything gets into the hose, it will only run into the carb, not out the bottom.
The above worked for me, I have been up to the seat in water without a problem.
You have the new style cv carb. On 2000 and prior it is the float bowl vents that get routed with a T. Previous descriptions were accurate.
I bought another TW today!
I have a watch on CL for TW's in Arizona where my brother moved to this past summer when he retired.
He likes riding my TW more than my other bikes so I talked with him about getting a couple TW's down there and I can visit him in the winter so we can go exploring.
I saw this one on CL and he contacted the owner and made arrangements to check it out today.
He called to tell me that I bought it and that it is like new.
2007 completely stock with very low miles.
Unfortunately I don't know when I can go down to AZ or even if I will be able to before it gets too hot...
He will ride it for me in the meantime...