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10 Posts
VIDEO: rough tw
Hello all. Sorta new here. I recently fell into the TW world when using a 2001+ front end swapped onto a 1976 Yamaha DT400 (then ultimately went a somewhat different route). But it got me interested in these bikes. Then I came across a ROUGH titled project near me and couldn't say no.
It was missing a handful of parts but I figured a little elbow grease, couple bucks, and patience would do the trick. I busted most of the rust and replaced what was too far gone. For reference: I could stick my finger through a rust hole in the tank (shoutout to reddave for selling me a replacement!). And the header was rusted completely off, leaving the "collar" rusted to the cylinder, which was a bitch to remove.
But even after the costs of parts and effort (and a broken ez-out in a snapped exhaust bolt) adding up to negate the "good deal" I thought I got, I am still struggling to get the thing running right.
Hoping some of the TW vets could send any tips my way to help me get this thing on the road. Its close.
Key details:
Symptoms:
This has got to be at least two separate problems. 1 of which is the carb, but I do not know what /why. I used new pilot jet. So unless there is still build up in the carb passages out of sight, I'm at a loss. Air leak in the choke assy??
The engine noise I am also completely unsure about.
***
Aside from this bike, a bulletproof '92 DR350 is the only other 4-stroke I've owned, and never had to mess with it. The rest have been 2-strokes. So I'm still not yet accustomed to all the extra moving parts when trying to bring a bike back from the dead.
Thanks in advance for any input!
Hello all. Sorta new here. I recently fell into the TW world when using a 2001+ front end swapped onto a 1976 Yamaha DT400 (then ultimately went a somewhat different route). But it got me interested in these bikes. Then I came across a ROUGH titled project near me and couldn't say no.
It was missing a handful of parts but I figured a little elbow grease, couple bucks, and patience would do the trick. I busted most of the rust and replaced what was too far gone. For reference: I could stick my finger through a rust hole in the tank (shoutout to reddave for selling me a replacement!). And the header was rusted completely off, leaving the "collar" rusted to the cylinder, which was a bitch to remove.
But even after the costs of parts and effort (and a broken ez-out in a snapped exhaust bolt) adding up to negate the "good deal" I thought I got, I am still struggling to get the thing running right.
Hoping some of the TW vets could send any tips my way to help me get this thing on the road. Its close.
Key details:
- 1990 rust bucket TW with 22k on the clock
- It sat outside for some time. Had not run for ~15 years.
- BUT previous owner did the marvel-oil-in-the-cylinder-trick to seal it off. And it worked. Cyl is in decent shape.
- 110 psi compression (good, not great?)
- Have solid spark (unrelated: new battery)
- Fresh lightly oiled air filter
- Carb was missing so I ordered a cheap rough carb off ebay needing rebuild (im cheap and would rather spend labor than $). Cleaned in ultrasonic cleaner. Then cleaned with aerosol carb cleaner and little brushes. New diaphragm kit, & some new bits but also kept some old bits. stock main jet (I forget the number now but I confirmed on the web it was stock... 128 I think)
- The oil was sludge. Bike is on its second oil change and the new oil is still instantly black after running it for like 2 minutes. I did not open the cover and blast the whole gearbox with brake cleaner, probably should have done that instead of wasting fresh oil.
- Valves: viewing window to be centered on the line NEXT to the "T"... On the compression stroke. Intake set to ~ .003 inch exhaust set to like ~.005.
- No change in RPM when spraying starter fluid around the intake/carb
- Mixture screw @ 2.5 turns out
Symptoms:
- When cold: On full choke it SCREAMS. Half choke it yells. No choke and it whispers. There is no in-between.
- Quick opening throttle = it briefly bogs. But with feathering the throttle, you can overcome the bog to rev it.
- Then when its warmer, the above changes. Can barely get it to run off choke at all. Unless I really raise the idle set screw. On choke it is all over the place. Keeps dying, inconsistent behavior. Dies on throttle twist. RPMs are high one minute then drop wayyy low (like in the video). Seems to do it's own thing.
- The engine itself sounds ROUGH. I am aware these bikes are born noisy little engines. But there is a higher pitched rattle - almost sounds like a loose washer is shaking around somewhere. But I don't think its external, it sounds internal. About 80% sure of it. Also sounds slightly rough on the bottom end too, like general metal on metal clang-y... Guessing that could be the sh*t oil build up - or I could just be not used to the noisy TW engines.
This has got to be at least two separate problems. 1 of which is the carb, but I do not know what /why. I used new pilot jet. So unless there is still build up in the carb passages out of sight, I'm at a loss. Air leak in the choke assy??
The engine noise I am also completely unsure about.
***
Aside from this bike, a bulletproof '92 DR350 is the only other 4-stroke I've owned, and never had to mess with it. The rest have been 2-strokes. So I'm still not yet accustomed to all the extra moving parts when trying to bring a bike back from the dead.
Thanks in advance for any input!