tuning/mechanical issues caused the most un expected problems.

joshua. c.

Well-Known Member
#1
I had a tuning problem with my bike. I put a temporary engine on my mtd trail flight so I could get it running while I re built and modified the original hs40. I put what I thought to be a good running carburetor on the engine. but It wouldn't run steady It would run for a bit and die then run a bit more and die. I cleaned the carb several times trying to solve the issue just to realize it was still getting dirt in the bowl. so I pulled the carb off and noticed my fuel filter was abnormally bent. the fuel filter had bent and broken internally due to having too short of a line between it and the carb and it was allowing dirt threw the filter. I never even thought it could have been my brand new filter. I spent an entire afternoon trying to fix that carb and it was the freaking filter.

you guys ever have issues like this one where you spent allot of time hunting down a tuning or mechanical problem and the answer was totally unexpected or ridiculously simple.? if so lets hear them.
 

ELT

Active Member
#2
I had a tuning problem with my bike. I put a temporary engine on my mtd trail flight so I could get it running while I re built and modified the original hs40. I put what I thought to be a good running carburetor on the engine. but It wouldn't run steady It would run for a bit and die then run a bit more and die. I cleaned the carb several times trying to solve the issue just to realize it was still getting dirt in the bowl. so I pulled the carb off and noticed my fuel filter was abnormally bent. the fuel filter had bent and broken internally due to having too short of a line between it and the carb and it was allowing dirt threw the filter. I never even thought it could have been my brand new filter. I spent an entire afternoon trying to fix that carb and it was the freaking filter.

you guys ever have issues like this one where you spent allot of time hunting down a tuning or mechanical problem and the answer was totally unexpected or ridiculously simple.? if so lets hear them.
Simple things can be the hardest to find. We tend look right past them.
 

joshua. c.

Well-Known Member
#3
since no one else has any to add yet hears another but not about a mini bike. and this one may be a common issue that can help someone else out.

I had a 1995 ford taurus. I liked that car alot. It was nice looking and drove well and was comfortable. one day my throttle just started surging out of control at random. It would start and stop unexpectedly. I took it to a dealership and they just started throwing parts at the issue and installed a new idle air control valve. and failed to solve the problem. so I took it to a local mechanic instead. he did some diagnostics and claimed he had solved the issue. a day later the car did it again. but this time I cough it doing it and parked it while it was revving. when I popped the hood I yanked off the intake and looked into the throttle body and it was fully closed. so It must have something to do with the idle air control valve. I told the mechanic this and returned it to his shop. and told him to look all the wires and connections over since the valve was brand new. he found out that the 3 wires connecting the control valve to the computer had rubbed raw where they sat behind a coolant line on the back of the engine. and they had begun arcing to each other and there surroundings. after nearly 700$ in diagnostics and parts it had been a 5$ fix. he just re wrapped the wires and good as new. I drove it for another year before replacing and selling the car and it never did it again. this final fix happened days before my first trip to Windber. I got lucky and it got fixed just in the nick of time. I honestly didn't think I was going to make it that year.

just for reference my moms 87 taurus had a similar issue once. my sister was on the highway and the throttle went nuts. she had to smoke the brakes to bring the car to a stop. my dad took a look cleaned and lubricated everything and thought he solved the problem at that time it was showing its age so it had become a spare car that we used when one of ours went to the shop. so it never got driven enough for it to happen again. the transmission died the next time we went to use the car. it was showing signs of going bad long before all of this happened it would bump hard at 45 miles an hour. another reason it became a spare car. Ill never know for sure but these cars are nearly identical under the hood so I'm cretin it was the same issue and woold have reard its head again if the car hadn't croaked first.
 
#4
All the freakin time! Usually my fault for too hastily diagnosing things or too lazy to test stuff. My old k5 blazer I drove for years with faulty brakes. If you push the pedal once it was fine. But push the pedal and too quickly push it again the power brakes dont work. It was a problem in traffic but otherwise just had to be aware of it. I replaced the booster didnt help. Finally decided to look at it again years later and discovered the steel vacuum pipe got wore through by a rubber hose. I never saw the hole or heard the leak because the hose covered it up. Another time it wasnt getting fuel pressure. I did the filter still wasnt up to spec so we did the pump. Dropped the tank and where the straps went were rusted out so did the tank and everything. It was good for a while but one day it just wouldnt climb the hill to get home. We figured out the fuel line was ran above the transmission and the body mounts were rusty so the body sank down and pinched the line. It was so stuck in there we just left it there. So that was the problem the whole time! The engine mounts were also non existant so the body held the engine down. I fixed the rust under the seat so it was nice and solid mounted to the frame but the rest of the truck was not. When i went over humps in the road it was a very weird feeling when the steering wheel and pedals go up and down and the seat stays solid. Got to love new york rust.
 
#5
My friends dune buggy usually runs real good but lately the engine has been running rough and missing most of its power. We checked over most everything possible but no improvement. One evening it was so bad he couldn't get it to go up his driveway. After removing both air cleaners he decided to move the buggy into the garage to remove the carburetors and VROOOM!!! That ride he took on a dirt road had the reusable air filters caked solid with dust thrown up from his tires and sticking to the oiled filter pleats, the engine barely got enough air to idle, no wonder it couldn't get up the driveway.
 
#6
Simple things can be the hardest to find. We tend look right past them.
That's why I like having a housemate that's a mechanic. Sometimes he'll catch something that I just totally glanced over or didn't even think about. Sometimes it's really stupid stuff too or it can just help to have a fresh set of eyes look at something.
 
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