TTR50 Electric Start Problems

So, I acquired a little '05 TTR 50 and have been working to get it going. There seem to be a few recurring issues. Firstly, the carb gunks SO easily that I have to drain it after every time I run the bike. There doesn't seem to be anything inherently wrong with the carb - if I take it apart and clean it, that seems to do the trick. Will re-jetting fix this? Alternately, is there a different aftermarket carb I can drop into the bike which might be less touchy?

Secondly, and much more troublesome to me - the electric start refuses to work. I can roll the bike downhill and pop-start it, which seems to work fine as long as the carb is clean ;) However, I just can't get the electric start to function. When the bike has proper battery power, it really tries but can't seem to turn over. I have checked all the connections, meter-read power to everything, and even checked the little electrodes inside the start button itself. Any ideas? Anyone have this problem? Have noticed quite a few postings on TTR 50 electrical drama...

Did you drain the tank and give it some fresh gas after you bought it?

 

For the starting issue, are you sure the battery is good?  Frequently, a battery will show good voltage, but as soon as you put a load on it, the voltage drops significantly.  Monitor the voltage while you try to start it.  Your normal DMM may not be able to see anything due to the slow update rate, but you might be able to see it on an analog meter.

 

How did you check the connections?  Did you just do a visual or take them apart and clean them?  The latter being the only way to assure the connections are good, no matter how good they look when connected.  I've learned that more than once.

 

The other thing you can do is measure voltage at different points in the circuit to see where you might have something (connection, relay, etc.) that has a high resistance.  For example, measure at the battery while trying to start.  If OK, measure at the next connection.  You want to make sure input and output are pretty close to the same value.  Make sure all the grounds are good - take apart and clean.

 

As always, you'll get the best information on how to solve this problem from a genuine Yamaha shop manual.  They're not that expensive.  There's no substitute for proper documentation (wiring diagrams, etc.).  Don't be tempted by the other non-Yamaha manuals out there just to save $10.

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