XT350 Jetting for 5,800ft

[garrywadams]

Hi all! I just got a 1989 Yamaha XT350. I am new to dirtbikes, and mechanics in general. I am having some trouble with the way the bike runs. It does great for the first 5 or 10 minutes, and then in the mid to high RPM's it starts to sputter. The motorheads I've talked to say it's probably a Carb. issue. Maybe it's not jetted right for my altitude. Does anybody know what jetting I should use for an XT350 at roughly 5,800ft?

I'm new to the forums, but look forward to some great participation. Looks like a pretty killer site. :cool: Thanks in advance for the ideas/help!

 

[Rich Rohrich]

it's highly unlikely that the jetting has anything to do with it. It's a 19 year old bike, which means it's probably wear and tear that needs to be addressed.

Start with the basics :

- Clean the carb, all the internal jets and set the float level (but leave the jetting alone for now)
- Clean and oil the airfilter. If it looks worn get a new one.
- Adjust the valves (chances are good this will go directly to your issue)
- Put in a new sparkplug
- Clean the electrical connections, the coil wire, the coil wire ground (very important)
- Do a compression check.

Once you do the above basic maintenance things, then start troubleshooting.

A Yamaha Clymers, or Haynes service manual will show you step by step how to do this maintenance and provide a troubleshooting chart if you have to look further.

 

[garrywadams]

Thanks for the tips. I'll definately start there.

1) Does the manual tell me WHERE to set the float level?
I was planning on cleaning the carb anyway. I'd have to get it apart to check the jetting and float level, so I figured it could use a good cleaning while I've got it off.
2) Already cleaned/oiled the air filter and changed the oil first thing when I got the bike
3) Spark plug was also on the list of "to do"
4) Just put in a new battery. Is the coil wire somewhere else on the bike, or is it there by the batt.? Those wires there are good to go.
5) As for the valves and compression, I guess the manual would show me how to do these then?

Thanks again for the help.

 

[garrywadams]

P.S. I would still like to know where the bike ought to be jetted since I'm going to have the carb off and apart anyway. I'd like to make sure that I've got all of my bases covered. Thanks!