Vintage Dirt Bike Q & A
https://vintagedirtbikeforums.alp-sys.com/

starting problem yz400f
https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=28&t=4269		 Page 1 of 1
Author:  ging-gur [ Sat Apr 05, 2014 8:12 pm ]
Post subject:  starting problem yz400f
Firstly hello everyone. Newbie here. Hoping for some advice please. I have a 79 monoshock yz400f. Ive had it 20 years. About 2yrs ago, I was riding steady and the engine just died. I tried starting it, but every 6/9th kick, it spits. Have checked fuel feed, reeds and spark. The spark is quite orange on the side of cylinder head. What would you experts suggest could be the fault? It could do with restoring as she is looking tired . I'm just looking to get here running again and possibly sell, not sure yet. Its had new main bearings and a first oversize piston and rings. Only run about 3hrs all in since I did this about ten yrs ago, scares the hell out of me as I'm not a biker lol. Any help, ways to test stuff with a multimeter etc, as in where to switch tester to and where to put contacts would be a start please. Thanks for looking, regards, Mark.
Author:  Scootern29 [ Mon Apr 07, 2014 11:24 am ]
Post subject:  Re: starting problem yz400f
By the sounds of it, your CDI box probably went south. It was/is common on those ignitions. Try looking on evil bay you may be able to find one.
Author:  winterwood [ Mon Apr 07, 2014 12:58 pm ]
Post subject:  Re: starting problem yz400f
...




Welcome. :D

If you got fire, try cleaning the carburetor.
Check the Pilot Jet.

Do you run a in-line filter?


ww




. 8)
Author:  Dave [ Tue Apr 08, 2014 11:31 am ]
Post subject:  Re: starting problem yz400f
Welcome! :D

the two men that posted before I have got it pretty well covered.at the time I don't have anything new.any other questions,don't be afraid to ask!
Author:  brett campbell [ Thu Apr 10, 2014 5:50 am ]
Post subject:  Re: starting problem yz400f
Did you try a new spark plug? Just because it fires out of the cylinder doesn't mean it will fire when it is under pressure.
Author:  tnr [ Thu Apr 10, 2014 9:39 am ]
Post subject:  Re: starting problem yz400f
Good spark is usually fat & blue. If it is firing on time it should hit with a squirt of starting fluid. If it had the bottom end apart,the flywheel may have come loose if it was not tightened enough or maybe the stator plate moved?
Page 1 of 1 All times are UTC - 7 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
https://www.phpbb.com/