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Old 11-24-2014, 07:01 AM   #1
cheftuskey121 OP
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Joined: Jul 2014
Location: Savannah GA
Oddometer: 17
1989 NX650 not starting

Hey guys, new here. I have a 1989 nx650. I bought it running and now it isn't starting. I will try to describe the situation best so bear with me, I can type a lot.

After I picked it up it started to be really intermittent when it wanted to fire up. I was having an issue with spark. I ended up replacing the coil and spark plug and that helped. Then the bolt holding the ground wire in near the coil came loose and that had me scratching my head for a bit. I even replaced the CDI so I have a brand new one (I didn't need it because it was only the ground wire but what's done is done). the ground wire was taken care of very quickly.

It rode fine for weeks, then one day I rode it home from work and put it in the garage. A few days went by and when I went to crank it up it would not start. the starter turns over and it sounds like its going to fire up but nothing. Choke on or off has no effect.

the first thing I did was get the carb off. the jets are clear as well as the passages. I also tried to use starter fluid directly in the carb mouth to start it and I got some backfiring but no start. I don't believe fuel/air is an issue. I have bright blue spark from my iridium spark plug which tells me the CDI and the magnetic pickup are working just fine. so I have fuel/air and I have spark, I am wondering if it has to do with the timing jumping in the top end?

Maybe even a piston/compression issue? the engine turns over and there are no metal on metal sounds. no grinding or clanking. it literally worked one day and the next day it did not work. The previous owner told me he had issues with the valve seals leaking and this motor uses about 1 quart of oil every 200 miles (that's a LOT).

that's all I can tell you. I am familiar with old bikes and working on them, I have two old cb750s that I restored. I am not familiar with this engine though. hopefully someone can help and point me in the right direction. if the engine has to come out to be rebuilt, so be it. I just don't want to overlook anything stupid, rebuild the engine only to find out it isn't starting.\

thanks in advance guys!
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Old 11-24-2014, 07:46 AM   #2
mcma111
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A quart of oil in 200 miles??? Time to pull the top end and take a look at the piston. Compression?? What's that???
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Old 11-24-2014, 08:20 AM   #3
cheftuskey121 OP
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Quote:
Originally Posted by mcma111 View Post
A quart of oil in 200 miles??? Time to pull the top end and take a look at the piston. Compression?? What's that???

yes, quite a bit. when it was running it ran very strong and only smoked on start up. I think the oil was just constantly seeping down the seals and burning off. never any issues with low power or loud engine noises. it must have had a hard life before I got to it, I am very kind to my old bikes.
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Old 11-24-2014, 08:27 AM   #4
mcma111
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No way is that much oil going past the valve guide seals. It's coming UP past the rings. The NX like the XR and XRL can seize and recover to continue o run once cooled off but the damage will have been done.

It's time to pull he top end. otherwise your wasting your time.
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BMW's
58 R26
79 R100s
91 R100gs

87 Harley FXRS-SP ~ 06 KTM 625 SMC ~ 72 Honda CB750/915cc ~ 92 XR600/654cc ~ 95 XR650l/675cc ~ 03 CRF450r ~ 05 CRF450x ~ 02 XR650l/675cc ~ 86 YZ490 ~ 93 YZ80 ~ 93 XR650l Project
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Old 11-24-2014, 08:32 AM   #5
cheftuskey121 OP
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Quote:
Originally Posted by mcma111 View Post
No way is that much oil going past the valve guide seals. It's coming UP past the rings. The NX like the XR and XRL can seize and recover to continue o run once cooled off but the damage will have been done.

It's time to pull he top end. otherwise your wasting your time.
I see. well that was the initial plan anyway, glad to know I was on the right track. I heard these bikes used some oil but I thought that amount was a bit insane.
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Old 11-24-2014, 09:25 AM   #6
mcma111
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In case you need some engine building guidance:

http://advrider.com/forums/showthread.php?t=713831
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Steve in SF

BMW's
58 R26
79 R100s
91 R100gs

87 Harley FXRS-SP ~ 06 KTM 625 SMC ~ 72 Honda CB750/915cc ~ 92 XR600/654cc ~ 95 XR650l/675cc ~ 03 CRF450r ~ 05 CRF450x ~ 02 XR650l/675cc ~ 86 YZ490 ~ 93 YZ80 ~ 93 XR650l Project
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Old 11-24-2014, 11:06 AM   #7
cheftuskey121 OP
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Quote:
Originally Posted by mcma111 View Post
In case you need some engine building guidance:

http://advrider.com/forums/showthread.php?t=713831
Hey brother. I've actually read through that thread 2 times now. A lot of great info there thank you!
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