85 Honda XR problems....help

[MPS]

Ok I know my problem isn't the carb anymore. I put in a Edelbrock Quiksilver 2 carb I got from Adrenaline Junkey. Before I put this carb in a had a little bit of problem cutting out at higher rpms....I figured the stock carb was dirty. So I put in the Eddy. The problem seemed worse. I pulled the Eddy out and cleaned it and I saw that the injector was spraying funky....so I got it spraying right. I put the Eddy back in and the bike still cut out when I hit the throttle. So I decided to clean the old carb and put that one in. I did that and stuck it in....the problem was the same.

So I think I have eliminated it as a carb problem. I am pretty sure it is a spark issue. What do you guys think?

So I am pretty sure your Eddy carb is good A.J! Im just pissed I put all the stock chit back in! haha

 

[Your-Dime]

What size is the XR ?
I used to have a 600 and still have the service manual download torrent link
http://http://www.nowtorrents.com/torrents/1985-honda-xr-600-service-manual.html
You might find a good Honda mechanic on thumpertalk forums

 

[MPS]

What size is the XR ?
I used to have a 600 and still have the service manual download torrent link
http://http://www.nowtorrents.com/torrents/1985-honda-xr-600-service-manual.html
You might find a good Honda mechanic on thumpertalk forums

It is a 350. I have a Chilton service manual for it. Ya I keep forgetting about Thumpertalk. Thanks

.

 

[heinracing]

does it start easily?

when was last time vavles were checked

 

[MPS]

does it start easily?

when was last time vavles were checked

No it doesn't start easily and the valves were just adjusted and I believe he checked the timing too. So I am thinking the ignition coil/CDI?


.

 

[Motley Doo]

I had TONS of problems with the CDI system in out 85 XR500, ended up just buying another one, problem went away. Would cut out at higher rpm, and just didn't run right. not saying we have the same issue, but i have heard of multiple people having issues with these cdi's.

 

[Your-Dime]

Ok, I emailed a Honda tech this morning
He emailed back
Do a compression check and leakdown to determine valve condition
Check the o-ring from the intake to head and make sure it is sealing and has no air leak.
Check the decompressor cable adjustment
Check valve adjustment
Test spark plug cap removed from the wire and try a new spark plug
Check the primary and secondary resistance of the coil
Test the stator
Test the kill switch
Other mentioned items in his reply was plugged exhaust or the needle jet and jet needle in the carb, he says they rattle around and wear that you cannot see but it throws it out of calibration.
If all else fails, try a good CDI

 

[MPS]

I had TONS of problems with the CDI system in out 85 XR500, ended up just buying another one, problem went away. Would cut out at higher rpm, and just didn't run right. not saying we have the same issue, but i have heard of multiple people having issues with these cdi's.

Thanks Motley....I am willing to put money on it, that it is the problem. Mine is doing the same, cutting out at higher rpm and it is getting worse. I give it any significant thottle now and it cuts out and falls on its face. It has to be electrical...since I'm confident I eliminated everything else.

Ok, I emailed a Honda tech this morning
He emailed back
Do a compression check and leakdown to determine valve condition
Check the o-ring from the intake to head and make sure it is sealing and has no air leak.
Check the decompressor cable adjustment
Check valve adjustment
Test spark plug cap removed from the wire and try a new spark plug
Check the primary and secondary resistance of the coil
Test the stator
Test the kill switch
Other mentioned items in his reply was plugged exhaust or the needle jet and jet needle in the carb, he says they rattle around and wear that you cannot see but it throws it out of calibration.
If all else fails, try a good CDI

Wow Your-Dime, thanks. The valves have been gone through. It has a new spark plug. I will test everything else mentioned. I have tried the stock carb and the edelbrock carb in it and it doesn't make a difference, so I dont think it is the needle or jet....eddy carbs don't have a jet. I also have an aftermarket muffler and put on the stock one...no difference. How would the decompressor cable ajustment affect anything? It hasn't been hooked up in a long time.

.

 

[cobbycat]

the decompresser works by holding a valve partialy open to decrease compresion. if it is partialy stuck, no compresion. I don't think that is the problem. check for vaccum leaks in the intake, but sounds like cdi/stator problems.it should say in the shop manual how to test the stator, coil and spark plug lead/boot. test these and if you find nothing wrong, it is probably the cdi.

 

[MPS]

the decompresser works by holding a valve partialy open to decrease compresion. if it is partialy stuck, no compresion. I don't think that is the problem. check for vaccum leaks in the intake, but sounds like cdi/stator problems.it should say in the shop manual how to test the stator, coil and spark plug lead/boot. test these and if you find nothing wrong, it is probably the cdi.

thanks cobby

 

[Your-Dime]

Little off topic, while looking for a downloadable Honda Xr350r service manual, OEM is the way to go for real diagnosis. I ran across an interesting post. This guy may know it too, but he is helping a whole lotta people out with his links provided. WOW
http://www.dirtbikeworld.net/forum/showthread.php?t=16753&page=2

That is a lot of service manuals for free

 

[BossRev]

Ok, I emailed a Honda tech this morning

Did ya? bet he was your buddy from the east.