About 5000 rpms 1st gear, engine cut out.

[siedlik]

Hello,
When driving on a 1st gear at about 5k rpms the engine is cutting out. On 2nd gear I think it was fine going over 5k rpms.
What could be the issue? TPS ? CDI ? or something else.
It's cutting out the engine at 5k and after it drops to 1k, it starts again with an exhaust backfire. Scared a few people by doing that


Will do a few more tests tomorrow.

[darrsi]

Hello mate.
What's your history with the bike, have you had it a while or is it new to you?


My immediate thoughts would be to start with the simple first (doing one at a time) and change the air filter, then the spark plugs.
A "badly" blocked air filter could stop the engine breathing properly and the extra fuel could cause the popping noises, but if that is the case then a service wouldn't go amiss anyway.

[darrsi]

Does the bike start okay, or is it troublesome?


I would also get some electrical contact cleaner spray (DO NOT USE ANYTHING BUT THIS) and give the ignition barrel a good soak inside, whilst moving the key up and down and turning it to loosen any possible gunge or dirt that might be in there.

[siedlik]

After today's ride, it was better than yesterday.
It happened twice today, I was going slow about 4k rpms and the engine cut out, rpms dropped to 1k and if I won't grab the clutch I will get a pop from the exhaust.
Its not a side stand as I bypassed it.
Its not the key barrel as I cleaned it with contact cleaner and turned it 100 times.
I tested the clutch sensor with multimeter and it looks fine.
New battery. 12.6v   when riding 14v
Tested the TPS and its perfectly on 5000.


I went on a 1st gear 10k rpms and it was fine, all other gears are also fine.
Just a random cut out. Could it be a CDI overheating or some other controller?


Waiting for the Heynes manual, so will know a bit more about where is what and whats what 


Will get a new CDI ECU and test it.
Could it be also a Fuel Pump Relay ?  "Its [/size][/size][/font][/color][/size]function is an electro-mechanical processor. It detects if the  transmission is in neutral, side stand is down, clutch is in. In turn it  enables the CDI to work and the starter relay to trigger the starter  motor"      Trying to find one, but they all for £60.   But for now, will replace CDI/ECU.[/color]

[darrsi]

Back to my question, how much history do you know about the bike?

[darrsi]

Had trouble recently with my bike cutting out randomly and it was a starter relay that i replaced about 18 months ago and even though it was in a secure weather free position next to the battery it just broke apart, and was obviously just a cheap copy.
Think I paid about £55 for the latest one and it's sorted things out.
But symptoms of that were total power failure, so no lights or anything, not just engine cutting out.

[siedlik]

The history I got is that at the beginning the bike had few services from Yamaha. Recently not much has been done.


Random cutouts sound like something is stopping the spark.
So it's either CDI or Fuel pump relay.  Bought another one from Ebay, hopefully that could fix it.


Stop switch is fine, Side stand is fine, Ignition Barrell is fine.

Where is CDI located on the bike ? At the back somewhere ? Will try to check it out, maybe clean the contacts or something.

[darrsi]

https://www.bikechatforums.com/viewtopic.php?t=332169

[siedlik]

I have disconnected every plug and sprayed some WD.
Went for a 2-hour ride and it looked fine, weird.
Also removed the cutout switch and sprayed it a bit.
Hopefully it's fixed. Thanks.