Serious Fault. Cut out on motorway. Help troubleshooting?

[ramonlv]

Hi guys,

Firstly, thank you to everyone who posted on my "leave it to the pros" thread. I managed to swap the radiator, forks and brakes with no problem at all. I now can't believe the mechanic wanted £500 for the forks alone. I asked if they could just be swapped, but he said no they need to be stripped!! Anyway, thanks a lot. I almost went through with using the mechanic so you saved me £££s.

Now the problem:

I had started the bike a few times and gone through the revs, no problem. I've taken it around the block a few times, again no problem. I went on my first decent length trip today and about 7 miles in on the motorway the bike started to lose power. I added more throttle and it sounded like it was revving up but the actual revs struggled to maintain themselves and the bike rapidly lost speed. I pulled over. It took a while to start again, then seemed absolutely fine for another few miles and did the same again. Pulled over, waited, started it up and then was fine for the next 45mins till I reached my destination.

When it cuts out, it feels like it's lost compression and is bogs down heavily. I was driving and this happened but I managed to rev myself clear of this heavy bogging and then things were fine.

Has anyone experienced this or similar? Could you guys help go through some troubeshooting of what to check, because I really don't know what could cause such extremes in the bike's behaviour

Thanks,

Ramon

[porndoguk]

sounds like dirty carbs dude,

mine did exactly the same thing when i got my bike, turned out the float valve filters had crap in all due to the missing sub foam filter,

and when they got warm they died.

give them a check before persueing anything else.

[ramonlv]

Thanks, its really reassuring to know someone's gone through the same thing! The bike's just come from the mechanic where the job was to clean and fit the carbs. Chances are I'm missing that sub foam filter as well.

[ibby4585]

Sounds more electrical to me, rectifier maybe?

Kris

[ramonlv]

A lot of the of her threads I've searched relate cutting out to the rectifier. I read on one thread that he couldn't do long journeys because the battery wouldn't hold its charge. That seemed similar to my experience. But, I still seem to be able to start it. Could that be rectifier?

[ibby4585]

Yeah I reckon it's rectifier I think Paul (Crm) had a similar problem with his RVF. Pull the plug on the rectifier and see if it's corroded might give you an indication of condition, check the wires also!

When your doing that take the battery off and give it a good charge!

Kris

[hardnutdvd]

time to break open the multimeter and my favourite link
http://www.electrexworld.co.uk/pdfs/Tro ... G-&-RR.pdf

follow the instructions to check your charging system.
look at all the connectors and wires. start at the alternator wires (normally 3 yellow ones going into a connector block on the right hand side of the bike)
as said, check the reg/rec connection block that plugs into it..

if you dont know how to use a multimeter call a qualified auto electrician.. just kidding! do what i did and watch a few tutorials on youtube and you'll find it very easy to use!

[Cammo]

Also worth replacing the fuel vacuum hose. When it gets hot it can collapse in on itself restricting or cutting off fuel flow. Fairly common issue on nc30's. It's the hose that attaches to the small spigot on the fuel tap, and runs to the r/h rear cylinder under the carbs.

Rick Oliver sells some thicker walled tubing that won't do this.

[ramonlv]

if you dont know how to use a multimeter call a qualified auto electrician..

I did think oh s**t for a second there. Honestly you got me! Thanks for the link, I'm gonna need it.

I read CRMs post and his experience sounded exactly like mine, so hopefully just a rectifier problem. It was pretty scary when power cuts out. I was on the outside lane of the m4 when it started, and the bike decelerates almost as quickly as it accelerates!!

[ramonlv]

Also worth replacing the fuel vacuum hose. When it gets hot it can collapse in on itself restricting or cutting off fuel flow. Fairly common issue on nc30's. It's the hose that attaches to the small spigot on the fuel tap, and runs to the r/h rear cylinder under the carbs.

Rick Oliver sells some thicker walled tubing that won't do this.

Interesting, very intersting in fact. When the bike first cut out I had a strong incline to check the tank, even though I had just filled it up. Well I have a good list of things to do and check to get started. Thanks a lot.