NT700 Hard Hot Start

[tawilke46]

I was talking to one of the parts folks at Friendly Honda, where I bought my NT.
He is having trouble with his 2010 silver NT starting when it gets hot and has been ridden for 30 minutes or longer. When the engine cools enough it starts right up. He has about 26,000 miles on it, cause he rides it to work every day, rain or shine.

I told him it reminded me of vapor lock in carburated engines. But this is a fuel injection engine. It seems that the engine is starved for fuel once it heats up. Could air be getting in the fuel line? Anyone have any thoughts what could cause such a malfunction on a NT?

Hope it is not contagious......

Since he works at a Honda dealership, he has had it in the shop twice now. At first they thought it was a battery problem and put in a new one. Did not fix of course.

My daughter was having a very similar problem with starting when hot on a Mazda 323 she once owned. The Mazda dealer traced it to a bad throttle body.

 

[Warren]

I vote for plugged vent in the gas tank or an electrical component failing when it heats up. Coils can sometimes have this problem.

 

[tawilke46]

I vote for plugged vent in the gas tank or an electrical component failing when it heats up. Coils can sometimes have this problem.

You know I did not ask him if their dealership had done a valve check on his bike! Hmmmmmmmmmm............
That would certainly be an opportunity to mess something up in that area.

 

[Rocky]

Does it run fine untill it is shut off or when coming to a light or stopping does it die? I am having a simialar problem with my Kawasaki and I think I have traced it to a worn throttle position sensor that does not realize it should be at idle and floods it, making start up again difficult.

 

[tawilke46]

Does it run fine untill it is shut off or when coming to a light or stopping does it die? I am having a simialar problem with my Kawasaki and I think I have traced it to a worn throttle position sensor that does not realize it should be at idle and floods it, making start up again difficult.

He told me it runs fine after a cold or cooled down start. The won't start occurs after he shuts it down after it is warmed up and hot.
Like I said above my daughter had a similar problem with hot starts with her car, turned out to be a faulty throttle body.

 

[seagrass]

Could it be that one of the inlet or exhaust valves is a bit tight and after stopping the engine, when the internal engine temperature increases that extra little bit (as the coolant has stopped circulating and no passing breeze etc) the valve is no longer closing fully?

Once the engine cools down the valve closes and the engine runs OK again.

Seagrass

 

[DirtFlier]

One thing to look at replacing are the spark plug caps, especially since it's a freebie repair. The symptom described in the Service Bulletin says "...misfire at idle in high temperatures..." so it could also affect hot restart. A great many times the people who work in dealerships are oblivious to information sent out by American Honda so it wouldn't surprise me if it was buried in a cardboard box in the Svc Manager's office! It was mailed out December 2010 and is bulletin # "NT700VA #1"

 

[tawilke46]

Went over to my local Honda dealer today to get started on the warranty claim on the broken latch on left saddlebag lid. While I was thereI talked with Damon, the guy with the hot start problem. He told me the service manager had the above Honda bulletin on the spark plug caps. So they will be looking at that and some other possible electrical problems. Damon also has burned out two rear tail light bulbs in the last month. Will be interesting to see what they can come with the root of the hot start problem.
While picking up my bike, I looked at Damon's bike that was parked next to mine. The exhaust outlet on the muffler had a lot of black soot on the inside. That to me would indicate a overly rich fuel mixture or insufficient burning of fuel mixture. Another hint?

 

[DirtFlier]

[...but mine I believe is starter related. It cranks but will not turn over...]

You're saying the starter motor is turning but the engine isn't turning? That would be truly strange.

A more likely situation is that the engine is being turned by the starter but it doesn't start.

 

[vzshadow]

I'd almost forgotten that I had trouble starting once, cold. It cranked and cranked. I was about to give up and it turned over. There was a lot of gray smoke. My dealer guessed it was probably bad gas. I never had an issue before or since. Any ideas?

 

[Chucksklrst]

Yes to your question, and the ethanol in the fuel absorbs water also.

 

[silverdevil]

It cranked and cranked. I was about to give up and it turned over.

how can it crank and crank and not turn over? now if the bendix in the starter motor has a bind or something and does not go into the fly wheel the starter is turning over but the engine is not turning.
or is it that the starter IS NOT turning but you are holding the key in the start position?
I had a car once that after you turned the car off and waited a few minutes(the engine DOES heat up when first turned off, it takes about 20 to 30 minutes before it starts to cool down), the problem was the starter got too hot and after it cooled down it would start. replaced the starter and all was OK.

 

[Chucksklrst]

A Motorcycle starter can turn but if the starter clutch is bad it will never engage the engine to turn the engine over. Bike should be too new to have a starter clutch issue. I am thinking wrong use of terminology. We just had a thread over on the ST forum with the wrong use of terminology. Turns out the engine would turn over but not fire, engine was flooded.

 

[Bear]

Rick,
The Ethanol is hydrophilic--it attracts water. The water can for a while be in suspension, but will eventually separate and settle on the bottom.

 

[Chucksklrst]

http://www.youtube.com/watch?v=YeCyFxoWPpo Check this out.

 

[elizilla]

I had occasional problems with the starter clutch on my old V65 Sabres. They had an arrangement of tiny pawls and springs. Each pawl had a spring like a cat hair (hi Rick) and a spring like what you find in a ball point pen. The ball point pen springs would get tired and the pawls wouldn't push out and catch properly to start the bike. You'd press the starter and get a sound like marbles rolling in a dish, and the bike would not turn over. The trick was to roll it forward or backward a couple inches, and try again. Eventually it would catch. I took one apart once and replaced the springs with heavier spring stock from McMaster-Carr, and made it work a lot better. So when my next Sabre did it too, I did the same fix, but everything has already got too worn and it didn't help. The bike always started anyway, eventually, so I just lived with it after that.

I don't recall exactly what it was, but there was some trick to lining the starter clutch up correctly, you want to not lose track of where it sits on the gears down there. It was under the clutch cover, a small wheel in at the bottom front of the clutch. Also, you want to make sure you get the bolts torqued correctly, and use locktite. I had one back out after one of my repairs, until it hit the inside of the clutch cover and made a terrifying noise when I started the bike. I did not ride like that. Instead I immediately took the clutch cover off and found the source of the noise. Tightened the bolt back down and all was fine.

The NT is a lot like the Sabre in other ways - I wonder if it shares this starter clutch weakness?

 

[ARKNT]

Here are a couple pics from inside the left side case looking at the gearing coming from the starter in case it helps.

Brad

 

[ddornier]

Update on my NT700 starting hot issue. The technician at Friendly Honda in Baton Rouge narrowed it down to something called a "crank position sensor" and replaced it. It works fine now. I can run my bike for an hour, stop at a gas station, and it actually will start up again! I'm happy he finally got the issue resolved. Thanks Jeremy!

 

[seagrass]

The crank sensor has been a problem in many vehicles over the years, hopefully this will not become a widespread problem on th NT700