Hard starting 18’ viper

[CooperT]

I’ll start by saying I’m still on the original battery with 11,300kms. Voltage is still 14+ and I always connect it to my optimate tender after a ride.

Sled almost always starts in the warm shop, but with hesitation. After it starts and runs throughout the day, it usually fires up right away.

If it’s out in the cold, even like -5 the sled becomes a nightmare to start. No kickback, sled has current flash, just cranks and cranks and cranks and won’t start for like 5mins of cranking. Then when it does decide to fire, I get a nice backfire, then it usually starts after that.

I’m thinking I’ll replace the battery for next season, maybe that will help, I have no idea. Anyone know what might be wrong or how I can possibly resolve the starting issue? Thanks!

 

[jonlafon1]

The valves need to be adjusted is my guess. I rode with a 2017 viper for 3 years and what you described is EXACTLY what it did. His would start terribly when cold and then it would run on two cylinders after you cranked on it forever.. Eventually straightening itself out after warmed to temp.
. He had the valves adjusted, and believe they were to tight(not within spec). After the service was performed it was better not perfect but better. Make sure you take it to someone/dealer that has good service and knows what they are doing as it seems service is iffy these days.

 

[CooperT]

The valves need to be adjusted is my guess. I rode with a 2017 viper for 3 years and what you described is EXACTLY what it did. His would start terribly when cold and then it would run on two cylinders after you cranked on it forever.. Eventually straightening itself out after warmed to temp.
. He had the valves adjusted, and believe they were to tight(not within spec). After the service was performed it was better not perfect but better. Make sure you take it to someone/dealer that has good service and knows what they are doing as it seems service is iffy these days.

Do the valves really need to be adjusted so soon? I didn’t think they needed to be adjusted until around 25000-30000kms?

 

[jonlafon1]

Do the valves really need to be adjusted so soon? I didn’t think they needed to be adjusted until around 25000-30000kms?

The sled I refer (2017) had around 4K on it.. I guess the question becomes do you want it to start and run on all 3 cylinders when its -5?
This issue (cold starts) and running on 2 cylinders is common and I would bet Yamaha knows what it is.. What amazes me is that a company known for quality engines didn't make it right for the years this was a issue.. I know they had flashes and most did NOT work, and even made some sleds worse.. Pretty sure they know its the valves and didn't want to cover the massive labor hours to make them right> so they tried with different fuel maps.

 

[jonlafon1]

adjusted so soon

I believe they were wrong(valves) from the factory in some years on that engine.

 

[ateick]

Do the valves really need to be adjusted so soon? I didn’t think they needed to be adjusted until around 25000-30000kms?

Manual states service around 25K I believe but seems to be an issue from as low as 4k and up. I would start with a fresh battery though. These seem to be very subseptible to any low voltage conditions.

 

[CooperT]

The bad valves I believe were in the 16’ vipers. My sled runs great, like the day I bought it. Just doesn’t want to start in a bit of cold weather. I’ll start with a new battery and go from there. I have noticed just this past season it is cranking a bit slower than usual.

 

[jonlafon1]

It’s not the battery. Good luck.

 

[ateick]

The bad valves I believe were in the 16’ vipers. My sled runs great, like the day I bought it. Just doesn’t want to start in a bit of cold weather. I’ll start with a new battery and go from there. I have noticed just this past season it is cranking a bit slower than usual.

Softer connecting rods started in 2016 and led to some turbo'd issues. I don't think the valve tightening was year specific.

 

[WillowAce]

I’ll start by saying I’m still on the original battery with 11,300kms. Voltage is still 14+ and I always connect it to my optimate tender after a ride.

Sled almost always starts in the warm shop, but with hesitation. After it starts and runs throughout the day, it usually fires up right away.

If it’s out in the cold, even like -5 the sled becomes a nightmare to start. No kickback, sled has current flash, just cranks and cranks and cranks and won’t start for like 5mins of cranking. Then when it does decide to fire, I get a nice backfire, then it usually starts after that.

I’m thinking I’ll replace the battery for next season, maybe that will help, I have no idea. Anyone know what might be wrong or how I can possibly resolve the starting issue? Thanks!

I assume you have checked your plugs and made sure you are getting a strong blue arc when grounded and turning over? If the valves are adjusted correctly and you are having starting issues other suspects would be fuel delivery or spark. Since you are starting and running fine after warming up I would check the rectifier output. Remember the battery doesn't provide current directly to the plug wires the rectifier converts DC to AC. If the rectifier is starting to go bad it might not put out enough AC current to turn the starter sufficiently to crank a cold engine.

 

[CooperT]

I haven’t checked my plugs and should probably just replace them as well, along with the battery and go from there.

 

[Yamasledder]

It's really not a big job to check the valve clearances on these. You only need to remove the valve cover and take measurements with feeler gauges. The real work comes if you find out that they are out of range.

 

[CooperT]

It's really not a big job to check the valve clearances on these. You only need to remove the valve cover and take measurements with feeler gauges. The real work comes if you find out that they are out of range.

I used to have to check the valve clearance on my old 2006 yzf 250. That required it like every 30hrs lol.

I just assumed it was a pain in the a** getting in there

 

[FrozenTows4]

Manual states service around 25K ...

It lied. My 2014 went tight at 6500 miles

 

[WillowAce]

It lied. My 2014 went tight at 6500 miles

All of Yamaha manuals lied to me. Viper, Grizzly, and Viking and I've had cold start problems with each caused by tight valves. All before the 2,000 mile mark to boot.