engine bolts

[accbr]

I still need a few bolts for a motor. Head to cylinder and cylinder to cases. Are the OEM bolts grade 8? They have an 8 stamped on them, but they don't classify metric bolts like that. They use 8.8, 12.9 etc.... Are the stock bolts just stainless class 8.8?? I already know class 8.8 metric is the same as standard grade 5 and class 12.9 metric is standard grade 8. Just trying to see if I can find them cheaper at Mcmastercar.

 

[parrdaddy]

Stainless hardware is not listed by grades, but by alloy type like 304, 316, 18-8. Don't quote me on this, but I think the 8 is for the bolt size???

 

[njfl]

The 6's and 8's on metric bolts have perplexed me too. The 8 is found on a lot of the 6mm threaded bolts, and they are clearly not grade 8. For example, the OEM zinc plated bolts that hold on the damper shroud.

The OEM Yamaha case bolts are nickel plated (chrome-like) and have high strength, I am almost sure that they have a higher yield strength than stainless. Stainless should not be used in high-torque applications, unless it is clearly marked as a high-strength stainless grade. Sometimes, some of the higher strength stainless metals have a bit of ferrous content to acquire that strength (you can tell because they are a little magnetic).

 

[accbr]

All the bolts have the an 8 stamped on them, but they're definitely different sizes. Head to cylinder and case bolts are M8x1.25. Cylinder to case is M10x1.25. Intake to case is M6x1.00.

Mcmastercar has all kinds listed, but I'm not sure what to order. If you look under metric bolts you can get class 10.9 in zinc plated. It's gonna cost over 60 bucks to get what I need from the dealer. I can get packs of 50 from Mcmastercar for about 30 bucks.

 

[keefer]

You could always pay the price and order them from Yamaha. You would think that there should be plenty of junk motors around to salvage what you need. I thought there was a jet ski salvage outfit in Havasu, dont remember the exact name. I am sure someone else will know it get you the contact info. I bet they would have them. Another thought would be to call the guys at SBT or the like and see if they would sell you the bolts you need.

 

[accbr]

I've called a couple places, but nobody seems to want to bother putting spare bolts together. I'd just like to know what grade or class the OEM bolts actually are.

 

[njfl]

I would definitely buy the eight nickel-plated OEM case bolts from Yamaha to ensure that they can sustain the torque.

For the intake, because it is low-torque, you will hav eno problem using off-the-shelf stainless M6 bolts.

I would be more comfortable with OEM for the head bolts as well because of the moderate torquing required, but that's your call.

To be honest, the price of the correct bolts is worth the pains and potential costs down the road.

 

[Kny21]

I thought there was a jet ski salvage outfit in Havasu, dont remember the exact name.

Not sure about Havasu, but there's a place in CA called M&M Marine that is into the PWC salvage biz.

http://www.mm-marine.com/

 

[Puffer]

I have a whole box of bolts.Which ones and how many do you want?

 

[accbr]

I just need one of the eight case bolts, and was gonna order that from the dealer. You can't check those once the motor is in. I need the 6 bolts that bolt the cylinder to the case, and the 10 bolts that connect the head to the cylinder. If you have any of these Puffer let me know. I'd really appreciate it.