Need some advice: Piston Drop-in Kit on a 800R

[aremka]

I also posted this in Perfromance/Modified:

I just installed a Piston Drop-in Kit with 13.5:1 domes on an 800R motor. Here are the details of the set-up:

1. 82mm dual ring pistons installed with arrows pointed towards the exhaust port. All bolts torqued and new gasket installed per the manufacturer's instructions. Lubed cylinder walls and piston rings with additonal semi-synthetic oil.

2. 13.5 domes installed with scribed "X" towards the exhaust port. Head torqued per manufacturer's instructions.

3. Main jets changed from 470 to 450.

4. Raised the needle one clip (position changed from #3 to #4).

5. Coolant replaced and all air removed.

I took the sled out yesterday and rode an easy 20-25 miles before opening the throttle wide open. During the break-in, I varied the throttle in rpm, but never wide open.

The 13.5:1 domes are spec'd for 3000-5000 elevation. I started out at 3200ft and went up from there.

I was running 92 octane fuel.

I came to an area where I could open the sled up on a slope. The sled appeared to run absolutely perfect. No noises, nice power. At a point when the sled appeared to be getting hotter during the climb, I could hear pinging or a metal type of rattling noise. I can only assume it was coming from the engine. I let off the throttle a little bit, and the noise went away. I'd get back into the throttle and it would come back again.

I could start the same climb over again, and get almost the exact same results, except the pinging would start a little sooner (hotter motor).

Then I could get back on the trail, riding it easy and no pinging at all. I could get into the throttle on the flats, no pinging.

Farther down the trail, I'd pull on a different slope, same results. It would start out running hard, no noises, then gradually start to ping again, I'd let out of the throttle, and it would go away. Full open, rattling would come back.


What do you guys think the problem is?

I didn't have any warning lights or beeps coming from the engine.

Thanks for your responses.

JL

 

[Crasher]

Get higher octane or lower the compression. Pre-detonation will ruin pistons and could cost you an engine.

Crasher

 

[Backcountrypro]

Yep-sounds like detno. Are you sure you want to start out with 350's. If you are really lean it will be more prone to detno. I would check the piston wash by pulling the head and look at the plugs. Make sure you have the right domes, accidents happen and maybe you have the wrong domes.

 

[Crasher]

Check your base gasket also. There are different thickness gaskets. If you installed the thinnest one, your compression may be to high.

Crasher

 

[dicey]

I also posted this in Perfromance/Modified:

I just installed a Piston Drop-in Kit with 13.5:1 domes on an 800R motor. Here are the details of the set-up:

1. 82mm dual ring pistons installed with arrows pointed towards the exhaust port. All bolts torqued and new gasket installed per the manufacturer's instructions. Lubed cylinder walls and piston rings with additonal semi-synthetic oil.

2. 13.5 domes installed with scribed "X" towards the exhaust port. Head torqued per manufacturer's instructions.

3. Main jets changed from 370 to 350.

4. Raised the needle one clip (position changed from #3 to #4).

5. Coolant replaced and all air removed.

I took the sled out yesterday and rode an easy 20-25 miles before opening the throttle wide open. During the break-in, I varied the throttle in rpm, but never wide open.

The 13.5:1 domes are spec'd for 3000-5000 elevation. I started out at 3200ft and went up from there.

I was running 92 octane fuel.

I came to an area where I could open the sled up on a slope. The sled appeared to run absolutely perfect. No noises, nice power. At a point when the sled appeared to be getting hotter during the climb, I could hear pinging or a metal type of rattling noise. I can only assume it was coming from the engine. I let off the throttle a little bit, and the noise went away. I'd get back into the throttle and it would come back again.

I could start the same climb over again, and get almost the exact same results, except the pinging would start a little sooner (hotter motor).

Then I could get back on the trail, riding it easy and no pinging at all. I could get into the throttle on the flats, no pinging.

Farther down the trail, I'd pull on a different slope, same results. It would start out running hard, no noises, then gradually start to ping again, I'd let out of the throttle, and it would go away. Full open, rattling would come back.


What do you guys think the problem is?

I didn't have any warning lights or beeps coming from the engine.

Thanks for your responses.

JL

who,s kit did you install 350s sounds wrong you must have meant 450s

 

[aremka]

Yes, you are right. I entered the wrong size when I was typing. I have put in 450's from 470. It is RK's kit.

What is a tell-tale sign of detonation?

JL

 

[jr_amsoil]

shiny spots(aluminum) on the spark plug

 

[revinit]

put it back to stock right now. rk may be able to build his personal motor but he can not build yours. if you do not have a dyno, if you do not have a very large amount of time, if you want to enjoy your sled again... go back to stock and prey that you do not skrew anything up.

 

[sloppy2nds]

get rid of that 020 base gasket its too thin and put on the stock base gasket, it will have 6 holes in its corner. do everything in your power to keep that kelsey kit safe and sound, this will solve your detonation problem. as for the wash you check it by pulling your cylinder head. you should have the entire top of the piston wet and sometimes a thin layer of carbon will build on the piston tops and that will be your wet spot. so you want the wet spot to extend out toward the cylinder walls to within a 1/4" to 3/8" of the wall all the way around leaving that narrow band dry. this is a safe wash. your spark plug wont tell you what you need. so dont depend on it. you can check it with a bore scope too. and sometimes you can pull your raves and put a small flash light on the spark plug hole and look in the rave slots.

 

[hymark860]

where does it say hes running a .020 base gasket?

 

[aremka]

Referencing the gasket:

Hymark860 is right. However, it does bring up the point. I did notice that the gasket Kelcey supplied is thinner than the stock gasket. Does anyone know what the stock gasket thickness is?

I can't be the first customer to have this issue. I followed the instructions to a tee, and it does this.

Would I be out of line to reinstall the stock head with Kelcey's gasket to rule out his domes? (still leave in the stock pistons).

JL

 

[hymark860]

Referencing the gasket:

Hymark860 is right. However, it does bring up the point. I did notice that the gasket Kelcey supplied is thinner than the stock gasket. Does anyone know what the stock gasket thickness is?

I can't be the first customer to have this issue. I followed the instructions to a tee, and it does this.

Would I be out of line to reinstall the stock head with Kelcey's gasket to rule out his domes? (still leave in the stock pistons).

JL

I don't know what thickness the supplied gasket is but a 5 hole is .02 and 6 hole is .024. Im sure the head was cut to work with the supplied base gasket.. But before changing heads, I would run some race fuel. You might check the squish also to see if its reasonable.

 

[hymark860]

where did you get the 92 fuel from? I detoed a sled running 92 from walmart on a 13.5 rk head. I since have only bought fuel from chevron and never had another issue. I do run some race fuel now. I figure its cheap insurance.

 

[eddy]

Deto

I would agree with the post of going to a main jet of 480 or above being the correct path. Thye motor is telling you its to lean and you're lucky it has not melted yet.

 

[dicey]

I have the same kit in the same motor ,my advice to you is wait and talk to Kelsey you will be happy if you do ,I am running 440 jets in mine on pump gas I ride at 2500 to 6500 and have the 13.25 heads I now have 1500 miles on my kit about 1000 of that is hill climbing to the pin I would like to be able to offer more advice but don't want to steer you wrong Kelsey posted on another site that he would be back in the shop today.

 

[aremka]

Problem Solved!!!

Josh,
You are correct, the supplied gasket is .020" and stock is .024".

After removing the head today, I found some interesting stuff. First of all, the wash was still too rich and maybe hard to tell with less than 60 miles on the new pistons. I had about a 1/2" of shiny piston top with black carbon build up in the center. No pitting or sandblasting-look at all. All smooth.

I called Kelcey and we got going on this. He was great through the whole process. He listened and was very empathetic.

During the discovery phase, we ruled out DETONATION, and a LEAN condition. The cylinder walls were flawless too. We both were scratching our heads on this one. I told him I would take some pics, email, and get back to him.

During that time, I discovered what had happened. What we thought might be pitting on the exhaust port edge of the piston, was really an indent left on the piston from the dome. The few marks were so small that if you don't have good vision, you would need a magnifying glass.

As it turns out, I measured the inside diameter of the stock dome that meets up with the cyclinder wall. It was approximately 82.88mm. This 13.5:1 dome was around 82.25mm (and even less with the patented spider-web circumference). When Kelcey builds these, he fabricates to 82.5mm. We attributed this discrepency to a dull cutter on his tooling equipment. This explains why I would hear pinging when in full throttle and not half-throttle. During WOT, the piston will actually extend a little further and kiss the dome, while in half-throttle the piston wouldn't touch the dome edge.

I also had Kelcey's 14:1 domes and measured those and they were 82.55mm. I had run those last year and had "0" engine noise.

We are quite confident that this was the issue. Kelcey is sending me new domes ASAP.

I want to thank Kelcey again for the great communication and excellent customer service.

 

[aremka]

Thanks again for all your input and suggestions. I've enclosed some pics too.

Here are the pics. Hopefully, you can see the mark that was left in the piston from the dome. The little indents were exactly .200" apart and that matches the spacing in the web-like marks on the dome.

Some of you might say that I should have been using the stock gasket... Yes, it might have got me the clearance needed not to hit the dome edge, but it would have hid a real problem.

By having the thinner gasket, we can squeeze out a little bit more compression too.

Thanks again fellas.

JL

 

[dicey]

Here are the pics. Hopefully, you can see the mark that was left in the piston from the dome. The little indents were exactly .200" apart and that matches the spacing in the web-like marks on the dome.

Some of you might say that I should have been using the stock gasket... Yes, it might have got me the clearance needed not to hit the dome edge, but it would have hid a real problem.

By having the thinner gasket, we can squeeze out a little bit more compression too.

Thanks again fellas.

JL

why does it look in your picture that the piston is sticking out of the jug did you just set it in there for the picture?

 

[aremka]

Optical illusion!!

Dicey,
Look at it the other way. My camera is able to take super-micro pics. I understand that it looks that way too. Kelcey thought the same thing!! The edge of the piston is ACTUALLY below the rim of the cylinder wall.

Good question!!




Regards,
JL