We just recently purchased a new Scrambler 400 equipt with a factory installed Hot Seat Exterminator kit. Pipe, clutching plus high performance carb, the full meal deal. I am not as familiar with 2-Strokes so I thought I would get some oppinions.

The engine seems to have a bit of a knocking. If it was a 4-Stroke I would be adjusting my valves. Is it normal for the 400's to have a knocking sound? It still acts and runs great. I am just wondering if it was normal or if I need to address it.

Thanks in advance.

GregV

 

Are you sure it is coming from the engine and not the clutches? Does it have the stock piston? The Wiseco piston has a little rattle to it, but I don't remember my factory one doing it until the skirt cracked all to heck. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Yes it has a Wesco piston. Go to my web page and then click on my videos. Click on the Scrambler photo to hear it. I stopped it short of coming in front of the engine. But it is definatly the engine.

 

I would say it is the Wiseco piston, it is known to have a little piston slap. I am at work and can't hear sound clips so I can't verify it, but by your description it sounds like it to me. Maybe someone who can hear it can verify??

 

The 2 stroke polaris engines are built a little loose and depending how it was broke in but it will have a slight knock (piston slap) The 250's are louder but nothing to worry about. Thats just the nature of the engine. You will notice it more in the winter.

 

Greg, the rule of thumb with these and a wiseco is that if you dont hear the piston noise, there's not enough clearance. I have to run 4 & 1/2 on my big bore and man does it rattle. You should be able to hear it coming from the cylinder if it's the piston. Also as mentioned before the primary clutch can have quite a rattle as well. Most of the time it is not real noticeable unless the clutch cover removed.

 

I've ridden the bike. GregV is paranoid. There is nothing wrong. If my guess is correct, he's looking to drum up an excuse to tell his wife(the owner) not to go ***** out on the drag strip and beat him.[img]i/expressions/face-icon-small-happy.gif[/img]

 

This is at idle right? There have been instances of mid-range detonation (too lean).

 

Yes it is at idle, I haven't done a plug check on it to verify if it's lean or not. I will though.

GregV (on Rhonda's computer)

Thanks guys.

What are you gonna say when she beats you AGAIN STecate925. [img]i/expressions/face-icon-small-wink.gif[/img]

 

Rhonda's icon Rocks!! [img]i/expressions/face-icon-small-smile.gif[/img]