Recently I fitted a Nitron rear shock on my xt660z.

It's a 2009 non-ABS bike which has been lowered about 3,5 cm by changing the linkage bones.

But when the bike is on its main stand the spring hits almost hits the engine. There is only about 0,000000001 mm between the spring and the part of the engine where the axle of the rear swing arm goes through the engine.



This is not a picture of my bike. But the spring on my bike hits the engine on the right side of that axle hole in this picture. When the bike is of the main stand there is enough clearance.

Is this a problem and can this damage my engine?

It will be a problem if it hits the casing on a regular basis, which it of course could do whilst riding and at full extension.

Odd though? Not heard of this before. Everyone who bought a Nitron shock that we've heard from here have been more than happy and never mentioned such an issue?

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The problem is that I really don't know what causes this problem.

Is it caused by the longer linkage bones I use? So the right hole (where the shock is fitted) in the pic will sit lower and the shock fits closer to the engine? I really can't figure it out.

Got a Nitron on my bike will have a look over the weekend and check the clearance.

Maybe the lowering dog bones change the geometry ??

That would be wonderfull!

It can't be anything to do with the lowering links (longer dog bones) as the shock position is related only to the triangulation of it's top mount, bottom mount and the linkage's engine mount. If you take the linkage bones off completely, the shock will still be in exactly the same position at full extension as it would be with them fitted. Full extension is limited by the internal bump stops built into the shock.

The only thing that would bring the shock spring closer to the rear of the engine at full extension is if the shock's free length was too long. Have they sent you the right length shock?

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I don't know if they sent me the right lenght shock. I will compare the free lenght of the Nitron with the standard Sachs shock. Would the seat height rise when the shock is too long?

No signs of any contact between the two and there is about 4/5 mm clearance between the shock and engine.

I'll see if I can get a more accurate measurement the garage floor was soaking wet so couldn't get down and have a good look.

Thanks for taking a look!

I took a pic of the spring. After taking the pic I took off the preload of the spring so I could turn the spring to a better position so it didn't hit the engine and the clearance was about 5mm. After setting the preload to the original position I now have a clearance of about 3mm.

But......when on its centre stand the lowest winding of the shock hits the triangular part where the dogbones and shock are bolted on.

When I sit on the bike the clearance increases and there is no problem. The problem only exists when there is no load on the suspension.

Is it wise to contact Nitron and sent the unit back?

Morning Arjen,

Just an observation and suggestion, might be worthless as I have no experience of the Nitron shock (yet).

Is the spring progressive ? if so, could it be upside down, with the heavy part at the bottom, when it should be at the top ? Might account for a few mm.

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