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New Cylinder Head


mau

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Joined
Jul 19, 2022
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Italy
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2016 KTM RC390
I bought the part code 93836020033 HEAD CYLINDER WITH CAMHOLDER (as new part), the one i received is dated 2021.
I have attached a couple of photos for what the surface condition of the head looks like.
I asked the KTM parts supplier for clarification, sending the photos as support, I was told they were aware of the surface condition. I was not advised of the condition of the part.
I also put here some photos of the camshaft holder from the head side, the surface will be due to the cast, ok.

They told me that:
- They can contact KTM for replacement and that takes much time than usual due to lack of personnel in KTM.
- I can send the package back to the them and they start the complaint with KTM directly.
I asked further:
- Was told that some cylinder heads are known to have these slight surface defects.
- They have often passed this information to the KTM manufacturer.
- And that being their spare parts dealers, they have no control over the quality of the components.

Apparently it is not the first time and it continues to happen, these parts are not blocked in quality control or even sent back by the parts dealers.
Over time I don't want to imagine that they replace it with one with similar conditions.
I address my question above all to those who bought the new cylinder head, were the conditions similar to this one in the photos?
What do you suggest?
 

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I wouldn't be happy with that. What happened to your old one?
Yes get I you, I'm not happy too.

They also suggest:
The depth of the surface damage is irrelevant for the function of the engine as the seal compensates for such surface damage. However, it is recommended to lightly rub the affected areas with sandpaper and to remove the possible edges.

Ok, but only because I bought it as new, I don't want to know about making adjustments.

Slight camholder damaged, then two threads for the camholder were finally boken, the cylinder head surface near the rim of the cylinder, intake side, was not the best. However there was no compression in the cylinder.
 
This is unfortunately true of Bajaj parts and KTM can't or won't fix it. I have to take them from the box new, and deck them as they are not flat.
 
This is unfortunately true of Bajaj parts and KTM can't or won't fix it. I have to take them from the box new, and deck them as they are not flat.

Each case is comparable, perfect
With "to deck" do you mean material removal machining?
 
Update: I sent the cylinder head to the deck, they removed 0.05mm. I reassembled the engine and then on the bike.
 
I can't count the number of heads I've seen brand new out of the box which were no in spec. As Paxton said, this is a problem at Bajaj. Fixing them isn't too terribly difficult if you have a granite surface plate, heavy thick glass, or marble counter top in a serious pinch. Just spray glue down some 220 wet dry, and start making figure 8's. Then go to 400 grind and remove any and all scratches. Then 800 grit. Once you are getting perfect contact across all of the flat, you're set. or, if you have a machine shop, or a knee mill, deck it with a fly cutter. Remove as MINIMAL amount of material as you can. Seriously! if you have to pull more than 0.004" to flatten it, the head is junk.
 
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