I got the Makita 6401 upgrade itch.

[Yotaismygame]

 

[Matt93eg]

Ran good, real good after you ported it. I probably should have done the NWP kit, I had looked at it on Baileys. I had read to use a caber ring. Even after buying the ring I could have came out quite a bit cheaper but had also read the quality was kinda all over and you never knew what you were really going to get so I opted for OEM.

 

[Yotaismygame]

OEM is better for sure. I put a caber in that saw. At first I even left the base gasket in and the squish was in the mid .030's. Not many AM cylinders I would recommend but that nwp one is one of them.

 

[Rob Stafari]

I suppose I should have specified squish will be too tight with an oem top end, but I was thinking that is what OP ordered.

 

[Ryan'smilling]

Squish will be too tight without the base gasket on these without some machining.

I'll have to check my notes to confirm this. I was thinking the opposite.

Anyone doing a base gasket delete should always measure their squish. Regardless of what someone's "notes" say.

 

[Yotaismygame]

Anyone doing a base gasket delete should always measure their squish. Regardless of what someone's "notes" say.

That’s a given. Point was there is saws out there that come with a decent squish from the factory and deleting the base gasket isn’t even an option unless doing machine work. If multiple people come on here with first hand experience and say you’ll need a gasket on that saw I would believe them.

 

[Yotaismygame]

On the older side decomp 79cc top end no gasket squish was .024". On the newer top end with the top decomp and stepped exhaust port no gasket left a squish of .013".

 

[Matt93eg]

I am right that my standard 6401 muffler will bolt up to the 7910 cylinder? In my reading the consensus was yes.

 

[Yotaismygame]

You are correct. Only difference in the mufflers externally is the brace that connects the muffler to the case. You could have bought the 7901 top end and not had to swap the top covers. Last time I bought one it was the 7901 cylinder with the 7910 piston which is better. The 7910 is setup for the SLR muffler. Some funky setup where the muffler actually goes into the exhaust port.

 

[Matt93eg]

You are correct. Only difference in the mufflers externally is the brace that connects the muffler to the case. You could have bought the 7901 top end and not had to swap the top covers. Last time I bought one it was the 7901 cylinder with the 7910 piston which is better. The 7910 is setup for the SLR muffler. Some funky setup where the muffler actually goes into the exhaust port.

Thanks for all your help man.

 

[huskihl]

On the older side decomp 79cc top end no gasket squish was .024". On the newer top end with the top decomp and stepped exhaust port no gasket left a squish of .013".

The older ones are only .013” out on the edge of the band

 

[Yotaismygame]

The older ones are only .013” out on the edge of the band

That's not what I measured last time around.

 

[Matt93eg]

79cc suppose to be delivered tomorrow. I came down with some sickness Wednesday and thankfully had a short day at work this morning. Been laying around all day with a fever feeling like total crap. Starting to feel better, I think fever broke so hopefully I will feel good enough tomorrow to get the current topend off

 

[huskihl]

That's not what I measured last time around.

Tight to the edge, they are. But the rest is about .020” or so

 

[Matt93eg]

Parts got here. Was looking everything over. There appears to be a small scratch on the cylinder, my fingernail does catch it but the ring will never make it that far down. Is it ok to run. See pic. I think it will be fine. Unless it make the plating peel off or something?

 

[Yotaismygame]

You're fine

 

[Matt93eg]

You're fine

Good. I figured so but wanted to check first. Thank you

 

[RTK]

Maybe lightly touch it with emery cloth.....

 

[Matt93eg]

Topend is on. Was after dark so I did pull it over a few times and she popped. Maybe tm I will put her in some wood.

All went smooth other than I stripped the damn threads on the left side of the chain brake mount. Was using a small T27 so those threads must have been about gone already. I'm going to have to get a tap kit.

 

[dgr]