61 to 272xp swap. On the cheap.

[tallfarmboy]

Here we go.
Step one remove 61 intake and see how well it matches up to 272xp AM cylinder.
View attachment 277423
Stock intake gasket was too small, so made a ghetto gasket out of some poster board that would match the 272xp. Also needed to use the carbides to open up the 61 intake to match the 272xp.
View attachment 277424
Got the new gasket and old intake blended together REALLY nice...
Decided to rethread my old intake bolts to 4mm threads (to save a few bucks)
View attachment 277425
No problems... Just remember to "break the chip" when cutting the new smaller threads.
Went ahead and mocked the carb/intake/filter elbow together to see how it looks...
View attachment 277426
Not bad... Day 1 is complete.
View attachment 277427
Stay tuned.
TFB

 

[Big_Wood]

total awesomeness. i've done this a few time and also (on the cheap) as you say. subscribed

 

[moody]

opcorn:

 

[SawTroll]

Are you going to use the carb of the 61?

 

[tallfarmboy]

Are you going to use the carb of the 61?

For now, the 61 carb will be utilized. The only reason I am doing this swap is because this was an open transfer 61. Ran perfect, but a little heavy for the power. I want to see what the 61 carb is like on the 272 cylinder before doing any other modifications. I know that the 272 carb is the way to go to fully utilize the power of the larger displacement. I just like tinkering... I want to get it running decent now, then I will think about porting and improving the intake down the road.

TFB

 

[SawTroll]

It is about 15.9 vs. 17.5mm venturi size, so not just a minor difference.

 

[tallfarmboy]

Decided to slap it together tonight... Comparing the 2 pistons
View attachment 277753
The exhaust studs transferred from the 61 to 272 cylinder.
View attachment 277754
One issue is that the compression release will not clear the chain brake handle.
Ready for almost final assembly
View attachment 277756
Check out the squish without base gasket...
View attachment 277757
Probably need to open up both halves of the muffler...
View attachment 277758
Will be starting tonight!
TFB

 

[excess650]

You can just plug that CR hole. My 272xp doesn't have a CR, and I don't recall there being one on my 268 either. I plugged the port on my 660 when I put it back together and have not seen the need for it.

 

[kmcinms]

Here we go.
Step one remove 61 intake and see how well it matches up to 272xp AM cylinder.
View attachment 277423
Stock intake gasket was too small, so made a ghetto gasket out of some poster board that would match the 272xp. Also needed to use the carbides to open up the 61 intake to match the 272xp.
View attachment 277424
Got the new gasket and old intake blended together REALLY nice...
Decided to rethread my old intake bolts to 4mm threads (to save a few bucks)
View attachment 277425
No problems... Just remember to "break the chip" when cutting the new smaller threads.
Went ahead and mocked the carb/intake/filter elbow together to see how it looks...
View attachment 277426
Not bad... Day 1 is complete.
View attachment 277427
Stay tuned.
TFB

TFB, where did you pick up your P&C kit?

It is about 15.9 vs. 17.5mm venturi size, so not just a minor difference.

.063 is a good increase in venturi dia.. What carb is on the 272?

 

[Cantdog]

Tilly 260A.....

 

[kmcinms]

T Hanks

Thanks Cdog. No love on the rep button, will hit you later.

 

[tallfarmboy]

TFB, where did you pick up your P&C kit?

It was an eBay special... last one in stock... closeout priced... Didn't have a ring.

Throttle response is good... no dead spots, starts easy...

Just need to dremel a hole in the white top for the spark plug boot...

TFB