• engine swap from howhit 150cc to the BD 175cc. carb, output shaft spacer and muffler questions

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 #12953  by msgennario
 Wed Nov 07, 2018 4:52 pm
A few months back I received my new parts from Buggy Depot for my yerfdog 3206 kart. I purchased the 175cc engine, a muffler, muffler gasket, unifilter, reverse kit, and a 30mm cvk carb. Finally getting around to swap it out and so far it’s going well. Have a few questions though that I can hopefully get answered in this forum. Please forgive my ignorance.

Regarding the output shaft and reverse kit. On the old engine there was a spacer between the engine case and the sprocket. Do i reuse this spacer or is there a spacer in the reverse kit I should be using instead?

Regarding the carb. I notice the new 30mm cvk card doesn’t have all the same hose connections the original had.. I am referring specifically to what appears to me as a possible vacuum line ( i could be wrong). The old setup had a hose from my gas tank to a petcock. From that petcock I have a line that appears to be the main fuel line to the carb, but also another connection from the petcock that splits into a “Y” connection. One of the connections from the “Y split went to the side of my old carb and the other end of the connection went to the intake manifold. There is no connection for this on the new carb nor is there a connection at the intake manifold for these hoses.. Do I simply take out the old petcock and run the fuel line direct to the new carb and the other connections are no longer needed, or am I missing something?

Regarding the muffler and muffler gasket. I bought a small size muffler gasket previously that fit snug around the end of the muffler. I bought a new small size gasket as well for this engine swap and it seems like its very loose when compared to the old gasket? Should there be any “play” or should it fit “snug” around the muffler? Not sure if I received the wrong gasket or if this is correct.

Any info/assistance is greatly appreciated

-Matt
 #12955  by Travis @ Buggy Depot
 Fri Nov 09, 2018 12:35 pm
msgennario wrote:
Wed Nov 07, 2018 4:52 pm
Regarding the output shaft and reverse kit. On the old engine there was a spacer between the engine case and the sprocket. Do i reuse this spacer or is there a spacer in the reverse kit I should be using instead?
You'll want to keep the old spacer on the shaft, and stack the new spacer next to it to get the right alignment.
msgennario wrote:Regarding the carb. I notice the new 30mm cvk card doesn’t have all the same hose connections the original had.. I am referring specifically to what appears to me as a possible vacuum line ( i could be wrong). The old setup had a hose from my gas tank to a petcock. From that petcock I have a line that appears to be the main fuel line to the carb, but also another connection from the petcock that splits into a “Y” connection. One of the connections from the “Y split went to the side of my old carb and the other end of the connection went to the intake manifold. There is no connection for this on the new carb nor is there a connection at the intake manifold for these hoses.. Do I simply take out the old petcock and run the fuel line direct to the new carb and the other connections are no longer needed, or am I missing something?
It's best to remove the "Y" and connect your vacuum petcock diectly to the port on the intake manifold. I usually recommend switching over to a manual petcock. The automatic vacuum petcocks are a real hassle to work with when you need to drain fuel eventually for maintenance and diagnosis later.

Petcock, Manual w/ Reserve (16mm)
https://www.buggydepot.com/product/181/ ... -16mm.html

On a slightly related topic, it's a good idea to put a couple wraps of teflon tape on the threads of that port on the aluminum intake manifold. They tend to come with a slight leak there at the threaded joint from the factory. This may have been fixed in recent batches. Checking to see if the barb is loose when the manifold comes out of its packaging should be good enough.
msgennario wrote:Regarding the muffler and muffler gasket. I bought a small size muffler gasket previously that fit snug around the end of the muffler. I bought a new small size gasket as well for this engine swap and it seems like its very loose when compared to the old gasket? Should there be any “play” or should it fit “snug” around the muffler? Not sure if I received the wrong gasket or if this is correct.
As long as it fits snugly into its slot in the head on the new engine, you'll get a good seal. Our engines use the large size exhaust gasket, so it's possible my shipper anticipated that you'd need the larger version and sent it instead of the small.