suddenly loosing RPMs on longer hills

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KX_Larry
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Joined: Wed Nov 07, 2018 4:19 pm
Location: Colorado

suddenly loosing RPMs on longer hills

Post by KX_Larry »

RH with 300 miles. 6G rollers, heavier spring, and Prima exhaust. Stock jetting but I live at 6,000'

Was going great up the hills, while the speed would slow to maybe 20mph, the RPMs stayed fairly high. Now over the last few days, the longer 1/2 mile hills about 6% grade, it is now loosing revs and the speed has fallen dramatically. Almost to the point of not making it to the top. Runs strong on mild grades.

Plug looked fine and I put in a new plug. Cleaned out the jets and put new gas in it. Does rev sort of high at 8600 with current setup.

Initial acceleration is slow so I may try going down on pilot jet given my altitude but that shouldn't impact my current problem.
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Stanza
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Location: Chicago

Post by Stanza »

With the prima pipe, you may actually want to upjet slightly. Even with the elevation change. If you were at 0 elevation, you'd want to run a 40 idle and 90 main. The roughhouse came stock with a 35 idle and 82 main, and I'd suggest going to a 38 idle and 86 main based on your elevation.

Also, the roughhouse came with 7.5g rollers originally. So by lightening the rollers, and stiffening the spring, you're making it harder for the front variator to get all the way to the highest belt ratio. So you're essentially putting it at the redline before you actually reach top speed. You may want to do a compression test to make sure you haven't hurt the rings.
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OBX Dan
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Location: Outer Banks, N.C.

Post by OBX Dan »

Stanza wrote:With the prima pipe, you may actually want to upjet slightly. Even with the elevation change. If you were at 0 elevation, you'd want to run a 40 idle and 90 main. The roughhouse came stock with a 35 idle and 82 main, and I'd suggest going to a 38 idle and 86 main based on your elevation.

Also, the roughhouse came with 7.5g rollers originally. So by lightening the rollers, and stiffening the spring, you're making it harder for the front variator to get all the way to the highest belt ratio. So you're essentially putting it at the redline before you actually reach top speed. You may want to do a compression test to make sure you haven't hurt the rings.
You know your stuff brother. I asked you in another thread what to jet for that prima which I just bought. Since I live at the beach Im at 0 elevation, lol, so 40 idle 90 main is what I'll go with. 8)
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