My HT engine is seriously down on power and I can't figure it out. It feels like the mixture is off and engine is struggling. It takes forever to rev up and is gutless even with a small smaller sprocket on front flywheel (its a SBP shifter kit motor). Engine was purchased new last summer and has 139.2 actual miles on it. It ran perfectly and had plenty of power on my last pre-winter ride.
Here's what I've done to date:
1. Fresh fuel mixture
2. Pulled carb, its clean and jets are clear..no gunk...engine was winterized with fuel drained and light machine oil (one teaspoon) poured into plug hole and engine rotated to coat interior.
3. Tried every needle position on carb, no luck.\
a. Even fiddled with various tapers on the needle valve (I have many spares lying around) with some improvement in starting but no improvement in power.
4. Cut new gasket for intake manifold to rule out leak (gasket coated with gasket sealer)
5. Replaced exhaust with freer flowing tuned pipe. Checked old exhaust to ensure it wasn't gunked up or clogged (its not and flows perfectly)
6. New quality plug gapped appropriately, I run all my plugs at 27 thousants of inch
7. Replaced CDI because the metal threaded part that sticks out of it was loose and possibly became disconnected internally....new CDI works just find but no improvement
8. Swapped carbs from other two bikes that run perfectly after winter storage. No improvement
9. New fuel filter and fuel lines (old lines were hardened a bit and had a spare new fuel filter lying around....carb is getting plenty of fuel and that isn't the problem.
10. I even installed a headgasket and torqued down the head bolts nice and tight.
11. Airfilter assembly removed. Airfilter not clogged or soaked with oil/fuel.
My last pre-winter ride on this bike easily got me cruising at 35mph. No apparent seal airleaks.
Any ideas? I've got a spare rebuilt engine lying around but installing it (SBP shifter kit) is something I don't look forward to doing.
Engine has plenty of compression and my right shoulder is sore from pull starting it.
Power loss is similar to that of having the engine running 2 needle valve clip settings too rich. It idles great, rev's freely in idle, but no ooomph when manual and centrifugal clutch are engaged. Can't even get the engine to rev as high as it used to when going down hill.
PS: Centrifugal clutch is not slipping..the drive gear is pinned with a woodruff key and bolted on with impact wrench. On my other two engines, impact wrench to the bolt is sufficient and woodruff key is overkill for the centrifugal clutch.
I haven't gained any weight since last summer
Manual clutch is not slipping either.
Here's what I've done to date:
1. Fresh fuel mixture
2. Pulled carb, its clean and jets are clear..no gunk...engine was winterized with fuel drained and light machine oil (one teaspoon) poured into plug hole and engine rotated to coat interior.
3. Tried every needle position on carb, no luck.\
a. Even fiddled with various tapers on the needle valve (I have many spares lying around) with some improvement in starting but no improvement in power.
4. Cut new gasket for intake manifold to rule out leak (gasket coated with gasket sealer)
5. Replaced exhaust with freer flowing tuned pipe. Checked old exhaust to ensure it wasn't gunked up or clogged (its not and flows perfectly)
6. New quality plug gapped appropriately, I run all my plugs at 27 thousants of inch
7. Replaced CDI because the metal threaded part that sticks out of it was loose and possibly became disconnected internally....new CDI works just find but no improvement
8. Swapped carbs from other two bikes that run perfectly after winter storage. No improvement
9. New fuel filter and fuel lines (old lines were hardened a bit and had a spare new fuel filter lying around....carb is getting plenty of fuel and that isn't the problem.
10. I even installed a headgasket and torqued down the head bolts nice and tight.
11. Airfilter assembly removed. Airfilter not clogged or soaked with oil/fuel.
My last pre-winter ride on this bike easily got me cruising at 35mph. No apparent seal airleaks.
Any ideas? I've got a spare rebuilt engine lying around but installing it (SBP shifter kit) is something I don't look forward to doing.
Engine has plenty of compression and my right shoulder is sore from pull starting it.
Power loss is similar to that of having the engine running 2 needle valve clip settings too rich. It idles great, rev's freely in idle, but no ooomph when manual and centrifugal clutch are engaged. Can't even get the engine to rev as high as it used to when going down hill.
PS: Centrifugal clutch is not slipping..the drive gear is pinned with a woodruff key and bolted on with impact wrench. On my other two engines, impact wrench to the bolt is sufficient and woodruff key is overkill for the centrifugal clutch.
I haven't gained any weight since last summer
Manual clutch is not slipping either.
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