The Intimidator

[gixxer6]

8500rpms are you running out of space length wise. Have you taken a black magic marker and mark the sleeves primary & secondary (inside) this should tell you how far the belt goes.
Example say you mark the clutches you hit the 8500 rpms you come to a stop the worn mark only goes 1/2 way on your clutches this means you’re not geared right (too high)

Yeah, I took some measurements of the pipes I'm running and sent them to an engine builder friend.  He did some calculations and said they should make good power 8300 to 8500 RPM, so I guess that's where I'll run it for now. 

I'm familiar with the magic marker trick, I have the Aaen clutching book and have been studying it as I go.  It's been warm here recently so the iced over dirt road I normally test on is turning brown in spots so my testing space is very limited. 

I do have it engaging just below 6000, pulling hard to 8500, then dropping to around 8200 or so and staying.  It was very warm when I tested around 34F, it's supposed to be colder on race day so I'm thinking it'll work well. 

[gixxer6]

Update:  Race day went ok...  With the lack of testing time, I just went on Sunday for the "Grudge Racing".  I ran a few times down the 660ft track.  It ran ok, but wasn't pulling full RPM after the first 100ft or so.  I also had an issue with the chain slipping which cut my day short. 

Since then, I was able to fix the slipping chain with a stronger spring and new chain.  I also fixed the dropping RPM with a different secondary spring.  I've got it dialed in really close but I am not happy with the results.  I have my modified 81 Invader 440 performing the same or better on pump gas.  So...it's back to the drawing board.  I have sent some 4/6 cylinders and Liquifire heads to my engine builder in Canada.  The ports will be welded and reshaped, the heads will be shaved and reshaped as well.  I am also replacing the pipes.  I have started to modify some 4/6 LTD pipes to specs given to me by the engine builder.  Tuning it to run 9200 and with open stingers, it'll be fast and loud! 

[sprocket]

Spring in the chain case ?.  Wahl brothers racing sells a kit to have adjustable bearing with a bolt to keep the chain tight you have to drill a hole in the chain case and this would eliminate the spring.

[gixxer6]

Spring in the chain case ?.  Wahl brothers racing sells a kit to have adjustable bearing with a bolt to keep the chain tight you have to drill a hole in the chain case and this would eliminate the spring.

The new chain and tougher spring seems to be doing the trick so far, but I'll definitely keep that option in mind.  Thanks!