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!

[gixxer6]

It's been a looooong time since I've given an update on the Intimidator...  I finally made a significant breakthrough with it the end of last season, I found that the aftermarket tach was reading a little more than 1000 RPM too low, so when I'd tune the clutches for it to run 9200 RPM on the tach, it'd actually be running 10200 RPM.  If you've ever looked at the power curve for these, or ever rev'd one yourself, you know that the power drops off dramatically.  This made tuning a nightmare.  Anyway, I have the tach fixed, and am running stock 4/6 pipes with ported 4/6 cylinders, and shaved and reshaped Liquifire heads on race fuel.  It pulls extremely hard at 8700 RPM.  I've got some fine tuning to do, and want to give my other pipes a try, but I'm really looking forward to this season. 

[mswyka]

What do you think caused the misread on the RPMs?  10% low sounds excessive.

[gixxer6]

What do you think caused the misread on the RPMs?  10% low sounds excessive.

I was using an aftermarket automotive tach, I believe that the way the Kaw ignition/lighting systems are designed caused the tach to read incorrectly and ultimately fail.  I switched back to a stock tach for the end of last season and have since bought a new tach along with a “tach adapter” that should allow proper operation.