250cc harrison question

[Mark Suter]

I have a Bruce Nicholson built motor that is essentially the same as the subject motor (I believe this one was used by Denny Henderson to win the PRO 250 hydro national championship in 1992). It uses Yamaha dirt bike heads with the exhaust port barrel-type valves. These valves do change the effective port timing thereby enable using more aggressive port timing on the top end. The valves are tied to the pipes so when going into the corners you let the pipes blow back. This pulls the exhaust port "curtain" down to achieve less aggressive port timing and thereby still have decent low-end torque.

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mark, gary, sam, and others,

i have the pipes that go with the engine. i'll do a 'upon further review' and see if that bar attaches to the other stack somewhere.

gary... i would like to get this set up and running before the race. incase i don't how much beer should i bring to make parts? my second race in 1971 i used a beer can for a fin because i forget mine. that was in lambertsville. wow was that a while back.

to solve the mystery of the boat here is a picture of the rig at the antique boat show at st michaels, md this year.

frank

[Dave-4Q]

heres a pic from the last time i remember this boat being set up

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dave,

it looks like the stacks are different than the ones pictured in your posting. i've got a call in to davie augustine to see if he gave me the right stacks. thanks for the picture. how did the boat run? i'm going to take it to lock haven for a ride.

frank

[Dave-4Q]

i dont remember,I think he only ran one heat ?

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dave,

from what i've been told he did not run very much. anyone ever see the rig run in fla races before matt bought it?

now to find the correct stacks.

frank

[Dave_E71]

how many sets did you get? if you only got one, then there is another set somewhere (here maybe)

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davie,

it's sunny out and your off today? what's that all about? i only have the one set and they do not look like the set dave-q posted. can you dig around for them and i can stop by and pick them up. i got fire out of it yesterday, not the fire we got out of the a looper, got the good kind. when can you come up and tinker with this thing? also the bezoat has 2 coats of west on the deck. gotta sand it now.

frank

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davie and gary,

here is the set of pipes i got with the harrison. there is no place to attach the bar to tie the pair together. there is no slot b for tab a to go into. any ideas?

frank

[GarE-12]

you have a conventional pipe arrangement, the free end of the bar attaches to the slot/tab on the upper pipe and the pipes will be in staggered configuration for conventional staggered manifolds with the stacks on the side of the motor. the other slot/tab on the lower pipe is where you hook up the pull cable from the boat. you may need to split the cable coming from the boat so you have two pulling cables, one for each pipe, then figure out the port cable off of one of the pipes.