250cc harrison question

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hi all,

welll i may be getting wet again this time in the 250 class. i picked up an '84 250cc kay harrison yamaha, etc on a pugh hydro. the number on the boat is f7. my question is this.... there is some contraption on the stack side of the engine that looks like it is connected to the stacks somehow. as the stacks go back the contraption moves. i've attached some pictures of it and was wondering if anyone knows what it is and where it goes? i thought it attached to the bar on one of the stacks but it won't fit. any idea who had this rig in fla and any way to contact him?

thanks for your help. lock haven here i come. also bringing the quincy a looper and takinfg it for a ride alomg with a 125 quincy z engine. i starting to feel like bobby thornton. reffing a high school football game friday night then driving to lock haven.

frank

[Mark75H]

I'm surprised Mike Schmidt hasn't beat me to this ...

its an exhaust port control, lower port for lower rpm's; higher for higher rpm

If I could see it in person, I'm sure I could correct the hook up

Mike may know it well enough to tell just from the pic, I think he built the same thing

Do both pipes have brackets like the one we can see? Looks like the cable might go

to the common connection between them with a little bracket that helps you adjust the

length to the rack.

What I am saying is ... I think a bracket is missing that sits on the struts that go to the pipes.

The end of the cable looks frayed, it may have originally been long enough to reach all the way

back to the common connection point; but you would still need a length adjustment feature to

make everything work together

[fbref5269]

sam,

i'll look thru some other things i got with this setup to see if i can see anything that might fit. there is a long piece on the one pipe but i can't see anywhere it would fit. i would like to get it set up before the race. i did however pput a few squirts of fuel in the carbs and did get fire and got the attention of my grandson.

frank

[GarE-12]

The long bracket, bar, is a standard connection between two pipes in conventional staggered, configuration, it ties the two pipes together so they move as unit.

[Bill Van Steenwyk]

The short cable with the bolt attached to the end attaches somewhere (maybe the flat piece with the hole in it) so the "eyebrow" in the port raises and lowers as the pipe is moves back and forth, effectively raising and lowering the exhaust port timing. If I'm not mistaken Brinkman and Harrison gave up moving the "eyebrow" in conjunction with the pipe most of the time, as they found there was not much advantage versus the problems of keeping the pipe and port syncronized. I had this type set up on a 125 made with a Honda cylinder with same type port, but we used a second cable wrapped around a capstan to move the port more positively and you could also vary the timing between the port and pipe. On that smaller displacement engine (1/2 of what you have) it was advantageous to move both at the same time. We also had to have a positive connection in some manner to hold it at the highest position if we weren't moving it with the pipe, or combustion chamber pressure would "blow it down" and the engine had no power.

Short and sweet, you might be better off to just tie the port up (highest location) and move the pipe only. That is what I would try first if you cant figure the linkage out. There may be very little to be gained the other way.

[Mark75H]

The long bracket, bar, is a standard connection between two pipes in conventional staggered, configuration, it ties the two pipes together so they move as unit.

I think the set up is the same as the Kaw that Matt Nolette has/had.

So the bar connects to the other pipe closer to the motor? The port control cable shouldn't have much trouble connecting to the left hand side pipe

Gary, do you know where Matt's boat is? Is it for sale?

[GarE-12]

You have to make sure the pipes move together, then just clamp down the port where the thing will run. I may be there to help out and there is no joy like fabricating complicated mechanical systems in the pits with bailing wire and beer cans.

Did the pipes come with the motor and/or were they used with that motor?

Will check my sources concerning Matt's boat.

[John Schubert T*A*R*T]

Frank,

I sent 2 e-mails to you about the transom pad installation tool, but haven't had a response. Probably too busy to check your e-mails.

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john,

going out this morning.

frank

[Dave-4Q]

That was Matt Notools boat !!

[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.

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gary,

the problem is there ias no place to attach the bar on the other pipe. there are 2 cables coming back to attach to the pipes. there are 2 pieces on the pipes where the cables attach. wondering where the the attaching piece went to. davie is looking for the other set that matches dave-q's picture.

frank

[Jeff Lytle]

That looks like Roy Conklin's old 250cc rig to me.

[GarE-12]

see how the bar attaches to the one pipe, it attaches to the other pipe in the same fashion. this bar is for a conventional setup, it is probably not used for this motor with the power head turned 90 degrees.

I don't think the bar is meant for this setup.

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jeff,

that was roys rig before matt bought it. any idea how it ran? oh, is it snowing up there yet:) had to get that one in, sorry:)

gary.... daivie is looking for the other set of pipes. i hope to pick them up on thursday. i sent you a pm.

frank

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jeff,

friends of mine live in wisconcin and had their sons graduation party in mid july. they wore sweatshirts. i was in myrtle beach getting sunburnt the same day. i will not make fun of canadian weather anymore after that one.

frank