Took her back out today and there was a steady 6-8mph wind. A friend of mine was out here with me that is into boat racing and gave me some tips on using the wind to my advantage for testing speed. I also gave it a 1/4 turn on the high and low. I hit 57.4mph! And in all of its glory that I used a bad word Coffman pipe bracket broke in half... It is a thick solid piece of steel too! I replaced all of the rubber dampeners, bolts, washers etc.. I even sanded the bracket and painted it so if there where any small cracks starting etc I would have seen them. @TheBuzzard Any tips on keeping this pipe from becoming a recurring headache? Should I add dampeners to the part of the bracket that bolts to the cylinder (Where it cracked)?
Yes we spent afew race days on the beach for this exact reason. The protec wasnt much better but it was still alittle better than these.Only advice is to make sure that there is no binding or pressure on the chamber when it gets bolted to that bracket. We did have to use a couple thin shims. It still broke but took longer. I looked last night and i still have a brand new complete system in the box.Must have been my last replacement from them.Never did use it. Glad to see this is fun for you.I remember going through all this 20 years ago.
Blaster Maxing out my 701cc blaster *UPDATE* 57.4MPH!
- Thread starter Quinc
- Start date
Quinc
Buy a Superjet
- Location
- California
Was it just the bracket that was breaking on you guys? Maybe instead of fixing this bracket I will make a new one out of AR400.
- Location
- the jetski grave yard
didnt you make that bracket that broke? i know the ones coffman made were about 1/2" steel. i dont see how you could rubber isolate that bracket where it mounts to the cyl. anything can be modified to work , but its going to be trial and error. that band clamp you have over the coupler makes the coupler last longer, but it also makes the whole pipe more rigid , vibrate more and cause cracking. you may have less cracking problems without that clamp, but you'll go thru couplers faster. i think i'd rater go thru couplers.
Quinc
Buy a Superjet
- Location
- California
This bracket came with the pipe. It could be home made, any recommendations on where I can buy a box couplers?
See post #79
Quinc
Buy a Superjet
- Location
- California
I think I am going to try one of these 5 ply silicone couplers off amazon. I could also loosen up the clamp that is holding it on. Coffman calls for 50ft/lbs of torque. Maybe I Can use 15-20lbs and lock tight it.
Quinc
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- Location
- California
Even broke the lock washer in half. Now I just need to figure out where the exhaust was leaking from..
88kawi5fiddy
pew pew lazers!
- Location
- So Utah
also try samco racing silicone couplers. samcosport.com/usa/ they have oil and fuel resistant ones. they build 1200hp supra's with these hoses so i bet they will last a lot longer than the amazon ones. once again you get what you pay for.I think I am going to try one of these 5 ply silicone couplers off amazon. I could also loosen up the clamp that is holding it on. Coffman calls for 50ft/lbs of torque. Maybe I Can use 15-20lbs and lock tight it.
Quinc
Buy a Superjet
- Location
- California
They dont make one big enough. I need a 4.5". Also I think all these places are getting them from http://www.siliconehose.com/ and putting there names on them.
Typical, weld a bushing over each hole and then a gusset to the plate behind. only needs to be across the top.Use the black marine exhaust hose. Blue stripe i think. Then no band clamp.Bolt it together with the bracket on the cylinder and no coupler.Check the alignment of the chamber vs the head pipe. Adjust with some shims if the two dont line up. Then assemble with the black couple only.
Quinc
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- Location
- California
Doing some more research it looks like a hump coupler might be better for absorbing the extra movement.
88kawi5fiddy
pew pew lazers!
- Location
- So Utah
samco is just the usa distrubuter for that company yeah. what are you using a 4.5" coupler for again? is it where the pipe half meets.
Quinc
Buy a Superjet
- Location
- California
Where are you finding the marine stuff at? The ones in the picture are good to 350F.
http://www.siliconehose.com/silicone-hump-hose/
Correct, it is for the pipe halves.
- Location
- Cruising Around
Awesome top speed. Wish I could get that. I got a case/cylinder ported ported motor with Wiseco light weight pistons at 720cc, Coffman pipe and Riva 48, Concorde 14/19. Maybe I'll vet there one day
Quinc
Buy a Superjet
- Location
- California
You should be way faster! I did notice a difference when I opened up and polished the exhaust manifold. I also have the water line that runs to the stinger T'd. Not sure if helps or hurts yet though. Have you hooked up a tach to see what your rpms are?
- Location
- the jetski grave yard
run all the water pressure to the stinger and you get more top end.the water dumping in closes the hole off and makes the pipe have a smaller stinger. more top end.
Quinc
Buy a Superjet
- Location
- California
The bracket was 3/8" thick. I cut off the broken part and added new 1/2" steel. Also cleaned up the 5 bolt holes on the other part of the bracket.
So what do you guys think, am I maxed out or would it be worth going up to a larger carb and adding an MSD Enhancer?
So what do you guys think, am I maxed out or would it be worth going up to a larger carb and adding an MSD Enhancer?