- Location
- the jetski grave yard
peak hp with that coffman pipe was achieved at 6750rpm 80hp. it looks like they got it to rev to 7200 but hp dropped off to 72.
Blaster Maxing out my 701cc blaster *UPDATE* 57.4MPH!
- Thread starter Quinc
- Start date
Quinc
Buy a Superjet
- Location
- California
Thanks Buzzard! I guess that means I have maxed her out.
Now I need another project to waste money on. Anyone know anything about WetJets?
- Location
- the jetski grave yard
the duo200 has some oddball motor in it , i think 440.bad electrical problems. stay away from those. the duo300 has a 61x motor 701. stay away from those too.
- Location
- Tempe, AZ
hahahaha thats hilarious. his name is the buzzard and he does not approve of wetjets. end transmission haha!
Quinc
Buy a Superjet
- Location
- California
I picked up a duo 300 with 61x that runs. Right now I have it in pieces and am redoing the pump. Plan is to use it as a loaner/spare parts ski. Damm they are ugly though..
Stock CDIWell my wife rode her blaster for the first time this weekend... "The throttle is too touchy, and it goes too fast when you give it gas"... So looks like she is getting a couch.
On another note, why are my rpms so low. I tried going up a jet size and they are same. Any guesses on what the bottle neck could be, and would it be worth going up to a 48mm a/m carb?
Quinc
Buy a Superjet
- Location
- California
I thought that too, but the 701 cdi goes up to 7200. Read a couple posts up and TheBuzzard explained what is going on with the rpms. They are right where they should be. =)
Yeah I didn't see his post. I may be wrong, but I'd think you could gain HP/top speed with a pipe that makes power higher up along with a CDI. Someone correct me if I'm off.
Quinc
Buy a Superjet
- Location
- California
Maybe if I come across a great deal on a factory pipe. But for now I am happy with where it is. I am impressed with how quickly it gets to 50mph. For now...
- Location
- Cruising Around
Not gonna see much if any switching to a Factory pipe. Might get a little with a Mod chamber but not worth the switch imoMaybe if I come across a great deal on a factory pipe. But for now I am happy with where it is. I am impressed with how quickly it gets to 50mph. For now...
scottie mac
X-
Try a smaller prop. For your application, a 10/17 ish hooker would probably be pretty close. Get the rpms up to 7200 or so and you won't believe how much harder the 'hit' will be.
SM
SM
- Location
- Cruising Around
Scottie, he is running an old straight cut Solas I impeller. You think a radial Hooker 10/16 will unload the engine more and allow it to rev higher?
Quinc
Buy a Superjet
- Location
- California
What do you guys think about going from a stock 44 to a buckshot 46 or 48mm carb? Would I see much if any gain at this point without a prop change?
Way back when we raced the limited blasters, they were turning 7050 rpms with the i prop.The speed on our radar gun showed 50.8 tops. The old school 9/17 scat reved alittle higher but not really gained any speed. 225 compression,stock cdi with rev mod,jetpro reed stuffers,dual 44s on shortened intake manifold,custom built chamber,61x/61x.Our ported 61x combos ran 7300-7400 and were only a couple mph faster,but they really pulled hard.These 61x cases can work well but require alot of port work.I have followed this thread and i will say im alittle confused on the numbers you have posted.If the cylinder s are ported and the cdi has the rev limit mod,there shouldnt be any reason that your combo isnt reving 7000- 7200. Yes the dyno numbers show the taper of the power but keep in mind that was a complete stock 61x. I was given a coffmans pipe in the early stages,and while they did perform well, we couldnt keep them from breaking.We did get replacements over and over but just wasnt worth the hassles.The dual carbs always netted an increase in rpm of about 150-250 on top. 62t cases showed alittle more power but the rpms were always about the same as the cylinder was kept the same.This would allow you to use a slightly taller prop.So you see why the 6750 rpm doesnt make sense to me,especially with the i prop and the mph.
Quinc
Buy a Superjet
- Location
- California
So far the max rpm on my tach is 6840. Compared to what others have posted mine does seem faster then it should be, especially since I am getting consistent 50's in choppy water. I believe the GPS is close because it is hitting expected numbers on the other watercraft we have tested. If you have any other suggestions on how to measure/test performance (that are cheap/free) I am all ears.
Not sure the rear lip was the issue. On the 96 hull there is a hugh hook at the rear of the hull. Needs to be sanded with 36grit .Glue sandpaper to a 2 or 2.25 tube then sand the bottom rear of the hull.Remove the hook at the back of the bottom hull.Not sure on the older hulls though.Always want a rougher surface on the bottom thats in the water.
I think the rev is 7000 on that cdi. maybe your just too close to the limit. Cheap free mod is to bypass the rev with a solder. As you say these numbers are in the chop the highest rpm recorded should be alot higher. The rev limiter doesnt really let the motor rev to that exact number,it may be cutting out as the pump looses presure. Have you ever been able to do a test run on smooth water? Is the rpm the same?So far the max rpm on my tach is 6840. Compared to what others have posted mine does seem faster then it should be, especially since I am getting consistent 50's in choppy water. I believe the GPS is close because it is hitting expected numbers on the other watercraft we have tested. If you have any other suggestions on how to measure/test performance (that are cheap/free) I am all ears.
Down near the drain plugs? Crazy.
Thanks for sharing your knowledge with us, always cool to learn on this site!
Quinc
Buy a Superjet
- Location
- California
I haven't been out on a smooth day yet. I think the CDI goes to 7200 on the 61x and 67/6800 on the 6m6? Also with the new impeller and blueprinted pump you have to put in some effort to get it to unhook. I guess I could rev it up on the trailer and see what it tops out at.
Quinc
Buy a Superjet
- Location
- California
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 brownie 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)?
The bottom of the hull.Basically a truing of the bottom. its really the tunnels between the chines from about midway to the back of the hull.And keep the surface rough.