Venus 50 (Now 96cc!)

[2strokd]

A whole bag ! On one pipe? Im just now finishing a bag up after 4 or 5 pipes. A little trick to keep the whole silencer covered when assembly.
Use some mechanics wire to hold the packing were ya want it. I just wrap a piece around the silencer as i go.

[90GTVert]

When I put it together last time it was covering the whole silencer, not just pushed over. It used a fiberglass mat stock and that was in there tight like I did this. I've seen varying opinions. I'm thinking this way... it is deadening the sound and I mainly hear of negative effects from under packing. If it's overpacked it would just kinda work like a regular exhaust pipe and that wouldn't hurt anything but your ears. Not sure if that's correct, but it makes sense to me.

[90GTVert]

Well, I must not have hurt it too bad packing the silencer tight. When I started it up and tried to ride, I could immediately tell that it was acting like a real tuned pipe. After packing the silencer it lacked low end power but I can definitely tell when it's on the pipe now. I moved the clip to the middle from all the way rich and part throttle picked up. I adjusted the idle and it's more stable. I took it for a test ride and did a 1/2 mile WOT plug read.

Here's the difference between an 80 main jet with the SP3 and an 80 main with the MRP. Bare in mind, the SP3 plug did have 100 miles or so on it.


I ended up with a 95 main jet and as much as 49MPH sitting up. That's about a 4MPH improvement over the SP3. Since the new pipe it feels like it could use lighter weights, but I'll have to mess with that some other time. I figured I should call it quits tuning a loud pipe at 10PM. Even with the weights seeming too heavy, acceleration is just about as strong as before. It lacks that low down grunt that made it want to wheelie, but I can do without little wheelies if I can cruise faster and accelerate the same or faster when it's right.

[2strokd]

:rockon: Good, glad to hear it helped out :cheers:

[90GTVert]

Carb seemed like it was in tune. Started easy, ran well. I just put all the fairings back on and now it decides it's not gonna start. Somehow everything goes alright until I put every fairing back on. Happened last time I messed with this scooter.

[90GTVert]

I went out and stripped down the fairings. When I tuned it last night, I actually thought the 95 main was too rich. Since my father was riding and melted a piston on the Airsal, I've been tuning rich. I don't really think it's gonna be an issue on cast iron kits nearly as likely on a close tune... but then there's that great desire not to go through that over and over again. Maybe one of you guys knows the feeling, maybe I just overreact unnaturally? I actually had a slight rich sputter at WOT and if not for the recent holy piston, I wouldn't have thought twice about going back to the 90.

So anyway, on a final test run last night I was doing about 48-49MPH at WOT and killed the throttle. BOOM! A nice loud backfire. I thought maybe my exhaust had a slight leak so I checked that today and it's fine. Well, my backfire went through the intake and not the exhaust. I found my no-start issue...

Notice the open reed window and the damper or whatever it would be called bent backwards...


...And the reed petal sitting in my crankcase....


Needless to say, I put the 90 main jet in. I cut all my stock reed cages up to make spacers, so I guess I'm gonna use the Malossi reeed block from T2 for now. I got an email this morning that my piston pin is on order so it won't need it for a while anyway.

2 things on the bright side...

- I have great faith in ThreeBond sealant. I had to use a hammer to free the reed cage and even then it didn't break free that easily. It seals so well that I think it is better suited on cases and should stay off of reed blocks and such.

- I got a picture of a broken reed to add to my no-start troubleshooting guide. lol

[stepthrutuner]

Wow! Amazing. I never would have believed that the stop could have been blown back in from a back fire.

[90GTVert]

If I'm good for nothing else, I blow things up in ways you've never seen.

EDIT : That's not the big thick stop if that's what you were thinking. The Autotech reeds have stops and then these little metal strips that sit between the reeds and the stops. I think the cage would blow apart before the stops would bend back. Hopefully I won't test that theory.

[90GTVert]

Back together with the Malossi reeds. Moved to 7.5g sliders for the best results. 49.5MPH sitting up. Before the pipe I could hit 41 max in my little tuning distance, did about 44 in the same distance tonight. It doesn't have the very low grunt to try and do wheelies now, but it goes faster once it starts moving.

[jimh]

Well, that's progress Brent...hopefully it'll give you some ride time! Your troubleshooting guide is going to be invaluable to many scooterists.

[90GTVert]

After all the stuff in the Who Ya Gonna Call? thread, I think it is pretty much done snapping belts way prematurely as long as I use decent belts. I have been maxding out around 50MPH in ideal conditions and tucked and it feels like it flutters at max speed. At first I thought it might be way rich (sometimes they kinda flutter when there is too much fuel up top), but the plug looks good. I checked the RPM and it did 49.8MPH @9200rpm max with the 7g sliders I've been using. I swapped down to 6g sliders and it did 48.3MPH@9250RPM max on that run. The biggest change was an increase in cruise RPM. 9200-9250RPM is pretty darn mild for a piped 70cc. My 99cc did about 10,000RPM after modding the exhaust a bit, and those engines are supposed to be kinda low revving. Something is holding it back, so I think a future project needs to be a little cylinder work or a different pipe. Either that or leave it alone and hope the low revs keep it reliable.

[2strokd]

Its got the Polini Sport kit right?
Mine never saw much over 10,000 without really trying to get it there.
They just stop making power around 9 with the stock porting. Mine did with a
Leo ZX anyway. Maybe if you add more port timing it will rev higher?
I cant remember what its set at???

[90GTVert]

Yeah, it's the Polini Sport. I figured I'd try to just raise the exhaust port slightly. Maybe raise it, depending what squish I can get without machining anything. That will not be happening right now though. It does run and I've put a few hundred miles on it lately with no belt snaps so I'm gonna leave it alone for the moment.

[2strokd]

I dont blame ya!
I few degrees more timing along with less squish will let it rev higher
for sure! Ide leave it alone for now too. Same reason Skeedr,s cylinder hasnt
come back off for port work. Runs good now, and im too busy. Not to mention
its leak free, and did i say it runs good now? lol

Im glad you arent breaking belts anymore. I thought it was the belt cause the same thing was happening to a friend with the same brand belt i believe. Stock belts and roller are tough!
The rollers dont wear fast but are supposedly harder on variators?

[WT100]

Rode my Venus all week while my Triton was being worked on.

Thinking seriously about starting on it next. But would have to figure out a front disc to start with. Bone stock i was over driving my breaks every ride. Shame your front end upgrade didn't work.

Do you have that issue or do the better / bigger tires help with that?