Re: Urban express variator questions

Jack Rutherford /

I guess a couple mm ain't a lot but I'll have to look at mine in person to figure out how that didn't affect low end especially with a bx belt.

Re: Urban express variator questions

On any CVT bike the real prowess of the bike is in the drivetrain tuning. Your top speed is just a number but how the bike responds to throttle input, accelerates from a stop, and cruises in the other 99.5% of scenarios that you ride is where you want your focus. All of that is in those little weights, springs, belts and pullies.

Re: Urban express variator questions

I've always understood it that a stiffer rear spring causes "down shifting" quicker when the throttle is closed and the clutch is disengaged.

Is there some sort of spacer in your pulley stopping the ramps moving fully?

Re: Urban express variator questions

Jack Rutherford /

you never mentioned what exhaust you were running? update?

Re: Urban express variator questions

Shawn Manthey /

I'm running the MLM h95 pipe. I've kinda put it on the back burner for other projects at the moment. There's no spacer or anything causing the ramps to not move fully outward. When it's in my hand it moves freely but once it's on the belt only rides to about the halfway point. If I put the cut down variator boss in then it'll make the belt ride to the outside of the variator giving me substantial speed increase. But the low end doesn't pull like it does with the uncut variator boss.

Re: Urban express variator questions

Jack Rutherford /

I've since cut down a boss 1.6mm. It's been fun to experiment with. I'll have to go back and look through this thread again as it's been so long.

Ok. I've done that right seal two or three times and I've had to put a torch to the gear while the puller was attached every time to get it off. I'm about to do it again soon.

What's your current weight in the variator? I notice you kept taking out weight. If it won't variate fully, I would add weight - maybe go to 24 or 27 grams.

What contra are you running now? The red contra has proven too much for my setup.

Still have the bx31 belt? ax31 might be worth a try.

still 85 jet in the vm18 and what plug are you running? I'm at 85 right now but with a really cold plug. Lately it's been running rich and the pipe won't hit when it does. I either need to go to a hotter plug or down to an 82.5 jet.

I've got basically the same set up and it will do just above 50. I prefer the Malossi belt which is thinner than the bx31 but thicker than the ax31. I've got the yellow contra but have a silver one to install. I believe I'm at 27 grams in the variator. Malossi gears and people's pipe.(edited)

Re: Urban express variator questions

Jack Rutherford /

btw, I've got the unmodified boss in this one. The shaved boss in a different one.

and I meant left seal.(edited)

Re: Urban express variator questions

Shawn Manthey /

I currently have a yellow contra in it. I have never tried the red. Only had the stock spring and the yellow. I've played around with variator weights quite a bit. Ranging from 15-45 grams. 45 grams variates in about 25 feet and takes me ten miles to get to top speed of 40. 15 grams variates how I like it to and pulls hard to the top speed of 40. Maybe I'll try that malossi belt and see what that does for me. Id have to track down my carburetor notes to double check but I believe I jumped to a 87.5 or 90 main jet

Re: Urban express variator questions

Jack Rutherford /

You've probably already done this to any extent necessary - you'll want to clean and/or lightly sand the front and rear pulley of all belt residue, rust, oxidation, etc. You may want to take apart the rear pulley and make sure it slides back and forth freely and lubricate it as needed. I tend to think that any hang up in the rear pulley would prevent the belt from fully variating on the front pulley.

You can lose a bunch of speed easy if it's over-jetted as well although you seem to be right in the ball park. I assume that h95 is hitting. I bought a used h95 and ran it some but not enough to compare it to the people's pipe yet.

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