Same speed with new gear

Maxi 70cc TCCD kit with 15mm carb and 80 jet. Techno boss pipe and case matched. Just added a 40 rear sprocket and stayed with the 16 on the front. Stock crank. GPS at 42 today which is what I was doing with a 45 on the rear. Only difference is the RPM's were lower and she wasn't screaming as hard. Sounded good and felt good. Is the 42 MPH good with the new lower RPM's?

Re: Same speed with new gear

Get an aftermarket crank or wait for failure. Or a new pipe.

Re: Same speed with new gear

Pipe is new. With RPM's and temps down, crank should be ok. The bike only had 1600 miles on it. It was stored for years without being ridden. So crank is relatively new, milage wise.

Re: Same speed with new gear

Overpriced Parts /

Ya boss pipe is a hi rpm pipe made for low gearing.

If you had a pipe like a techno circuit you could run 17x40 and may hit 48mph

If jetted and timed correctly .

But ya like what Adam just said a aftermarket needle bearing crank should be used especially with low gears (like stock and 16x40) and a hi rpm pipe like boss.

So your got a missed matched set up

Re: Same speed with new gear

My main purpose was to keep the 40mph and lower the rpms. I was just wondering if I could have gotten more speed as well. But I would think with lower rpms and 40mph it isn't bad for the bike.

Re: Same speed with new gear

Overpriced Parts /

Ya but get a pipe that is in the lower rpm range like a circuit and you will go fast at a lower rpm with proper gearing.

Re: Same speed with new gear

So much fail in this thread. You don't need a new crank. So many people think that everyone needs a new crank. They don't. It might not hurt, but you probably won't know the difference either. As long as you run a high enough oil ratio (50:1 or 40:1), the bushings should last. I think the problem comes in when people start running low oil ratios. Bushings need more oil than bearings, but a lot of old bikes had bushings and they worked great at higher RPMs... As long as the owner didn't skimp on oil.

You might want to fiddle with your timing a little bit. My TCCD, 15mm bing, and stock modified pipe was getting me to 48 on that gearing. You should be hitting around 48-49 with no port work and a proper pipe. ( about 9.8-9.9k RPM)

Assuming no clutch slip:

Before you were hitting 9577 RPM

Now you're hitting about 8513 RPM

Your boss should be pulling well from 8k up, and the TCCD has port timings for high RPM if you have enough base gaskets to miss the head. A 15mm carb is a little small for a 70cc kit, but it should still work ok. A 19mm carb will really make your kit wake up. Really high compression will also hold back your top RPM. Do you have any idea what kind of compression you have?

What is your timing set at?

Re: Same speed with new gear

Overpriced Parts /

After seeing about 100 stock puch crank bushings and finding 1/2 of them bad to begin with and kitting dozens of puchs with e50s and za50s I keep the hi rpm set ups to needle cranks and even if your 30 year old bushed crank is perfect condition it will fail/melt with prolong hi rpm use .

I just finished rebuilding a e50 for a young guy who just wasted his crank. He ran a boss pipe, 15.15 sha, 50cc tccd Kit and 16x42 gears. The carnage includes a melted bushing and a damage at the piston pin that required a new piston. Lucky he shut it down when it made clatter noise

I sold him the e50 last year and it only had about 1200 miles on it and the top end and bushing were mint . I helped him with his kit, clutch, timing and jetting. He ran a beat Proma circuit that I sold him and 16x38 gears. After he broke his Proma off he got a boss then he had to down gear to 16x42 gears stay on the pipe and he actually went faster near 50mph.

About a week later the bushing melt like I said And though I'm cheep it still cost him almost 300.00 with crank, bearings, seals, gaskets and piston.

Run circuit/estroil pipes, run medium gears on your stock crank and enjoy riding this summer

Re: Same speed with new gear

I am mixing at 3oz per 1 gallon. SHould be about 50:1 - 40:1. I still have some throttle left and it just seems once it gets to a certain point, it won't go any more. I had the timing set by a shop and from what I have seen the strater is maxed out. The shop told me it is 18 degrees. He also said my compression was 150. Slide needle is at second from the top and I have an 80 jet in the carb in a 217 atomizer. I went from 28 MPH to 42 MPH. Once I put the 40 gear on I noticed that I still got the 42 just she was running lower rpm, which is good. I feel better to be getting that speed and she's not screaming.

Re: Same speed with new gear

What about downhill, buddy.

Re: Same speed with new gear

I live in Fort Lauderdale area. No downhill. All flat.

Re: Same speed with new gear

Overpriced Parts /

You got to dremel the stator slots to get 17 degrees

You prolly got a smaller then 17 thousand point gap too because with a 17-18 point gap your closer to 19-20 degrees timing. The shop could be wrong

Or lying

If your running less then 400 degrees head temperature @ WOT leave timing

But I bet your not

Re: Same speed with new gear

Ken, just out of curiosity, what oil mix was he running? I'd be willing to bet he was running synthetic at some really low oil content? Bushings need more oil. Just because some engines can be run on the bare minimum for oil content, that doesn't mean all can.

I have big end bearings go before the bushings ever fail. Needle bearings in the small end like to turn into time bombs. I've never had a costly repair (aside from the new crank) from a bushing failure. Wrist pins, and even pistons in the rare case that you need one, are cheap. Cylinders are usually the costly part when you're running some irreplaceable kits like autisas, zetas, and sadly metras too.

Also, he was running over 10.5k. For an extended period of time, that'll mess up a roller crank too.

Oh, and to the Michael, I would recheck your numbers on timing if you can.

Re: Same speed with new gear

GET REALIZED! BE HERE NOW! /

I wouldn't want to ride a ped in Florida really at all. Maybe just get a motorcycle. I grew up there and got hit on bikes and such a few times by. Lud hairs and dumbass tourists. Plus everyone drives like its i95 everywhere

Re: Same speed with new gear

small end bearings aren't like big end bearings... they should be replaced every 1000mi if you want to play it safe. Also depends on which small end bearing you buy too.

Re: Same speed with new gear

Deadped Ryan Wrote:

-------------------------------------------------------

> small end bearings aren't like big end bearings...

What I was trying to say is that the crank usually needs to be rebuilt before the bushing goes anyway.

Re: Same speed with new gear

Id say by switching to a smaller rear sprocket, your motor isn't going to push through to increase your speed. You are just lucky you have plenty of torque to keep you where you are, I would say you are running a lower RPM now, but that RPM is taking more abuse because of it.

Re: Same speed with new gear

What if I put a bigger carb on it? Will that give me more power to push up the rpms.

Re: Same speed with new gear

Shane Antisocialite /

I think Steve is building different engines than the rest of us. I've seen a few bushings fail. We all run 50:1. Needle bearings are infinitely better. The rods on Ritos are stronger as well, one of our group ripped a stock rod clean in half on a fairly mild 50mph e50... not to mention the oiling is better, they aren't 30 years old, and they weren't designed to handle 2 hp at 7000 rpm. How is this even in question? I won't let anyone build a decent kitted bike on a stock crank. Not worth it.

Here's what a failing stock crank can do. That is cylinder skirt stuck in the case, which also had a bunch of holes punched through it from the rod bashing into everything at 9 grand.

He has a Rito now :)

526064_10150877907011796_124618517_n.jpg

Re: Same speed with new gear

Shane Antisocialite /

On topic, if you want to go faster, do things in this order- temp gauge, new crank, a real pipe (MLM, Destroyer etc), bigger Mikuni.

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