SBP Shift Kit - Ratios, Speeds and Pedal-starting

[AussieSteve]

The standard FW can fail in either mode, free or locked.

That's more or less what I thought. The HD type would probably be the same, if it does fail in the pawls.

The HD, which I believe you have has not failed due to the pawls failing. We have only seen 2 fail and both were bearing failures.

That's comforting, from my kick-start point of view. I'll get a spare soon and keep it on hand, just in case. At the first sign of potential failure, I'll fit the new one.

I guess I will have to try one of those heads to see how difficult it is to turn over. I forget that not everyones engine, bike etc are like mine. Mine is so easy to turn over it is ridiculous.

I am an extreme case, at 50 kg, (110lbs), and not much puff, but yeah, the 66cc with billet head is hard to turn over. The stock head was 115psi, the billet is 142psi. Doesn't sound like a huge increase, but even a 23yo friend of mine was shocked by the compression and has trouble turning it over and he's a lot younger, stronger and fitter than I am.

I really don't think you will have any issues with your starting technique. I just wanted to point out to the rest of the audience that it is not the preferred method.

No worries, Jim, and as I mentioned, I'll just buy a spare HD freewheel when I buy the sprockets etc and keep it on hand, just in case. The cost is worth the ability to kick-start.

The rain has finally stopped, so I'm off for a test-ride shortly.

... Steve

 

[cabinfever1977]

You know they sell a pull start dont you,i have one and my engine starts with the first pull.

 

[Pablo]

I may just get a pull start!

Unlike Jim, I run a pretty extreme compression ratio. I have a shaved slant plug head. Mid winter, my engine is pretty tight first turn over after sitting a week or three. But once I crank it, the next crank is not so bad and then it fires up.

When I put the regular head back on, it's like butter!!

 

[Fabian]

Hi Paul

Is there any chance of SickBikeParts making a decent slimline billet pull start mechanism for the Chinese 2-stroke engines.
This would allow me to change to a much desired 9T - 48T jackshaft to chainring gear ratio.
I would not have the issues of trying to pedal start the engine.

I've got my credit card at the ready should it be put into production.

Fabian

 

[Pablo]

Thinking about it.

Why would it need to be from a "billet"?

 

[Fabian]

The pull-start doesn't have to be made from billet.

I was just thinking from the perspective of a totally redesigned slim line system made up in CAD, keeping the thing nice and compact and free from pedal crank interference with standard width cranks.

I guess it would be easy to punch the parts out on a CNC mill if it's designed as a CAD file.

I've heard that the standard Chinese pull-start mechanism is not very well engineered and prone to breakage.

Fabian

 

[Skyliner70cc]

I've got 2 bikes with pull start. The only failure I've had with them is the cheap pull rope. Once the pull rope was replaced, both have been very reliablable with no issues.

As for pedal starting, I had one freewheel fail on a high compression head. I then upgraded to the heavy duty freewheel as a precaution. I usually pull start on first start of day and then pedal start when I'm riding-I shut motor off and pedal by pedestrians and other bikes on the trail and restart after I pass them.

 

[Ghost0]

I agree that a quality, compact pull start would be cool. The problem is the SBP R&D department already has a full plate. Maybe the Manic Mechanic can take on the challenge. He sounds like he is buys too though.

 

[AussieSteve]

I considered a pull-start, but had heard that they fall apart quickly.
Also, I wasn't sure how a pull-start would go with the hi-comp head.
The other issue, as mentioned above, is the width.
If there was a good slim one on the market, with a decent ratio for starting with the billet head, then like Fabian, my credit-card is at the ready.

Had my first spin with the shift kit yesterday. No problems, everything is working well. Wow, what a difference. Only had a short ride, to let things settle a bit. A quick chain adjust etc and I'll have a decent ride later today and give it a real test.

... Steve

 

[Fabian]

Ok, so there is some consensus that manufacturing a compact slim line pull start is economically viable - 2 people with credit cards at the ready!

Someone, please manufacture a decent pull start and get it happening ASAP!

I'm going to create a new thread, calling for manufacturers to create a compact slim line pull start and a new design multi plate wet clutch.

Fabian