SBP Shift Kit - Ratios, Speeds and Pedal-starting

[Fabian]

Steve, i'm glad you never had trouble starting the engine with 142 PSI of compression but when i put the billet head on my standard engine with 115 PSI, the effort needed over the 20 or so meters to get it going nearly had me taken to the Prince Alfred Hospital for emergency resuscitation.

My next door neighbour came outside, wanting to know if i needed an ambulance as i was almost passing out on the nature strip from a Lance Armstrong effort on a Tour De France hill climb.

Fabian

 

[Fabian]

Compression release is not an optional extra - it's a required necessity!

Fabian

 

[gothicguy64]

A slimline add-on kick-start would be equally acceptable.
I'll buy two of either.

Just had my second and third rides. My carb tuning is up the s..t at the moment, so I can't wind it out much, but as I said yesterday, wow.
And I thought it turned heads before.
Previously, after sealing all of the inlet leaks, everything went over-rich, beyond slide-needle tuning, with the stock setup. Now, after a bit of port matching etc and fitting the SBP slimline air filter, it's gone fairly lean. A good sign, indicating that gas flow is much better, but I have to re-tune for a day or two to get everything right. It's suddenly much better at mid-throttle, (where it was too rich before), but won't rev out at WOT. Not bogging and running hot hot hot, so I'll go back to near standard jetting and start again.
This will be a beast when it's tuned. I'm rapt.
I'll report properly on performance when the engine is tuned.

Gearings are next after that. The ratios I mentioned earlier will improve things enormously, but equally important is the ratio spread of the rear freewheel cassette. I have 6 speeds, 14-16-18-21-24-28. Too close. I found today that everything was happier if I shifted 2 gears at a time, giving me 3-4 true gears. (Still using a LHS toggle type gear shift - waiting on my grip-shift.)
As listed in my original post, there's only 3-5mph difference between the lowest gears.
Ideal for me would be a 6-speed cassette with about 14-?-?-?-?-32 or 34 teeth.
Finding one isn't easy though. Most cassettes are 7,8,9,10 or even 11 speed and 6 speeds are disappearing. Don't want to replace the derailleur unless I really have to. I've spent too much already.
I'll post in 'Parts and Accessories' for sources of 6-speed cassettes - eBay (Oz) didn't yield useful results with a quick search.

... Steve

let me know what u need in the way of a cluster (type an ratio),ill go find u 1 in sydney an let u know cost etc .

i did mention gasman has a 180 buck disk bike its 18 speed tho ..

im using his rotor 25 bucks an my wheel with road tyre 12 bucks (k mart) its a swinn an antithorn repco tube 10 bucks(big w )...
300 bucks more an i get my cell mtx1 :helmet:

 

[Fabian]

and, the use of the optional 9 tooth jackshaft sprocket and optional 48 tooth chainwheel sprocket combined with a billet cylinder head would make pedal starting an "impossibility that simply could not be done!

 

[AussieSteve]

let me know what u need in the way of a cluster (type an ratio),ill go find u 1 in sydney an let u know cost etc .

Thanks for the offer, Brad, I really appreciate it, but I've already sorted that out with a 13-34 MegaRange cluster and derailleur. I can idle along at 5mph in 1st now - luxury.
All I need now is the 11T and 24T sprockets from SBP, for 11T to 36T, 24T to rear cluster. That'll make kick-starting 25% easier and lower my overall gearing.

Regarding a disk front-end, I can get a good quality second-hand one from my local bike shop if I need it, but for now I'm sticking with the linear pull and buying better grade shoes that don't melt at 50kph.

Fabian, as you know, I have emphysema. There's no way that I can pedal down the road to start my engine. I would end up in hospital.
I'm still kick-starting on the centre-stand. I put the RHS pedal at 2 o' clock, then one smooth push to the bottom and the engine spins over nicely, without the extra load of pedalling my body-weight. As I've mentioned, one kick with full choke and it fires once or twice, then one kick with no choke and it starts, every time. Easy, for me, so no-one else should possibly have trouble. I can't even walk 200 metres without becoming breathless, but starting my engine hardly makes me puff.
I know that this might cause the early demise of my freewheel or centre-stand, but that's a small price to pay.

 

[Fabian]

Steve, we have to swap bikes to compare pedal start heroics.

I'll fit the billet cylinder head and i want you to organise an ambulance with double oxygen supplies, just in case i suffer acute low altitude hypoxia.

Fabian

 

[Pablo]

Sorry - our real goal is to get you in shape!

Seriously we are listening.

We fully understand with raised compression engines it's a bugger to kickstart, especially after a long sit. I have the same issue with my speed bike. First and foremost - make sure everything else is tip top start mode.

Next, try the drill motor start method. I can't remember the head size - 13mm(?) - bolt that size socket up in your drill motor. Remove the magneto cover. Spin the engine right up.

Pull start - we may make some slight improvements, and we certainly have a longer spindle to have a pull starter.

For those of you with disabilities - wait for the 4 stoke shifter kit, and certainly a shaved high comp head on the 2 stroke is out.

Problem with a compression release - it's another mode of failure and it's not ideal for best engine performance.

 

[AussieSteve]

Next, try the drill motor start method. I can't remember the head size - 13mm(?) - bolt that size socket up in your drill motor. Remove the magneto cover. Spin the engine right up.

I read a post here where that method stripped the thread off the end of the crankshaft and that wasn't with a high-compression head.
I wouldn't do it that way.

For those of you with disabilities - wait for the 4 stoke shifter kit, and certainly a shaved high comp head on the 2 stroke is out.

A bit of a generalisation. Depends on the disability and the person.
I had the billet head fitted before the shift kit and, as mentioned, I have no trouble starting. I just chose to use a different method than others and the onus is on me if the HD freewheel fails.

Also, a hi-comp head is no problem unless you fit a shift-kit, because then 'bump' starting no longer works.

 

[Pablo]

Sure there is the risk of stripping the cheap threads....especially if it wasn't threaded properly in the first place. I must have missed that case, but we have done it on a couple bikes, no issues.

True enough, I meant disabilities that make kick starting difficult. Some people have weakness in the legs from strokes and such.

I was referring to shift kit bikes. Thanks.

 

[AussieSteve]

Paul, I've been trying to find that post about the stripped crankshaft thread, but can't find it again. It was buried in a thread about something else.
In my search, though, I found a couple of other instances of drill-starting but no other mentions of threads stripping. Might have been an isolated case.
The other thing mentioned in the same post was that when the engine starts it could over-rev the drill, but a bit of common sense with the throttle and that wouldn't be a problem, I wouldn't think.
We used to start the lawnmower that way. My step-father had a cruder approach - socket and ratchet. Worked OK, but more often than not the socket would stay on the crankshaft. Then he'd hold a bucket over the top of the engine and shake the h@&% out of it until the socket flew off.
Back to the point, I'd still be wary, or at least careful, of starting the high-compression engines that way. As far as I can tell, all threads on these HT engines are cheap rubbish.

There are heaps of references to spinning an engine that way with the plug out, to test for spark.

I've re-started mine a couple of times without the stand, after stalling and while the engine is still warm, by rolling down a slight hill then 'kicking' the engine over, but I can't do it on the flat.