The Sensible Twin

[Grumph]

Some call it the clutch. I figure the FZR will take a bit of abuse if required.

I was surprised to do a side by side comparison to a 400 clutch. Primary gear same tooth count - 250 narrower.
Basket uses same plates - 250 again narrower.
If you wanted/needed to, you could uprate it to a 400 clutch.
Might be useful to know if your turbo ever produces enough HP...

[Grumph]

Id would agree by that was the fastest year for it, oldest bike and still won a race that year. modern mx bikes often have resonator tubes to broaden HP curves i wonder if thats what the lower half of them are. they act if the pipes longer at longer revs. plus drop a few DB's.

Probably two reasons for going well that year - Edwards got on well with it. And at a guess, Yamaha finally put the cams in the right place. They persisted with a very odd lobe center setup even in the kitted stuff.
I'd doubt if the lower joiners have any effect at all. When Yosh started marketing pipes with joiners years back, I tried them on my pipes for various things.
They work if they're at a point where the energy in the gas is still high.

[husaberg]

Probably two reasons for going well that year - Edwards got on well with it. And at a guess, Yamaha finally put the cams in the right place. They persisted with a very odd lobe center setup even in the kitted stuff.
I'd doubt if the lower joiners have any effect at all. When Yosh started marketing pipes with joiners years back, I tried them on my pipes for various things.
They work if they're at a point where the energy in the gas is still high.

I seen this the other day
http://www.factorypro.com/ some people don't want help.
Those 5 valves are either top speed or acceleration never both They could be fast through the traps but not on the laps.
Everything i have ever seen suggests, Give them decent comp and they accelerate well but have no top speed. and visa vera i dont think there is any real way arround it.
Great on the street in low tune but not on the track.
Rossi got them to get rid of the 5 valve as they wanted to win more than they cared about corporate pride.
the resonance tubes are a little different they work well at lower velocities and they have only a drilling entry hole to not effect top end. in the pic the angle to me suggests the lowers are closed in the middle. as the angle is silly.
They could have easier joined them front to back but didn't.

We could likely find out i guess someone will know for sure.
Maybe they were just there to hold the pipes together for easier fitment.

[Grumph]

Little things are getting done. Clutch cable - Phazer - arrived and fitted. Perfect length. Bar ends done. Sorry Rob - what was there I didn't like. Large rough lumps of nylon. Smaller, tidy lumps of nylon now. Pipes made. Rough enough, we'll see how it runs on them. Mounting the dinky alloy mufflers is a pain. Under the motor so SFA there to mount to. RHS will have a hanger from the bottom two screws on the clutch cover. LHS at present looks like it'll hang from the oil drain plug, LOL. It's a substantial lump of sump casting in just the right place - with a large dia screw in it.

Tank stage 1 won't be back till next week at the earliest so it's carry on with things like mounting instruments and the OE top fairing. When the new ignition arrives I'll mock up the ignition and spin it over...

Apropos of this - spinning it over - I'd seen Steve Ward starting the fleet of RS125's with a battery drill...And thought, hmm, mine's only 75cc cylinders...
The one-way socket used by RS125 owners is ex the US and quite expensive (by my standards) so I looked for an alternative.
Found a "ratchet adaptor" locally - 3/8 drive male one end, female the other, about 40mm long and 30 OD. An inline ratchet - reversible. $40 off the shelf in ChCh. Used with a 10mm hex X 3/8drive ex my set here in a drill and a long 14mm inpact socket on the other end, It'll do to spin this thing over I think.
And I can use it with any 3/8 drive socket - unlike the ones from the US.

[husaberg]

Little things are getting done. Clutch cable - Phazer - arrived and fitted. Perfect length. Bar ends done. Sorry Rob - what was there I didn't like. Large rough lumps of nylon. Smaller, tidy lumps of nylon now. Pipes made. Rough enough, we'll see how it runs on them. Mounting the dinky alloy mufflers is a pain. Under the motor so SFA there to mount to. RHS will have a hanger from the bottom two screws on the clutch cover. LHS at present looks like it'll hang from the oil drain plug, LOL. It's a substantial lump of sump casting in just the right place - with a large dia screw in it.

Tank stage 1 won't be back till next week at the earliest so it's carry on with things like mounting instruments and the OE top fairing. When the new ignition arrives I'll mock up the ignition and spin it over...

Apropos of this - spinning it over - I'd seen Steve Ward starting the fleet of RS125's with a battery drill...And thought, hmm, mine's only 75cc cylinders...
The one-way socket used by RS125 owners is ex the US and quite expensive (by my standards) so I looked for an alternative.
Found a "ratchet adaptor" locally - 3/8 drive male one end, female the other, about 40mm long and 30 OD. An inline ratchet - reversible. $40 off the shelf in ChCh. Used with a 10mm hex X 3/8drive ex my set here in a drill and a long 14mm inpact socket on the other end, It'll do to spin this thing over I think.
And I can use it with any 3/8 drive socket - unlike the ones from the US.

Wouldn't an Air Cylinder and a Impact driver be way cooler and make a better whirring noise.


i thought you would just use a sprag clutch of an old starter say off a Pitbike bendex

But off the shelf i can't picture it.

[F5 Dave]

Yeah ease of starting was a reason I didn't buy a mate's 256 Rotax GP bike, but a set of rollers or a drill starter would have fixed it. Hadn't really seen them back then. . . Circa 15 yrs back.

Being post 82 was the final nail and we don't do Bears up here really. Good chch bike.

[Grumph]

Without looking at the pics you've posted, remember that this would need to spin clockwise. Right-side kickstarts go the wrong way, left side ones are rocking horse poo.
This is the assembly. Hex end goes in drill, little dohickey in the middle is the in-line ratchet.

[F5 Dave]

Think a mate made something like that for Rogans RS.

[husaberg]

Without looking at the pics you've posted, remember that this would need to spin clockwise. Right-side kickstarts go the wrong way, left side ones are rocking horse poo.
This is the assembly. Hex end goes in drill, little dohickey in the middle is the in-line ratchet.

I thought you had joined the internet 1999 revolution and Horrarata had got broadband?
i was picturing the one way clutch of a tiny Starter motor

[Grumph]

Yeah ease of starting was a reason I didn't buy a mate's 256 Rotax GP bike, but a set of rollers or a drill starter would have fixed it. Hadn't really seen them back then. . . Circa 15 yrs back.

Being post 82 was the final nail and we don't do Bears up here really. Good chch bike.

You'd have been fit enough to push it back then Dave....
Went and looked at the SoT practise today. 3 New V4 Panigales...one being ridden by someone called Beaker...
No, not Tony Maxwell, I asked, LOL.

[F5 Dave]

Ha. Think he bought it of Maxwell

Yeah the 256 started just fine with a helper. On by yourself if you were energetic but if it failed you were stuffed. I arrived at a track day lineup sweating like Mike Tyson at a spelling bee.

I figured Holden etc always had an entourage to help.

[husaberg]

Ha. Think he bought it of Maxwell

Yeah the 256 started just fine with a helper. On by yourself if you were energetic but if it failed you were stuffed. I arrived at a track day lineup sweating like Mike Tyson at a spelling bee.

I figured Holden etc always had an entourage to help.

The old way for problem bikes was starter rollers and a 6 cylinder car.
the battery ones or the small engined ones were years later.
From memory the car was in reverse with the roller starter but Grump will remember
You needed a couple of strong lads to hold the bikke for the bit twins down while "Sheryl" reved the nuts of the VC Valiant wagon
Robert likely had more friends.

[F5 Dave]

Yeah seen those old school starters but just me in my van doing meetings it just wsnt going to work. Using TonyMacs starter at ruapuna was addictive. Foot on button drop clutch, pull it in move off. One person easy.

Nicest one was. . Memory. . . Budhas brother. . . Um, it'll annoy me, which one was Darryl, or Darren, ahh screw it but was made of ally treadplate and looked cool.

When at Paul's place couple of month back they used one of those lawn mower engines with a space saver size wheel contraptions to start the YZR . Again need a 2nd person.

[husaberg]

Yeah seen those old school starters but just me in my van doing meetings it just wsnt going to work. Using TonyMacs starter at ruapuna was addictive. Foot on button drop clutch, pull it in move off. One person easy.

Nicest one was. . Memory. . . Budhas brother. . . Um, it'll annoy me, which one was Darryl, or Darren, ahh screw it but was made of ally treadplate and looked cool.

When at Paul's place couple of month back they used one of those lawn mower engines with a space saver size wheel contraptions to start the YZR . Again need a 2nd person.

Darryl me thinks
Never met him but but i have an idea he do Alloy fab for a job.

[Grumph]

The nice stainless and treadplate ones are "Rosco" starters, originally made by an old neighbour of mine in Brighton, Ross Ennis.
His place was badly damaged in the quakes and I really must find out how he is now.
He gave up making them but his son who is/was a partner in a light engineering business in Oz took up the design and was selling them in Oz.
Ross had health probs and gave up racing too, haven't seen him for several years.
Last I heard, Ross got no royalties or cut from the ones sold in Oz...

I've fixed a couple of them in the past. Contemplated making one too. Never got around to it.
Big Rob locally has one ex Russell Bleach. Russ sold it cos it wasn't up to scratch. I went through it and found nothing.
The penny dropped eventually - it's a 24V version. Two batteries and it'll start most things.

Was at a SoT some years back with a customer bike which we were starting on rollers under his van. Britten was there for a demo.
Starting one of them from cold is probably the hardest job any set of powered rollers would be asked to do. The van struggled....