Will I get my 100 ready in time for Taupo?

[jasonu]

Why you guys waste your time with the MB stuff is way beyond me. If it was any good don't you think more people would be using it?

[kel]

Why you guys waste your time with the MB stuff is way beyond me.

You know you want one! Might as well have Chris off load that pointless hoard of old KE motors.

[F5 Dave]

My H was stoneax reliable. People don't build 2 strokes, they buy FXRs. Don't want to follow the crowd.

Anyhoo I have the new piston, just getting it honed. Kart guy reckons the Kart tech rings are less supported at the tips & the Yam ones never break tips ever, the tech ones occasionally on real high rev'rs. Looked like a bit of chamfering at the boostport which I'd assumed happened after the tips came off, but he pointed out that there was no 'gap' where the tips were gone so it happened when the ring was new. We'd gaped a size up ring so it might have been too tight. Yam rings have heaps of ring gap so that won't be an issue this time.

[jasonu]

You know you want one! Might as well have Chris off load that pointless hoard of old KE motors.

any suggestions as to what to do with that worthless stuff...

[F5 Dave]

Don't sell it, keep it for when that coal burner turns out to be rubbish & sound dreadful.

[Grumph]

My H was stoneax reliable. People don't build 2 strokes, they buy FXRs. Don't want to follow the crowd.

Anyhoo I have the new piston, just getting it honed. Kart guy reckons the Kart tech rings are less supported at the tips & the Yam ones never break tips ever, the tech ones occasionally on real high rev'rs. Looked like a bit of chamfering at the boostport which I'd assumed happened after the tips came off, but he pointed out that there was no 'gap' where the tips were gone so it happened when the ring was new. We'd gaped a size up ring so it might have been too tight. Yam rings have heaps of ring gap so that won't be an issue this time.

From memory there isn't a lot of the original reed housing left on your barrel...I'd reckon that box lends quite a bit of stiffness to the std casting.
Cromwell said to the house of commons "I beseech you in your bowels to consider you may be wrong"....There are people on here who are getting good HP without case reed mods.
And no - i didn't know Cromwell....old but not that old.

[speedpro]

With the KT piston and rings don't forget that you buy a piston and size the bore to fit, then fit the correct size ring for the bore, typically one size up from that marked on the piston. It isn't like the jap pistons and oversizes where the numbers match. I check the end gap and if it's big go up one size ring and check the ring gap again.

[speedpro]

We use MB engines because they are small and light and the sweet MB50 6-speed gearboxes go straight in. Nowadays in the light of recent tuning knowledge the cylinders limit things a bit with limited port T/A and achievable blowdown with the single exhaust port. I have a twin port motor running, not your standard bridged port setup, at the moment which is running reliably but only making lowish power. Plenty to try on the dyno yet. Plus I have a triple port cylinder which is a long way off running but should be interesting with knowledgeable input.

[husaberg]

They were the best of what was available. esp back in the 100cc days
the major limit i see now days is the cylinder stud placement and as mike said the exhaust and Cylinder reed i have a RSV copy set up in front of me with triple exhaust beautiful transfers but if one was to be attempt to be fit one to a MB there would be very little Honda left in the crankcases.
Its going to be a struggle to fit one to the much larger NSR.

The MB/H100 is a Robust little engine and Mikes make 300HP/liter Which is impressive by any standards.

[F5 Dave]

With the KT piston and rings don't forget that you buy a piston and size the bore to fit, then fit the correct size ring for the bore, typically one size up from that marked on the piston. It isn't like the jap pistons and oversizes where the numbers match. I check the end gap and if it's big go up one size ring and check the ring gap again.

yes & yes that's what we did with the next 0.1 size up ring, but it appears the ring gap may have been insufficent even when gapped to typical KT clearance. I'll check whatever Yamaha gave me this time & not run it any tighter & see if we can get this working ok.

Heck I was pulling 24hp with the YZ piston, leaking cases & a reedblock that was a dirty big hole & pointed into the crank webs with little area above the webs to flow & the side 1cm edges of the reed bigger than the crank so hitting metal. With a shorter tract & flowed reedblock the correct size, aimed below the barrel in sound cases with a much better shaped head, a piston with thinner ring & transfer bottoms rounded off this time (gave my old H 1hp when Sketchy did it) I had been expecting to get some 1/2 way decent power.

My original wc'd MB barrel I did 16 yrs ago had a triple ex, just it leaked like a sieve with a hole in it.

I'm up at 4 in the morning planning restarting a WC head (well its a std one cut down but needs finishing), but its all just a bit pointless if I can't keep the basic plot together.

Another GP a year older & a bike that isn't going to be up there in the pwr stakes. (not that I've finished the GP on this bike yet).

[koba]

From memory there isn't a lot of the original reed housing left on your barrel...I'd reckon that box lends quite a bit of stiffness to the std casting.
Cromwell said to the house of commons "I beseech you in your bowels to consider you may be wrong"....There are people on here who are getting good HP without case reed mods.
And no - i didn't know Cromwell....old but not that old.

Valid thoughts.

My next step had been rattling around in my head lately.

To use the RS frame I have I need to change engines or make the MB100 fit.
Making it fit is major work, it may be possible without going to a case reed but will certainly be damn difficult.

I imagine Dave's case reed builds will have started motivated by power but in light of Mike and others being pushed by big ponies (while using the standard position) I guess it's more about packaging (in an RS frame) than power now.


EDIT: Thankfully we are likely have better treatments for beseeching stubborn bowels than whatever was used in Cromwell's time!

[TZ350]

To use the RS frame I have I need to change engines or make the MB100 fit.Making it fit is major work, it may be possible without going to a case reed but will certainly be damn difficult.

If its the carb thats getting in the way, you could try one of these 24mm Tillitson HL360A's, they are very compact and easy to tune.

[F5 Dave]

Actually that may not be a bad sort of idea. the carb is considerably in the way. I've seen Diesel's shock & wasn't prepared to go that way & I'd considered knocking a frame rail out but it is major work to both frame & SW. I've also considered linkage in conventional manor, but the SW is too narrow.

[Grumph]

Valid thoughts.

My next step had been rattling around in my head lately.

To use the RS frame I have I need to change engines or make the MB100 fit.
Making it fit is major work, it may be possible without going to a case reed but will certainly be damn difficult.

I imagine Dave's case reed builds will have started motivated by power but in light of Mike and others being pushed by big ponies (while using the standard position) I guess it's more about packaging (in an RS frame) than power now

Invert the bastard - and reverse the barrel.

[TZ350]

Team ESE RS/GP125's use the original rear Honda engine mounting position (un modified) and hang brackets from it that pick up the rear top and bottom mounts on the engine case. The front uses an original piece of the Suzuki frame and the Honda RS frame gets a rubber vibration bush and is heavily re inforced where the front engine stay stay plate bolts onto the frame.

I will see if I can take some better pictures of how Av's and NedKellys engines are mounted in their frames when I get back to work Wednesday.