ESE's works engine tuner

[wobbly]

Three Bond 1104 Liquid Gasket Grey is available from Northern Accessories, the very best and is copied as Yamabond etc.
You must remember that ANY RTV based goop is NOT fuel resistant, so will not seal anything properly that is exposed to petrol long term.
The red hi temp RTV works well on exhaust spigots etc, even works to kill noise, when beads of it are run along a chamber.

[F5 Dave]

I got lazy getting an engine ready about 15 years ago & o-ringed the head by the chamber, but didn't have time to mill a square groove for the outer barrel so just used a smear of Loctite Red RTV & it coped great & have done ever since in a few engines as it is fine for water jackets & easy to machine a round groove, not so much the rounded corners of a square one.

[jasonu]

I got lazy getting an engine ready about 15 years ago & o-ringed the head by the chamber, but didn't have time to mill a square groove for the outer barrel so just used a smear of Loctite Red RTV & it coped great & have done ever since in a few engines as it is fine for water jackets & easy to machine a round groove, not so much the rounded corners of a square one.

That is all I have ever done too. Never let me down.

[TZ350]

My brand new 24mm pumper carb has finaly turned up. Its about 30mm shorter than the Keihin. Now the inlet tract will be closer to the 135mm that Wobbly suggested.

The pumpers adjustable jets look fun to play with too, and there are other dinky toys, like the pop off gauge for setting the needle seat pressure, which is a bit like adjusting the float height in a conventional carb.

I am looking forward to seeing if I can make this fit and tuck in out of the way any better than the current gravel scoop does.

[husaberg]

My brand new 24mm pumper carb has finaly turned up. Its about 30mm shorter than the Keihin. Now the inlet tract will be closer to the 135mm that Wobbly suggested.

The pumpers adjustable jets look fun to play with too, and there are other dinky toys, like the pop off gauge for setting the needle seat pressure, which is a bit like adjusting the float height in a conventional carb.

I am looking forward to seeing if I can make this fit and tuck in out of the way any better than the current gravel scoop does.

I was mulling over my original hideously over complicated idea to retard the disk valve timing for more top end power. The set up withith a jackshaft and a reverse rotation disk with bob weights is obviously over the top .
But with a clever shaped blade with angled cut outs with a kind of rgv power valve up and down motion you could achieve the timing changes ie retard disk timing for more top end without hurting mid range with out either much more additional complication or the additional width of the V TEC just a thought?
Either that with the right shape you could maybe try the 24/7 idea again (Probably not ideal with the pumper carb though) if the blade was shaped to reduce the duration to a level to with the engine would start and run with a taper shaped for duration at full lift.

Lastly with an air cooled single cylinder such as TZ's I asume it is better to just have a simple lapped on head with a simple lipped recess spigot seal for better heat transfer?
But I wonder if the copper to alloy head to cylinder joint could be hurting some possible aditional heat transfer.probably moot

[F5 Dave]

I was mulling over my original retarded idea to hideously over complicated the disk valve timing for more top end power. .
. . .

Here fixed that for you.

[wobbly]

TZ - you will have to run pretty low popoff, and high finger height, to get sufficient fuel into your 100cc making 30 Hp.
And I would reverse jet it from the start - 2 turns on the bottom, 1/2 turn on the top - and play from there.
You will soon get a feel for how much pump pressure to run with those settings.

[husaberg]

Here fixed that for you.

I laughed so hard I nearly wet myself
I guess like most geniuses, Your humor will only be truely appreciated after your gone.
The supermoto ride is still available Dave.

[TZ350]

TZ - you will have to run pretty low popoff, and high finger height, to get sufficient fuel into your 100cc making 30 Hp.
And I would reverse jet it from the start - 2 turns on the bottom, 1/2 turn on the top - and play from there.
You will soon get a feel for how much pump pressure to run with those settings.

Thanks for the advice, I expect to be able to try it on the dyno next week. I don't want to do anything before the next race meeting on Sunday.

I have a pop off gauge and some spare springs, it is set for 9lb now, what do you suggest?

Also I called into a cart shop today to look at their air box's, they had some neat ones with adjustable air inlets and different volumes, what do I need to look for.

[Buckets4Me]

Also I called into a cart shop today to look at their air box's, they had some neat ones with adjustable air inlets and different volumes, what do I need to look for.

A winning lotto ticket

[ac3_snow]

I spotted a pair of dellorto 22mm cabrs and I'm considering getting them and boring one out to 24mm.

Has any one done this before? I know that to do it I want to off set the hole so the bottom stays where it is and I take the material off the top/sides. Could this be done, carefully, with a drill press or would a lathe or something else be required?

[wobbly]

Easy to do in a lathe even simply by putting a spacer shim under 1 jaw ( opposite the bowl ) to get the eccentric offset needed.
Have done plenty like this - just use the fatest boring bar that will fit to reduce chatter at the tip,for a good finish.
Leave at least 0.5mm down each side to prevent leaks around the slide.

[TZ350]

........ a spacer shim under 1 jaw ( opposite the bowl ) to get the eccentric offset needed.......Leave at least 0.5mm down each side to prevent leaks around the slide.

Some carbs like the OKO are strong enough to hold in the lathe but the common die cast ones are pretty soft and easily crushed by the lathe jaws.

When we were machining old 22mm GP100 carbs out to 24mm we made up a split clamping ring.



The hole in the center was bored offset by putting a shim under one jaw, just like Wobbly suggested.



The lathe cuts more out of the carb at the thick side of the ring.



The split in the ring allows the jaws to clamp up the ring onto the carb. With a split clamp ring the carb can be held very firmly in the lathe without damage.

A carb that is bored out until there is only a minimal amount left on the sides to seal the slide flows more air than a standard carb because there is less disruption to air flow around the slide area.

Of course one would strip the carb down before spinning it up in the lathe.

[husaberg]

I spotted a pair of dellorto 22mm cabrs and I'm considering getting them and boring one out to 24mm.

Has any one done this before? I know that to do it I want to off set the hole so the bottom stays where it is and I take the material off the top/sides. Could this be done, carefully, with a drill press or would a lathe or something else be required?

I once put the slide in back to front in a early dellotto flat slide.Funny now not so funny at the time I kicked for hours.
ps Snow I have sent the package up yesterday I hope the bag is large enough.Sing out if you want a carb I have a 28mm rg250 or 500 one lurking arround.

A while back there was a set of three MVX250 carbs on trademe $60 or $80. I am pretty sure they are 24mm flat slide downdraft keihins.

Tz I should have your stuff sorted this weekend.

[F5 Dave]

And Dellorto carbs are pretty miserable. + getting jets isn't that easy

must get around to putting a keihin on my Trials bike.