bullfrog

In normal operation down a hill with the throttle off, the piston compresses a charge . . . then that charge fires and drives the piston down. We are talking idle speed charge . . . but a firing charge, none-the-less. With the compression release open, enough raw air is drawn in to the cylinder directly (not through the carb) that combustion does not happen. So the piston is not driven down by a "fired" charge. There is no power being produced by "fire" and the rear wheel rotation must "power" the piston down, resulting in braking effect. (Ever push start a balky machine? ) Ed

Jay . . . and just one more, "Oh yeah" comment. Didn't I see a pair of genuine Hodaka head braces bolted up? Which will be big time brace/stressed engine frame re-inforcements! So the front frame members will just be helping out a bit - could be A-OK. Dibbies on first position in the test ride queue! (Well, after you of course!) Ed

oh yeah, sometime why don't you take a full (direct) side view photo of the machine so we can see a sort of "engineers" view? Ed (what I said earlier about the rubber side . . . and down)

Hot dang I had fun reading all 5 pages of this thread! While the "engineer" side of me worries a bit about the combination of the "bent down-tubes" (which aren't tubes), the length of those front frame members and the hardware store variety of the aluminum bar (usually dead soft) - the "experimenter" in me is tickled pink watching this project from the side lines (and I agree that bracing to the front of the engine is a good idea . . . and further, I sure don't have any clear recommendations on how to handle it any better for low bucks on the first design iteration.) It is coming together!!!! If it turns out that the added front frame members need a tweak later . . . so be it . . . just let me know when the queue starts to form for test rides! Ed Keep the rubber side down!

Hooooboy, there are a LOT of choices! Modern bike? (which one?) Vintage/Twin-shock bike? Is there a machine from the days of yore which you still lust after? Have fun . . . and keep the rubber side down! Ed

Nice work! A very well done series of modifications! I'm curious. 1) After the mods, if you stretch string between the axle centers, are the foot pegs above, on, or below the string (by how much)? 2) What is the final wheel base? 3) What is the measurement from the front axle center to the center of the pegs? Thanks, Ed

Oops! My apologies to the harness maker! In the photo in this thread, the tool bag looks sort of angular and flat panel-like so I mistook it for a plastic affair. But when I saw it in the Norton thread (in the back ground) it was quite obvious that it was a rather well constructed leather tool bag. Once again, my apologies for the mistake!

That is a VERY nice looking bike . . . and quite effective by the looks of 'er. Is that a "tool box" on the rear fender? It has the look of hard plastic. Does it get in the way? I like the fender "skirts" on the rear fender. Keep the rubber side down! :hat:

I'm doing the same thing in a Mikuni mounted on my Hodaka custom trialer. Will have the divider plate both in front of the slide and between the slide and the engine. Just be sure there is NO WAY the plates can come adrift and hold the slide from closing. I'll be setting up with approx. 1mm clearance from the plates to the OD of the slide. Ed Keep the rubber side down!

I would sure want to hook up a timing light to establish the actual spark timing - regardless of what the timing marks "say". On vintage (points/magneto) systems on a two-stroke, either severely advanced timing (say 30-35 degrees BTDC) or severely retarded ignition timing (say 10-15 degrees BTDC) seem to result in an engine which is more willing to run backwards than a properly timed engine. In my experience, strongly advanced timing often leads to running backwards through the following process: 1) a less than energetic kick brings the piston up relatively slowly 2) spark happens well before TDC and builds enough pressure to reverse the piston travel before it reaches TDC. Voila, engine is running backwards! (with spark timing now @ 30 some degrees After TDC) Ed

. . . and while you are asking. Are there any trials in NW Arkansas or SW Missouri or Eastern Oklahoma on the weekends of Oct. 1 & 2 or Oct. 15 & 16? I've been looking, but haven't found anything yet. I know there is an AHRMA National Vintage Trial in TN on Oct. 8 & 9 - but I'll be busy with ISDT Reunion Ride that weekend. (If I'm going to drive 1,950+ miles -one way! - to attend an event, maybe I can come up with another event to cut my cost per event in half

. . . um, is there any possibility that you might have stayed in bed bit too often in the past? . . . what with the 3 year old plug, fork seals about to go . . . It does seem like getting up to go to an event was tempting fate!?

I am a vintage rider on a vintage scoot, so I tend toward the slow side too! If I might impose upon your willingness to share information just a bit further, how do you "feel" about the "gap" between 1st and 2nd? Would you like 2nd to be "closer" to 1st? Or possibly "farther" from 1st? Or maybe you like it just fine? Thanks.

As a matter of fact, my machine was a by-product of the "lighter is better" movement in about 1969/1970/1971. I believe it was Peter Gaunt who did a bunch of development work with the small bore Suzuki including the dual range transmission unit. I'm certainly keeping the differences in engine displacement/torque in mind . . . but the data requested will also be helpful. Right now I am "saddled" with "normal" trail bike ratios, but the engine has been modified to be quite effective in terms of "plonking power", immediate throttle response and ability to rev. The addition of the possibility to have a 2nd gear option in sections is terribly tempting - and being able to analyze rather completely all the data I can find on matching ratio transmissions/machines would help me decide the best proposed plan to proceed. It is already almost certain that proceed I will! But the details on exactly "how" are a bit unsettled.

Sirs: I am now continuing the