Topic: Time to freshen up the F Model bracket bike

[dragracer]

The electronic kill appears to be a "one shot" circuit: it outputs a pulse of the same time duration, whether the shift button is depressed for 2 milliseconds or 2 seconds. My question is what sets the time the shift solenoid is energized? Your thumb? The solenoid takes time to operate, and the air cylinder also takes time. If, for example, the solenoid takes 10 milliseconds, and the cylinder takes 30 milliseconds, the button needs to be depressed for at least 40 milliseconds for the shift to complete.

I'm sure thats correct in terms of the way each reaction. I feel thats the reason the air shifter instructions recommend that you make the line to the air kill longer than the line to the shift cylinder. 6" is the number if i remember right.

[scottly]

I'm wondering if the same type timer could be applied to the shifter solenoid? Might not be necessary with the proper kill timing??

[dragracer]

I'm wondering if the same type timer could be applied to the shifter solenoid? Might not be necessary with the proper kill timing??

Correct, if the overall kill time is increased, both components will have sufficient time to complete their individual task. However, If the engine does not "kill" long enough to unload the pressure on the transmission, then the full throttle shift cannot happen when the air cylinder pulls the shifter up to the next gear change. An improperly timed ignition kill for tranny "unloading" can only result in an inability to force the upshift.  Sequencial kill/shift timing is a must. 

Crazy how this thing has worked fine in all those years. I feel there is something other than the air shifter components causing my problems. Heck, its got all new parts now and i've tested each for correct operation. I'm going to take a long hard look at the shift pawl operations in rotating the drums once i pull the shift forks out of the way. There is something simple going on and i have to work through it till it get it right or i'll be parking the damn thing in the corner again. It might stay there a long time this go round.

The shame is, its a true 10.xx second 1/4 mile dragbike and i can't successfully get it down the dragstrip anymore.

[POPS 911]

FRANK: They all talk numbers !!!! Little number lesson from last weekend at my home track = 300lb. rider on a all motor " GOT BRUCE " KZ motor running 8.90 w/ throttle stop...... can run 8.20 on spray same rider and with my 155lb. rider 7.90s.  These are the folk I have to run late in the year [ all one class ] 1/8 mile.  Me and the Turtle ran 11.90 twice and I dial 11.88 the other lane "A GOT BRUCE BIKE " KZ dial in 5.60 w/ great air and track. My light .073 his light .108 = he ran 5.613 and me a 11.878, I lose. The other racer watched at the big end and asked why did you not look back and lift = my answer I never look back and like can you see .002 of a second   First time in 20 year I did not win a big event at my home track......... went only 5 times this year!!!!

[madmtnmotors]

can you see .002 of a second

Amen!

[scottly]

What is the status of the transmission?

[dragracer]

Good question Scottly. I got the cases split and don't see anything obvious thus far. Shift forks look good and the drum seems fine. No sign of wear on the undercut dogs. I'm still going to put a stock transmission in it for now but intend to replace all the outer shift mechanism's, could be something going on with the pawls etc...  Got side tracked tonight and made no progress. Will try to take a part of the day off tomorrow to get make up for lost time. Was shooting to test with Bill at Atlanta Friday night but that's doubtful given my loss of a few nights work this week so far. I will have this problem sorted out before Valdosta's race. Oh, I found an MPS kill box in my stash of parts from a previous build. Missing the female plug in but I downloaded the wiring diagram so I'll but other ends on it and go from there. At least this way I can control the kill time between shifts better.

[scottly]

An undercut trans is more difficult to shift. A stock trans is more likely to pop out of gear under heavy load. Your call....

[dragracer]

An undercut trans is more difficult to shift. A stock trans is more likely to pop out of gear under heavy load. Your call....

All true Scottly.

Fact is, i raced this bike for over 10 years with no issues from the stock, uncut tranny using an airshifter. If i can finish out the season with the stock tranny without failure, i'll be satisfied. I'll evaluate my next move over thw winter time. Likely send a tranny out to R&D or APE to have it cut this time around.

[dragracer]

Well, i got the transmission out of the cases and on the bench. Started cleaning up the mating surfaces. Will put the stock tranny in tomorrow, install another shift drum and button up the cases. Will Look through my parts for a another shift pawl set and install that also. Still shooting for testing with Bill on friday night in Commerce. I guess i'll be taking tomorrow off from work if i expect to get it done and back in the bike.

[Bill/BentON Racing]

Best sick days there is! 

[madmtnmotors]

It is a sickness!

[bwaller]

   We'll never tell!

[dragracer]

Best sick days there is! 

No guys, I'll do it right and take a vacation day. I've got a lot to burn off before the end of the year.

[dragracer]

So i never got the motor together in time to test with Bill on last friday. I did go watch him make some really good passes though. WAs gone all weekend so no progress made on my own project. I did remove the clutch hub/basket and primary gears from the input shaft tonight after searching everywhere for the tool i needed to remove the dang hub nut. Funny, i found it in my cordless impact case when i was charging the battery for another purpose. I likely out it there in case i had to remove the clutch pack at the dragstrip. Got tired and called it quits for tonight. I'll get a good jump on it tommorow night. Its got to be ready to test on friday night. I may go to race in the MIROCK super bike series at Rockinghham on this weekend if all goes well. I need seat time before the Cup race. Don't want to embarrass the crew by going out forst round.

[dragracer]

Alright, i've been screwing around with getting the cases bolted back together for 2 nights now. Why so long you might  say? Well, that was my question since i never had an  issue getting the cases to close up tight with a little gentle pressure. The only change i made was to pull my original undercut transmission out and put a stock transmission i got from one of our members  into the engine. Hmmm, light bulb came on, maybe i need to just pull both shafts out and see if the cases will close. Yeap, close right up when empty of the driveline. Okay, got to looking at the gear on the output shafts of each that meshes with the final drive gear on the sprocket shaft. Hmmm, interesting revelation, the gears do not have the same tooth pitch. I then rolled each gear around the sprocket shaft gear. Of course the original gear meshed perfectly but the stock donor gear did not even come close. Crap, i thought both were from the same model. Now i've got to figured my next course of action as i do not have the sprocket shaft gear from the donor tranny. This is forcing me to rethink using the undercut again. I'm going to take a trip back to the machiist tomorrow to get him to look at the undercut to see if he might need to back cut a few of the gears a bit more. I've changed out the outer shift pawls and mechanism with more pieces. I intend to install the MPS kill box in lieu of the mechanical kill. I'm hoping one or all of the changes will solve the shifting issue- running out of time.

Anyone have comments on the transmission differences.

[dragracer]

I need to rephrase my problem, it seems I have two different year transmissions in my possession. There is a good chance that the previous owner/(s) of the bottom end may have mixed and matched some parts as far as the transmission matching the case numbers. Definitely have an F2 clutch basket but now I'm unsure about the transmission. I got an F2 transmission from a member here  to source the clutch basket and then bought the transmission afterwards. I can only assume the entire assemble I bought at separate times was all F model. I know Honda changed final drive ratios at some point in later production. Can anyone enlighten me on my dilemma? Just looking for ways to identify exactly what I need to do and what I have in my hands. I'll admit right here that my knowledge of Honda transmissions is not strong versus the rest of the engine. I haven't torn up enough to be proficient with them- now ask me about a KZ tranny and its a different story, lol.

[dragracer]

Just looked up the fiche sheets on the HondaChopper site on transmissions and final/primary drive specs. Now I just need to identify what I have by tooth count. Learning something new!!!

[Bill/BentON Racing]

Need a gear, let me know, probably got one, Bill

[Jerry Rxman Griffin aka MuthaF'er]

630 vs 530 final drives?

[dragracer]

630 vs 530 final drives?

Using 530 now Jerry.

In counting the teeth on my original transmission, it seems I have an early model transmission, not a later F model as I assumed. Not certain what happened along the way by the previous owner(s) before I got the engine but they changed it out. I know they kept the F2-3 clutch basket. Going to see if I still have the transmission from the old, blown engine that was in the chassis when I got it from the junk yard. It should have the sprocket shaft assembly and I may swap it out so I can use the later F model stock tranny for now. I'm still riding down to the machinist this evening to get him to touch up a few of the dogs on this transmission in case I want to put it back in. Not much time left so I need all options in place to be able to make a TNT session before the race.

[Jerry Rxman Griffin aka MuthaF'er]

Get Bill to bring one back from San Diego.

Single or double row bearing?

[dragracer]

Get Bill to bring one back from San Diego.

Single or double row bearing?

If you're refer to the sprocket shaft output bearing, I  can't remember if its single or double. Will have to stop by the shop later and look.

And how much would you like to bet that at least one 915 SOHC Honda will be at this event??

[Jerry Rxman Griffin aka MuthaF'er]

I know you are referring to an Auto!? Beats finding and ordering rings?      Wonder what rods are under there?

Bill, you driving back? I can help you unload probably Wednesday. 

[dragracer]

I know you are referring to an Auto!? Beats finding and ordering rings?      Wonder what rods are under there?

Bill, you driving back? I can help you unload probably Wednesday. 

Naw, that one won't be an auto. Our friend is traipsing across the country doing who knows what when he's got a patient sitting on the operating table with a torn out heart. Time constraints will now preclude open heart surgery so a brain transplant is likely in the works instead.