Topic: Time to freshen up the F Model bracket bike

[dragracer]

Thanks for the link Scottly. I replaced the forks but not the drum because it looked okay to me at the time. I may need to split the cases and reinspect it if adjustment of the kill time doesn't work. Yes, it was cut up and down. If the weather cooperates, I intend to find a local track this weekend to make a few passes and will report what i come up with.

[scottly]

If the dogs are cut in both directions, either too much or to little kill time will place more load on the air-shifter. The 1-2 shift takes much more travel than the other up-shifts at the lever, so I would rule out the linkage as an issue before resorting to splitting the cases.
Please post a side view of the shifter, so we can see the geometry of the linkage.

[dragracer]

Will do. I had to redo a bracket for my footshifter. I misplaced the original aftger taking pics of it for Bill. I'm certain i left more than enough travel but i'll let you take a look too. The more eyes on the problem the quicker the solution.

[dragracer]

Scottly,

One pic shows the shifter and air cylinder in the normal position. The other, with my hand present, shows it extended for the 1-2 shift.

[scottly]

The angles and travel on the shifter look good. When you get a chance to test the bike on a track, try manually shifting from 1st to 2nd, in a slow and sure manner, and see if it pops out. If it does, it's a trans problem. If it doesn't, it's an air-shifter issue. Can you alter the timing of the cylinder independently of the kill time?   

[dragracer]

The angles and travel on the shifter look good. When you get a chance to test the bike on a track, try manually shifting from 1st to 2nd, in a slow and sure manner, and see if it pops out. If it does, it's a trans problem. If it doesn't, it's an air-shifter issue. Can you alter the timing of the cylinder independently of the kill time?   

Delay can be manipulated by changing the length of the air lines. Its not a problem manually shifting the bike under a light load- it stays in gear. Its not really set up to footshift in race mode.We'll see what happens after i adjust the kill time.  I'll be inspecting my shift pawls also before pulling the motor.

[scottly]

Frank, you need to determine if you are missing shifts or popping out of gear: two different issues... If you shift under light load, and it stays in gear under a heavy load, the issue is with the air shifter. I was under the impression you had an electronic timing devise on the shift button?

[dragracer]

Its a basic electric over air system. The length of air line to the kill and to the air cylinder can change the synchronization between the 2.

[scottly]

The basic system I'm familiar with kills the ignition the instant the shift button is pressed, but the air solenoid has an inherent delay, both in engaging and releasing, and the cylinder has a delay as well. Perhaps you are expecting the SOHC trans to shift as fast as a newer bike? They are clunky transmissions, and do require a 100 milliseconds or so to lock in after a gear change...   

[dragracer]

The basic system I'm familiar with kills the ignition the instant the shift button is pressed, but the air solenoid has an inherent delay, both in engaging and releasing, and the cylinder has a delay as well. Perhaps you are expecting the SOHC trans to shift as fast as a newer bike? They are clunky transmissions, and do require a 100 milliseconds or so to lock in after a gear change...   

That air shifter has been on the bike from the day i built it- over 16 years ago. Never really had any problems with it shifting the bike. It might be time to replace the air cylinder. Lots of possible explanations for the bike not shifting. I'll work to eliminate them one at a time. You've been very helpful to me thus far.

[scottly]

I just recalled an issue with the air cylinder operated spindle brake on my CNC mill: The brake was slow to apply, and worse yet was slow to release. The problem ended up being the solenoid. Based on that experience, I would consider the solenoid first.

[dragracer]

I just recalled an issue with the air cylinder operated spindle brake on my CNC mill: The brake was slow to apply, and worse yet was slow to release. The problem ended up being the solenoid. Based on that experience, I would consider the solenoid first.

I usually run WD40 through the systems every year. I didn't do it this time. It helps clean out moisture byproducts from the system and can help renew sealing to eliminate minute' air leaks. Also lubricates the air cylinder.

[scottly]

The solenoid on the Bridgeport was merely gummed up; I was able to take it apart, clean and lube the piston, and put it back together. That was at least 15 years ago. WD 40 tends to dry out in a short amount of time. Perhaps a fresh shot will help?

[dragracer]

I'll be ordering new air shifter parts tomorrow. I think i may have a faulty air kill assembly. Easier for me to bolt on parts than to pull that darn motor and split the cases right now. Its getting cold so not but a few races left before the season is over for me. I'll then have a lot of time to yank the motor to inspect the tranny. I'm just thankful that my friends on here pushed me to get it back up and running so i could have my SOHC at the race with my team mates, Bill and Sam. The rest will be easy and she'll be ready and completely tested before the 2014 race season kicks off!!!!!!. It'll be on the rider to perform at 100%.

[dragracer]

Getting ready to race a Camaro this past saturday at Orangeburg Dragstrip. I lost this round to a redlight, plus the damn thing spun the tire and had me sideways. Still ran a 6.83 on my sandbagging 6.80 dial in. I got to put a Shinko Hookup on that bike by next season.

[Sam Green Racing]

Would love to see what Samauto would do over the 8th with the right gearing you'll have to DRAG him down there Frankie. 

Sam.

[dragracer]

Would love to see what Samauto would do over the 8th with the right gearing you'll have to DRAG him down there Frankie. 

Sam.

We've had Bill come down to race with us once Sam. Samauto was still being sorted out then. I know it'll do much better now with the bigger motor and more seat time.

Next season, our CSRA Dragbike Association will hold at least 4 ET points races at Carolina Dragway. I'm hoping Bill will come to a few of them.

[jweeks]

Sam,
     With a proper launching rear brake, running it through 2 gears in 660', you may get the front end a little light. Just a guess at around a high 7.5/low 7.6? It should launch with a low 1.9 60' time when the brakes work correctly. 

Frank,
     You ran the bike again... Longer engine kill with same results? Weather down there must be frustrating for a racer...

                                                                    Jon W.

[dragracer]

Sam,
     With a proper launching rear brake, running it through 2 gears in 660', you may get the front end a little light. Just a guess at around a high 7.5/low 7.6? It should launch with a low 1.9 60' time when the brakes work correctly. 

Frank,
     You ran the bike again... Longer engine kill with same results? Weather down there must be frustrating for a racer...

                                                                    Jon W.

Jon,

Yes, i took the bike out again. I think i have a faulty air kill assembly as the bike failed to shift into all gears a few times during each run. I'll test it in the shop this weekend but think I'm just going to switch out the kill and see what happens when the weather breaks. One thing about the south in the winter, if you wait a few days, it'll go from right at freezing into t-shirt weather. Most tracks are open year round down my way with the exception of the time from Xmas to New Years. If its 50 degrees and warmer, its race time!!!. If this air kill replacement doesn't work, i'll pull the motor later and replace the drum, pawls and shift forks.

I took a good look at that rear tire and its cracking in places. Although it was new/used, it could have been a leftover tire from who knows how long. I had it over a year myself before it ever hit the dragstrip. Its one of the Mickey Thompson MC2 shootout tires. I've used them successfully in the past but they've always been from a fresh batch that season. I'm going to wait til the beginning of the season and get a fresh Shinko Hookup tire like the one on my old KZ Crazy 8's bike. I'm not used to that bike not hooking up- that little 5.5" MT slick has spoiled me.

[dragracer]

Alright folks, i finally found a little motivation this tonight to start putting the transmission parts back in the motor. I used the thickest center fork i could find in my stash, put in another shift drum and fork rod. Got it all buttoned up and ready for the covers that i intend to install tomorrow night. Also got my new Shinko hookup tire to replace the Mickey Thompson shootout tire since i couldn't get it to hook. Although the MT was new when i put it on the bike, it had been sitting for almost 2 years and the compound deteriorated. Hopefully the Shinko will be okay. I've got the same tire on my KZ and i've been 8.60's @156mph with it with a 1.38, 60'.

Hoping to get the motor done and on the frame by wednesday and complete it all and running by friday. Got a race i want to run it in on saturday.

See Bill, the more you do on yours, the more motivated i am to work on mine.

[dragracer]

I think the tire meets the shop puppy's approval.

[Bill/BentON Racing]

K. I see bling... Anodized APE manual tensioner! Haha, go Frank, working on mine sometime today!  79 days to Valdosta!

[TurboD]

Good to hear. That Shinko is my first choice.

[dragracer]

K. I see bling... Anodized APE manual tensioner! Haha, go Frank, working on mine sometime today!  79 days to Valdosta!

Well, since it didn't come in flat black, I had no choice but to leave it nice and shiny- it might be bling but its hidden from view. Lol.

[dragracer]

Good to hear. That Shinko is my first choice.

I never had a problem with the MT shootout tire until this one- i got a great deal on it when it was bought. I can only attribute my traction problems to the age of the tire. Shinko's are the best bang for the buck if you need a sticky tire for racing. They're inexpensive and last longer than some of the other performance tires. I use the 180 cause it spreads out on the wider rims to give a better footprinton the track. Too bad those tires are made in an 18" size. If this one doesn't work for me then my next step is to look into buying some progressive rate shocks with rebound and dampening adjustability. I could be shocking the tire on launch causing it to unload at the hit.