Author Topic: Another dragbike project. Kawasaki based wheelie bar bike  (Read 3032 times)

0 Members and 1 Guest are viewing this topic.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #25 on: July 29, 2023, 01:25:33 AM »
I'm still plugging away at this project.  I trying to work on it everyday. I test  mounted the ignition controller last night. I think it'll work well in this location.  I've got to order a full wiring harness for the Schnitz box and then buy some ground and primary wire. I'll  need a fuse box and a few relays. I made a panel to mount my main power switch and nitrous arming switch.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #26 on: July 29, 2023, 01:30:17 AM »
Last night I finished fabrication of a front bracket caliper hanger. Tonight i mocked up my brake lines. I've got to get some banjo bolts and a few fittings to complete everything.  I got the back brakes set up to and a line figure out. Doesn't matter how quick these things go, its more important to be able to safely stop them.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #27 on: August 06, 2023, 08:14:46 PM »
I think I've got the rolling chassis about complete. Ran into an issue with the rear brakes dragging some. I think the pads have gotten so worn its causing the pistons(4) to come out to fsr and not retract. I'm going to source some pads for this old PM caliper and hopefully be successful in locating a set. Time to move on to the engine program.  I had a take out dragbike engine i customer sold to me about 12 years ago. Its a low compression 1425cc engine. After tearing i down completely, it looks like i can use the cases and match it to a high compression 1425cc big block and i pistons i already had on hand from the wifes on bike. I stepped her up to 1500cc on the new build several years ago. I also had a nicely ported, big valve j head given to me about 8 years ago by a friend. I came across a  pair of .485 lift cams. The transmission is just undercut but i should have a 1-2-3 auto 5 speed GPZ transmission in a box. I'm not going to use the crank because I have a freshly welded Mark 2 crank ready to drop in. This week I've got to get busy ordering parts like new rings, valve springs and seals, gaskets and other odds and ends. Once the parts arrive I'll get busy building the engine. In the meantime, I'll be cleaning up the engine parts and have everything laid out to begin the process.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #28 on: August 06, 2023, 08:17:56 PM »
Glad I'm a parts hoarder. 😌

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,910
  • Bought her new 4/75
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #29 on: August 06, 2023, 09:49:16 PM »
That crank looks HEAVY! I'm used to our lightened cranks I guess
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #30 on: August 08, 2023, 06:07:24 PM »
That crank looks HEAVY! I'm used to our lightened cranks I guess

It is heavy Jerry. Its a roller bearing crank, pressed together and welded at the throws to restrain twisting. The j model and later GPZ cranks are lighter.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #31 on: August 14, 2023, 12:23:48 AM »
I had to sideline the dragbike project for the moment.  We've got the Man Cup series race this weekend and I need to work on our race ready bikes. I pushed the ugly duckling project in the back of the shop for now. I may pick at the engine parts cleanup in between the maintenance of our other bikes.

Stay tuned. It'll get its turn next week. I should have this things running by the end of August if all goes as planned.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #32 on: September 06, 2023, 11:26:01 PM »
Haven't posted in a few weeks. While at the Cup race i came across a nice looking ported head with a recent valve job. Fella was asking $450 with some small cams. It was a good price fir  j model head, with cam tower conversion and stainless stock size valves. I git budy racing as didn't think about the head again until we were loading up at the end of the event.  He had already boxed the head up but pulled it out and sold it to me for $250. Cool. Well I got home and started messing with it the next day. I typically unload all of the valves, drop a cam into the rmpty head and rotate it to be certain there's no resistance.  Dang that cam rolled great and seemingly passed my test. I was feeling darn good about the deal until i decided to check end play. The cam moved way more than it should have from side to side but most unexpectedly, it moved up and down on one end even with the cam caps tightened.  Okay. No real big deal i thought. I'll mixed and match cam caps from a spare stock head to take away the clearance.  Wrong answer. Now the cam is extremely difficult to turn. Alright, I've run into this before.  You simply need to massage the cam bearings until you get free play. I commence to playing that scenario and finally got very little rotating resistance. Cool. Ummm, maybe not so cool because the up and down play is beyond my comfort level. Tried a few more things and concluded this head will require line boring of the cam journals. Crap. Junk head. Back to my original ported head. No harm, no foul just  $250 lighter in the pocket. The cams would work great in a street motor but are much to small for anything i would ever build.

Moving ahead with the first plan.

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,910
  • Bought her new 4/75
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #33 on: September 07, 2023, 10:26:25 AM »
Keep at it Frank
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #34 on: October 16, 2023, 11:19:29 PM »
I haven't posted in a while but the bike is now completed and will be making its maiden voyage down the dragstrip in a few days. I decided to drop an engine on the chassis that i forgot was sitting on the rear of the shop floor. Its just a little 1200cc powerplant so I'm not expecting big numbers. If i see 5.90s in the 1/8th and maybe 9.50s in the 1/4 mile I'll be happy. In the interim,  I'll continue to work on the bigger engine as i sort the current package out for the remainder of the season.  One of my older brothers has expressed a desire to ride this one. He's never been on a dragbike before so the smaller engine is the best choice right now to teach him basic riding/racing skills.  I can always add nitrous to this engine if he wants to go a tad bit quicker.

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,353
  • SOHC4 member # 2605
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #35 on: October 16, 2023, 11:36:08 PM »
Frank, may good fortune smile on the bike and it's rider...
Congrats on the motor revealing itself for a new lease in that chassis.
Hope you and Gladys are well.
David- back in the desert SW!

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #36 on: October 17, 2023, 07:01:50 PM »
Frank, may good fortune smile on the bike and it's rider...
Congrats on the motor revealing itself for a new lease in that chassis.
Hope you and Gladys are well.

I've got one final thing to do before taking it out to test. I gave to remove it from the stands, start it ip and check to see at what rpm the bike tries to move on the 2 step. It has a slider clutch(centrifugal) so the 2 step rpm setting has to be just below the point the bike tries to creep at full throttle.  It usually takes a few attempts to get it right. I'll load it in the trailer and take it up to Darlington Dragway for testing on Wednesday night. 

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #37 on: October 22, 2023, 11:45:52 AM »
After all the hard work getting this thing pieced together,  i was able to load it up for a trip to test at the dragstrip. My expectations were limited to just making an "A" to "B" pass. Since this was just a  small street engine with only 1200cc,  i wasn't expecting much. I  was shooting for a 6.00, 1/8th mile ET on the shake down run. The bike did a good burnout twith the baby engine turning that big 28x10.5x15" tire so i decided to make a full pass. I had the 2 step set at 4750rpms which really was too low for that motor to move that heavy chassis. Fortunately it left the line fairly well with the transmission shifting perfectly through every gear. The bike handled well throughout the run and the brakes slowed  it down at the end of the track. I got my time slip and i was pleased to see a 6.08 ET at 110 mph. This tells me i probably let off the throttle a tad bit early. I decided not to make anymore passes last night because it was late and i wanted to check the bike over completely before the next run. I loaded up and came home. My next move is to adjust the stall springs on the slider clutch so the launch rpms increase from 4750 to around 5250- 5,400. This should lower my 60 foot time and bring the ET into the high 5 second range. I'll run thi engine for the remainder of the season while i continue to build the bigger 1425cc engine that'll eventually have nitrous oxide added.

Offline dusterdude

  • Really Old Timer ...
  • *******
  • Posts: 8,481
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #38 on: October 22, 2023, 01:31:13 PM »
Excellent frank

Sent from my SM-G973U1 using Tapatalk

mark
1972 k1 750
1949 fl panhead
1 1/2 gl1100 goldwings
1998 cbr600 f3

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,353
  • SOHC4 member # 2605
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #39 on: October 22, 2023, 03:54:27 PM »
Very nice Frank! Good to have pleasant surprises sometimes...
David- back in the desert SW!

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #40 on: October 22, 2023, 05:54:31 PM »
Lowered the stall spring height from. 780 to .720. By decreasing the spring height, it increases the tension  thereby causing the lockup arms to require more rpm  to push against the slider hat before it clamps firmly  into the clutch pack allowing the bike to move. I want at least 500 rpm more than i have now before the bike creeps on the 2 step so this theoretically should put me close to my ideal launch rpm. I'll have to put the bike on the ground and start it up to check my work since this is a centrifugal type clutch. Before I verify where i am with the slider clutch, I'm going to thoroughly go over every nut, bolt and washer on the bike to be certain everything is as it should be prior to the next track test session.  If the weather is good  Wednesday night, i plan to go to Darlington Dragway to test. I need to see a 1.29-1.31 sixty foot time to get this thing into the high 5.90 range in the 1/8th mile. I may make a full 1/4 mile pass if it feels good. I'm hoping my gearing is correct and it should net a 9.50-9.60 1/4 mile ET,  OPTIMISTICALLY speaking. Its a new build so it'll be baby steps for a while.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #41 on: October 22, 2023, 07:04:10 PM »
Me, trying to be optimistic before the maiden voyage on theUgly Duckling.

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,353
  • SOHC4 member # 2605
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #42 on: October 22, 2023, 07:34:36 PM »
She's gonna be a swan before you know it...
Sounds like she has good potential even with this smaller motor.
Glad you are having fun!
David- back in the desert SW!

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #43 on: October 22, 2023, 08:45:34 PM »
She's gonna be a swan before you know it...
Sounds like she has good potential even with this smaller motor.
Glad you are having fun!

Thanks. Its the challenge of building one from scratch and then making that 1st successful pass that keeps me motivated.  Many times you have a formula for building one and the outcome is as expected.  Sometimes you're disappointed and have to back track. Through it all, i do my best to stay focused and remain positive. I'll report back once i get it down the track again.

Offline Kelly E

  • Geriatric Hooligan
  • Master
  • *****
  • Posts: 2,350
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #44 on: October 23, 2023, 08:18:03 AM »
Me, trying to be optimistic before the maiden voyage on theUgly Duckling.

Well hopefully you have the same smile at the end of the run. 8)
I'm always happy to make it home from a test ride on a recently resurrected bike. ;D
Never Give Up - Never Surrender

The Rust Bros. Garage Collection
1974 Honda CB 550 K0                                            1971 MGB/GT
1975 Honda CB 400F Super Sport                          1972 MGB/GT
1977 Kawasaki KZ 1000 LTD                                   1985 GMC S15
1978 Kawasaki KL 250
1980 Suzuki GS 1100E
1982 Honda CB 900F Super Sport
1983 Honda CB 1100F
1984 Honda VF 700S Sabre
1984 Honda VF 1000F Interceptor
1990 Moto Guzzi 1000 Le Mans
1994 Kawasaki Concours ZG 1000A9
2005 Harley Davidson Fat Boy

Offline Jerry Rxman Griffin aka MuthaF'er

  • This MuthaF'er is getting to be a
  • Really Old Timer ...
  • *******
  • Posts: 14,910
  • Bought her new 4/75
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #45 on: October 23, 2023, 01:31:27 PM »
Frank, I haven't seen that look before haha
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #46 on: October 28, 2023, 09:48:12 PM »
We took the Ugly Duckling project dragbike out to  test today. I made a last minute decision to enter it into the bracket  race with the drag cars. We were able to make rounds and got down to one of the final 4 left in the race. Unfortunately,  a blown fuse to the 2step button/delay box ended our march into the final round. We did walk away with $100 and some valuable seat time. The bike was consistent after working out a few glitches. I think its earned a spot inside the race trailer.

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #47 on: October 28, 2023, 09:50:28 PM »
The wife was acting crew chief today and kept me safe throughout the event.

Online RAFster122s

  • I feel like a really really
  • Really Old Timer ...
  • *******
  • Posts: 12,353
  • SOHC4 member # 2605
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #48 on: October 28, 2023, 09:57:30 PM »
Congrats, glad you did well and got some seat time with the new build. She's got potential from the sounds of it. Hope the blown fuse issue is an easy fix.
You and Gladys are looking good!
Happy Halloween...
David- back in the desert SW!

Offline dragracer

  • Really Old Timer ...
  • *******
  • Posts: 5,105
  • CB750F Dragbike
Re: Another dragbike project. Kawasaki based wheelie bar bike
« Reply #49 on: October 29, 2023, 07:30:19 AM »
This is what happens when you have an electrical problem.