Author Topic: Salt Racer CB 750 OZ style (Read 169735 times)

Old Scrambler · « **Reply #1125 on:** March 17, 2015, 07:26:29 AM »

Inversion............not likely.........at least not a consideration until ..........Lift the floats in the carbs............make sure fuel can flow from tank to carbs as needed.........

You will be running below sea-level so yes.........larger jets

I would go down one tooth on the tranny sprocket which should get you to about 153 mph at 8000 rpm.

With richer mixture at speed the timing should be retarded from full advance so 33 or 35 sounds good.

I don't think notches on the needles mean anything at WFO..........

You must factor wind resistance that was not present on the dyno..........

Your rider may have to run the rpms up to 9,500 or more in 3rd and 4th to hold 8,000 in 5th

No piston carnage

Now you have a race-horse.............give that MJR HEAD a chance to RUN

cbornotcb · « **Reply #1126 on:** March 17, 2015, 02:04:05 PM »

Have you pulled the plugs for a look after the dyno pulls Johno ?
When are ya leaving for the Lake? , we are off Friday morning
Good luck mate, CYA lakeside
Tiny

johno · « **Reply #1127 on:** March 17, 2015, 02:43:42 PM »

It was a long day yesty,.......I was tired and excited , dumped the bike off the trailer , posted went to bed,
this morning I went to drain the carbs and tank.............walla .......no fuel, it run out of fuel on the vineger stroke, well I'll be , that explains a few things like the rapid lean off at 8,000

off to work ciao

Old Scrambler · « **Reply #1128 on:** March 17, 2015, 04:09:40 PM »

I sort-of ran out of fuel using the TM Mikuni on my Tiger Cub. Raised the float and all was well. On later observation..........the inlet at the float-needle valve was small but can be exchanged for a larger size.

My tank holds 2.2 gallons...............I made three runs and some riding back to the pits.........I figure 18 miles.........I had about 0.2 gallon when I drained the tank. I use two high-flow petcocks to the fuel rail.

Lesson.............be sure to refuel for the RETURN RUN

MRieck · « **Reply #1129 on:** March 17, 2015, 04:40:18 PM »

Quote from: Old Scrambler on March 17, 2015, 04:09:40 PM

I sort-of ran out of fuel using the TM Mikuni on my Tiger Cub. Raised the float and all was well. On later observation..........the inlet at the float-needle valve was small but can be exchanged for a larger size.

My tank holds 2.2 gallons...............I made three runs and some riding back to the pits.........I figure 18 miles.........I had about 0.2 gallon when I drained the tank. I use two high-flow petcocks to the fuel rail.

Lesson.............be sure to refuel for the RETURN RUN

That's a very important point on that WFO application. I agree with Dennis about the float height and needle height too. If you were 16:1 with 130 I'd go up to a at least to a 140.....probably 145 Johno. There is power to be made....it just needs fuel. If you get the main close I'd bring main air jets to trim it when you are there.

scottly · « **Reply #1130 on:** March 17, 2015, 07:42:04 PM »

Quote from: johno on March 17, 2015, 05:57:57 AM

Oops wrong screen, this is the AF runs, red first , jet change then yellow

If you were out of gas, that would explain the lean conditions at high RPM, but it appears to be extremely rich up to about 5000 RPM with the 115 main, and 6800 with the 130???

Old Scrambler · « **Reply #1131 on:** March 18, 2015, 07:14:05 AM »

I have yet to experience a dyno-day...............Scottly notes the graphs the concur with my thoughts.........The TM float bowls were being drained faster than fuel was allowed to enter.

Question.......are the TMs from a 2-stroke app? If so, the height and end-shape of the emulsifier tubes may direct more fuel into the center of the venturi, as opposed to a 4-stroke design. Maximum fuel-flow and maybe hotter plugs (below sea-level) should narrow your tuning to selecting the correct jets.............I'd start with 140s to be safe and be ready to go down in size. Don't worry about being rich from start to mid-range..........concentrate on the 8,000 level where you should find the best power to pull the gearing.

cbornotcb · « **Reply #1132 on:** March 18, 2015, 01:29:15 PM »

Iv'e used the TM32's on 4 stroke singles 125-145 & 175cc, gas & fuel, no probs, although my current setup on the blown 250/4 showed the limitations of the single Mikuni's ability to supply enough fuel to feed 70 hp .It does make me wonder about Johno's jetting,,they come std with 250 mains (4/042 hex)
Tiny

johno · « **Reply #1133 on:** March 18, 2015, 02:04:31 PM »

Hi Tiny,
The Mikuni's will fine, gear her down , jet her up, give her a good slappin and she should show some sense.
I think the jetting is getting close, i looked at the computer dyno charts last night and the short intake exhaust combo really cuts loose about 8,000 rpm, thinking suddenly needs lots of fuel,
Hope weather is good,
Race number is 1323 Jockey is Jamie McGregor

Will pit north end again, going sunday.
fair winds and good tides Tiny, see ya at the end of the 9 mile this year .

cbornotcb · « **Reply #1134 on:** March 18, 2015, 02:19:09 PM »

Quote from: johno on March 18, 2015, 02:04:31 PM

Hi Tiny,

Race number is 1323 Jockey is Jamie McGregor

Will pit north end again, going sunday.
fair winds and good tides Tiny, see ya at the end of the 9 mile this year .

I recon the short course will do me, & if not, we'll up the boost to 15 psi, my "other" rider is Wilso #1197
Pitting closer to registration & scrutineering this year the knees are giving us the #$%*s, except Phil's, in his case, his knee is fine, is is the Shovelhead's staged Nos system, he's looking at 160's+
I'll be the Scrutineers offsider Sunday, beer or port might get ya thru,,lol
Tiny

bear · « **Reply #1135 on:** March 18, 2015, 03:01:31 PM »

Say G'day to the one legged, hairy, flying, little badger for me Tiny.

Good luck Johno.

Cheers,
Brian

cbornotcb · « **Reply #1136 on:** March 18, 2015, 03:13:53 PM »

Quote from: bear on March 18, 2015, 03:01:31 PM

Say G'day to the one legged, hairy, flying, little badger for me Tiny.

Good luck Johno.

Cheers,
Brian

Will do

Retro Rocket · « **Reply #1137 on:** March 18, 2015, 03:16:46 PM »

Good luck Johno...

bwaller · « **Reply #1138 on:** March 18, 2015, 03:53:41 PM »

Good luck for sure guys, give er.

scottly · « **Reply #1139 on:** March 18, 2015, 05:56:45 PM »

Good luck, and have fun!

Jerry Rxman Griffin aka MuthaF'er · « **Reply #1140 on:** March 18, 2015, 07:19:26 PM »

Kick some ass Johno. Put the pressure on Dennis while you're at it....

dragracer · « **Reply #1141 on:** March 18, 2015, 09:42:16 PM »

Good luck!!!!!!! Most of all, have fun!!

mick7504 · « **Reply #1142 on:** March 19, 2015, 02:34:31 AM »

You've come ahead in leaps and bounds with Mellow Yellow over the last 12 months johnno and shown us that persistance will wear down resistance.
Good luck mate.

Bill/BentON Racing · « **Reply #1143 on:** March 19, 2015, 06:17:02 AM »

G'luck mate, make it happen, but have fun! K, Bill

sohc boy · « **Reply #1144 on:** March 19, 2015, 04:06:11 PM »

Good luck guy's , an safe riding ..... keep an eye out for the Blown 100cc of AAA Racing

Medyo Bastos · « **Reply #1145 on:** March 19, 2015, 05:02:42 PM »

zooom a zoom zooommm!

johno · « **Reply #1146 on:** March 20, 2015, 10:46:42 PM »

HI folks ,
thanks for all your well wishes, they are encouraging .

I just finished packing , and finishing the plan B suspension and swing arm, looking OK

Well, lets see what this baby can do in the desert, this week

Well Bear ! the thread is dedicated to you so I'll have a quick think of you and Sam while on the test track at full noise, just dont tell the organisers its me.

cheers boys, catch you soon

Retro Rocket · « **Reply #1147 on:** March 21, 2015, 12:17:15 AM »

Go hard Johno....

mick7504 · « **Reply #1148 on:** March 21, 2015, 02:22:32 AM »

Hook into 'em johno.
Show 'em what these Honda 4's are all about mate.

Old Scrambler · « **Reply #1149 on:** March 21, 2015, 07:23:45 AM »

Go Johno Go...................so your off to the land of limited communication. SAT-phones will do the job for the next week. You know a lot of enthusiasts and followers will be lurking-about to cheer with you and the bike's success. Your rider will need your input about how the bike likes or dis-likes certain parts of the journey to reach top speed. I hope all goes well and the shifts are smooth and firm.

News:

Author Topic: Salt Racer CB 750 OZ style (Read 169735 times)