Author Topic: Bike from scrapyard Saudi  (Read 21482 times)

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Offline Stev-o

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Re: Bike from scrapyard Saudi
« Reply #200 on: December 13, 2023, 08:36:37 AM »
The motor sounds awesome!

What else is need before a test ride?
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........

Offline Gamma

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Re: Bike from scrapyard Saudi
« Reply #201 on: December 13, 2023, 02:55:36 PM »
Thanks Stev-o
Next I plan to balance the carbs a little.  I spent quite a time on YouTube etc: trying to find out how the CR carb adjusters for this work.  Luckily I came across Mike Reicks video which explains this.  Unfortunately I’d already tentatively loosened the nut (which is actually the adjuster) and not the centre screw on one of the carbs 😬 I’ve now double checked what I’m doing so I don’t bugger it up😃
I can’t really use the bike on the road as yet, as I have no papers for her and will have to try and matriculate her which won’t be easy. But needless to say I need to check that she is running reasonably well carbs wise and take her for a quick spin around the estate to check she goes through the gears and is safe for inspection.

Offline Nightshift

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Re: Bike from scrapyard Saudi
« Reply #202 on: December 14, 2023, 05:36:41 PM »
So I checked out the CR29 carbs to see what jets are installed etc: so that I have a known starting point.  Mains were 120 and slow jets 60, needle clips in 4, as per spec. Air jets are 240, standard spec is 250. Starter jet is 40, standard is 45.  From what I’ve read about that, 40 is better.  I then statically balanced them.
Then installed them and am now working on making barbs, so I can balance them

Wow that is really creative. I'm gonna make a set of those barbs as well for mine. Very slick! Bill
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Offline Gamma

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Re: Bike from scrapyard Saudi
« Reply #203 on: December 15, 2023, 02:19:18 PM »

Offline Nightshift

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Re: Bike from scrapyard Saudi
« Reply #204 on: December 15, 2023, 02:49:13 PM »
The barbs work well😄
Sweet. Just one question for you guys with 4 vacuum gauge setups for tuning ... how do you know the gauges are calibrated to each other before you start? I was thinking I would just use 1 gauge on a 4-port manifold with ball valves on each so I can read the vacuum on each cylinder individually to eliminate this unknown. Cheers, Bill
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Offline Gamma

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Re: Bike from scrapyard Saudi
« Reply #205 on: December 15, 2023, 03:20:35 PM »
My gauges are very old, about 40 years, and I haven’t balanced carbs for about the same time.  I did swop them around between carbs whilst doing the balance to check that they were reading correctly.  But I think one gauge and selecting each carb in turn would be fine.  I’m sure that others with more recent experience would be able to advise

Offline BigAl

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Re: Bike from scrapyard Saudi
« Reply #206 on: December 15, 2023, 07:10:12 PM »
Wow Gamma, just perused your build, great story and great looking project.
1978 CB550K4

Offline Gamma

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Re: Bike from scrapyard Saudi
« Reply #207 on: December 16, 2023, 11:49:46 AM »
Thank you BigAl😃

Offline BenelliSEI

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Re: Bike from scrapyard Saudi
« Reply #208 on: December 19, 2023, 05:03:40 AM »
The barbs work well😄
Sweet. Just one question for you guys with 4 vacuum gauge setups for tuning ... how do you know the gauges are calibrated to each other before you start? I was thinking I would just use 1 gauge on a 4-port manifold with ball valves on each so I can read the vacuum on each cylinder individually to eliminate this unknown. Cheers, Bill

Bill…… my old Motion Pro instructions recommend calibration before every use. I set them up as usual but tie the 4 hoses to a multi barbed connector. Then use a single line to connect it to one vacuum nipple on an intake port. Start the bike and using the equalizing valve (small needle valves on my unit) adjust so every gauge reads the same. Pull them off the multi connector, attach to 4 intakes and start adjusting carbs.
« Last Edit: December 19, 2023, 11:25:05 AM by BenelliSEI »

Offline Nightshift

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Re: Bike from scrapyard Saudi
« Reply #209 on: December 19, 2023, 05:19:22 AM »

Sweet. Just one question for you guys with 4 vacuum gauge setups for tuning ... how do you know the gauges are calibrated to each other before you start? I was thinking I would just use 1 gauge on a 4-port manifold with ball valves on each so I can read the vacuum on each cylinder individually to eliminate this unknown. Cheers, Bill

Bill…… my old Motion Pro instructions recommend calibration before every use. I set them up as usual but tie the 4 hoses to a multi barbed connector. Then use a single line to connect it to one vacuum nipple on an intake port. Start the bike and using the equalizing valve (small needle valves on my unit) adjust so every gauge reads the same. Pull them off the multi connector, attach to 4 intakes and start adjusting.
John that makes sense. I was thinking 1 gauge with a 4-port manifold would definately be accurate, but a PITA when calibrating the carbs. Your method is better I think. Cheers, Bill
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Offline BenelliSEI

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Re: Bike from scrapyard Saudi
« Reply #210 on: December 19, 2023, 11:27:19 AM »

Sweet. Just one question for you guys with 4 vacuum gauge setups for tuning ... how do you know the gauges are calibrated to each other before you start? I was thinking I would just use 1 gauge on a 4-port manifold with ball valves on each so I can read the vacuum on each cylinder individually to eliminate this unknown. Cheers, Bill

Bill…… my old Motion Pro instructions recommend calibration before every use. I set them up as usual but tie the 4 hoses to a multi barbed connector. Then use a single line to connect it to one vacuum nipple on an intake port. Start the bike and using the equalizing valve (small needle valves on my unit) adjust so every gauge reads the same. Pull them off the multi connector, attach to 4 intakes and start adjusting.
John that makes sense. I was thinking 1 gauge with a 4-port manifold would definately be accurate, but a PITA when calibrating the carbs. Your method is better I think. Cheers, Bill

Bill…. I’ve also noticed that quite often when you adjust one carb, the one next door can change. It helps to see all four at the same time.

Offline PeWe

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Re: Bike from scrapyard Saudi
« Reply #211 on: December 19, 2023, 08:23:28 PM »

Sweet. Just one question for you guys with 4 vacuum gauge setups for tuning ... how do you know the gauges are calibrated to each other before you start? I was thinking I would just use 1 gauge on a 4-port manifold with ball valves on each so I can read the vacuum on each cylinder individually to eliminate this unknown. Cheers, Bill

Bill…… my old Motion Pro instructions recommend calibration before every use. I set them up as usual but tie the 4 hoses to a multi barbed connector. Then use a single line to connect it to one vacuum nipple on an intake port. Start the bike and using the equalizing valve (small needle valves on my unit) adjust so every gauge reads the same. Pull them off the multi connector, attach to 4 intakes and start adjusting.
John that makes sense. I was thinking 1 gauge with a 4-port manifold would definately be accurate, but a PITA when calibrating the carbs. Your method is better I think. Cheers, Bill

Bill…. I’ve also noticed that quite often when you adjust one carb, the one next door can change. It helps to see all four at the same time.
Especially 3 & 4 for me
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline Ley.Alexander

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Re: Bike from scrapyard Saudi
« Reply #212 on: June 09, 2024, 10:57:09 PM »
So I checked out the CR29 carbs to see what jets are installed etc: so that I have a known starting point.  Mains were 120 and slow jets 60, needle clips in 4, as per spec. Air jets are 240, standard spec is 250. Starter jet is 40, standard is 45.  From what I’ve read about that, 40 is better.  I then statically balanced them.
Then installed them and am now working on making barbs, so I can balance them

Very nice build! I wonder if you come any further with the jetting? I have CR29on my stock 650 engine with 4-1 exhaust. My starting point for the jetting seems very rich. I’m looking for a better starting point for the jetting.

My jets now:

120 mains, 62 pilots, YY8 needles, 2.5 slides, and 250 main airs.

Thanks in advance!

Offline Gamma

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Re: Bike from scrapyard Saudi
« Reply #213 on: August 14, 2024, 10:51:31 AM »
Not got any further yet. Been busy with other projects and family.  Hope to restart in a couple
 of months