Author Topic: CB500K1. Cafe Racer to Original...sort of!  (Read 2847 times)

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #45 on: September 27, 2017, 11:35:08 AM »
My sidecovers should be ready for pickup at the end of this week! ;D
Also have a sync kit on its way.  The leaking carbs (overflow after a day or 3) are still unresolved as #3 dumped today.  :(
Anyway, I'll sync the carbs and at a later date pull the carbs if the o/flow issue with petcock ON still occurs.
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #46 on: October 02, 2017, 11:05:01 AM »
The carb sync gauges arrived today.  Being relatively cheap I didn't expect "professional" quality and I didn't get it!  :(
The needles at rest were all in different spots so I figured there must be a way to make them all the same.  The "way" was to ease off the front faces of each gauge and "reset" the needles to the proper spot.  This done, I then set up my trusty old vacuum cleaner to provide a pretty constant vacuum for the 5mm hoses.  Fortunately, all 4 gauges read within a gnat's c0ck of each other!  8)  Unexpected roadblocks notwithstanding, I'll do the sync tomorrow.

Long story short, the original side covers are now being replaced with a set from Joe (www.fb-stuff.com) which I ordered over the w/end here, so hopefully will see them in the next couple of weeks.
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #47 on: October 05, 2017, 10:32:43 AM »
Still wasn't happy with the gauges, so borrowed my mate's Motion Pro Synchroniser to confirm what the gauges were saying.

It was interesting to watch the interaction between the carbs as adjustments were made.  I was able to get all 4 carbs pretty well exactly the same and also confirm that the gauges were close, but not quite as accurate.  I believe this type of comparison has been discussed elsewhere but it's nice to see it in the real world!

I still have this current problem though, if I restart the bike after 15min/30mins/1hr/6hrs etc. it stumbles and farts and sounds like at least one cylinder is not firing properly, if at all  ???.  It's very hard to get running 1st off.
But once it “clears its throat” it idles quite well and seems to accelerate without coughs or splutters.  Blipping the throttle, it comes back to idle without drama.

This lack of normal start has only occurred since I put some Nulon (Aussie stuff) carb cleaner in the tank, hoping at the time it may have cleared the problem with the overflow on #2 carb.  In fact #3 has started o/flowing as well!  :o

I have new hoses from the tank to the carbs, but maybe the small hoses that interconnect 1 to 2, and 3 to 4 have reacted to the carb cleaner and particles from them are now clogging the float needle(s) and maybe the slow jets ……either that or crud that has existed in the carbs before “dosing”.   In any case, a complete carb refurb seems to me to be the best approach now.
Sound like a good idea?

Cheers, Andy (aka Himble)
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline MarkCR750

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #48 on: October 05, 2017, 06:47:03 PM »
I think a carb strip down and clean/refurb sounds like a good idea Andy, at least it will rule out the carbs as the issue one way or the other, will you be sending them to a specialist or doing them yourself?
Ducati Scrambler 803.
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Ducati 900SS
CBR1000F
"Eff yir gitten awvestear yir gooin te farst"
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Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #49 on: October 06, 2017, 01:19:44 AM »
I'll do them myself Mark, with the assistance of my mate who has an ultrasonic cleaner.
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline MarkCR750

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #50 on: October 06, 2017, 09:48:43 AM »
Let me know how you go on, I often have the "starting on three" issue, after about 30 seconds the 4th chimes in, or if I take no4 airfilter off and squirt carb cleaner into the brass balance pipes it starts immediately on 4, so definitely a carb issue, float heights are all good though, never been enough of an issue to warrant a deeper look for me though, but if you find the fix I'll do the same! 😄👍
Ducati Scrambler 803.
1977 K7 CR750 lookalikey
Ducati 900SS
CBR1000F
"Eff yir gitten awvestear yir gooin te farst"
Sir J.Stewart.

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #51 on: October 06, 2017, 10:49:56 AM »
Let me know how you go on, I often have the "starting on three" issue, after about 30 seconds the 4th chimes in, or if I take no4 airfilter off and squirt carb cleaner into the brass balance pipes it starts immediately on 4, so definitely a carb issue, float heights are all good though, never been enough of an issue to warrant a deeper look for me though, but if you find the fix I'll do the same! 😄👍

No probs mate!  Following a suggestion from a US forum member, I drained all 4 carbs in turn with petcock on (actually an aux tank for synch work!) and found a fair few varnish type (very small) fragments in the capture.

I may be wrong but these bits may be contributing to the issue.  Anyway, I've definitely decided to pull the rack and completely refurbish the carbs.
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #52 on: October 09, 2017, 11:57:20 AM »
Removed the carbs and deracked them.  Have removed all jets, emulsifiers etc. and given them a good bath in Simple Green in the ultrasonic cleaner.  Amazing how much rubbish is removed with this method.

The emulsifiers were seriously clogged up but all other jets looked OK.   I've completed carbs #1 and #2 and did have to adjust the float levels slightly.  Carbs #3 and #4 tomorrow, then I'll do some further checks on float levels etc., before re-racking.
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #53 on: October 10, 2017, 11:09:01 AM »
OK, carbs have been removed, de-racked, disassembled, cleaned, refurbished, reassembled, re-racked and now on the bench for some checks before returning to the bike.
All is good….so far!

Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #54 on: October 11, 2017, 11:17:34 AM »
Carb sync....almost there!  8)

https://youtu.be/ns_NmBi9Hl4
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline MarkCR750

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #55 on: October 11, 2017, 08:56:55 PM »
Has the starting on 3 cylinders issue?
Ducati Scrambler 803.
1977 K7 CR750 lookalikey
Ducati 900SS
CBR1000F
"Eff yir gitten awvestear yir gooin te farst"
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Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #56 on: October 12, 2017, 03:10:37 AM »
Yep, runs perfectly well now Mark.  The carb cleanout/refurb did wonders it seems.  :)
« Last Edit: October 12, 2017, 10:07:02 AM by AndyH »
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT

Offline Jamesh_sussex

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #57 on: October 12, 2017, 06:05:10 PM »
Great work, well done..!!

Offline MarkCR750

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #58 on: October 12, 2017, 07:02:57 PM »
Good news Andy, I really must get mine sorted properly, trouble is every time I feel like doing the job the weather turns out good so I go for a ride on one of my other bikes instead, still winter is almost here!.
Ducati Scrambler 803.
1977 K7 CR750 lookalikey
Ducati 900SS
CBR1000F
"Eff yir gitten awvestear yir gooin te farst"
Sir J.Stewart.

Offline AndyH

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Re: CB500K1. Cafe Racer to Original...sort of!
« Reply #59 on: October 13, 2017, 01:00:36 AM »
Good news Andy, I really must get mine sorted properly, trouble is every time I feel like doing the job the weather turns out good so I go for a ride on one of my other bikes instead, still winter is almost here!.

I can relate to that!  Fortunately we're moving well into Spring here and my restoration is almost complete so rides are gonna happen!  8)   32°C (~90°F) in Perth today!
Andy

1972 CB500 Four K1 (AUS version) 8)
Previously owned..
1967 Honda Sports 90
1971 Yamaha CT2 175
1973 Yamaha RD250
1975 Kawasaki KX125
1979 Yamaha XT250T
BMW R65
BMW R80
BMW R100LT