Instant red lining in neutral

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LC Cnd
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Re: Instant red lining in neutral

#31 Post by LC Cnd » Thu Jul 14, 2016 3:21 am

Yep, the choke tube was in place. Pulled apart the carbs and one float appears to be oh so slightly higher - time for a measurement. Purchased some 3 bond for the reed gaskets today. Kinda messing with a few issues at once with this thread. House reno's took priority over the last 48hrs. Kinda of a tease when my carpentry tools are beside from my benched/disasembled carbs.

hondaror
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Re: Instant red lining in neutral

#32 Post by hondaror » Thu Jul 14, 2016 11:13 am

2smoke wrote:I`m sorry but syncing carbs has nothing to do with instant redlining in neutral or a no start condition.
No one has mentioned the air screws yet. Are they in place with their springs? How many turns out?
Also, several people have mentioned the choke tube that connects the carbs but you haven't replied if its in place or not. Its a crutial piece.
Yes, we did get off topic. This is just as important. Badly sync'd carbs do pose a hard start situation, so there is some correlation.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

LC Cnd
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Re: Instant red lining in neutral

#33 Post by LC Cnd » Thu Jul 14, 2016 6:58 pm

Rory did you purchase the single (4025) or double carb reading (4027) balance? They are available at Lordco & cheaper than Ebay or Amazon by an average of $20 - because of shipping online cost. Surprise.

hondaror
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Re: Instant red lining in neutral

#34 Post by hondaror » Thu Jul 14, 2016 9:46 pm

Dual carb sync out of PA for $35 cad. They are all basically the same. From Moorepartssource.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

seahorse
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Re: Instant red lining in neutral

#35 Post by seahorse » Fri Jul 15, 2016 5:54 am

hondaror wrote:
2smoke wrote:I`m sorry but syncing carbs has nothing to do with instant redlining in neutral or a no start condition.
No one has mentioned the air screws yet. Are they in place with their springs? How many turns out?
Also, several people have mentioned the choke tube that connects the carbs but you haven't replied if its in place or not. Its a crutial piece.
Yes, we did get off topic. This is just as important. Badly sync'd carbs do pose a hard start situation, so there is some correlation.

As I said syncing carbs need to be done first. It has everything to do with it.

Syncing carbs does not just mean synchronising the slides so they lift at the same time.
Its everything, including ensuring pilots, mains, emulsions, needles, are clean the right size and setting. The cutaways are they the same? The float heights need to be spot on, the clear tube method is better than the measurement method.
The throttle stops, as mentioned are probably the most important to be set correctly before anything, then and only then do you finally Sync the slides so they lift at the same time.
A one eigth drill bit is close to a base setting, mark the screws with a dob of paint and keep them identical in or out as your increasing or decreasing idle.
As suggested misplaced or ill fitting vac or choke tubes are a bad thing.
Its pretty simple, for it to be achieving 8thousand revs at idle, its either on the edge of fuel starvation, sucking huge gobs of air, the throttle cable is stuck, the slides are stuck, or the slides are not returning to bottom idle position.
I think its the latter. ( which will be discovered when you sync the carbs).
81 RD 250 LC Hybrid .Widened frame with Aprilia RS250 Back end & Front end, strokd RZ 421, Kennys TSA's, 31KVM26SS Carbs M-360 P-25 ALBA Ndl Pos 3, Air 1.3/4
81Rd350lc resto 2016
81 Rd250lc resto 2017
1999 ZRX 1100

LC Cnd
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Re: Instant red lining in neutral

#36 Post by LC Cnd » Fri Jul 15, 2016 12:18 pm

Thank-you Seahorse for the ck list - appreciate it and will work it thru. Did discovered a variance in the needles I installed purchased fm Economy Cycle. I kept the OEM originals completing the carb re-build. The OEM needles are longer (2-3mm) and the tappering is wider to the tip(s). Cleaned the OEM needles and swapped them back in. Don't believe it effected the idle by the thousands but may have some effect. A bike mechanic bud of mine suggest I go back to the originals. We'll see if it make any dif. Back to the ck list this evening.
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seahorse
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Re: Instant red lining in neutral

#37 Post by seahorse » Fri Jul 15, 2016 8:46 pm

The OEM needles are definitely the preferred items to use.
5K1?
Are the Keystar marked the same
81 RD 250 LC Hybrid .Widened frame with Aprilia RS250 Back end & Front end, strokd RZ 421, Kennys TSA's, 31KVM26SS Carbs M-360 P-25 ALBA Ndl Pos 3, Air 1.3/4
81Rd350lc resto 2016
81 Rd250lc resto 2017
1999 ZRX 1100

yam4l0
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Re: Instant red lining in neutral

#38 Post by yam4l0 » Sat Jul 16, 2016 6:27 am

AFAIK the Keyster kit KY-0346 shown in your photo is for the early 4L0-00 carbs, they are supplied with 160 main & 27.5 pilot jets.

The kit for the later 4L0-01 carbs are KY-0551 supplied with 220 main & 22.5 pilot jets.

Keyster needles are not stamped with the Mikuni numbers but their own numbers.

LC Cnd
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Re: Instant red lining in neutral

#39 Post by LC Cnd » Sat Jul 16, 2016 1:39 pm

So, wrong kit to start out with? Suspect time will tell. Ck'd the Economy site and they only offer the Keyster KY-0346 kit - apart fm thr RZ one.

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2smoke
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Re: Instant red lining in neutral

#40 Post by 2smoke » Sat Jul 16, 2016 11:22 pm

seahorse wrote:
hondaror wrote:
2smoke wrote:I`m sorry but syncing carbs has nothing to do with instant redlining in neutral or a no start condition.
No one has mentioned the air screws yet. Are they in place with their springs? How many turns out?
Also, several people have mentioned the choke tube that connects the carbs but you haven't replied if its in place or not. Its a crutial piece.
Yes, we did get off topic. This is just as important. Badly sync'd carbs do pose a hard start situation, so there is some correlation.

As I said syncing carbs need to be done first. It has everything to do with it.

Syncing carbs does not just mean synchronising the slides so they lift at the same time.
Its everything, including ensuring pilots, mains, emulsions, needles, are clean the right size and setting. The cutaways are they the same? The float heights need to be spot on, the clear tube method is better than the measurement method.
The throttle stops, as mentioned are probably the most important to be set correctly before anything, then and only then do you finally Sync the slides so they lift at the same time.
A one eigth drill bit is close to a base setting, mark the screws with a dob of paint and keep them identical in or out as your increasing or decreasing idle.
As suggested misplaced or ill fitting vac or choke tubes are a bad thing.
Its pretty simple, for it to be achieving 8thousand revs at idle, its either on the edge of fuel starvation, sucking huge gobs of air, the throttle cable is stuck, the slides are stuck, or the slides are not returning to bottom idle position.
I think its the latter. ( which will be discovered when you sync the carbs).
Sounds more like a carb rebuild than a carb sync... :smt018
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

LC Cnd
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Re: Instant red lining in neutral

#41 Post by LC Cnd » Sun Jul 17, 2016 12:27 am

Actually it evolved into eliminating as many issues/suggestions that caused the race/reving idle while the carbs are apart. Replaced the mains and pilots back to 220 ect and working on the floats currently. Can't believe the port side is 25mm high - kinda explains the flooding in one exhaust but not the other as it was 23mm. Wondering if I should also clear out the crank case as it is probably contains copious amount of unspent fuel like th spanies (thx John for that insight). (sigh..) Bk to work.

LC Cnd
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Re: Instant red lining in neutral

#42 Post by LC Cnd » Sun Jul 17, 2016 9:24 pm

Discovered that one of the support posts for the floats was snapped off at the top. The float pin still remains in place but all attempt to fix it maybe with JB weld - that's later. Have a set of 31 carbs but decided to stick with a 4L0 replacement. Found the retaining clip interesting on the 31 float spring. Levelled off the floats. Tried to use looking glass/cut-aways for the carb slides but they r so yellowed they r useless. Attempted to clean/cut polish - again useless. Apart fm buying new carbs, any other suggestion getting glasses to function?
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seahorse
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Re: Instant red lining in neutral

#43 Post by seahorse » Mon Jul 18, 2016 6:01 am

Use the 31 k carbs they will work very well.
Vm26 ss all the same basically
Use the 4LO mains and pilots and I'll think you will find the emulsion tubes are the same.
Just attach a small tube and block off the right31 k vac inlet ( smaller spigot just under the right carb choke spigot).
I have a set of 31 k carbs on my 4LO they are perfect and my preferred carbs across the RZs and RDs
81 RD 250 LC Hybrid .Widened frame with Aprilia RS250 Back end & Front end, strokd RZ 421, Kennys TSA's, 31KVM26SS Carbs M-360 P-25 ALBA Ndl Pos 3, Air 1.3/4
81Rd350lc resto 2016
81 Rd250lc resto 2017
1999 ZRX 1100

LC Cnd
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Re: Instant red lining in neutral

#44 Post by LC Cnd » Mon Jul 18, 2016 4:35 pm

Gonna save the 31 carbs for the hybrid. to So, re-cap: the found the leak causing high rev's - one carb had the wrong carb slide in it, hence reversed and leaving it stuck wide open (this is not the one initially found damaged oddly). The set of carbs inherited with this project were totaly messed but I learnt alot about them through this process. Had a spare proper slide to replace it and it slid perfectly. Decided against using the uni-sync balance and went with the 5 cent popsicle sticks to balance the carbs eliminating the use of the sight glass(s). With the sticks in place as if facing the air box, I twisted the throttle slightly and watched the sticks move up & down. Initially one stick move before the other, but using the carb throttle stops, I was able to adjust so both sticks were moving in vertical unison - balance. Decided to use a thin seal of lithum grease were the carbs contact rubber on both ends to stave off any other possible air leakage there. Ck'd all tubing - tight. Reed block gaskets new and sealed. Created a vid about the popsycle sticks but couldn't load it on the thread - a pic was the best I could do. Used 220 mains and 25 pilots as I'm at sea level. Idle next - thx to all who made suggestions.
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seahorse
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Re: Instant red lining in neutral

#45 Post by seahorse » Tue Jul 19, 2016 4:54 am

Adjust the throttle stops so that they bottom out at exactly the same point on the Popsicle sticks.
Mark throttle stop screws with a dob of paint at 12 o'clock. They then should be adjusted relevant to each other forever. You have found the stopping point of the slides both up half a turn or down quarter or in an eighth or out a full turn to increase or decrease idle but they should remain the same.
Put the carbs on the bike and get all the cables sitting how they should, tighten the tops down, now get a mirror and look at the slides from the back air intake side, this is where you adjust the cables ( the cables) to get the slides lifting at exactly the same time.
The cables lift the slidess together.
The throttle stops position the bottom point of the slides to set idle.
81 RD 250 LC Hybrid .Widened frame with Aprilia RS250 Back end & Front end, strokd RZ 421, Kennys TSA's, 31KVM26SS Carbs M-360 P-25 ALBA Ndl Pos 3, Air 1.3/4
81Rd350lc resto 2016
81 Rd250lc resto 2017
1999 ZRX 1100

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