Carb sync & rejet....approx how many shop hours?
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
87 octane gas has more energy in it than 93 octane. That is why it can cause pre detonation on compression.
Most people believe the opposite. You should always use the lowest octane rating the motor will tolerate.
Most people believe the opposite. You should always use the lowest octane rating the motor will tolerate.
Senior Member
Superstock
Joined: Jul 2007
Posts: 433
From: Los Angeles & Winston Salem
Why not just learn to do the job yourself? It's not the most difficult job to do on a superhawk. If you are methodical, and work carefully you will be rewarded for you do work. Only basic mechanics tools are needed. Nothing special, just a clean area to work in.
1, Best to do this with little gas left in your tank, not hard to accomplish on a superhawk.
2, remove seat.
3, remove gas tank, carefully remember where each hose goes (take pictures with cell phone)
4, remove Airbox
5, now you have access to the the carbs, carefully disconnect throttle. And very, very carefully remove choke cables. They are made of plastic and easily break.
6, loosen rubber carbs clamps and pulls up on carbs.
7, now study the carb thread, and carefully remove one carb at a time the float bowl, clean jets and read jet sizes, all you are really looking for is the main jet size and pilot jet size. If you decide to remove the the carb tops go slowly and carefully so as not to damage rubber diaphragm. Best to clean one carb at a time , as some parts are for the rear carb and some for the front carb.
Just cleaning your carb and finding out what is in there is half the battle!
I've done this many times to superhawk carbs, and can have them out of the bike and on the bench in about 15-20 minutes. For a newbie I would say you looking at double or triple that time going slowly and carefully.
Yes, its also important to block of the pair valve. Just buy some block of plates for $25 of flea bay Honda Super Hawk Superhawk 1000 Exhaust Reed Plate AIS Smog Pair Block Off Kit | eBay
Then all you need is a plug to cap the hole left in the bottom of the airbox.
The superhawk carb its not black magic, its really quite simple once you understand how it works. Also there is a member here on this forum that sells very nice air/fuel mixture screws that allow you to adjust the mixture without having to remove the carb.
I'm sure some one will chime in. As to balancing the carbs. You a can make your own carb balancer for about $20! I have a few times, works fine for our simple twin carb bikes. Only one screw to turn in or out. Good luck with want ever route you go, personally I won't let anyone work on my bikes.
1, Best to do this with little gas left in your tank, not hard to accomplish on a superhawk.
2, remove seat.
3, remove gas tank, carefully remember where each hose goes (take pictures with cell phone)
4, remove Airbox
5, now you have access to the the carbs, carefully disconnect throttle. And very, very carefully remove choke cables. They are made of plastic and easily break.
6, loosen rubber carbs clamps and pulls up on carbs.
7, now study the carb thread, and carefully remove one carb at a time the float bowl, clean jets and read jet sizes, all you are really looking for is the main jet size and pilot jet size. If you decide to remove the the carb tops go slowly and carefully so as not to damage rubber diaphragm. Best to clean one carb at a time , as some parts are for the rear carb and some for the front carb.
Just cleaning your carb and finding out what is in there is half the battle!
I've done this many times to superhawk carbs, and can have them out of the bike and on the bench in about 15-20 minutes. For a newbie I would say you looking at double or triple that time going slowly and carefully.
Yes, its also important to block of the pair valve. Just buy some block of plates for $25 of flea bay Honda Super Hawk Superhawk 1000 Exhaust Reed Plate AIS Smog Pair Block Off Kit | eBay
Then all you need is a plug to cap the hole left in the bottom of the airbox.
The superhawk carb its not black magic, its really quite simple once you understand how it works. Also there is a member here on this forum that sells very nice air/fuel mixture screws that allow you to adjust the mixture without having to remove the carb.
I'm sure some one will chime in. As to balancing the carbs. You a can make your own carb balancer for about $20! I have a few times, works fine for our simple twin carb bikes. Only one screw to turn in or out. Good luck with want ever route you go, personally I won't let anyone work on my bikes.
Last edited by speedkelly@aol.com; Mar 6, 2016 at 09:59 AM.
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SuperSport
Joined: Aug 2009
Posts: 731
From: Las Vegas, NV
The numbers you see for fuels, when we are talking about unleaded fuel, are a comparison to the detonation resistance of a theoretic ratio of iso-octane:n-heptane in said proportion. This is because there are additional stabilizers, detergents, etc that are also in the fuel.
Iso-octane has a theoretic octane rating of 100, while n-heptane has a rating of zero. The higher the octane rating, the higher the percent-composition iso-octane there is.
It is because of this theoretic ratio comparison that the octane does not refer to the energy content of the actual fuel. It simply gives a ratio between a controlled burn versus uncontrolled explosion under compression. Furthermore, iso-octane and n-octane both share the same chemical formula but the difference in arrangement in the carbon structure of the n-octane yields a theoretical octane of -10 compared to 100 of iso-octane. However, the heating values and the flame speeds are virtually identical between the two.
Iso-octane has a theoretic octane rating of 100, while n-heptane has a rating of zero. The higher the octane rating, the higher the percent-composition iso-octane there is.
It is because of this theoretic ratio comparison that the octane does not refer to the energy content of the actual fuel. It simply gives a ratio between a controlled burn versus uncontrolled explosion under compression. Furthermore, iso-octane and n-octane both share the same chemical formula but the difference in arrangement in the carbon structure of the n-octane yields a theoretical octane of -10 compared to 100 of iso-octane. However, the heating values and the flame speeds are virtually identical between the two.
Thread Starter
Member
Squid
Joined: Dec 2015
Posts: 52
If I had a garage....or covered space to work I would go for it.
Plus, it rains here on this side of the island daily.
I still can't get over how much better the bike runs on 87 gas!!
Plus, it rains here on this side of the island daily.
I still can't get over how much better the bike runs on 87 gas!!
Last edited by 118811; Mar 6, 2016 at 04:46 PM.
Senior Member
Superstock
Joined: Jul 2007
Posts: 342
From: CA, South of Heaven
I just got this job done. I worked out a deal with my long time shop for $450. Went to pick up the bike, and the 60+ yrs old tech told me it took him 2 full days (16 wk/hrs!), disassembling the carbs at least 5 times and lots of curses to figure out the proper setup. He honored the price we agreed upon, but admitted that had to put in way more hrs than what $450 buys you these days in CA. And that's a dude that restores carburated bikes for a living.
Member
Squid
Joined: Feb 2016
Posts: 60
Yeah these bikes aren't the sort where you can go "dave uses 48 pilots and 180 pilots that will do" because apparently theyre all massively differen't and none seem to run similar or even close. i found out the hard way, im getting my carb removal and rebuild times down now i could work for a honda dealer and fix these day in day out with my eyes shut.
must have pulled my carbs a good 10 times so far, i can do it in the fading light with no issues in a quick time.
maybe 15 minutes to remove the carb from a fully built bike now.
must have pulled my carbs a good 10 times so far, i can do it in the fading light with no issues in a quick time.
maybe 15 minutes to remove the carb from a fully built bike now.
Senior Member
MotoGP
Joined: Jul 2007
Posts: 5,066
From: NYC
Killemall did you print out any of the carb threads on this forum to give to father time to have a baseline of what works? That may have sped up the process.
I am always leery when a shop tells me that. It seems to mean you owe them that money and if you return there, they will get it back from you somehow.
Yes I am a bit paranoid but I have seen it happen so have some reason. Keep an eye on that if you bring it to them to service it.
Did he write down or tell you exactly what he put in? Does it start and run perfectly?
A canopy from walmart woulda been way cheaper & you could've learned about the carbs.
Also, did you remove the pair system?
Glad you at least got it done...
I am always leery when a shop tells me that. It seems to mean you owe them that money and if you return there, they will get it back from you somehow.
Yes I am a bit paranoid but I have seen it happen so have some reason. Keep an eye on that if you bring it to them to service it.
Did he write down or tell you exactly what he put in? Does it start and run perfectly?
A canopy from walmart woulda been way cheaper & you could've learned about the carbs.
Also, did you remove the pair system?
Glad you at least got it done...
Senior Member
Superstock
Joined: Jul 2007
Posts: 342
From: CA, South of Heaven
Hey Smokinjoe, thanks for the reply. No I didn't print the baseline but i'll do it now since I want to take the bike back to the shop. I'm not happy with how it runs. It starts great and accelerates with no dips but when running it I hear quite a lot of random misfires and carbs clunking sounds. This ain't right, and I don't have the time to figure it out myself. I had a long relationship with the shop so hopefully they'll look into it for free, but this time I want a dyno run and A/F readings. The tech told me that in order to do that he has to drill the pipes to place the sensors in. Are there any alternative methods you are aware of? Could be the 91 oct fuel I'm running? Thinking to test it with 87, I read some dudes reporting it runs better with it.
I'm not sure the setup I have right now on the carbs. He was supposed to let me know but never did, so one more reason for me to go back. He did tell me that he had to use different jets for the front and back carbs. The explanation was that the front cylinder tends to run a beat leaner due to the better cooling. Is that also typical for the SH? Sounds a bit odd to me.
The pair system was eliminated yrs ago when I got the bike.
(Sorry OP for hijacking the thread, didn't mean to, I actually posted in the sticky but nobody replied)
I'm not sure the setup I have right now on the carbs. He was supposed to let me know but never did, so one more reason for me to go back. He did tell me that he had to use different jets for the front and back carbs. The explanation was that the front cylinder tends to run a beat leaner due to the better cooling. Is that also typical for the SH? Sounds a bit odd to me.
The pair system was eliminated yrs ago when I got the bike.
(Sorry OP for hijacking the thread, didn't mean to, I actually posted in the sticky but nobody replied)
Senior Member
Back Marker
Joined: Nov 2012
Posts: 211
From: Henderson, NV
Hey Smokinjoe, thanks for the reply. No I didn't print the baseline but i'll do it now since I want to take the bike back to the shop. I'm not happy with how it runs. It starts great and accelerates with no dips but when running it I hear quite a lot of random misfires and carbs clunking sounds. This ain't right, and I don't have the time to figure it out myself. I had a long relationship with the shop so hopefully they'll look into it for free, but this time I want a dyno run and A/F readings. The tech told me that in order to do that he has to drill the pipes to place the sensors in. Are there any alternative methods you are aware of? (Yes, there is but not everyone has the old school tail pipe sniffers.) Could be the 91 oct fuel I'm running? Thinking to test it with 87, I read some dudes reporting it runs better with it.
I'm not sure the setup I have right now on the carbs. He was supposed to let me know but never did, so one more reason for me to go back. He did tell me that he had to use different jets for the front and back carbs. The explanation was that the front cylinder tends to run a beat leaner due to the better cooling. Is that also typical for the SH? Sounds a bit odd to me.
(This is the way the SH comes stock, 175 ft, 178 rr)
The pair system was eliminated yrs ago when I got the bike.
(Sorry OP for hijacking the thread, didn't mean to, I actually posted in the sticky but nobody replied)
I'm not sure the setup I have right now on the carbs. He was supposed to let me know but never did, so one more reason for me to go back. He did tell me that he had to use different jets for the front and back carbs. The explanation was that the front cylinder tends to run a beat leaner due to the better cooling. Is that also typical for the SH? Sounds a bit odd to me.
(This is the way the SH comes stock, 175 ft, 178 rr)
The pair system was eliminated yrs ago when I got the bike.
(Sorry OP for hijacking the thread, didn't mean to, I actually posted in the sticky but nobody replied)
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