Author Topic: Carb insulator questions... (Read 5418 times)

j2dawson · « **on:** April 04, 2015, 07:12:38 PM »

I got no replies to my previous carb question but the lack of response gave me time to research the answers so I'm going to try another question.

On my recently acquired '76 CB750A the carb insulators are not only hard as rocks but #2 an #3 are split at the engine end. I've scoured eBay and the net looking for replacements with no luck. Has anyone successfully repaired cracked insulators?

I've tried to soften them up with the wintergreen/Xylene trick but I guess they are too far gone because that didn't work.

I have to use these split ones so I'm trying to find a way to seal them.

Thanks for any help.

FunJimmy · « **Reply #1 on:** April 04, 2015, 07:18:48 PM »

If you can't source good flexible stock rubbers consider some large silicone hose. Most industrial hydraulic suppliers will stock it in various ID's. Much better than split couplers.

hondamad · « **Reply #2 on:** April 05, 2015, 01:07:40 PM »

I have the same problem , the insulators are as hard as metal. My research and feedback from rubber manufacturers that once the flexibility is lost there is no way to "infuse" a plastiser into the material. I investigating having them made but the tooling is expensive to make the piece part cost is relatively small. I will continue to progress this angle but am thinking of using Yamabond or hondabond to allow good sealing of the insulaters and the sealant should withstand the heat. If i find an answer then i will share. How about a class action approach to Honda LOL

j2dawson · « **Reply #3 on:** April 05, 2015, 03:03:27 PM »

Good luck with your quest. I'll be waiting to hear some good news from you.

jukku · « **Reply #4 on:** April 08, 2015, 04:08:12 AM »

http://forums.sohc4.net/index.php/topic,109557.0.html
I made those 2010 or 2011 and still working well.
Only got a little brownish.

flatlander · « **Reply #5 on:** April 08, 2015, 04:52:06 AM »

i found new oem insulators at cmsnl.com for my 550. don't know if they have them for your bike but might be worth checking.

Badluckhonda · « **Reply #6 on:** April 08, 2015, 11:56:39 AM »

They're still available thru Honda, also you can get them off of 4into1.com and on eBay. For around 80 bucks from all three places

j2dawson · « **Reply #7 on:** April 08, 2015, 04:31:12 PM »

Thanks but none of those site have them for 750A, only for the regular 750. If I can find that lined silicone hose I'll try making some.

Thanks for the help.

dave the welder · « **Reply #8 on:** April 09, 2015, 04:08:58 PM »

i have a set off a 77a not super soft but not rock hard either.no clue what they are worth.maybe a moderator or someone can chime in on there value

Bokeh · « **Reply #9 on:** April 09, 2015, 07:34:08 PM »

Not a moderator but I watched most parts on ebay for about a year. Still watch most matic stuff, but don't need as many parts. Take it for what its worth - Most boots (for the set), if there are not cracks that go all the way through from the outside surface to the inside that will seal usually go foar about 50. Then the price usually goes up to about 80 if they are no cracks and in good shape. They do go higher if they look great and are still plyable. Again I am only basing this off what I have seen them go for over the past year. That being said, no one here is looking to make profits, most off us try to help the other members out as they do in-turn. Great bunch here. I sold an extra set I had to a member that only had a few tiny outside surface cracks for 40 and threw in an accelerator pump valve so he could see if it was the carb problem he was trying to fix. And since he was nearby he offered to help me tune mine if I need, not to mention he has put quite a few great tips on the board as well. Great Kharma!

dave the welder · « **Reply #10 on:** April 10, 2015, 10:21:41 AM »

thanks for info

dave the welder · « **Reply #11 on:** April 13, 2015, 07:47:43 PM »

J2 got a deal for you. I will send the intake boots to you.if you can use them send me a check for $50 bucks plus shipping.if they won't work just ship them back to me.i will pay the shipping to you and you pay shipping back to me.does this sound fair to you???thanks

j2dawson · « **Reply #12 on:** April 13, 2015, 08:30:28 PM »

That sounds great Dave.

Jim

dave the welder · « **Reply #13 on:** April 14, 2015, 12:27:12 PM »

pm me your address

j2dawson · « **Reply #14 on:** April 14, 2015, 09:27:54 PM »

PM sent.

Thanks!

dave the welder · « **Reply #15 on:** April 16, 2015, 03:48:53 PM »

sent today

j2dawson · « **Reply #16 on:** April 16, 2015, 04:37:35 PM »

Thanks a lot, Dave.

jukku · « **Reply #17 on:** April 17, 2015, 09:15:07 AM »

http://www.ebay.com/itm/HONDA-CB750-1977-1978-CARBURETOR-INSULATOR-3-NOS-JAPAN-16213-393-010-/171437876012?hash=item27ea7e632c&vxp=mtr

j2dawson · « **Reply #18 on:** April 17, 2015, 02:27:24 PM »

That's not for a CB750.

jukku · « **Reply #19 on:** April 18, 2015, 09:14:32 AM »

Perhaps CB750A

j2dawson · « **Reply #20 on:** April 18, 2015, 01:11:34 PM »

Touché, what I meant was, the one on eBay has a different part number than the CB750A.

Badluckhonda · « **Reply #21 on:** April 18, 2015, 07:39:14 PM »

Jukkus suggestion of using the silicon hose seems like a really good idea. If you look at his pics the fuel flow looks like it would be better too doesn't have that step like oem. But then again the step might help with the flow

hondamad · « **Reply #22 on:** April 22, 2015, 11:38:00 AM »

I am getting confused with these insulators. As far as i understand the two centre i.e. Nos 2,3 are the same and the two outers are also the same.
part nos 16211-393-000 and 16212-393-000 for the 76a - 2 of each. The 393 denotes the model as automatic. The last 3 digits change for the 77 and 78 models to 010 and 020. The CSMNL show 4 different nos for the 77 and 78 models ranging from 16211 to 16214 -393 with corresponding 010 and 020 as last digits. Could one of the old hands confirm if the 76, 77 and 78 models use the same insulators ?

hondamad · « **Reply #23 on:** April 22, 2015, 01:03:20 PM »

See pics of centre insulator has both 2 and 3 markings on top and bottom recspectively can therefore be used in either position. Same applies to outside insulators marked 1 and 4

POPS 911 · « **Reply #24 on:** May 15, 2015, 04:19:21 AM »

On my 750a drag bike I use 69-73 750 insulators which are bigger and softer [ new on e-bay ] they clamp on head with no leaks but I use CV XJ750R SECA YAMAHA CARBS that are bigger in size. I have another CB750A with stock F- CARBS and they mount also onto those boots. You might be able to build up the necks [ RUBBERIZED TAPE THEY SALE ] on the stock CB750A carbs to fit snug into those boots and use the wider automotive clamp to tighten down with no leaks. I do not run a air box but use PODS so for the stock fit the cb750f boots could be a little long. Their is NO NEW [/b]INSULATORS as I live in OHIO [ very close to the plant ] and have been to the MAIN HONDA plant and they have a order desk for their workers that can buy parts for any HONDA PRODUCT MADE and will locate it in the WORLD and you go back and pickup at that location. Bought a NEW CM400A cam for my Hondamatic 1981 at this location and picked it up 4 days later.

POPS BK911
It's nice to know someone who works at this plant in Central Ohio........... again NO NEW BOOTS FOR CB750A, I got 4 sets like brand new !!!!

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Author Topic: Carb insulator questions... (Read 5418 times)