Replacing carb shaft seals may be in my future

After about 3 years of no problems, my XJ700n started increasing rpm sometimes at idle and sometimes after blipping the throttle. I think all the linkages are good but I'll look this weekend. When I rebuilt the carbs several years ago I did not replace the shaft seals, and since my boots look very good, I'm thinking that I have a leaking seal. Other than that the bike starts and runs great, so if necessary, I plan to just replace the seals. I know there is a link somewhere on here but haven't been able to find it. So, if someone will post it I would appreciate it. So the seals come in a kit, or individually? I assume Chacal has them, if not are there other sources?

 

https://www.xj4ever.com/downloads.html

will get you to:

https://www.xj4ever.com/hitachi throttle shaft seals.pdf

Len does have kits, maybe go for the rubber kit which will include most of the rubber including the fuel pipe O-rings, which are a must

HCP29063 Aftermarket Hitachi HSC32 and HSC33 series CARB RUBBER PARTS KITS

There has been a few references to other bikes (Honda Suzuki) for a throttle shaft seals, but I don't recall anyone actually saying that they used them and they worked

 

You will have to break the crack apart , the hardest part is removing the small screws for the butterfly plate , if you have Mikuni carbs the screws are staked in , Hitachi carbs are not . Put a dab of valve lapping compound on the head of the screw this will give more grip to remove screws . Once the plate is removed you can remove shaft and get the old seal . When I reassemble I use a dab of silicone grease ( Super Lube from Harbor Freight is awesome) . Last set of carbs I rebuilt I went to ACE hardware and they had allen screws that were the right size and length . Make sure you use some blue locktight on the screws before tighting screws make sure the butterfly plate is centered . Reassemble carbs back on the rails do bench synch , I use two number 20 drill bits put one under the number three carb butterfly and put the other bit under number one adjust synch screw till you get a slight drag gently pulling drill bit out , move to number two and do the same , move to number four . Now look at three adjust idle knob till you get a slight drag on bit ,pull bit out hold carbs up to strong light you see a half moon on the bottom of butterfly plates . You should be close and do a synch. Sorry I know long winded .

 

We have them in stock!

What Rooster was referring to is this kit, which has all of the replaceable rubber parts in it, which is ideal in your situation, where the carbs were rebuilt a while back but may need a minor refresh:

HITACHI CARBS RUBBER PARTS KITS:

nn) Aftermarket Hitachi carbs RUBBER PARTS KITS contain all of the rubber parts needed when rebuilding a carb set: the throttle shaft seals, the fuel pipe o-rings, the choke plunger shaft dust seals, and the mixture screw o-rings and their washers (yes, we know the washers aren’t rubber, but you’ll probably need them, so they are included!). Note that the float needles / valve assemblies are not included. Can be used in conjunction with our lower-end rebuild kits listed below, but in most situations, you’ll be better off purchasing one of our complete carb rebuild kits (listed further below), but some people prefer to just do a “rubber refresh” periodically, and this kit gives you everything you’ll need.

HCP29063 Aftermarket Hitachi HSC32 and HSC33 series CARB RUBBER PARTS KITS.

 

I replaced the throttle shaft seals on my bs30 mikuni carbs, and it really wasn’t too hard.

I took my time with the butterfly screws and had no issues at all removing them (though I think I got lucky).

I’d recommend getting them from chacal. He’s a huge resource on this board.

 

Well, now--sometimes I feel like a nut, sometimes I don't. I do now! As hard as I tried, I could not duplicate the high rpm. I put enought propane around the carbs and seals to to cook a Thanksgiving turkey and got nothing but a nice steady idle. I checked the linkages and they are fine. So, just for grins, I opened the "choke" and lo and behold, there was the high idle! At this point I think I was just dumb enough to leave the "choke" on and that was the problem all along. I rode today and had no issues at all. So it looks like I don't have to tackle the shaft seals at this time. I guess I'm getting careless in my old age.