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Post by 6of1halfoftheother on Jul 13, 2018 23:02:11 GMT -5
I have a 72 H2 and it suddenly started surging, at 3-4000 rpm after warm up. Motor has one season on it after a total rebuild. I ran unoiled 1 stage pod filters for 1 season, then I decided to oil them, my problems started sometime after that. Coincidence? I think so.
Carbs are stock except for 107.5 mains with Wirges chambers.I checked the timing, checked and cleaned the carbs, changed the fuel, checked the exhaust, tried different filters and no filters but still the same. Adjusting the air screws did nothing. I lowered the needle from #2 to #1 and the bike ran better with 50% less surging and the plugs looked good BH9S
As I have no spare parts except for 74 and 75 parts. I’m wondering if I should get one of Ivan’s kits or get some different carbs from Niche cycle? Newer carbs would be nice as mine have the old plastic pins in the carb body. I have broken 1 before while riding And it was scary with no kill switch.
If I decide to go with new carbs which one should I try? I want something that will accept stock throttle and choke cables and fuel lines for a stock petcock I don’t want to change That unless I have too.
Any suggestions? Thanks......
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Post by Walms on Jul 14, 2018 7:51:42 GMT -5
If the bike was working well and the surging started out of nowhere, confirm no air leaks first. If you are still in the jetting phase, at what throttle position are you getting the surging at? If with throttle closed to 1/8 open, richen the idle screw, if less than 1 turn out already, go to your next pilot jet richer. 1/4 to 1/2 throttle surging? Raise the needle 1 notch.
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Post by Walms on Jul 14, 2018 7:53:49 GMT -5
Oiling the filters should have made it richer tho, (just a guess) that is an odd one!
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4 stroking
Jul 14, 2018 11:47:25 GMT -5
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Post by Curtis on Jul 14, 2018 11:47:25 GMT -5
What do the plugs look like ? What fuel are you running ?
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4 stroking
Jul 14, 2018 12:53:35 GMT -5
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Post by shiloh on Jul 14, 2018 12:53:35 GMT -5
I was under the impression stock 72 h2's were prone to surging while at a steady cruise, and the fix was to shim the jugs. How much, idk I never owned a stock 72 h2 mine was a hot rod lol. At least thats what an old kawi tech once told me?
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Post by 6of1halfoftheother on Jul 15, 2018 21:41:45 GMT -5
If the bike was working well and the surging started out of nowhere, confirm no air leaks first. If you are still in the jetting phase, at what throttle position are you getting the surging at? If with throttle closed to 1/8 open, richen the idle screw, if less than 1 turn out already, go to your next pilot jet richer. 1/4 to 1/2 throttle surging? Raise the needle 1 notch. Surging or 4 stroking is 1/4 to 1/2 throttle. I can’t load a pic of the plugs but L&R look good C a bit rich. I changed the pilots from 35s to 40s it’s all I had. Tried the needle in 1,2 and 3 position Twisted the air screws every which way Carb manifolds and gaskets are good I even put a bit of silicone on to be sure. ( no air leaks ) that I can see. Bike still runs like SHIT after warm up. Top end and idle is great. I have always run Mohawk gas 94 octane it has methanol. Like I said before bike ran great before then suddenly problems. I think I want to try new carbs or would Ivan’s kits help? 30s would be fine as long as I can use stock cables and petcock. What is anyone else using? Suggestions please...
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Post by Jim on Jul 15, 2018 23:13:22 GMT -5
Wait a minute... is it surging or 4-stroking? Surging is lean, 4-stroking is rich. Surging feels a little like a bucking bronco, while 4-stroking just sounds odd, no bucking. If your problem is 4-stroking, that makes sense, because as Walms said, oiling the filters would tend to make things richer.
The fix for surging is just to upshift, but some guys like to go to a richer slide cutaway. The fix for 4-stroking is probably to go 1/2 to 1 needle clip leaner, or remove some of the oil by rinsing the filters in Varsol (AKA mineral spirits, AKA paint thinner).
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Post by 6of1halfoftheother on Jul 16, 2018 7:58:04 GMT -5
Wait a minute... is it surging or 4-stroking? Surging is lean, 4-stroking is rich. Surging feels a little like a bucking bronco, while 4-stroking just sounds odd, no bucking. If your problem is 4-stroking, that makes sense, because as Walms said, oiling the filters would tend to make things richer. The fix for surging is just to upshift, but some guys like to go to a richer slide cutaway. The fix for 4-stroking is probably to go 1/2 to 1 needle clip leaner, or remove some of the oil by rinsing the filters in Varsol (AKA mineral spirits, AKA paint thinner). Since you described it that way it is 4-stroking. (Sorry) I have tried pilot from 35 to 40 (all I had) I have leaned out the needle as much as possible. Needle is in #1 Tried other never oiled filters and no filters. All of the messing around has just made the sound either deeper or crisper. Its is general in town riding, up shifting and I’m speeding. I don’t have any other slides, if that could be the fix I would rather go with new carbs.
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Post by Walms on Jul 16, 2018 8:21:08 GMT -5
Did you try leaning out the needle with the #35 pilot jet yet?
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4 stroking
Jul 16, 2018 11:30:01 GMT -5
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Post by 6of1halfoftheother on Jul 16, 2018 11:30:01 GMT -5
Did you try leaning out the needle with the #35 pilot jet yet?[/quote Yes it originally had stock 35’s and needle was in number 2. I move the needle to number 1 position. 4 stroking was 50% better but still horrible . Then I tried 40 pilots With no real difference All the problems start when the bike starts to warm up
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Post by kawonda750 on Jul 16, 2018 15:41:13 GMT -5
40 pilots are making it richer. 4 Stroking is usually a function of the main jets, or I thought that anyway.
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4 stroking
Jul 16, 2018 18:11:39 GMT -5
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Post by Curtis on Jul 16, 2018 18:11:39 GMT -5
I am more thinking you have other issues. You oiled the filters and this problem occurred and doesn’t change with no air filters? You have other issues.
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Post by Walms on Jul 17, 2018 8:59:38 GMT -5
I'd have to agree with Curtis, I looked it up, stock pilot is 35's so if 4 stroking with pods and expansion chambers, you likely have something else at play. Pressure test the engine and check the resistances on the electrical side of things. kawtriple.com/mraxl/cdih2/h2ignitiontest.htmAs far as jetting goes, don't pay attention to what rpm you are at, that has nothing to do with it other than different RPM's are more forgiving than others. Focus on throttle position. I use Keihin carbs and they focus quite a bit on the needles but pretty much the same concept for jetting, use this chart. Make a pointer for your throttle so you know the actual throttle opening.
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Post by acceleration on Jul 17, 2018 11:55:56 GMT -5
Another problem these bikes can have quite often is with the fuel petcock. When they start to go bad they will seep just the slightest amount of fuel and not totally shut off.The carbs will over fill creating a flooding over rich effect.And you might not realise it is doing that ,until you look more closely at it. And too they can get dirt in them slude etc and block off steady fuel flow and cause surging.Then there is the diapram that goes bad and the vac won't work and pull fuel. Man we recently had an RD350LC come into the shop and the pet cock was bad. It filled up one of the exhaust pipes full of gas!! We had to dump the fuel out of the pipe and then rebuild the fuel valve !!
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Post by 6of1halfoftheother on Jul 17, 2018 22:09:43 GMT -5
Another problem these bikes can have quite often is with the fuel petcock. When they start to go bad they will seep just the slightest amount of fuel and not totally shut off.The carbs will over fill creating a flooding over rich effect.And you might not realise it is doing that ,until you look more closely at it. And too they can get dirt in them slude etc and block off steady fuel flow and cause surging.Then there is the diapram that goes bad and the vac won't work and pull fuel. Man we recently had an RD350LC come into the shop and the pet cock was bad. It filled up one of the exhaust pipes full of gas!! We had to dump the fuel out of the pipe and then rebuild the fuel valve !! Fuel flow,petcock and vacuum line are fine tank is clean. I cant post my circuit test sheet so I will tell you my results. High speed coil should read 5 ohms I get 6 Low speed coil should read 200 ohms I get 205 Ignition coils should read .8 they are .8.8.9 Secondary resistance at the spark plug caps should be 4,500 ohms I get 9,000??? Ignition signal coils should read 200 I get 168, 173, 170 one reference says not less then 180 another says 160 so? I have Lakeland iggy boxes so I did not check them. Someone suggested I check the electricals so I have. Now I don't know WTF to figure.
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