Custom cruisers.

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2wheelover51
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Joined: Fri Aug 07, 2015 9:12 pm
Current Ride: 2012 Burgman 400 Limited
Location: Poole, Dorset

Re: Custom cruisers.

Post by 2wheelover51 »

Well, while I was optimistic about Metric Cruisers being professional and looking into my problems by removing a few parts and checking the carbs out, it seems their "mechanic" just took it for a spin and said it was ok. No parts were removed in their inquiry. They didn't try to find the cause of the popping and banging on the overrun (weak mixture) in fact they said it wasn't. Nor did they explain why the carb piston isn't moving. One of them said "often rear carbs are tuned differently with different size jets etc" - (they aren't according to the manual, nor would they need to be with a water-cooled motor). Another bull-shitting dealer.
Well they won't be getting my custom again. :( :?

Ferret
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Re: Custom cruisers.

Post by Ferret »

Popping on the over run will be an air leak either exhaust or induction manifold . There are many reasons why the slide does not lift at the same time as the other ,holed or stretched diaphragm,blocked vacuum pipe or kinked ,bad seal at manifold . Someone may have over stretched the spring in the slide or even fitted the wrong one . Slide may be worn as may the needle and emulsification tube . If it pics up and balances higher up the Rev range this could be any of the above , however if slide parts are worn it usually causes fluttering of the slide from my experience. Oh if yours is a USA model it may well have an evap canister or the like these can also cause popping etc ,that's why many blanked them of just like the Yamaha AIS . You could lift the needles to richen it up a touch bear in mind this won't richen it at the top only from pilot to 3/4 throttle.

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2wheelover51
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Re: Custom cruisers.

Post by 2wheelover51 »

Aye, they were my thoughts too. It's a California model and has the evap system with all the old rubber hoses which that entails. I need to strip it down and either renew the hoses or take it all off and ditch it, which I'll probably do.
Carbs will have to come off as I'm thinking at the low miles it's done for the age (22,000 on a 30 year old bike) besides the diaphragms, it will probably have stood for a while and there could be some varnishing or corrosion in the airways and passages. I also thought about lifting the needles a notch or two to richen it up. I'd really like to lift the head and check the valves and seats, but that means the motor will have to come out and it looks like a heavy old lump! :? :)

Ferret
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Re: Custom cruisers.

Post by Ferret »

Buy or borrow one of those inspection cameras that go down the plug hole or a compression tester , I doubt it's the valves my self .

SH125Paul
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Re: Custom cruisers.

Post by SH125Paul »

The CCM i had, twin carb single had emission canister and pipe work originaly, with a solenoid... All removed and blanked off, so check the little pipes..
A way to check if on the in take, while its running, blip the throttle and squirt some wd40 around the inlet manifold area, listening for any change in pitch or idle...

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2wheelover51
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Current Ride: 2012 Burgman 400 Limited
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Re: Custom cruisers.

Post by 2wheelover51 »

Cheers guys. I've started stripping the evap system and trying to figure out which are the vacuum take-offs and which are the float chamber vents, it looks quite straight forward so far, just awkward to get to with all the wiring etc in the way... :?
The "Mechanic" at Metric Cruisers said he got 150 psi and 155 on his compression test, but I don't think he did one. My new Machine Mart gauge gives both carbs at 120 psi, which is low. I'm not sure how accurate the Machine Mart gauges are, but if correct it could mean valves need lapping in. It's only done 22600 miles, but I'm not sure how long its been running weak.. :?

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2wheelover51
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Joined: Fri Aug 07, 2015 9:12 pm
Current Ride: 2012 Burgman 400 Limited
Location: Poole, Dorset

Re: Custom cruisers.

Post by 2wheelover51 »

Well I finally got the carbs off and.. you could have knocked me down with a feather, both diaphragms are intact, no tears, holes or pinholes. The carbs have the specified main jets (158) and all the passageways and jets are open. Since I've got the EVAP system off I'm going to make new breathers on the tank and float chambers and blank off the vacuum tubes and see what happens.
Popping on the overun I would normally accept as holes in the exhaust (there are none) or poorly fitted at the joints. I'll be redoing those with exhaust paste as well. The thing is the whitish plugs point towards there being a leak on the inlet side so that's where I'll be concentrating my efforts. I wonder if the inlet for the CVAC valve or whatever it's called has failed and is letting air in through that side. It's just as well it's only twin cylinder - I've got all the rear carb bits on the left of my dining table and all the front carb bits on the right.. Having to eat my dinner on my knee. :lol:

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2wheelover51
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Re: Custom cruisers.

Post by 2wheelover51 »

Further to my carburettor adventures..
I kept the main (float chamber) vents between the carbs and routed it with the original hose to atmosphere. The rest of the outlets on the carb I blew through, to divide them into vac points and vents, and blanked off 2 vacuum points and 2 vents on the pair of carbs with short lengths of hose with short bolts sealed into them with gasket sealant. The evap system and associated hoses came off and the carbs went back on and the bike seems to be running a bit better, and the rear cylinder piston is now moving when it's revved, but the plugs still arent the colour I'd like them and there is still some popping on the overun. In the morning I'll check the carb "stubs" (insulators) with WD40 while the motors running..
Arent motorbikes interesting... :lol:

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2wheelover51
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Joined: Fri Aug 07, 2015 9:12 pm
Current Ride: 2012 Burgman 400 Limited
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Re: Custom cruisers.

Post by 2wheelover51 »

I've found a US seller selling "jet up kits" for just such problems as I've got (exhaust popping, running too lean etc) which gives needles, shims (washers to raise needles) bigger main and pilot jets etc. all for $40 plus postage. God bless America! :kiss: :)

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2wheelover51
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Joined: Fri Aug 07, 2015 9:12 pm
Current Ride: 2012 Burgman 400 Limited
Location: Poole, Dorset

Re: Custom cruisers.

Post by 2wheelover51 »

I've just fitted the jet-up kit to the Shadow. Main's up from 158 to 170, pilots from 43-45 and raised the needles by 2 washers (about 1mm or 1.5mm. I'm just going to put the carbs back on tomorrow morning and see how it runs. The mains looks quite a big step but in fact it's less than 10% so I'm not expecting clouds of black smoke or 20 mpg.. :D
Lets hope I don't get it! :o If it starts and runs ok I'll balance the carbs again and take it for a run to check plugs, adjust pilots etc.

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