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Magua
26th February 2008, 21:12
Recently I bought a Cb400n. It's had the original mufflers and cross member silencer.. thing removed. Reading the manuals that came with the bike, removing the cross member does nothing but decrease performance.

The bike performs well, but I believe it could have more. On full throttle, the bike floods. Likewise at 100kph, a quick twist and you may be greeted by bogging.

I tried reattaching the cross member silencer thing(trademark pending), but it didn't go on very well and nor did I have the orig mufflers. I did not see much of a difference performance wise, I suspect someone has been played with the carbs.

I could try to change everything back to stock if I could find the parts I require. But otherwise, what could I do with the carbs?

Ixion
26th February 2008, 21:19
First check the float levels. And jet sizes. If the silencers are non stock some dildo with half a klue may have said "duh, i've heard dat when you fit aftermarket can yu can increase da jet sizes and da boike will go 300kph. Lemme at it".

Check they match standard.

And check the float needles are seating. You can't lap them in nowdays (BECAUSE SOME CUNT IN THE LAST THIRTY YEARS HAS TURNED EVERYTHING INTO PLASTIC ! AND SEALED ALL THE ROADS! BASTARD . ). So you'll need two carb kits. They'll come with lots of goodies to make your carbs all nice n tight just like they were that first night. Just don't get them pregnant this time.

Motu
26th February 2008, 22:00
Rich or lean? Are you sure it's running too rich? Bogging is more likely a lean condition.How is the air filter?

Magua
26th February 2008, 22:04
I assumed rich as it's running shy of the mpg most riders quote. I'll check out the air filter in the day light.

Magua
26th February 2008, 22:06
First check the float levels. And jet sizes. If the silencers are non stock some dildo with half a klue may have said "duh, i've heard dat when you fit aftermarket can yu can increase da jet sizes and da boike will go 300kph. Lemme at it".

Check they match standard.

And check the float needles are seating. You can't lap them in nowdays (BECAUSE SOME CUNT IN THE LAST THIRTY YEARS HAS TURNED EVERYTHING INTO PLASTIC ! AND SEALED ALL THE ROADS! BASTARD . ). So you'll need two carb kits. They'll come with lots of goodies to make your carbs all nice n tight just like they were that first night. Just don't get them pregnant this time.

lol _b
How do you go about checking float levels and jet sizes?

Edit, never mind. I now know how.

Magua
9th November 2008, 22:10
Thread dredge.

Did a compression test with xwhatsit's tester at uni. Maybe not the most reliable, but in any case it returned 175psi in each cylinder. Manual says 185 +/- 14, so that's good news. I need to replace my head and base gaskets, but as I don't appear to be loosing much compression (28 years old and a loss of 10psi) I don't see this as the root of the problem.

Also, I purchased an original exhaust system off of trademe for $75 and attached it. Headers -> cross member -> silencers. There has been a noticeable difference, but I've still got fairly crap performance around 100kph. Riding along the North Western last night into a headwind I was maxing out at a whopping 100kph.

Xwhatsit has suggested that perhaps the camshaft has worn down? Therefore not allowing valves to open far enough. Plausable?

Uni's over for the year now, will be checking carbs properly this week.

xwhatsit
10th November 2008, 01:11
Xwhatsit has suggested that perhaps the camshaft has worn down? Therefore not allowing valves to open far enough. Plausable?
From riding it, it feels like it gets very breathless at the higher end of the rev range. Low down it does quite nicely, shoots off like a rocket, I got the front wheel up without meaning to away from those silly onramp traffic lights. However as soon as the revs climb, it suddenly hits a brick wall. You try and hook another gear but you realise you're already in 6th. This happens around 90-100kph in top, and instead of carrying on steam-train style it tails off and crawls up to speed.

As it doesn't appear to be low on compression (hell, I could barely hold the gauge in the spark plug boss), and it has this breathless feel, I thought perhaps a really worn camshaft (fairly common for a Honda from that era, innit?). Would explain the decent grunt but inability to rev, wouldn't it? I don't understand CV carbs at all, but the fact they're not linked to the throttle cable means that if they've been messed around with, it's possible they aren't fully opening or something?

Ignition advancer unit not advancing fully?

Ixion
10th November 2008, 08:31
That worn a cam Id expect a really clattery top end.

Perished diaphragms? That would explain it getting pregnant, too .Try a plug chop at various throttle/load settings.

Magua
10th November 2008, 09:37
That worn a cam Id expect a really clattery top end.

Perished diaphragms? That would explain it getting pregnant, too .Try a plug chop at various throttle/load settings.

What is a plug chop?

I'll take a video so you can listen to the top end chattering away.

Squiggles
10th November 2008, 11:37
What is a plug chop?

Ya do a couple of k's at certain rev's then kill the engine and rip the plugs out to see what they look like

Magua
11th November 2008, 15:15
Well this is all on hold for the time being, a new problem has arisen. I have no electrics.

As I rode in last night my neutral light wouldn't work, a quick check and I see that none of my lights were working. Tried to start it this morning and now nothing is working. _b

Ixion
11th November 2008, 15:37
Blown fuse

Magua
12th November 2008, 12:26
Negative. All replaced, no change.

Ixion
12th November 2008, 12:35
Checked for loose broken wires, signs of burning. Dont forget that some bike shave a master fuse in a different place to the main fuse block. Do you have a multimeter or test lamp?

The Pastor
12th November 2008, 12:37
yeah i dropped my multi meter off, batterys got charge - but didnt have time to see where the power went to.

could only see 3 fuses on the side - surely there should be alot more than 3?

Magua
12th November 2008, 16:58
Checked the manual, only three fuses and all are fine.

Magua
14th November 2008, 15:23
Meter to the positive terminal of the battery and the other to the fuses, there are 12 volts across both the 7a fuses, but not to the main fuse. However the "continuity" light lights up.

Ixion
14th November 2008, 15:34
Check connections.

Magua
14th November 2008, 16:09
Check connections.

Dirty connections to the main fuse, all working now :)

Edit, just as I was getting the main fuse going my headlight died, soon to be followed by the park light.
Sorted now bar the park light. Wof issue, not a safety issue so it can bloody well wait another five months.

xwhatsit
17th November 2008, 13:12
Dirty connections to the main fuse, all working now :)

Edit, just as I was getting the main fuse going my headlight died, soon to be followed by the park light.
Sorted now bar the park light. Wof issue, not a safety issue so it can bloody well wait another five months.
Don't need a park light. AA/VTNZ testers may get shitty as a park light is standard equipment but you don't have it; solution is go to bike shop or a garage or similar.

Ixion
17th November 2008, 13:31
No requirement for a park light. Half my bikes have provision for it but they doesn't work. Never had a tester check it. Just tell them, if they grumble , that it was for a market that didn't specify park lights.

The Pastor
20th November 2008, 20:46
ive faild before on parklights.

parklights are so stupid. wtf do they do? drain your battery real quick. And my garage has heaps of lighting in it. HEAPS! I dont need any extra when parked!

Bloody pack of wankers.

being serrious now - what about cars? Do they have to have parklights for a wof?