My 400/4

[hondatri]

  My 77 400/4 is running rich and plugs fail after a while I am going to remove Carbs (God help me) to clean and adjust them, is there a simple way to remove carbs. I have a small sonic cleaner but dont know what liquid to put in it to clean jets. I have the use of a vacuum set for synchronizing. Also the Timing chain is noisy and want to do a job on it at the same time and replace chain/guides/and adjusters can this be done with eng in frame. Any info appreciated.

[Bitsa (Ralph Wright - RIP)]

Hi,
All of what you have asked for can be done in the frame except changing the cam chain and primary chains.The 400/4 motor is a gem to do nothing hard except the cam chain adjuster a right bastard if seized.In my past the running rich is caused by the rubber rings around the main jets but dont take my word for it there are loads of 400/4 guys on here that are well into them.
Best of luck
Cheers
Bitsa

[Piki]

Hello, have you check the ignition system??  Points Gap,  Timing Adjust,  Plug Gap, Check the Coils.............Many times, the problem is from the ignition system......

[hondatri]

 Thanks Guys I bought this 400 2 yrs ago and it was never really right thats why I need to rectify things. The previous owner fitted Boyer Branson Electronic Ign. I have a Haynes Manual. I saw somewhere a tip for easily removal of Carburettors but cannot remember where.

[Dan]

I had my carbs off recently. Getting them off is simple but putting them back on can be a pain, or rather getting the air box rubbers back onto the carbs can be a pain - if they have age hardened.

Undo fuel hose from tap and remove petrol tank

Undo / remove throttle cables from carbs

Loosen off clamps on the rubbers between carbs and head / carbs and air box

Pull air box back off carbs and remove air box rubbers then pull carbs back from the head rubbers

You should have enough room to get the carbs out to the side now. I leave all petrol lines and overflows connected to the carbs.

I ended up buying new air box rubbers From DS to make refitting easier after using a heat gun previously to soften up the hardened rubbers.

[kent400]

Having removed and re-fitted  a bank of 400f carbs only last weekend my memory of the task is very fresh! Yes the task is a bit of a pig. Just to add to the good advice above, you need to loosen the clip on the airbox where it joins air filter/battery box and pull out the oval tube from the inside of the box. The air box and the carbs come out on the right hand side. Fortunetly the air box rubber are still good, a spot of WD40 on the inside of air box rubber helps them slip on a little easier. Take a note of the route of the 4 overflow hoses and the 2 breather hoses. There is also a larger hose on the bottom of the airbox. Feeding these hoses down the back of the engine upon re-assembly is a bit of a fiddle.

[Dan]

When I had the old hard rubbers I should have tried your method Kent.
I guess as you get to learn your bike you find your own way and methods.  If there's room to get the carbs and air box into the frame together my swearing vocabulary would be a bit smaller :-)

[hondatri]

Hi Guys Thanks for info on your experiences . I saw on another site that a Strap around the Airbox and pulling back gives more room by 1/2".Fingers crossed as job progresses. Anyone have idea of cleaning parts in Sonic cleaner or is Carb cleaner enough.

[Lobo]

Sonic cleaner... the general consensus seems to be "yes".

But... I bought a cheap sonic cleaner from ebay (£100 thereabouts & intended for jewellery / watch straps etc)... and wasted my money. It wasn't beefy enough (I now realise), and you also need the right cleaning agent... which I didn't really appreciate. If the parts were actually cleaned it was likely more to do with the long / hot soak in a warm cleaning fluid! (it was heated)

What I'm trying to say here then, is sonic cleaning prob very good if done by someone who has the right equipment / knowledge etc.

I also forced pressurised carb cleaner etc through the galley ways... I got them clean in the end through a variety of means versus, simply, a sonic cleaner.

[kent400]

I too have a heated ultrasonic cleaner and I share lobo's views. However they do work rather better with a special carburetter cleaning fluid. The fluid I have is produced by R & D Laboratories, it's used at 80c There are fluids listed on ebay and whilst it does improve the cleaning process it's not a 'silver bullet' as far as carb cleaning is concerned. Will shift the general dirt and grease. Carb cleaner in a spray can is effective.  The unheated cleaners are not much good, well good for cleaning false teeth apparently

[Lobo]

Just a word of caution if indeed using a sonic cleaner... be very mindful of just what cleaning fluids you use. Ie you shouldn't really go putting solvents etc in it... with its sparky / buzzing electrics below.

Like wot I did (out of frustration)

But, I'm still here...

(Hi Peter, long time no hear, trust all's well. Insts still looking great - thanks. S)