Carb, model fit

[huskysteve]

Hello there I am new to this forum and just bought my first 400fzr not saying I am new to motorcycles just to one of these TROUSER FIREWORKS I wondered if any of the members out there would be able to help.
I bought a 400fzr but the carbs need replacing as the previous owner said it was a very bad runner but after the carbs where taken off and cleaned it was even worse I was wondering if the carbs off a 3TJ would fit the 3EN1 as there is a bank on ebay and would like to bid if they would fit there is a set from a 1WG but they need stripping and cleaning too, not saying I cannot so this just they might be in the same state as the ones I have already on the bike.
Thanks for any help
Steve

[Evilchicken0]

When you say it runs rough ... how exactly ???

Is it between any rev range, does it run better at low revs ... up to 6000 or better above (main or idle jets blocked)
Are the diaphams holed ... that will mean it won't pick up very well.
Does it take time to start and idle badly ... smelling of pertrol ??? the float bowl gaskets are leaking.
Have you change the in line fuel filter, and the fuel tap filter, is the tank rusty ????

Do you get a "weep, weep" noise when you turn the ignition on ???
Take the chrome EXUP cover off (it's on the exhaust where the 4 downpipes join into 1) Examine the cables and see if the pulley turns when the ignition or kill switch is turned on.

[uniquefzrfreak]

3TJ carbs will technically fit on a 1WG.

You can fit them to either the standard 1WG carb rubber inlets, or you can swap the inlets for shorter/shallower 3TJ ones (this changes the powerband, but I can't remember if you get more top end and less acceleration, or the other way around). Either will work, but you may (or may not) find some minor jetting changes could be required to ensure perfect running.

- Personally, I don't think you will needs to make any further changes to the standard jetting, but I'm not an expert in that area and I've not fired my project up yet, so I can only confirm fitment based on prior good advice I've received.

The 3TJ carbs, will not take the standard 1WG throttle cables - they are too long. Personally, I've purchased a 3TJ throttle and throttle cables, which subsequently will need shortening.

Based on what I've see so far, the message is, if you fit 3TJ carbs, you will need a set of custom throttle cables making up. Venhill can do this for you. I'm just going to give them the 3TJ cables and ask them to make a set like that which are the same length as the 1WG ones (as the 1WG ones are shorter).

In your case, I'd say that you should hold out for a set of 1WG carbs as the bespoke throttle cables would add to the cost of buying the 3TJ ones you've seen.

I hope this helps, mines still a working progress and as Evil indicates, you may not need to replace the carbs to fix the problem.

- Back to you Evil....

[huskysteve]

thanks for the posts you guys
Firstly I have just bought the bike it was a Spares or repair and the engine was said to be running, the seller tole me the bike was running really bad on tickover
and in fact did not run at all on tickover so the seller stripped the carbs down to see what the problem was, When he put them back together after the rebuild he found that starting was also a now a problem.
When I went to pick teh bike up it took a good 30 mins and 2 car batteries to get the bike fired up there is a noise from the exup valve when the ignition is turned on and the negine was firing on one for quite a bit of time and eventually came on to 3 cylinders as you can imagine the bike would not tickover at all and would only keep running with a blip from the throttle the seller recommened that another set of carbs might be the answer to the problem.
he romoved the airbox and placed his hand over the carb rear intake to force fuel into the engine this again seemed the only way of starting the engine all in all the bike is in fair condition with some of the casings being resprayed and a new chaien and sproket set as well as the forks being rebuilt and the rear subframe having a respay there is a few bit missing like fairing panels but this is the whole idea of a project bike to source bits and pieces.
will have to check the carbs diaphram,like i said the bike is new to me and in fact is still in the back of my van, I am looking forward to getting STUCK IN!
Steve

[Evilchicken0]

Valves.

It sounds like the valves shims need doing. As they older they stretch due to the high revs - you can do it with the engine in but it's far easier with it out. These bikes sufferfrom it more so because they're getting older and running out of tollerance but I'll nail my flag to the mast on this one it sounds like the classic symptoms.

[rrsp]

As evil said, i would deffo check valve clearances, there a pig to start if they have closed up ! ps
ive got a decent set of 1wg carbs cheap if you are after some ?