hi,
anyone knows where i can buy fz cam and valve spring?
or is anyone selling 2nd hand?
where can i buy the jetting for our v2 mikuni carb? and how much per piece?

Hi guys. I've done the below modifications, but experiencing some problems;

1. Yamaha FZ block, cam and valve spring - DONE.
2. Standard head + port and polishing - DONE
3. Standard BS25 carb - DONE. Main jet changed to #120. Pilot jet remain unchange.
4. Standard exzos + change to bigger manifold - DONE.
5. All else maintain as stock including air box + filter and CDI.
6. Valve clearance set at 0.10 intake and 0.15 exhaust.

Currently it is still running in, but I've a few question;
1. Engine starts fine, but the lifter/tappets is loud. What is the ideal valve clearance for FZ cam? I will re-adjust after run-in.
2. During 1/2 - 3/4 throttle, there is slight hesitation/jerking on the engine. It's not consistent, but noticable especially when cruising at 60-80km//h. I've not gone any faster so can't really say if there's any issue at full throttle. From first gear to fifth is OK. There's no noticable jerking when going through the gears.
Is there anything else I should do to the carburettor?
I've tried to set air screw to 2, 2 1/2 and 3 turns, but slight jerking is still there.
Is there a way to change the jet needle height in the cab?

Alexei,

Thank you for the feedback. appreciate it.
1. Can't find service manual for FZ. But for R15 it's;
Intake 0.10–0.14mm
Exhaust 0.20–0.24mm
Mine is currently set at 0.10 and 0.15. I thought it's louder when it's looser, no when it's tighter?
2. It's definitely engine jerking. Chain is OK. I checked the plug when I reached home. It was slightly jerking on the highway. It's very whitish. Seems to indicate it running hot or lean based on the spark plug chart. I couldn't kill the engine when it was jerking as I was on the highway. Will have to try it again on a normal road. But from the toll exit to my house, it's only 2-3 mins with very minimal traffic. don't think it affected much.

Is it possible to set the jet needle to make it richer or leaner?
Is it possible to change to a bigger jet needle?
Will changing pilot jet have any effect? as I understand, pilot jet and air screw only affects idle to 1/4 throttle?

Noobboyzz,

I'm trying to maintain fuel economy and reliability, which is why I'm sticking to the standard carb/air filter/CDI combo. If after all the trial and errors, I still can't get it to run well, will need to look at chaging the card.
Btw, I've removed the metal cover on the air filter for better airflow.

TQ

This post has been edited by msapi: Jan 7 2013, 08:43 PM

i had a look at the pdf link and parts catalog for LCv2 and it seems the jet needle can be dis-assembled. Any one tried this before on a BS25 carb?

alexei,
will take out the jet needle this weekend and have a look at it. last time, could not see any cir-clip. there's like a plastic hat on top of the needle. wasn't sure whether it can come off or not.
When you say "sand paper the 1/2 to 3/4 taper to make it richer", I assume you are looking at it, from the bottom up, right? bottom being the pointiest part of the needle?
Any idea how much to sand off?

Noobboyzz,
Noted. TQ

ken_ng,
Yes please. Appreciate your help.

alexei,
I've disassemble the jets. I can't seem to find any pilot jets for BS25. Most of the shops have pilots for V1 Carb which is VM22. Do you know where I could buy the pilot jets?
As for the needle, based on the pdf you linked to, is it possible to install needle shim instead of sanding off the needle?
The needle is labeled #30JY14. I'm assuming it's size 30. If I want it to run richer, should I increase the size or decrease it?

alexei,
thank you for your support. did the shim needle method. cut out from a plastic/tupperware cover. about 0.5-0.7mm in thickness me think. managed to put it underneath the needle. it nows run much better without the jerking. able to cruise around the 60-80km/h. not sure whether it's now running rich or lean.
air screw is set at 3/4 turn out for now. will run it for a few days while varying it +- to see where's the best response before having a check on the spark plugs.
noobboyzz,
changing carb would be last resort and i'll also need to change cdi right? else ori cdi will detect tps error.
is the rxz carb a stright swap? do i need to change throttle cable? LC has 2 throttle cable right?
is it staight fit into the existing manifold and rubber tube?

Alexei,
Wanna check with you, does changing the needle height will affect idle - 1/4 throttle.
Cause now when moving from stand still on 1st gear, there's a slight hesitation, as if the response is bad.
Maybe my needle shim is too big. will try to make it thinner.
As for spark plug. It's not as whitish as before. but I'm gonna increase main jet to 125 soon and see whether the colour is better.

alexei,
the air screw is located at the back of the carb. as i understand fully closed, makes it rich. open makes it leaner. but funny thing is that, even though it's fully closed, the engine does not die. it use to stop running, before i adjusted the needle.
will try to make the shim thinner and compensate by upping main jet by 1 size.
you think it's a good idea?
can't find the pilot jet for the BS carb. most shops have the pilot jets for the VM carbs.

Alexei,
Seems to be running smooth now. Idle, off-idle and cruising is ok. Will check plugs later.
Btw can you please find out whether you are able to source for the needle jets and pilot jets?

Alexei,
Sorry about the spoiler. Not really a "tegar" forumer.
For jets, 1 size up is ok. Now is 15. 20 would be good.
Jet needle is now at 30 (I think, based on the code I wrote earlier). 1 size up to make it richer would be good, so that should be 25 right?
PM sent.

Noobboyzz,
Sorry to hear about the accident.

Wanna check with you guys, is it true that the FZ valve spring is shorter than a standard LC valve spring?

is this spark plug colour ok? pilot #15 main #125. needle jet dah up 0.3-0.4mm.

alexei,
less than 5000km i think...