Author Topic: advice for low rev / starting problems? (Read 5250 times)

unsped · « **on:** March 13, 2005, 01:29:08 AM »

ive got a 1992 bandit with about 14,000 or so miles on it in great original shape.

i havent ridden it in a couple months and am running into some trouble with it.

- batter was run down and now cant seem to start bike it cranks over for awhile but never fires.

- if i push start the bike in 2nd with choke it starts very easily

- bike will not idle well under 4k (it slowly looses rpm then stalls but still sounds pretty smooth)

- if i push start and keep the rpm's up it runs like a dream although if it hasnt run in awhile i notice a bit of throttle lag ... i give it gas and it takes a moment to get the response.

bike had a tuneup maybe 8 months ago and they said i needed to clean the carbs but they wanted 250 at the time so i figured i would just deal with the rough idling problem. but it seems to have gotten annoyingly worse.

Maniac · « **Reply #1 on:** March 13, 2005, 01:48:56 AM »

First of all, Welcome aboard!

My '93 had about that many miles on it when I got it, so your doing pretty good there. Many people on this forum recommend against push/bump starting the bikes, as if they backfire they can cause all sorts of problems. I don't think anyone has had one yet, but we've heard horror stories.

Chances are your carbs are gummed up to the point that the low speed jets are nearly, or completly, blocked. There is no way around it, it sounds like your going to have to either clean them or have them cleaned professionally. I tried cleaning mine twice before I finally broke down and had them gone through. Typical problems are:

Varnish and dirt in the jets.
Worn out needle jets and jet needles
Worn/missing O-rings

unsped · « **Reply #2 on:** March 16, 2005, 02:28:26 AM »

hehe thanks

i took apart the carbs and they didnt really seem that dirty .. thought i would clean them while i had them apart (might as well)

boy was i wrong!

they had some pretty serious varnish, i pretty much did a full tear down on them and cleaned them proper ...

OMFG! is all i have to say ... the idle is now super smooth at low rpm, and the throttle response is so quick i cannot believe its the same bike.

this was a bike that wouldnt start, or stay running at a stop just days ago, it also had alot of throttle lag.

thanks for the info!

here are some pics for the super curious:

Maniac · « **Reply #3 on:** March 16, 2005, 04:54:35 AM »

Hey, those cleaned up nice!

Glad it did the trick!

PitterB4 · « **Reply #4 on:** March 16, 2005, 02:25:24 PM »

Those look purdy! I'm cringing looking at that throttle cable hanging there. I've had mine off 3 or 4 times now - at least an hour of frustration each time getting it back on.

Maniac · « **Reply #5 on:** March 16, 2005, 03:01:11 PM »

Yeah, those carbs cleaned up really nice!

How are you guys installing the throttle cable? I've had my carbs off at least 10 times and never had trouble with the cable. I tend to install it -before- I slide the carbs onto the intake manifolds, that might be why.

badidou · « **Reply #6 on:** March 16, 2005, 08:31:19 PM »

Good job on cleaning the carb, looks brand new.
Looks like i'm not the only one with the same problem, the only difference is that mine wont start anymore, after all the hassle.
I cleaned the carb and it did not fix it. Guys i surrended and took it to a mecanic shop. 3 of them refused to take it after i gave a brief description of the problem (lazy). The fourth guy explained that it will take him a week at least to call me back

looks like they are slamed after the couple weeks of good weather. Anyway i cross my finger and we'll how much this will cost me.

Thief400 · « **Reply #7 on:** March 16, 2005, 10:44:52 PM »

Wow I should start mail order carb rebuilding business

Maniac · « **Reply #8 on:** March 17, 2005, 02:17:13 AM »

A lot of people say the carbs on the Bandit 400 are hard to clean. I don't think thats really the case, it's not like they are some sort of fancy special carburator. They are just small, thats all, and prone to gumming up because of this. You just have to be thorough. That being said, a lot of shops don't want to touch the 400 because it is a 10+ year old bike with parts that are -really- hard to get at times.

Something else that can cause the symptoms your describing, Badidou, is either a failed voltage regulator or the Igniter going bad. The igniter is a pain, the regulator not so much...

There is a FAQ on this forum somewhere about repairing your own igniter, though, so if this turns out to be the problem you may want to try that route.

badidou · « **Reply #9 on:** March 17, 2005, 04:35:49 AM »

Thanks for the advice, i have already replaced the capacitor and the regulator on the CDI. The byke worked great for a couple weeks and vlannn troubles again.
I don't think it 's a CDI problem since i have sparks on all the cylinders.