Jump to content
Search In
  • More options...
Find results that contain...
Find results in...
always1more

Getting a bit pissed off now with this vaccum cap problem.

Recommended Posts

Think I'm gonna have to do a compression test later today as like I mentioned a few week back about the vaccum cap keep blowing off number 1 cylinder.

Well just got back from the gym, and I was using a short piece of hose with a screw in one end that was very tight, but no it went west in Town, spat the screw off my make shift hose.

Spoke with Rob last Sunday in quickish fashion and he's advised me to do a compression test which I'll do when I come back from the Docs.

Funny thing is I've recently noticed a slight knocking in my left foot which is travelling through the left side footrest. It only seems to happen when I'm taking it easy and a constant revs.

Wandering if I have a stuck intake valve on number one intake pot as I've had the cover off 3 times now and dbl checked the valves to stop me worrying but no it's still doing odd things for a few weeks now.

Checked my drive chain today thinking it maybe that on one revolution I feel this wee knock in my left foot. All the links are moving freely and I've oiled the chain regulary so maybe can rule this out Sad

I'm censored stumped now m8's scratch

Share this post


Link to post
Share on other sites

hope you get it fixed matey and it doesnt cost too much. thumbs

Share this post


Link to post
Share on other sites

I do to m8 but it don't rain it pours with me.

Just took off the seat and plastics removed tank for the umpteenth time, found my compression tester, removed the plugs, guess what ?.....my compression tester don't fit motorbikes, guess I'll need a adapter for the gunson...ohwell at least it's gonna piss down tomorrow so it's going to have to stay like that till I sort out whats is wrong with it thumbs

Share this post


Link to post
Share on other sites

You know you're right ITCHY but...it's still a pisser Laughing

Well her indoors just gave me the go ahead to order a adpater off Amazon so I can use this on my bike thumbs

I'll have to wait for it to be delivered but they rekon it's gonna piss down all day tomorrow for us thumbs

http://www.amazon.co.uk/Laser-G4055b-Hi-gauge-Adaptor-12mm/dp/B002WMZD0Q/ref=sr_1_112?s=automotive&ie=UTF8&qid=1302629937&sr=1-112

Share this post


Link to post
Share on other sites

Gud luck with it Tim,
your compression should be 178 psi standard, minimum of 124 psi and a max difference between te cylinders of 28 psi. Smile

Share this post


Link to post
Share on other sites

Cheers Rob...I can't post back here until the adapter arrives so I'll give you the readings m8 when the adapter arrives thumbs

Share this post


Link to post
Share on other sites

Hope you get her sorted Tim, as im sure you will thumbs

Share this post


Link to post
Share on other sites

Cheers Stu n Yankee...yeah will let you know how it goe's thumbs

Wouldn't mind tho, on the center stand in neutral and tickover to full revs the engine is sound. The strange little knock is only happening under load Surprised

Share this post


Link to post
Share on other sites

Morning Rob, will take a look later m8 if it stops raining and let you know, I'll take some pictures of it for you thumbs

Share this post


Link to post
Share on other sites

Yep defo hooked Tim, knackerd m8, get it changed m8 before it knackers your chain too. thumbs

Share this post


Link to post
Share on other sites

Thanks Rob thumbs

Do you know of any decent place to purchase a new one m8 that's the right price ?

Thanks pal thumbs

Share this post


Link to post
Share on other sites

Share this post


Link to post
Share on other sites

Cheers Rob all sorted thumbs

So do you think this will stop this little knock through my foot that I feel like I say she runs fine without any load.

That just leaves me to sort the vacuum cap blowing off all the time. Hopefully the adapter for my tester will arrive in a few days from Amazon so I can check the pressure.

It doe's now seem the 2 things I'm experienceing are both seperate and not all down to 1 thing.

Share this post


Link to post
Share on other sites
changing the sprocket will almost certainly cure the knocking through the pegs, as for the cap, well the compression test will at least tell you if your valves are seating right,

have you tried to run her with the offending cap off, yep it will run pretty crap but it might be worth running and putting your finger over the vac outlet and see if you can detect a blowing instead of a vacume,

Share this post


Link to post
Share on other sites
That's good then for the knocking.

Yeah there is a very slight difference without the cap on...only noticeable thing Rob it's popping more when you ease off the throttle say at lights and waiting for the lights to change the revs drop from 1200 to 1000 sounds like it's running on 3 1/2 not 3...just slightly if that makes sense m8 ?

Share this post


Link to post
Share on other sites
It will pop more and have a very uneven tickover as its sucking in air thriugh the vac inlet with the cap off and the mixture will be too lean on that cylinder, hence the poping in the zorst.
What i meant was just on tickovet, on its stand, put your finger near the vac inlet with the cap off then rev her slowly up the rev range and see if you can feel it blowing out of the inlet instead of drawing air in. I reckon if you feel a regular blowing, it would indicate the inlet valve not seating right.

Share this post


Link to post
Share on other sites

Ok Rob I'm with you on that, will give that a go tomorrow m8y as it's a bit late now. Will post back here tomorrow m8 and update you Smile

Thanks Rob thumbs

Share this post


Link to post
Share on other sites
Update @ 12.00 noon 14th April.


Hiya Rob.

Just tried what you posted above.

Thought things were going good for the 1st 2 minutes. Started the bike up let her run for a minute or two then opened the throttle slowly and no probs so far the number 1 intake was sucking my finger and not blowing.

To make sure I got a piece of paper and placed that over the vacuum cap and it stayed in place when I gave her some gradual throttle.

Thought that was a good sign until I put my make shift pipe back on with threaded bolt to block the end off then it spat it out again and it was a tight fitting bolt/screw I put in.

But when it spat it out there was a distinct small pop as if you have you're tickover too low and it spits and farts a little.

This is when it's spitting back on very low revs.

So I put the screw in again and opened the throttle very slowly bout 1/4" and you can here in one of the cylinders a slight pop then it blows the cap off.

If I open my throttle suddenly it's perfect, it's just the first blip is making this happen scratch

Share this post


Link to post
Share on other sites
On that.cylinder.that's poping the cap off, just check what the pilot screw setting is, if you don't know what or where it is I will explain to you how when I get home and have use of my comp,
Maybe its set too weak, should be 1 and 3/4 turns out from lightly seated. Worth checking just in case.

Share this post


Link to post
Share on other sites

Thanks Rob Smile

Will hang on till later m8 as I'm not sure.

Got to nip out anyway so I'll be back a little later. It's really bugging me this cos if it's a valve then why was it ok a month ago same as the carbs noting been touched only ajustment to the valves. It is something or nothing yet still annoying.

Even if I have to check the inlet valve again on pot 1 I don't mind as the tank is off ready for when this adapter arrives so I can star eliminating things.

Catch you later Rob...thanks m8 thumbs

Share this post


Link to post
Share on other sites

I will do a little vid for you when I get home showing how its adjusted and upload it. thumbs

Share this post


Link to post
Share on other sites
I will do a little vid for you when I get home showing how its adjusted and upload it. thumbs



Top man Rob....appreaciate that greatly m8 thumbs

Share this post


Link to post
Share on other sites

Rob don't know how to thank you m8 for stopping what you are doing to video this, bloody marvelous m8 thank you and I'll let you know how I get on tomorrow as hopefully the adapter will have arrived and the front sproket thumbs

Also I've been reading thru the haynes and I'm also tempted to buy a new set of feeler guages from screw fix cos on the ones I got from Halfrauds a cpl year back now although metric there is a few blades not there on what I wanted to use think you need to add a cpl of blades together to get the measurement correct. To me it's a bit fidly as I like to use just one blade for intake and one for exhaust thumbs

Share this post


Link to post
Share on other sites

My pleasure m8, its no trouble, was messin about with her anyways for my next little mod...
Gud idea to get the feelers cos it can be a bit tricky anyways without having to hold to feelers together, thumbs

Share this post


Link to post
Share on other sites

Yeah ditto to the latter part Rob, screwfix have a 32 blader in so will pop in and pick a set up just to narrow things down m8y.

I'm tempted also to put the stock can back on and see if this helps to, what do you think Rob ?

Taa m8 thumbs

Share this post


Link to post
Share on other sites
Don't think its the can tim, see what the compression tester says first m8, check the pilot and take it from there, by the way what colour is the plug?

Share this post


Link to post
Share on other sites
Ok m8 will leave the original off...plugs look fine m8 they are a greyish colour.

Forgot to ask Rob, should I just adjust number 1 carb seeing as it's this one that spits the vacuum cap off ?

Share this post


Link to post
Share on other sites
Yep, check number 1 pilot, in fact check all the carbs and reset to suit, 1 3/4 to 2 turns out, if num 1 was out, after reseting trey again and see if it blows off, you know the odd spitting when its cold aint gonna do any harm, if it spits when warm to then it will need seein too, i would just put a dab of super glue on the cap, this should hold it on if it does spit.

Share this post


Link to post
Share on other sites
UPDATE 12.30pm 15th April.



Afternoon Rob.

Sprocket is on as that arrived today along with the adapter for my compression tester.

Just checked them m8 and here are the figures.

Cylinder 1 = 130psi

Cylinder 2 = 120psi

Cylinder 3 = 125psi

Cylinder 4 = 126psi

Good or bad m8 ?

Share this post


Link to post
Share on other sites

Hmmm they seem low to what you typed earlier on Rob in this thread, just nipping out now to purchase another set of feeler gauges Cool

Share this post


Link to post
Share on other sites

they are getting near the bottom limit but all are within 28 psi of each other so wouldnt worry about them readings.
check them clearences again tim and air them on the generous side, better to have a bit of a tick than a burnt out valve, paying particular attention to that number 1 cylinder that is blowing the cap off, and to be honest i aint seen a Bandit, pre water cooled that dont tick, Very Happy

Share this post


Link to post
Share on other sites

Muchos Gracias Roberto thumbs

That's made me feel better m8.

OK just back from screwfix with new set of feeler gauges the go right through the range.

What thickness do you recommend please Rob, I do have a Haynes here m8 but I'd rather listen to you're advice to be honest m8 thumbs

Ohhh and I travelled 30 mile round trip to screwfix and there is NO knocking now thru my foot peg thumbs .....glad thats sorted m8...Thank you thumbs

Share this post


Link to post
Share on other sites

nice 1 Tim, glad the knockings sorted thumbs
go for intake valve - 0.15 mm, and exhaust valve 0.23 mm, a gud sliding fit with the feeler and do the clearences on a stone cold motor, o yeh and recheck the clearence when you have tightened the locknut, the gap can tighten up when locking up the nut.
gud luck,

Share this post


Link to post
Share on other sites

Yeah me to Rob thanks m8 thumbs

Yes I'll leave her out tonight then she'snice n cold for tomorrow Cool

Yeah I've been rechecking them cos like you say Rob the feckers go tighter when you give it a slight turn on the nut to tighten up.

1 more thing as I've picked up imperial & metric gauge, in the picture just dbl checking it's right tabs as I want it right from tomorrow mucker thumbsLaughing

The numbers read if you cannot make them out...

.006
.152 I've gone paranoid over these figures now dammmm.

Click the img/ Rob for a bigger picture thumbs

Share this post


Link to post
Share on other sites
Yeah me to Rob thanks m8 thumbs

Yes I'll leave her out tonight then she'snice n cold for tomorrow Cool

Yeah I've been rechecking them cos like you say Rob the feckers go tighter when you give it a slight turn on the nut to tighten up.

1 more thing as I've picked up imperial & metric gauge, in the picture just dbl checking it's right tabs as I want it right from tomorrow mucker thumbsLaughing

The numbers read if you cannot make them out...

.006
.152 I've gone paranoid over these figures now dammmm.

Click the img/ Rob for a bigger picture thumbs


cant tell from the pic if its imperial or metric set tim, what does it say on the box? the figures i quoted were metric
0.15 mm = 006 thou (imperial and 0.23 mm = 009 thou (imperial)
its critical that you dont get metric and imperial mixed up m8.

Share this post


Link to post
Share on other sites

Right I'm off to sort this now....worked out which is what Rob on the Gauge...catch you all later thumbs

Share this post


Link to post
Share on other sites
Update @ 16.24 16th April.

All done @ 3pm bout flippin time to Laughing

She sounds so much smoother now, adjusted the carbs yesterday thanks to Rob, synced the carbs again today after checking the valves, no banging in the cylinder now just after tickover

Did 3 short videos, 1st one is before I checked the carbs well just after installing the valve cover, 2nd one is of the gauges showing slightly out of sync then the 3rd is after I adjusted them.

Many thanks Rob for purseaveering with me to get this sorted...thanks pal







Share this post


Link to post
Share on other sites

×
×
  • Create New...