Topic: Help to analyse compression test results

[Mikal]

Thanks all. I don't have tryed motorbike yet.  My mechanic told me something about " ...is not pushing/going up at high revs"
I will ask him better about this (if I correct understood...).
Today I tried only to run the throttle while motorbike engine was on (I don't have insurance yet to run on the road).
Engine is fast to go up revs but if I open too fast the throttle, it shutdowns, is this normal?

Well, mine has done 80 000km, and is a 500. Had it for three years now and I have never ever been able to snap the throttle open, too much air and it bogs down. It's just the nature of the beast I guess.

When everything is clean, synchronised, adjusted etc etc she will sing Like this:

And not like this (from when I bought it):

[bochnak]

So if I'm reading the graph correctly, you have 103-110psi across all 4, correct?

D'oh, I see how to read the graph now. That is a neat tool, however I don't see why anyone needs to spend the extra dough on a graphing feature. A pencil and notepad are pretty these days.

To the OP, along with what everyone else mentioned, make sure you check for vacuum leaks.

[strynboen]

these" registrators" is common in Europa..they fit in the car logbook..and is fine for dokimentasion ..in sale or reparation..its nice to hold the messurings..and by tvisting the plate you can make a later test and hold them up..against the erlyer test

[_mark]

Hi guys I will keep motorbike tomorrow.

Today I've spoken with the mechanic about the problem of cold starts; he told me that the reason are not the carburators.

If it is for real due to carburators, what is the difference between a cold and an hot start from carburators point of view?
 
The reason of fail to start in cold conditions is because of the lack of compression; once the engine is started and warm the problem disappears because some of the compression is recovered.

Any comment? Thanks a lot.

[strynboen]

a veared aut engine starts fine..its use a lot of oil..or rattel..but starts fine...so find an other mecanic ..-he dont have any idea of this type engines....old diesel engines...dont start easy..bu kompresion lost..but a small gas engine..dont have this problems...

[_mark]

Hi. Today I rode my bike. I post here some videos I did while it was stopped after 3 hours (almost cold conditions):

when is cold the minimum is lost but we are talking of a inimum of 800 rpms . Rpms are increasing smooth and fast. For the moment I keep the bike as it is and then i will see how behaves in the next tousands Kms.

Thanks. Regards

[_mark]

video 1 and 2 were recorded some moments later (let's say 1 minute) after I start the bike with chocke comand ON .After this minute I released the choke command and I start to record the videos. So in no one of the videos I used the choke.
In video 3 the RPMS were slighty over 1000 because the throttle was twisted a little.

The pourpose of my video was to undestand if the minimum is good in cold conditions and without choke (video 1 and 2)and to know also if the response of the throttle is good (video 3)

Thanks

[Stev-o]

The pourpose of my video was to undestand if the minimum is good in cold conditions and without choke

Thanks

If you are referring to the RPM setting, it needs to be set once the engine if fully warmed up [5-10 min].
I set it by ear, the gauges on these bikes are not super accurate, can be off 10-15%.
And I like the idle a little higher than what the manual states, about 1500 rpm.

[_mark]

thanks. Could be helpful a smartphone app to understand RPMS ? is possible?

[grcamna2]

I know it has been mentioned but did your mechanic do the full 3000km service including adjusting the valves,cam chain,points,timing,replacing the plugs and synchronizing all 4 carburetors? I am also curious if the carburetors may have dirt in the small pilot jets(possibly coming from the fuel tank?)which would cause an erratic idle speed.

[_mark]

Yes, everything : cam chain checked, valves clearance , timing , new condesnators, new sparks, complety revised carbs ( I think kit from kyster), new manifolds, new points,  new battery, new pinion sprocket and chain etc

new tyres and frame incision and adjustion also ( see here what happened...   http://forums.sohc4.net/index.php/topic,152832.msg1764733.html#msg1764733   )

Thanks

[Stev-o]

complety revised carbs ( I think kit from kyster),

This could be problem. Keyster = Krap

Only use Keihin parts!!

[DaveBarbier]

Yes, everything : cam chain checked, valves clearance , timing , new condesnators, new sparks, complety revised carbs ( I think kit from kyster), new manifolds, new points,  new battery, new pinion sprocket and chain etc

new tyres and frame incision and adjustion also ( see here what happened...   http://forums.sohc4.net/index.php/topic,152832.msg1764733.html#msg1764733   )

Thanks

Diachii condensers? They often cause problems also.

[grcamna2]

complety revised carbs ( I think kit from kyster),

This could be problem. Keyster = Krap

Only use Keihin parts!!

+1 

[_mark]

complety revised carbs ( I think kit from kyster),

This could be problem. Keyster = Krap

Only use Keihin parts!!

 

[_mark]

I don't know if I had the stock jets from beginning. Replacement was needed because when I bought the bike the throttle command was stuck in two carburators.

At 1200 rpms the engine is smooth and regoular with no esitations even in cold conditions.

Thanks

[_mark]

I don't know if I had the stock jets from beginning. Replacement was needed because when I bought the bike the throttle command was stuck in two carburators.

Fair enough, but stuck SLIDEs has nothing to do with your JETS and NEEDLES.

the slide is not connected directly to the needle? thanks regards

[bochnak]

I have used Keyster kits several times with no issues. They are the only kit that comes with the emulsion tube, which can wear over time.

Not to hijack, but what were some of the negative experiences with Keyster kits?

Thanks,
Matt

[grcamna2]

I have used Keyster kits several times with no issues. They are the only kit that comes with the emulsion tube, which can wear over time.

Not to hijack, but what were some of the negative experiences with Keyster kits?

Thanks,
Matt

the new Keyster brass stuff seems mismatched and generic which causes poor/too rich,etc. carb. performance

[bochnak]

I have used Keyster kits several times with no issues. They are the only kit that comes with the emulsion tube, which can wear over time.

Not to hijack, but what were some of the negative experiences with Keyster kits?

Thanks,
Matt

the new Keyster brass stuff seems mismatched and generic which causes poor/too rich,etc. carb. performance

Thanks. Does Keihin still produce the emulsion tube?

[_mark]

Hi Guys. Good news. Bike is behaving very good ! I run two hours in the last two days and it starts from cold without the need of any spray.

[grcamna2]

I have used Keyster kits several times with no issues. They are the only kit that comes with the emulsion tube, which can wear over time.

Not to hijack, but what were some of the negative experiences with Keyster kits?

Thanks,
Matt

the new Keyster brass stuff seems mismatched and generic which causes poor/too rich,etc. carb. performance

Thanks. Does Keihin still produce the emulsion tube?

You can check the online parts ordering and see,like motogrid.com

[flybox1]

Hi Guys. Good news. Bike is behaving very good ! I run two hours in the last two days and it starts from cold without the need of any spray.

Great....sooo, what fixed it?

[bochnak]

I have used Keyster kits several times with no issues. They are the only kit that comes with the emulsion tube, which can wear over time.

Not to hijack, but what were some of the negative experiences with Keyster kits?

Thanks,
Matt

the new Keyster brass stuff seems mismatched and generic which causes poor/too rich,etc. carb. performance

Thanks. Does Keihin still produce the emulsion tube?

You can check the online parts ordering and see,like motogrid.com

Yes, I usually check Honda fiches first. Often times they are not available. I'm not talking about any particular model here either.

[flybox1]

Emulsion tubes were never sold as an individual part.
Unless yours are severely damaged, yours can and should be reused.