75 T500 Compression

[bikingbagga]

About 5 years ago I did crank seal check everything was OKI have not checked it again

I now have these readings what readings should I be getting

Left cylinder compression is 110 Psi
Right cylinder compression 130 Psi

Also bike will not idle with the idle screws completely turned in

[titan performance]

Have you been in the carbs? Check your slides are round the right way.....ie, cut outs to the rear. If not, then your pilot jets are blocked.

[Craig380]

Between 120 and 130 psi is normal/good for a standard road machine. About 10% difference is the maximum you'd want between cylinders.

Are you measuring the compression with the engine hot, with throttle held wide open, and after 6-7 kicks in rapid succession? If not, test again doing it like this ...

[bikingbagga]

Bike has been running for over five years I will check the pilot jets to see if they are plugged. Slides are not in back wards

I did check the compression when bike was cold I will re-check using your method.

[Coyote]

If you've been burning ethanol blended fuel, that stuff loves to plug pilot jets - especially if the bike is allowed to sit for a long period. It somehow coagulates and leaves this jelly like substance in the jets. Happened to me twice now. Different bikes - same problem. Another indication that the pilots are blocked is turning the air screws has no effect at all.

[bikingbagga]

I used regular 91 gas & yes I don't ride it that often. So I'm going to take a good look at the pilots

I'm still thinking compression is an issue as well

[bikingbagga]

Did a crank seal check its not holding 6 psi but to be honest you wonder if everything is completely sealed & you are actually checking the crank seals & yet the bike starts & runs. Not sure I really want to do a complete dissection & new crank seals etc major expense. Can a crank seal leak cause bike not to idle & cause bike not to rev up crisply. Revs just seem to build when you turn the throttle quickly. Will be looking at the pilot jets next

I have now taken the barrels off. Inserted the top ring in to the left barrel bore below the skirt, Ring gap is get this 2.3 mm when the max limit is 1 mm (not good0 yet. Piston to bore clearance is 0.004" so we are OK.

Looks like new rings for sure any thoughts on the crank seals

[Craig380]

Well, with that big of a ring gap, you've certainly found the compression problem

If the cylinders are otherwise pretty good, feed her a new set of rings and put the top end back together. My 10 cents is, leave the crank seals until you've ruled out all the other possibilities.

At least the carbs are easy to remove and pull apart on the T500. Just be methodical, have a big can of carb cleaner handy, and get rid of any crud you find in the jets and passages. Household fuse wire is good for clearing the tiny holes in the jets, it is softer than the brass jets so will not damage them.

[bikingbagga]

Top end now rebuilt & I did find that the right carb pilot jet was completely plugged so I replaced it

Never got time this weekend to start it

[bikingbagga]

Been consumed by other projects.

Finally I had my crank seals replaced by Bill Bune Enterprises using OEM seals now engine is rebuilt back in frame.
I actually got it to start on a full choke but it was very hard lots of kicking. was able to set idle & re-start bike again & again when engine was hot first kick

Guess what now it want start when its cold: Man I'm tired of this

1. Fully charged battery
2. Strong spark
3. Kick it and kick it till you are exhausted full choke not getting any fuel into combustion chamber.
4. Plug is bone dry not a hint of any fuel.
5. Had someone cover carb inlet to see if they could feel air being pulled apparently just felt more like a pulse.

I'm now going to take the carbs off and go through them again.
Any ideas welcomed as to what is causing this very hard starting issue I'm having

[tz375]

I would start by checking fuel supply from tank to carbs.

Then I would take off the carbs and see if the bowls were "full".

Then I'd strip and clean the carbs and check or replace the pilot jets. Treat them to a nice long bath in a sonic cleaner and check all the drillings for flow and compare each circuit in one carb with the same circuit in the other one. And set teh FUEL level before you fit them.

Also check the intake manifolds for air leaks.

[Vintageman]

Tz made me think of something with "fill the bowls" statement

If the bike sets a spell and hard to start cold here is a problem I have had and method to improve.

The bowl drain gasket may drip slowly and the bowl goes empty over time. Or the gas just evaporates via normal venting.

It will take many kicks to fill carbs if the petcock is in the normal setting: the setting that relies on engine vacuum to flow fuel. Before you start it, put petcock on Prime and give it several seconds to fill carbs. Then start. I always do this on my bikes with this type of petcock if they sat for a time and usually a kick or two it starts where as it could have taken a dozen kicks to prime up empty carb(s) for example.

Maybe not it, but still something to consider

[Vintageman]

Also, Maybe the little hole jet passage in the bowl the the starter tube to pick up fuel is plugged so choke not working.

I say this and last post for sounds like your bike doesn't start easy cold but once warm OK. correct?