1975? T500 wont idle

[tz375]

That partial invoice is sobering for sure. I see tires and tubes and float valves and carb gaskets and two sets of brake shoes and so on. Nothing on that list that we would probably would not have replaced if we did the work, but we might have found lower prices on line - or perhaps not. Lucas D.O.T. approved indicators are probably a little expensive and one might argue that there are cheaper or better ways to fix the indicators, but you ask a dealer and they simply order what they think will work.

I don't see anything egregious on that list. It's a cost of getting someone to do the work at retail prices. Old bikes with problems take a lot of work to fix and time costs.

The issue here is why doesn't it idle. In all probability it's a combination of low compression and probable leaks from the crank seals coupled with blocked jets and/or circuits in the carbs. 145-125 PSi are not particularly low, but the spread between teh two is high and indicates a problem.

I would recommend stripping and cleaning the carbs as a first step and replace the pilot jets. Then I'd carefully check the ignition timing and see if it has a decent spark. If it runs acceptably at that point, the next question is whether to strip the motor and replace the crank seals.

The "right" answer is YES, of course, but let's see if the other cheap fixes work before going down that path. The risk is that running it with a leaky seal is that it may blow a piston and that just adds to the cost, but the OP can do the easy stuff in house at very low cost.

[Jakeyz333]

Alright I'll pull them off n once over everything. The more I talk to u guys the more upset I'm getting about this ticket but at this point what's done is done. I'm in Louisville Kentucky idk where would be a good place to eventually get the seals done correctly. I figured with all the carb work they did everything "should***" be sound but I'm not trusting them so much anymore. What's the possibility that it is lack of compression coupled with leaky seals being means for no idle? Thanks for all the help -Jacob

[Jakeyz333]

How much would it be for the seals as well as a bore because apparently the cylinder is scored on rh cyl so if I'm going to do it I'll get it all done I just need to find someone who isn't a shop and who knows what they are doing, and are passionate about bikes not jus $$$

[mike1161]

I can recommend Bill Bune up in Minnesota to install the seals, I just had my T350 crank done a few months ago, total was $192 (check/true crank, install inner seals), plus my cost of the seals (about $80). But it's worth it if you really want it to run right & have long term reliability. Not sure how much a bore job would be...
I also agree with the previous comments, working on these old 2 stokers is best done by someone who is really into it and/or wants to take the time to learn about them. Most shops these days just don't have anyone with the experience, that's just the way it is. For me & most everyone on this board I'm sure, half the fun of these old machines is working on them, the other part is riding them, they have such a unique character & sound.

[ConnerVT]

For engine work, I can also suggest speaking with both snowmobile shops and (some) marine engine shops. Both still have a bit of 2-stroke engine work that comes through their doors, unlike modern motorcycle shops. Snowmobile shops slow down in the summer, marine in the winter, both should be happy for the extra work in their off-season.

While the engines may look different physically, a 2-stroke crankshaft rebuild or a cylinder bore job are very much the same, regardless of the vehicle it is attached to.

[Jakeyz333]

What would you guys think about Dealerships. There is a Yamaha of Louisville near me n I actually job shadowed there in highschool but they are Suzuki Polaris etc. It seems like they would get two stroke dirt bikes but they may not have any time for it. I'm just trying to get on the road. And the shop o took it too is cycleworkslouisville.com they didn't seem to be a "modern shop" by any means they were a bunch of older dudes, but didn't seem to know anything about these bikes

[yeadon_m]

I would second TZs comment and say that if the bike needs a 'shop' to fettle and fix it, its unaffordable and may not be the machine of choice for you. If I paid myself burger-flipping wages for the amount of time I tinker my GTs to work well, I'd be very rich. But, its cheap that way, like me
Good luck!
Mike

[tz375]

Mike is right that old bikes like these become very expensive if they have to be brought back from the dead by a dealership. The cost of parts is bad enough, but it's the labor that kills. What I have always done is to do the basic labor myself and to only pay for specialist work such as crank rebuilds and machining.

Fortunately a T500 is a very basic motorcycle and one on which it's easy to learn. Start with a copy of the parts list and a Factory Shop Manual. They are not as comprehensive as you might hope, but are a great place to start.

Things like carb rebuild, ignition work etc, you can learn to do proficiently at home. Cranks can be sent to companies such as Bill Bune. They also do re-bores should that be necessary. I'd start with the carbs though and take lots of pictures and ask lots of questions as you go.

There's a ton of experience and expertise on here to expeditiously extricate you from the excrement.

[Coyote]

It sounds to me like they completely shut the air screws off to try to richen the idle circuit. That is completely wrong. Everything points to the pilot jets are clogged, You need to inspect these carefully under magnification. Especially if ethanol laced fuel has sat in it for a while. What happens is the ethanol coagulates in the tiny holes in the pilot jets. This does not allow sufficient fuel to idle. Had that exact thing happen to me on my GT550. I have no idea where your air screws should be set as I have no 500 experience. Others can chime in with the proper setting, but I KNOW closed ain't it.

[Jakeyz333]

Awesome more things I have to rule out the better. So get some magnification and maybe a toothpick or something thin n make sure you can see light thru the other side right? Its jus I have no place to tear that engine apart at so that's sort of an issue on top of me being 18 I'm not confident for major engine repair alone, I know limits so I don't break anything haha

[tz375]

Poking things through those tiny holes tends to create problems of enlargement. For the pilot jets, I'd just pull the carbs, strip them and soak them first. Inspect all teh tiny holes as Coyote suggested and with the pilot jets, I'd simply order a new pair of the same size and type. Come back here and we can advise which ones after you do the research.

The first bike I stripped was in a kitchen, the next was in an attic. I have done a few in the basement and I completely & stripped rebuilt one in my 5th floor apartment. Paint was done with rattle cans out in the back lane when there weren't too many people around to complain about the smell.

Grab a manual first and get a parts list to see where parts go in relation to each other.

[Jakeyz333]

BTW any info on why the throttle is loose until about 75%?

[tz375]

What do you mean by "loose". A video might help or at least a picture.

[yeadon_m]

Maybe you mean, physically loose, ie no resistance to rotation at first? if so, it is likely to be throttle cables badly adjusted. It may be you mean something totally different
Mike

[Jakeyz333]

Hey guys I'm out here piddling and I just noticed they blocked off the vacuum line with a rubber cap. They did have to put a different petcock on it and this one doesn't have a vacuum line on it..