Thoughts on slightly wandering idle

[Guest]

Well the valves are all adjusted and now in spec, and thanks to tom203 for giving me one of the needed shims!

I am guessing that the valves haven't been checked in quite a long time due to the condition of the gasket which took about 2 hours to remove all the bits from the cover and the engine side. Three of the valves were tight and one was in spec.

I also installed a new petcock, new front pads and replaced the brake fluid.

The difference with the valves in spec is much more than I imagined it would be. The bike started right up with the choke, which now appears to be behaving normally (hopefully that continues), and warmed up quickly, and is holding its idle extremely well now with no wandering at all. It also seems a bit smoother under acceleration which surprised me since it didn't seem to be unsmooth before.

The only issue I have run into with all the work is that the new OEM petcock is slightly different then the original one. The point where the vacuum hose attaches is in a slightly different spot which means my hose is now a bit too short. Slightly annoying but obviously pretty minor.

So big lesson learned, check the valve clearances! Buy the new gasket, buy the feeler gauges, get a dang zip tie (which has got to be on the most simple and brilliant idea) and just do it!

Oh and the whole process really makes me glad that I bought a twin. I am happy to have only had to clean 2 carbs and dealt with 4 valves.

Awesome news! Glad to hear it

And yes, I'm also very glad I only have 2 cylinders and carbs to deal with...

 

[Phil]

Well unfortunately it seems it is not starting normally with the choke. I guess there is something in the choke circuit.

...The difference with the valves in spec is much more than I imagined it would be. The bike started right up with the choke, which now appears to be behaving normally (hopefully that continues), and warmed up quickly, and is holding its idle extremely well now with no wandering at all. It also seems a bit smoother under acceleration which surprised me since it didn't seem to be unsmooth before.

 

[BigD_83]

Well unfortunately it seems it is not starting normally with the choke. I guess there is something in the choke circuit.

Can you explain further:

What do you understand as "normal" and what is actually happening now?

 

[Phil]

Normal would be that I should be able to engage the choke to some degree, usually somewhere in the neighborhood of halfway, and the bike should start from cold and not struggle to keep going.

Unfortunately, it seems to struggle and needs some amount of throttle to keep from stalling. Adjusting the amount of choke either doesn't change anything or makes it stall out.

Luckily it doesn't take very long for the bike to keep itself on without any choke.

At this point there can't be much else to cause this other than something clogging up the enrichment circuit.

Can you explain further:

What do you understand as "normal" and what is actually happening now?

 

[tom203]

Of course after the shim fun, you went back and checked/adjusted the mixture screws just in case ?? You said it was pretty close with Carbtune before valve fun, what about after?

 

[Phil]

Of course after the shim fun, you went back and checked/adjusted the mixture screws just in case ?? You said it was pretty close with Carbtune before valve fun, what about after?

The vacuum sync was spot on after and I didn't even need to adjust it. I didn't change the mixture screws though the thought did occur to me last night that they may need to be looked at again.

Its very odd because it seems like it almost works properly. It will work normally for like a couple seconds and then it will dive back down the to sub 1k and struggle until you blip the throttle.

On the positive side though, I have done about 100 miles since I finished the valves yesterday and the idle has been rock solid.

 

[Phil]

Sounds like the choke circuit quickly loses its fuel supply- strange. I'd just ride some more. At some point, you can drop the fuel bowls and look for obvious clog. Basscliff had something regarding fuel bowl gaskets, see attached pic

Yeah it can't be anything too crazy since the bike, otherwise, runs so well. That and I clearly remember it starting well from cold with the choke after I cleaned and rebuilt the carbs. Getting the float bowls off will have to be another rainy day project. Hopefully not as rainy as this past weekend.

 

[Phil]

General Update

General Update

Yeah it can't be anything too crazy since the bike, otherwise, runs so well. That and I clearly remember it starting well from cold with the choke after I cleaned and rebuilt the carbs. Getting the float bowls off will have to be another rainy day project. Hopefully not as rainy as this past weekend.

Well I have had my license for about 6 weeks now and rode almost 1,500 miles now on the 450. Today I did about 150 through western Maine and New Hampshire. The bike is running great other than the strange choke issues.

I did finally get new tires. If you need the 110/90 17 for the rear I would suggest DennisKirk.com, it was by far the cheapest (by like $25 bucks), and it seems that IRC is the only maker of this size. Also, if anyone is in the greater Portland area and is looking for an inexpensive place to get tires mounted I would suggest Century Tire in Portland.

Now if only the seat on the 450T was a bit more comfortable! I am thinking I might try the Kancamagus Hwy tomorrow. Who knew a $650 30 year old bike would work out so well!

 

[tom203]

Phil said ...."Who knew a $650 30 year old bike would work out so well! "

Yeah, it's sorta amazing! take some time, do the maintenance, and be surprised!

 

[Guest]

It's great ain't it?

I've done over 5000 km's on my 450 since getting her back on the road in December last year and I just can't get enough.

In less than 1000km's she'll need service number 2 and I plan on keeping those km's ticking over... havin' a ball!

 

[Phil]

Phil said ...."Who knew a $650 30 year old bike would work out so well! "

Yeah, it's sorta amazing! take some time, do the maintenance, and be surprised!

Yes, it has definitely reinforced my idea that my next bike will be an 850G. If I can find a job in the near future I will be looking late in the Fall for one and I can spend the Winter and early Spring getting it up to par.

You would think an out of work CPA should be able to find a job easily, but its been a bit over a month so far.

 

[tom203]

Lots of bikes on maine Cl- of course, most folks aren't realistic about what they are worth! lots of these owners will be desperate/flexible come fall (if not before !), so you'll have no problem. Big guy? 850 is great choice.

 

[hjacobmiller]

Yes, it has definitely reinforced my idea that my next bike will be an 850G. If I can find a job in the near future I will be looking late in the Fall for one and I can spend the Winter and early Spring getting it up to par.

You would think an out of work CPA should be able to find a job easily, but its been a bit over a month so far.

Fellow CPA???? Good to see another number cruncher..... and a GS rider to boot!

I'm studying for the exam currently.

Sorry to hear about your luck... Keep at it though!

 

[Phil]

Lots of bikes on maine Cl- of course, most folks aren't realistic about what they are worth! lots of these owners will be desperate/flexible come fall (if not before !), so you'll have no problem. Big guy? 850 is great choice.

Yeah, I would say somewhat big. I'm 6'2" and about 275 lbs. I had good luck with finding the 450. At $650 the price was more than fair, the only relatively expensive thing it's needed was tires, though it certainly helped that it was November. Turned out to be a great first bike, which had only been my guess since I had never been on a bike when I bought it. If it had a more comfortable seat I would consider keeping it longer. Either way I think I will keep it around as my wife is considering taking the MSF Basic Rider course next Spring and I think the bike would would work well for her, and would probably be all the bike she would ever want.