Used engine first time maintenance

[ben2go]

If the engine compression test good,then I would change the pilot jets to non bleeder type 40's.They are the ones that are the hardest to keep from plugging up.Even a little varnish inside them is enough to cause the engine to run bad.Mine should be around 145 with the V&H and lunch box filter.I don't see why the smaller head would be a problem as long as the slide needle can drop down to it without bottoming out.

[Dizzledan]

I would change the pilot jets to non bleeder type 40's. Mine should be around 145 with the V&H and lunch box filter.

The pilot jets are the ones I have to buy from the dealership because they aren't produced aftermarket, right? Also, when you say 145 what are you referring to?

I don't see why the smaller head would be a problem as long as the slide needle can drop down to it without bottoming out.

This makes sense. The height of the head is the same as the old jet, but the diameter is just smaller. Everything fits together, and appears to be working when I thumb the slides.

[ben2go]

I would change the pilot jets to non bleeder type 40's. Mine should be around 145 with the V&H and lunch box filter.

The pilot jets are the ones I have to buy from the dealership because they aren't produced aftermarket, right? Also, when you say 145 what are you referring to?

I don't see why the smaller head would be a problem as long as the slide needle can drop down to it without bottoming out.

This makes sense. The height of the head is the same as the old jet, but the diameter is just smaller. Everything fits together, and appears to be working when I thumb the slides.

The pilots and the mains should be Mikuni and they are available from many sources.145 should be your main jet size with a V&H exhaust and lunch box air filter.Depending on elevation above sea level,anything from 142.5 to 150 will work.One of my GS runs 145s and one runs 142.5.Both run non bleeder type pilots in a size 40.

[Dizzledan]

Ahh I gotcha now. I found these based on the part numbers from the wiki. Is this about right pricewise?
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=1725145&store=&catId=111&productId=p1725100&leafCatId=11101  Main     
http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=17339940&store=&catId=413&productId=p173399&leafCatId=41306  Pilot

[sledge]

.I wouldn't do any parts changing until I did a full compression check with a gauge and see where the issue might be

I agree fully, any used engine with an unknown history should be compression tested before even considering using it but your first suggestion to the OP was to throw time and money at it and clean the carbs, check the valves, and change the plugs and oil!!

Lets hope the problem is related to valve clearance and not something more serious like a holed pistion or something similar eh?

Another newbie gets dubious advice............If you were my mechanic I would have fired you off a long time ago 

Yeah,I was kind backwards on that but I assumed......

Yep.....and not the sort of thing you would expect a mechanic with an alleged 17 years under his belt to do!!

You tend to make a lot of assumptions Ben.....and a lot of claims and statements....... in a lot of different forums. After reading a few of them I struggle to see exactly where in your world reality stops and fantasy starts. Consequently I hope you dont mind me looking upon you as something of a dreamer. I am sure your intentions are good but you dont know as much as you think you do.

[Dizzledan]

Well the verdict is in......... $850 parts/labor for new valves. 

Edit: Or a plain $700 for just a head swap and new rings on the pistons. Tell me I can do this at home and save myself a ton of money!

Edit 2: Talked him down to $400 for the head swap, a good cleaning, and a guarantee. I may just do this just so I can ride again in a week and have a guarantee on the 20 year old engine.

[twinrat]

get yourself a manual and do the job your self spend mony on tools .you have the engine on the bench proves you can do it yourself you have got this far .more satisfaction and a great learning curve ,YOU CAN DO IT.
Cheers Rod

[ben2go]

.I wouldn't do any parts changing until I did a full compression check with a gauge and see where the issue might be

I agree fully, any used engine with an unknown history should be compression tested before even considering using it but your first suggestion to the OP was to throw time and money at it and clean the carbs, check the valves, and change the plugs and oil!!

Lets hope the problem is related to valve clearance and not something more serious like a holed pistion or something similar eh?

Another newbie gets dubious advice............If you were my mechanic I would have fired you off a long time ago 

Yeah,I was kind backwards on that but I assumed......

Yep.....and not the sort of thing you would expect a mechanic with an alleged 17 years under his belt to do!!

You tend to make a lot of assumptions Ben.....and a lot of claims and statements....... in a lot of different forums. After reading a few of them I struggle to see exactly where in your world reality stops and fantasy starts. Consequently I hope you dont mind me looking upon you as something of a dreamer. I am sure your intentions are good but you dont know as much as you think you do.

Thanks.Your opinion means a lot me. 

get yourself a manual and do the job your self spend mony on tools .you have the engine on the bench proves you can do it yourself you have got this far .more satisfaction and a great learning curve ,YOU CAN DO IT.
Cheers Rod

I agree that a top end can be done at home with the proper tools.Make sure to keep everything extremely clean.A manual is a must and follow it step by step.Got questions,ask here.Since I am an incompetent mechanic and dreamer,as stated above,I will let the real pros guide you.If you have a friend or family member that is knowledgeable about mechanics,ask them to lend a hand or check over your work at different stages.

[sledge]

Sorry abut that last comment Ben, I must appologise.

Thing is I have this medical condition that makes me highly alergic to BS` and BS`ers. Perhaps when I get to see this GS5 based trike you are building, or your GS5 race race bike or the fuel injected GS5 finished I might feel a bit different....perhaps even one or two of the non GS projects that you talk about in the other forums   

Leave it with ya 

[Dizzledan]

Glad you too made up haha. Where can I grab a good set of gaskets?

[Dizzledan]

Well it took me long enough, but 4 days ago I finished the head swap and got everything back together  The first time out was rough, because I put in new 5/16" fuel hoses that didn't like the way my fuel filter fit, and my clutch cable wasn't adjusted quite right. The following 3 days have been wonderful riding, but a new problem has cropped up:

The engine rpms are dropping whenever I slow to a stop. It will idle at 1500 rpm when I blip the throttle and let it come down, but after a few seconds it will drop down to 700rpm, and then eventually (5 seconds or so) die out. If I restart it, it idles again at 1500rpm and repeats.

Things I've checked:
1. Carbs (pilots and main jets are clear, bowls are still sparkling clean)
2. Clutch cable- regardless of what gear I'm in, it will still die out
3. Carb boots- Brand new, cinched tight
4. Sea-foamed the engine, by means of the carb intake to check for leaks, couldn't find any

I have the vaccum-less petcock and the caps I put on the carb ports are still there.
Jetting is 150 main, 40 pilot, K&N lunchbox, and V&H exhaust.
I haven't noticed any dead spots accelerating, and the bike otherwise performs fine.
Is it possible that I didn't torque something engine wise down enough?

[burning1]

Loss of compression is due to a few issues.The piston to head clearance is what it is and is set by the design of the engine.The main things that cause a loss of compression are:valve clearances to tight,valve or valves seats damaged or cracked,piston rings seized or not sealing against the cylinder wall,scored or cracked cylinder,cracked or burnt piston.These are what are reported.Usually it's valve clearance being to tight,a damaged valve or seat,and some times bad rings or cylinder.I wouldn't do any parts changing until I did a full compression check with a gauge and see where the issue might be.

Valve timing being way off would do it too. I would definitely check that. Pouring a few CC of oil down the cylinders can help to seal rings, and is a good way to determine if your compression numbers are due to bottom or top end problems.

[afterbooster]

This thread has been awesome to read, I'm way Impressed... I just installed a used motor in mine this year... by any chance Is the crankshaft from the original motor good, (not with any scratched up journals)? Also... I might happen to have some good forks laying around that could use some road time...
thanks,
Booster

[Dizzledan]

Valve timing being way off would do it too. I would definitely check that. Pouring a few CC of oil down the cylinders can help to seal rings, and is a good way to determine if your compression numbers are due to bottom or top end problems.

Thanks for that reminder, I should definetly check out my compression numbers now that I have something that actually compresses the gas and air 

afterbooster:
I haven't split open the cases from the old engine yet (having too much fun riding the new one), but I will definetly get in there and check it out for you. From what I can see, the bearing broke, and pitched the crankshaft into the front wheel side of the lower case (see pictures on page 1). I'm thinking that pretty much everything in the lower end is going to be worthless. As for the forks, I ended up using a standard socket end and lots of penetrating oil to get them loose. Oddly enough, only the caps are rusted to crap, the rest of the forks appear to look/function fine.

I'm in central Ohio if anyone wants to pick up a busted engine that has a good jug, pistons, and head case. The valves are bent, and the lower end is undetermined.

[Dizzledan]

So I go out to test compression on the new engine today, all I get is a clicking noise. The lights dim, so I figure the battery is dead. No sweat, I grab the jumper cables, and hook em up. I let the big battery charge the little battery for a few minutes (both engines off), and after about 10 minutes I unhook and try to start the bike; it fires right up. I go for a quick test run to charge up the battery, but lo and behold, after 4 minutes of riding, she dies on me. The battery is fairly recent (3 months), so I looked for problems with the charging system. Coming from the recitfier, I find this:


My theory is this: The wires were taking too much of a load and melted the plastic connecter. Eventually the plastic melted into the connector and burned, separating the connection, and ergo not giving the battery any of the charge generated by the alternator.

My question is, can I just clip the connecter and directly solder the wires? I figure there would be less resistance without a connector.

[Dizzledan]

Update:

I directly soldered the wires from the rectifier with some 16 gauge wire, charging system works flawlessly (if not better). Monitoring the temperature/condition of the wires to make sure that it doesnt melt and short out.

I added 2 #4 washers to the carb needles (which I hadn't done previously upon rejetting)
Got a new fuel filter and a longer fuel hose to route underneath the frame crossmember (for better fuel flow)
Re-wound the spring on the left hand side needle (slide was getting caught partway up)

It idles perfectly now!!!!! 
I'm not sure what did the trick, but I finally have a semi-normal working bike again, it feels good.
No more bogging down while stopping, and the idle doesn't jump up and down; but most importantly, it doesnt hang while decelerating.

I just have to re-set the mixture screws, and I'll be golden until the next learning experience. 

[Dizzledan]

 
I spoke too soon. Now I've got flat spots from 1500-3000rpm. It's so bad that when I start off, I have do rev up to 3500 to get off the line. Should I take a washer off the needle or put another one on? I'm not sure if its a fuel or air issue.

It'd help to add my setup:

V&H Full
K&N Lunchbox
150 main
40 pilots
3 turns out
2 shims under needle

Apart from bogging down on take off, the bike runs slightly rich, backfiring on deceleration.