Valve Tappet too Small 1.6-1.8mm?

[Guest]

When you're done sanding the cam journals start sanding the shims.
Good luck.

 

[zathros]

Being disabled and unemployable, I also try and save on everything I do. I have a small machine shop but still know when to call it quits. You'll spend more on that head than a good used one would cost. There is probably a member here who could sell you one. Try posting in the wanted section.

You still have aluminum traveling around that motor and if it where mine I'd split the cases and go for it, or just look for a whole used motor.

 

[nisom512]

Being disabled and unemployable, I also try and save on everything I do. I have a small machine shop but still know when to call it quits. You'll spend more on that head than a good used one would cost. There is probably a member here who could sell you one. Try posting in the wanted section.

You still have aluminum traveling around that motor and if it where mine I'd split the cases and go for it, or just look for a whole used motor.

agreed also look on craigs list for a parts bike and maybe the guy could sell you the head for 50 bucks.

I was gunna buy a maxim 650 and it needed a cyclander head so I found a guy with one for 50 bucks and turns out he lived 15 min from my house

Jake

 

[Roland]

Valve Shims Nearly there.

Valve Shims Nearly there.

I appreciate all the helpful advice and I take it all to heart but all I want to do is to try to improve the performance by completing a Tappet Clearance adjustment. Nessissm gave the most likely answer to my original question,

Q) "What would cause the #1 Intake Tappet to be that far out of Specc."
A) "Lower Journal being worn down.

I am not quite ready to give up on this head due to one bad Cam Cap which Nessissm was so kind to provide the replacement. Not just yet anyhow. I have already cleaned up the journals and verified the best I can that the bore is identical or at least close enough that I can't measure an issue. As I stated in the previous post the oil starvation was something in the bikes past. There is no oil starvation at this point. The oil is flowing quite well to all parts of the Cam.

I am not ready to do a complete engine overall not in the middle of riding season anyhow. I have already been off the bike for a solid week and I can't take not riding any longer. I look pretty goofy on my wifes little 250 VStar.

If I were to go through the trouble of replacing the head it would be a waste of time and money unless I did a complete engine overhaul, pistons, valves, valve seats, valve guides, shims, oil seals, etc.. Who knows what I might find or cause to go bad as I get further into it.

There is no promise that the head I would end up with might not have a whole different set of issues. Not to mention the potential for causing issues with the Exhaust mount, Carb Boots, or unexpectedly breaking off bolts(remember she is over 30 years old)

The 78GS750E engine is a beast and is nearly bullet proof. Look at the pictures of the severely worn out Journal Cap and realize I was still able to do 90+MPH without even trying hard. This bike has received a whole lot more TLC from me than it's previous owner and I plan to conitnue to improve it for many years to come. This winter would be a much better time for me to do a complete overhaul.

Today's Results after 2 trips to exchange shims
Valve Shim Gap Result
E-1 2.50 .08-.10 Too Loose Need 2.5x
E-2 2.60 .06-.08 Good
E-3 2.60 .10-.13 Too Loose Need 2.60x not 2.65 &not 2.60
E-4 2.55 .05-.06 Good

I-1 1.75 .35-.38 Too Loose Need 1.95
I-2 2.70x .05-.06 Good
I-3 2.90 .03-.04 Slightly too tight Need 2.85x
I-4 2.70 .06-.08 Good

Before Starting the swap the originally shims were
Exhaust-Original Shim
1------------2.5
2 -----------2.6
3 -----------2.6
4 -----------2.65

Intake-Original Shim
1 ----------2.55x
2 ----------2.70
3 ----------2.80
4 ----------2.70

 

[zathros]

Winter is the best time to overhaul. Start looking for the parts now and keep looking till you find something good enough and in your price range. You may find a whole motor for the price of a used head. Some people just need to get rid of stuff. You are right, without doing the rest of the motor you could end up with a pile of trash by doing a half a$$ed job. On the other had, if you drop that valve you'll still trash the motor. Just keep in mind that as the cam journal wears further and or the throw of the valve gets loose, the valve retainers will get loose and you could drop a valve. So enjoy riding, but don't get too crazy with the rpm's or you could face a seized engine, something you don't want to happen in a turn, or with someone on back.

You'll know at the end of the season how it's all worked out. Who knows, I drove an MG for years and when I took it apart for the rebuild every ring was broken in at least two places. I only decided to rebuild it because the web between the intake and exhaust valve cracked and burned a hole threw a valve. God only knows how long that car was like that.

 

[Roland]

Timing Chain Tension Adjuster Stuck

Timing Chain Tension Adjuster Stuck

O.K. So I just finished polishing up the lower "C" journal with 500grit followed-1000grit followed by super fine steel wool and it is looking quite nice and is nearly as smooth as the original. After finishing that I pulled out the cam so I could polish it up as well but once I put it back in and got the timing correct the Timing Chain Tension Adjuster is now stuck but the chain and cams move very well but I used to be able to release the chain by holding the tensioner 1/4 turn then releasing.

What would cause this?

I am monitoring this thread while continuing to work on the bike.
Any help would be greatly appreciated.

 

[Guest]

You needed to remove the cam chain tensioner in order to remove cams. If you didn't you need to and cock it before reinstalling.

 

[Roland]

Idler freed up

Idler freed up

Never mind apparently the Tension adjuster got jammed when I re-torqued the idler. I loosened up the idler held teh Tension adjuster in it's released mode and re-re-torgued the idler. Now the Auto Tension Adjuster is working as it should.

 

[Roland]

Idler freed up

Idler freed up

Thanks Chef, the cocking is what I forgot the 1st time.

 

[Roland]

Started up right off the bat

Started up right off the bat

Well it's been 7 days and several hours but my baby is back together and she started with no hesitation.

Now I am off to bed. I will give her a full test tomorrow.

 

[posplayr]

Before hitting 9 grand, I think i would have made sure the cams spin freely:-&. Plasti-guage is cheap as well.

 

[Guest]

Before hitting 9 grand, I think i would have made sure the cams spin freely:-&. Plasti-guage is cheap as well.

It seems right as rain.

 

[BassCliff]

Well it's been 7 days and several hours but my baby is back together and she started with no hesitation.

Well, I've got two words for you....


Yeee Hawww!


Nice work. Thanks for sharing your success.


Thank you for your indulgence,

BassCliff

 

[posplayr]

Yeee Hawww!


Nice work. Thanks for sharing your success.

Now that is the kinda talking that will see 12 GRAND

I guess I'm to blame, I suggested sandpaper. :-s

If he did not get those cams to spin easily he could be in for a long walk home.

 

[Nessism]

Roland,
So what did you do about that valve that didn't have any clearance? Regarding that, did the valve bucket spin freely? I'm wondering if the bucket could be binding which is leading you to think the valve is sitting high and requiring that thin shim?

 

[Roland]

Smooth as a babies butt

Smooth as a babies butt

Smooth as a babies butt

Here is are some images of my cleaning up of the journals. The Journal Cap was the one that was really beyond repair. Note when the cam was not pushing on the tappet and the cam was not under pressure the gap was on the Cap(top) side so the cap took the worse of the wear.

The replacement Journal Cap fit perfectly. I have ordered the Pastigauge to verify all is perfect but the cam fit feels perfect.

At the moment I am saving my new gasket adn using the original gasket until I get in the proper shims to get all the tappet gaps within perfect spec.

Today I will run engine tests to see how everything is working but turning it by wrench all appears to working quite well.

 

[Roland]

Smooth as a babies butt

Smooth as a babies butt

Here is an image of my test fit of the replacement journal Cap. Measuring multiple key points between the caps revealed they were milled exactly the same or at least as close as I can measure with my digital caliper with .01mm precision.

 

[Nessism]

So what did you do about the shim on that one valve?

 

[Roland]

Valve # 1 beyond spec.

Valve # 1 beyond spec.

I got the two smallest ones they had at my local shop to test out and to be able to get something close so I can get an accurate measurement. Unfortunately my local shop doesn't have all the shims I need to get her within spec so I will be surfing the Internet.

I-1 1.75 .35-.38 Too Loose Need 1.95
I-1 2.15 .04 = too tight

At the moment I have the 1.75 installed because I don't want it to be too tight for my running tests. Now I just need to find some shims online in and purchase 3-4 in the range of 1.90-2.10 so I can get it as close as possible. I suspect it will take me another week before I can ride her more than just in front of my house.

Valve-----Shim-------Gap-------Result
E-1-------2.50------.-08-.10----Too Loose Need 2.5x
E-2-------2.60-------.06-.08----Good
E-3-------2.60-------.10-.13----Too Loose Need 2.60x not 2.65 &not 2.60
E-4-------2.55-------.05-.06----Good

I-1-------1.75-------.35-.38----Too Loose Need 1.95
I-2------- 2.70x-----.05-.06----Good
I-3-------2.90-------.03-.04----Slightly too tight Need 2.85x
I-4-------2.70-------.06-.08----Good

This mornings test revealed a really good sounding engine with the exception of hearing the cam #1 slapping the tappet. Now the engine noise is coming from the exhaust and not so much the engine.

 

[Nessism]

There is no such thing as a shim thinner than 2.15. Where did you get a 1.75 shim? If you are getting .04mm clearance with a 2.15 shim you can run it and call it done.