[Guest]

how much for me to just mail my engine to you?

 

[fog]

I'll happily do it for you for a mear $100 + shipping. Were in the ZIp of 72653.
Mt Home, AR.

FOG

 

[bitzz]

I'll do it for the same price. I'm in Toronto if that is closer. Canadian dollars though!

 

[Shadowninja]

I'll happily do it for you for a mear $100 + shipping. Were in the ZIp of 72653.
Mt Home, AR.

FOG

What if I took a road trip to AR and helped/learned/got in the way? I'm good at holding a flashlight!

 

[fog]

Deal,

FOG

 

[Hielke]

Because of the difficulty in determining the exact point of the valve opening we use “Lobe Centers” To convert the chart above to lobe centers Do: 65-45+180/2=100 . 100 degrees lobe center for the intake cam
70-40=180/2= 105 Lobe center for the exhaust cam.

Ok if you did all that above and you got something different, here’s how you fix it.
Remove the cams and remove the sprockets from the cams. Elongate the Bolt holes about 1/8 “ in each direction. Replace the sprockets with the bolts located in the center of the elongation.

Hey, thanks for describing the procedure. When I put my engine together after lapping the heads, I noticed the timing marks on the crank and cams were slightly off. It looked like chain stretch has retarded valve timing (as in: the crank runs +/- 1 degree ahead of the cam shafts). I can't tell the real-life influence on engine power....however it does feel a bit gutless under 4000tpm, even with correct valve clearance, adjusted and synced carbs, airbox mod, new plugs etc etc. I kinda got the hang of this whole engine tweaking business since lapping the heads, so I'm definitely considering degreeing the cams and redoing the valve seats in time. I actually regret being in such a hurry to get it going again.

One thing I don't understand yet: what is the purpose of converting to lobe centers? Is that for like....halving the inherent inaccurary of measuring the point of valve opening and closing? And if I degree the cams, can I keep using a timing chain that is near its quoted stretch limit? Or is there a real risk of snapping it?

 

[fog]

Yes, Cam timing is normally expressed in terms like Intake open X degrees before TDC. This is a hard thing to measure and is effected by valve clearance .

Fog

 

[onetworide]

Very helpful. Thanks, FOG.

 

[Lynx]

It would be great if someone could do a tutorial with pics on degreeing cams, since it is such an important part of EX500 maintainance.

 

[fog]

I just did can't you read?

FOG

 

[Lynx]

I just did can't you read?

I can. But I cant see pics.

 

[fog]

Ok I re posted the picture

FOG

 

[Lynx]

Ok I re posted the picture

Thanks. Too bad you dont have more of them. Btw, why isnt this maintainance job mentioned in Haynes manual?

 

[fog]

I doubt it This would be considered Modifacation. To make adjustments you need to elongate the sprocket mounting holes. Finally your "Marks are no longer valid, although they won't be far off. Just to clear up an misconseption that the Degreeing is to put the marks spot on . It's not, It is to put the cams spot on.

FOG

 

[88ex500projector]

Anyone in Portland/Vancouver area (within an hour drive) capable of doing this? I would prefer someone with experience...I don't trust myself.

 

[Lynx]

Ok, two questions considering cam degreeing.

1) I found out that cam degreeing kits can be bought: will universal cam degreeing kit do or has to be specific for this type of engine?

Example: http://www.summitracing.com/parts/SUM-G1056/

2) If cam chain is stretched beyond service limit and I do camshaft degreeing, will that be enough for restoring engine performance (at least for a while) or will I also have to buy new chain?

 

[fog]

The cam chain stretch is what your correcting for. As the chain wears or stretches the cams get retarded. Degreeing them restores to nearly the factory settings and power. Provided all else is OK. The stretch between the 24 pin spacing will not be a factor.

A degree wheel can be had for about 10 bucks , and indicator for the same. then you must figure out a way to mount the indicator to detect the moment of the valve. I made a pointer from a coat hanger and bolted it to a cover bolt.

FOG

 

[Lynx]

FOG, I bought degree wheel, dial indicator, pointer, then removed engine from the frame, so now its ready for cam degreeing. This is the first time I am doing it, so I have some additional questions, help would be great.

1) I understand how to set degree wheel 0 at TDC - that part is simple.
2) ER5 readings for valves in manual are: inlet open 31 BTDC, close 51 ABDC; exhaust open 56 BBDC, close 26 ATDC. So a little different, but I still get this part.
3) What I dont understand is when exactly to measure valve movement/degree position. Do you measure when valve moves dial indicator just a little (first noticable movement) or is there a prescribed value when to measure? I hope my question is clear: I want to know when exactly to look at degree wheel ... when valve starts to open/close and dial indicators shows first change, or when indicator shows specific change, for example 2 mm?
4) I dont get last part. How to adjust camshaft position? I know there are some adjustable cam sprockets, but you mentioned alternative method. Could you please post a picture of your modified cam sprocket or at least write more extensive explanation (for a novice). This last part worries me the most.

 

[fog]

OK this is the part (copied and pasted from above) you don't get

Because of the difficulty in determining the exact point of the valve opening, and the fact that EX cams are semitrical, we use “Lobe Centers” To convert the chart above to lobe centers Do: 65-45+180/2=100 . 100 degrees lobe center for the intake cam
70-40=180/2= 105 Lobe center for the exhaust cam.

Now you set you indicator up on the valve spring surface. so it detects the instant the valve moves. That not what you measure yet, now turn the crank a bit more till you degree pointer is at a nice whole number on the wheel. write it down, and note the exact indicator reading, set the dial to -0- continue turning the crank in the same direction until the valve returns the indicator to -0- the same setting on the way up. write down the degree wheel number. Do the math. this is the lobe center.

The sprockets are bolted to the cams at two places the hole in the sprockets must be elongated to allow the cams to be shifted withing the sprockets. about 1/16 each way is enough. you can do this with a dremel.

FOG

 

[Lynx]

The sprockets are bolted to the cams at two places the hole in the sprockets must be elongated to allow the cams to be shifted withing the sprockets. about 1/16 each way is enough. you can do this with a dremel.

FOG, thanks, now I understand the whole process. But how to accurately elongate holes in the sprocket? Did you used some sort of vise or did you just do it by feeling? I am afraid that by doing it just by hand (by feeling) accuracy wont be high enough.