Topic: Measuring valve guide ID?

[DavePhipps]

I'm trying to make sure everything is perfect for this rebuild and want to check the valve guides ID. I'm finding split ball gauge kits for anywhere from 300.00 to thousands of dollars. I just need one of these buggers but can't find them individually.
Does anyone know of a source that sells them individually or an alternate method for measuring the ID of a vale guide?

[Airborne 82nd]

Why not take them to a good machine shop? If you are not going to do that often. If it were me I would send the whole head to MRieck he has the best reputation that I know of. Just depends if you are going to use the tools needed enough to justify the cost. I don't buy budget tools especially measuring and setup tools.

[DavePhipps]

Lets see. I'm in school, working 2 part time jobs, single parent with three sons to take care of and my disposable income is sparse so MReick is out of my price range. Most machine shops are out of my price range. It's why I learned to work on bikes myself. I  can't afford to let others do the work for me. Heck last year due to my class schedule I only made 14,000 dollars.
Now can you give a budget constrained option or advice on finding a single split ball gauge?

[70CB750]

I suppose you checked Enco and Grizzly?

Guides are usually checked by the  play the valve has in it, are you trying to measure ID before installing these guides?

[DavePhipps]

I'm measuring the guides ID, valve wear and spring length in a spare head from an old parts bike. So they are already installed. It's unknown if there were any issues with the parts bike as I got it years ago not running.  I thought it would be good to check before installing it on my sons rebuild.
I've got calipers and micrometers but no dial gauges to measure lateral movement, and nothing small and long enough to measure the 5.52mm ID in the middle of the guide 

[dave500]

measure the stem then check for wobble in the guide like 70cb750 says.

[scunny]

^^ +1  that is the easiest way to do it.

[70CB750]

Here is a good howto:

https://www.youtube.com/watch?v=LIL1lV_xtHI

you can get this set, I use it myself:

https://www.grizzly.com/products/G9849

[calj737]

Lets see. I'm in school, working 2 part time jobs, single parent with three sons to take care of ... It's why I learned to work on bikes myself. I  can't afford to let others do the work for me. Heck last year due to my class schedule I only made 14,000 dollars.

Dave - you are a true Hero. Living proof that determination, priorities and commitment are the essence of a successful man, and not his wallet or assets. Your sons are indeed very lucky, and I'll bet dollars to donuts, they are all fine young men with great character and humble, self-assured dispositions.

You have my deepest respect-

[AJK]

Lets see. I'm in school, working 2 part time jobs, single parent with three sons to take care of ... It's why I learned to work on bikes myself. I  can't afford to let others do the work for me. Heck last year due to my class schedule I only made 14,000 dollars.

Dave - you are a true Hero. Living proof that determination, priorities and commitment are the essence of a successful man, and not his wallet or assets. Your sons are indeed very lucky, and I'll bet dollars to donuts, they are all fine young men with great character and humble, self-assured dispositions.

You have my deepest respect-

+1 on that CalJ,

To continue.....

It is possible to compute the guides internal diameter with a bit of maths (by similar triangles) if you don't have the appropriate bore gauge.

I have attached a diagram that should make this clear. In the diagram the:
- Guides internal diameter (I.D) is shown as black.
- Valve is shown as brown.
- Length 'L' is the length from the end of the guide (rocker side) to the end of the valve face where the side-to-side measurement will be made (which is dimension 'B').
- Guide Length 'GL' is the length of the guide itself.
- Dimension 'B' is the side-to-side valve rock measurement.
- Dimension 'A' is what we are computing which is the stem to guide clearance.


What you are wanting to compute is the dimension 'A' in the diagram, because once you have 'A', then your guides I.D becomes 'A' + Valve O.D, where valve O.D can be measured with micrometres or verniers.

You need to measure the valve side-to-side rock (dimension 'B') preferably at a valve lift/height where the worn section of the valve stem is still inside the guide. Measure 'B' whilst keeping the cotter end of the valve hinged (pushed) against the guide as shown in the picture.

Then the guides I.D is expressed as:

GuideID = (GL x B)/L + ValveOD



[Update], If you don't want to hinge the valve when you take dimension 'B' (by pushing on it at the cotter end), then you can just rock the valve side-to-side as normal and take that measurement. This measurement will now be twice the distance compared to the hinged version measurement, so take this measurement and divide it by 2 and call it 'B', then plug it back into the expression above.

[calj737]

AJK - there is nothing cheaper than math! And nothing more accurate! Great resource and great info

[DavePhipps]

AJK your are amazing thank you. Did you come up with that method? It's a beautiful practical application of math.

Cal I'm no hero. I'm just doing what I can and the best I can till I get out of school and can get a proper job.

70CB750 I found a set at http://www.grizzly.com/products/Small-Hole-Gages-4-pc-/T24810 Thank you very much. I think I spent many days searching for those.

As per Dave's suggestion, I did the wiggle test on some of the valves and some don't move at all. In fact there is no clearance. It's like someone replaced the guide previously but didn't ream them. Others have a touch of play.
 
I'll be using the method proposed by AJK, and checking work with the bore gauges. I know it's an extra step but it's too amazing not to try. Also i'll be teaching it to my son as we work on the bike.

Thank you all.

[70CB750]

You are welcome, Dave!

Frankly, I never knew small hole gages existed - and I am Mechanical Engineer with several years in tool and die factory.

[lucky]

I'm trying to make sure everything is perfect for this rebuild and want to check the valve guides ID. I'm finding split ball gauge kits for anywhere from 300.00 to thousands of dollars. I just need one of these buggers but can't find them individually.
Does anyone know of a source that sells them individually or an alternate method for measuring the ID of a vale guide?

The book (Clymer's) says to insert the valve into the guide and measure the amount of side play. It  should not exceed .004 thousands of an inch. There is a photo of this measurement process in the Clymers's workshop manual.

[AJK]

The simple method is really just to obey the book at lucky says. If the side play is more than the servicable limit, then its due for new guides. After playing with motors for a while, you get to develop this 'feel' without a gauge, when you can compare what a good fit feels like compared to a sloppy fit.

The method is something i whipped up on the spot, because the original question was how to measure the guide ID. There are tools to do it, but it can also be done with a bit of maths if you dont have the appropriate bore gauge.
 Actaully, the same method can be used to calculate side play in the swing arm, which is something i'm doing at the moment as well.


I just wanted to add to CalJ's comment. Not having much money can be a real blessing in disguise. I didn't have much growing up (and still don't have a great deal now), but i learnt to improvise a long the way, making heaps of mistakes but always wanting to improve on the last job i did. After a while, you learn to work out what matters in a repair and what you can make concessions with given a tight budget. Being like that, you tend to look at the mechanic in the mirror.

[lucky]

When these motorcycles were manufactured most people did
not have the tools or money they have now.
Keep it simple.

[AJK]

Here is a reasonably priced tool for the job
http://www.grizzly.com/products/Small-Hole-Gages-4-pc-/T24810

[DavePhipps]

Thanks AJK. I'll be ordering those this weekend. I did hit a setback though. I just cleaned out my shed/workshop and found that my valve spring compressor, compression guage, and many hand tools are missing. Great area I live in.  At least I still have my timing light and multimeter.
I'll have to work on other parts of the bike till I get those replaced. electrics and paint will take up my time till then.

[dave500]

MAN THAT SUCKS!