07-18-2020, 05:41 PM
(This post was last modified: 07-19-2020, 12:04 PM by Terry Bentley.)
Chapter 51
I sure am glad Steve was over today. Especially taking it upon himself to clean the shop and those Tillotson carburetors we picked up from the scrap pile. Since I am done scratching my head over the flywheels for now, time to get focused on other aspects of the engine.
![[Image: attachment.php?aid=4715]](https://www.vintagekartforum.com/attachment.php?aid=4715)
Horizontal and vertical blocks
I had not realized until we tore down the Cates Clinton and started comparing parts to that lawn mower engine sitting here in a box are some obvious differences. It is a vertical shaft engine. Surprising to see the crankcases are very different. This is mostly how the mounting bosses are cast in relation to the rest of the crankcase.
It does not look like the lawn mower block can be machined out for a pto ball bearing. Almost certain all of the others we have can be done. Horizontal and vertical shaft blocks have different mounting bolt diameter circles too. The vertical shaft block is 4 inches on center. Horizontal shaft block is at 3 5/8 inches. The E-65 and chainsaw blocks I have sort of measured look to be about a 3 inch diameter bolt circle.
Another thing different is the orientation. Lawnmower block is square, as inline with the cylinder. The others are indexed at 30 degrees from square. This makes the lawnmower blocks problematic bolting up to any of the motor mounts. But without a pto ball bearing, seems useless anyway.
Like a bonehead, I didnt look close enough at the carburetor from the Cates engine. I thought it was an HL115A. But turns out it is just an HL-15A. There is a really big difference in these two carburetors. The HL-15A has a smaller throttle bore of 13/16", venturi of 11/16" and air horn is 7/8".
Looking thru all of the pages in the Clinton engine catalog, there is a section covering Tillotson carburetors. Giving model numbers, applications and dimensions. Also part numbers to diaphragm and rebuild kits. Seems most of the chainsaw carburetors are the same size dimensionally. There are a few exceptions. Most of the Clintons have carbs with a smaller venturi.
My big hopes of that HL-115A would have been the shiznits. It has a much larger throttle bore of 1". Venturi is 3/4" and air horn is also 1". This carburetor is made specifically for kart racing. No specific application or particular engine. Just all the best from all the years of development. It should be an awesome carburetor to put on any kart engine. But doesnt matter, I still dont have one.
![[Image: attachment.php?aid=4716]](https://www.vintagekartforum.com/attachment.php?aid=4716)
HL-115 sheet
Looking at the few Tillotsons I do have, it does not appear any of them can bore out nearly big as the new HL-115A. Just from checking with my vernier caliper, it may be possible to increase the throttle bore to 7/8". The venturi should be no problem going bigger to 3/4" tho. That might be the one big improvement. I dont think the air horn can get larger than 15/16" But only guessing right now.
Suppose I use one test carburetor, then try to bore it out on the little Craftsman lathe. Should I go for it and keep cutting to find out how big it can get? Guess it could be worth loosing one carburetor to confirm this. One of these bored out might not flow good as this one new model, but at least will be more that what it is capable of now. Yes I can afford to loose one carburetor to find this out. It is that important. Well I think it is. No, yes it is.
Here I am going crazy off the deep end over something before even getting an engine together and ready to run again. I know some of the things I want to do will help a lot. But nothing will make any difference without a running engine and rolling chassis to put it on.
All this work and trouble and still I have not even raced yet. Geez, I need to get it together and focus on one thing at a time. Get the kart finished. Get the engine running. Put the two back together. Then start racing at the track and learn how to drive. Especially in traffic. Learn how to set up the chassis and make adjustments thru the night as track conditions change. The only time on the track, I got knocked off and never saw it coming. Then find myself wrapped in a cocoon thinking I screwed up big time.
Maybe then some of the things I have been working on might make a difference. Without driving experience, without track time, nothing else is going to make up for it. OK get my head on straight and focused. Keep it simple. Baby steps. Argh, this makes too much sense. I have got to go jump in the deep end. It is way much more fun this way. But can and will be frustrating if I dont have the basics down first.
It seems there is a big problem brewing. I dont know what to do. After that big work day at Gasset we now have so many choices for engines. Not anything new or really even sold as a kart engine, but good choices to build a couple of solid engines. If me and Steve can come up with another kart, or end up building one, we could possibly have two matching engines and run together in the same class.
Another option is keep with just the one kart right now. Then maybe swap out every other race we get lucky enough to attend. I dont see either of us doing anything more than weekend racing anyway. That is all I really would be interested in right now. It takes up too much time and I can not even imagine the expense to race on a higher level. Maybe if we ever get a kart finished and running, possibly try to run a regional race when there is one at any of the local tracks.
I would enjoy just going to watch the regional races. There sure are some serious drivers out there. Way too intense for me. At that level I dont think it would be as fun. Maybe I am wrong. But right now racing locally without needing the latest model engine, clutch, tires or best kart money can buy seems the smartest way to go and like more fun to me.
Just since we got the Cates kart project going, I have been overwhelmed with satisfaction from repairing and rebuilding the frame. Learning how to set things up correctly for the best performance. Now we have a ton of engines that can potentially get us going competitively at a local level. That just feels where I should be right now.
I sure am glad Steve was over today. Especially taking it upon himself to clean the shop and those Tillotson carburetors we picked up from the scrap pile. Since I am done scratching my head over the flywheels for now, time to get focused on other aspects of the engine.
Horizontal and vertical blocks
I had not realized until we tore down the Cates Clinton and started comparing parts to that lawn mower engine sitting here in a box are some obvious differences. It is a vertical shaft engine. Surprising to see the crankcases are very different. This is mostly how the mounting bosses are cast in relation to the rest of the crankcase.
It does not look like the lawn mower block can be machined out for a pto ball bearing. Almost certain all of the others we have can be done. Horizontal and vertical shaft blocks have different mounting bolt diameter circles too. The vertical shaft block is 4 inches on center. Horizontal shaft block is at 3 5/8 inches. The E-65 and chainsaw blocks I have sort of measured look to be about a 3 inch diameter bolt circle.
Another thing different is the orientation. Lawnmower block is square, as inline with the cylinder. The others are indexed at 30 degrees from square. This makes the lawnmower blocks problematic bolting up to any of the motor mounts. But without a pto ball bearing, seems useless anyway.
Like a bonehead, I didnt look close enough at the carburetor from the Cates engine. I thought it was an HL115A. But turns out it is just an HL-15A. There is a really big difference in these two carburetors. The HL-15A has a smaller throttle bore of 13/16", venturi of 11/16" and air horn is 7/8".
Looking thru all of the pages in the Clinton engine catalog, there is a section covering Tillotson carburetors. Giving model numbers, applications and dimensions. Also part numbers to diaphragm and rebuild kits. Seems most of the chainsaw carburetors are the same size dimensionally. There are a few exceptions. Most of the Clintons have carbs with a smaller venturi.
My big hopes of that HL-115A would have been the shiznits. It has a much larger throttle bore of 1". Venturi is 3/4" and air horn is also 1". This carburetor is made specifically for kart racing. No specific application or particular engine. Just all the best from all the years of development. It should be an awesome carburetor to put on any kart engine. But doesnt matter, I still dont have one.
HL-115 sheet
Looking at the few Tillotsons I do have, it does not appear any of them can bore out nearly big as the new HL-115A. Just from checking with my vernier caliper, it may be possible to increase the throttle bore to 7/8". The venturi should be no problem going bigger to 3/4" tho. That might be the one big improvement. I dont think the air horn can get larger than 15/16" But only guessing right now.
Suppose I use one test carburetor, then try to bore it out on the little Craftsman lathe. Should I go for it and keep cutting to find out how big it can get? Guess it could be worth loosing one carburetor to confirm this. One of these bored out might not flow good as this one new model, but at least will be more that what it is capable of now. Yes I can afford to loose one carburetor to find this out. It is that important. Well I think it is. No, yes it is.
Here I am going crazy off the deep end over something before even getting an engine together and ready to run again. I know some of the things I want to do will help a lot. But nothing will make any difference without a running engine and rolling chassis to put it on.
All this work and trouble and still I have not even raced yet. Geez, I need to get it together and focus on one thing at a time. Get the kart finished. Get the engine running. Put the two back together. Then start racing at the track and learn how to drive. Especially in traffic. Learn how to set up the chassis and make adjustments thru the night as track conditions change. The only time on the track, I got knocked off and never saw it coming. Then find myself wrapped in a cocoon thinking I screwed up big time.
Maybe then some of the things I have been working on might make a difference. Without driving experience, without track time, nothing else is going to make up for it. OK get my head on straight and focused. Keep it simple. Baby steps. Argh, this makes too much sense. I have got to go jump in the deep end. It is way much more fun this way. But can and will be frustrating if I dont have the basics down first.
It seems there is a big problem brewing. I dont know what to do. After that big work day at Gasset we now have so many choices for engines. Not anything new or really even sold as a kart engine, but good choices to build a couple of solid engines. If me and Steve can come up with another kart, or end up building one, we could possibly have two matching engines and run together in the same class.
Another option is keep with just the one kart right now. Then maybe swap out every other race we get lucky enough to attend. I dont see either of us doing anything more than weekend racing anyway. That is all I really would be interested in right now. It takes up too much time and I can not even imagine the expense to race on a higher level. Maybe if we ever get a kart finished and running, possibly try to run a regional race when there is one at any of the local tracks.
I would enjoy just going to watch the regional races. There sure are some serious drivers out there. Way too intense for me. At that level I dont think it would be as fun. Maybe I am wrong. But right now racing locally without needing the latest model engine, clutch, tires or best kart money can buy seems the smartest way to go and like more fun to me.
Just since we got the Cates kart project going, I have been overwhelmed with satisfaction from repairing and rebuilding the frame. Learning how to set things up correctly for the best performance. Now we have a ton of engines that can potentially get us going competitively at a local level. That just feels where I should be right now.