Hello everyone! I hope that you are all doing well today.
I got home with my Penton Six Day project bikes this weekend. I'm about to start tearing them down to rebuild one AHRMA cross country bike for next year. They are practically identical. One was built in November 1971 and the other in September 1972. Both CMF. Between the two, I should be able to get one bike running. I will have to do a total engine rebuild. In the deal, I got four large boxes of parts: engines, heads, ignition covers, etc.
I have read through the forum and the newsletters. They are a wealth of information. I have a question for the AHRMA cross country experts (regular Penton experts feel free to voice your opinion). If you were going to build a Penton Six Day to compete in AHRMA cross country (mostly woods, hills, rocks, and short straights), how would you build it out?
1. Engine - 5A, 5B, 6A, or 6B. Any mods.
2. Gearing - sprocket sizes and brands
3. Carb - size and brand
4. Tires - size and brand
5. Brakes
6. Intake mods
7. Exhaust mods
8. Suspension
9. Other common mods
I'm going to try to get this done in time for the next season. I have a pretty good budget for the project. I would rather do it right the first time.
Any comments and opinions would be greatly appreciated. I'm trying to not reinvent the wheel here. Thanks in advance.
John
Maybe I need to start off with a more simple question. I'm going to build the engine first. Which Sachs engine would be best for a cross country bike?
The more that I read about the Sachs engine versions, the more confused I become. I have at least four bottom ends. From reading, it appears that most prefer the "B" engines. Before I go spend a fortune on getting an engine rebuilt, I'd like to know that I'm building the best engine.
If you have a 6B then use it. The smaller crankcase volume makes more power. Use a modern ignition. Use a stock 27mm carb. Gear for the tracks you will run on, 13/57, 13/54, 14/57 and 14/54 are good choices.
Don't cheap out on your suspension. Spend the the money on doing the forks and buying quality shocks. Also, buy quality tires. Forget "period correct." Buys tire that work in the conditions you are riding in; rocks, roots, and mud. Remember, you are building a race bike, not restoring a bike, big difference. Have fun building it!
1976 250 MC5 Original Owner
1976 Penton 175 XC
Just finished looking at my engine inventory. I have the following choices:
6A - I have a complete engine that is locked up. It is in very good condition cosmetically. I have two bottom ends that are moving freely. I should be able to have a 6A rebuilt with the parts that I have on hand and normal rebuild parts.
6B - I have one bottom end with all internals intact and moving freely. It is missing all ignition components and all clutch components. It has minor (repairable) damage on the case and ignition cover from a thrown chain. I have extra cylinders, heads, ignition covers, and clutch covers. I would have to find the missing parts, have the engine case repaired, and engine rebuilt.
Any suggestions?
Quotequote:Originally posted by Rick Bennett
If you have a 6B then use it. The smaller crankcase volume makes more power. Use a modern ignition. Use a stock 27mm carb. Gear for the tracks you will run on, 13/57, 13/54, 14/57 and 14/54 are good choices.
I just posted on my engine options. Do you think that the 6B parts would be available?
Which modern ignition would you suggest?
Quotequote:Originally posted by skiracer
Don't cheap out on your suspension. Spend the the money on doing the forks and buying quality shocks. Also, buy quality tires. Forget "period correct." Buys tire that work in the conditions you are riding in; rocks, roots, and mud. Remember, you are building a race bike, not restoring a bike, big difference. Have fun building it!
1976 250 MC5 Original Owner
1976 Penton 175 XC
Any suggestions on sources for the suspension? I agree about suspension. An hour straight getting beaten to death by poor suspension is no fun.
Hip ignition and Gary Ellis can hook you up for a good price.
Larry P
HPI
Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Penton
1976 MC5 400
1978 KTM 78 GS6 250
L78-79 MX6 175-250 KTM's
1976-78 125-400 RM's
2007 CR125R Honda
1977 MC250 Maico
2017 KTM Freeride 250R
Thanks Mike. Pain meds and fat fingers.
Larry P
Here's an update on my build so far.
I'm going to use a 1972 CMF frame. I just ordered parts from Al to replace almost everything that was worn or needed servicing. I'm going to get it powder coated. There is a local guy that does a great job and is very reasonable.
I'm using a 6A engine. It has the transmission with the larger selector rod. I have two engines that should make one good engine. Gary Ellis is hooking me up with new engine bearings and an HPI ignition system. I'm going to have the engine completely gone through and every gasket, seal, and bearing replaced. I have one piston and cylinder that look almost new. It has a two over (54.43) piston. The cross hatches still look new in the cylinder. If it measures out okay, I'll use that. If not, it will be another call to Al.
I'm going to get an original Bing 27mm carb from Larry Perkins.
I'm going to run 13/57 sprockets and a case protector.
Thanks so much for all of the great advice so far. As a newbie, I really appreciate the help. Both Al and Gary are very knowledgeable about Pentons. They have been very helpful.
Now, on to suspension! Does anyone know a good source for AHRMA legal suspension parts? I'll need both fork springs and a complete set of shocks.
Race tech sells fork springs that are high quality. They even have a place on their website that will calculate spring rate based on your weight and intended use. Ceriani forks were actually pretty good for their era. Work fairly well in the woods. As far as shocks go it comes down to how much you want to spend. Race tech has those too and I have heard they are excellent but too rich for my blood. I have Koni and gas Girling on mine, modern equivalents are Ikon and Hagon.
Just to follow up on the suspension discussion, I used the 35mm Cerianis from the 73 thru 75 Pentons on my 1972-based build (the 72's used a 32 mm Ceriani). But they can be hard to find (Larry P - I thought you were trying to sell a set of these for awhile). I've used WER suspension (Drew Smith, former ISDE racer) to source fork springs if/when needed on my other bikes, but my stock springs were in good condition.
If you can find a used set of "newer generation" works performance (13.5 inches) shocks, they are the way to go. Rebuildable (again, I've used WER) and my understanding is that there are parts available, even though "Worx" (their new renamed company) is not making shocks anymore last I heard. I don't have experience with Ikon or Hagon, but Hagon's high-end build shock is still pretty affordable vs. Ohlin, Noleen, or Race Tech. Maybe someone here at POG has ordered a set of those.
I'll confess my first set of shocks on my Six Day were the Red Wings, not sure if they are still available. They were rebuildable too. Finally, some folks use Progressives, but my understanding is that they are not rebuildable.
HAH - just saw your "wanted" shocks post over in the For Sale board. You're way ahead of me. ; - )
Where are you located John? What AHRMA XC series (national, regional...)will you be racing?
Quotequote:Originally posted by johnbowman
Hello everyone! I hope that you are all doing well today.
I got home with my Penton Six Day project bikes this weekend. I'm about to start tearing them down to rebuild one AHRMA cross country bike for next year. They are practically identical. One was built in November 1971 and the other in September 1972. Both CMF. Between the two, I should be able to get one bike running. I will have to do a total engine rebuild. In the deal, I got four large boxes of parts: engines, heads, ignition covers, etc.
I have read through the forum and the newsletters. They are a wealth of information. I have a question for the AHRMA cross country experts (regular Penton experts feel free to voice your opinion). If you were going to build a Penton Six Day to compete in AHRMA cross country (mostly woods, hills, rocks, and short straights), how would you build it out?
1. Engine - 5A, 5B, 6A, or 6B. Any mods.
2. Gearing - sprocket sizes and brands
3. Carb - size and brand
4. Tires - size and brand
5. Brakes
6. Intake mods
7. Exhaust mods
8. Suspension
9. Other common mods
I'm going to try to get this done in time for the next season. I have a pretty good budget for the project. I would rather do it right the first time.
Any comments and opinions would be greatly appreciated. I'm trying to not reinvent the wheel here. Thanks in advance.
John
Richard Colahan
1969 V1225
Upper Black Eddy PA
Quotequote:Originally posted by Richard Colahan
Where are you located John? What AHRMA XC series (national, regional...)will you be racing?QuoteRichard Colahan
1969 V1225
Upper Black Eddy PA
Richard,
I'm in Germantown, Tennessee. Right outside of Memphis. Last year, I floundered my way through a few events in the John Penton/Preston Petty National Cross Country Series. I plan on riding in as many of the series events as possible this year. Hopefully, I'll graduate from Novice Beginning Rookie Third Class to Novice Beginning Rookie Second Class this year!
John
tooclose,
Will the 35mm Ceriani front ends from other Pentons bolt on to a 72 Six day without modification? I have a 35mm front end from a 75 hare scrambler. Would that work?
John
Quotequote:Originally posted by tooclose racing
Just to follow up on the suspension discussion, I used the 35mm Cerianis from the 73 thru 75 Pentons on my 1972-based build (the 72's used a 32 mm Ceriani). But they can be hard to find (Larry P - I thought you were trying to sell a set of these for awhile). I've used WER suspension (Drew Smith, former ISDE racer) to source fork springs if/when needed on my other bikes, but my stock springs were in good condition.
If you can find a used set of "newer generation" works performance (13.5 inches) shocks, they are the way to go. Rebuildable (again, I've used WER) and my understanding is that there are parts available, even though "Worx" (their new renamed company) is not making shocks anymore last I heard. I don't have experience with Ikon or Hagon, but Hagon's high-end build shock is still pretty affordable vs. Ohlin, Noleen, or Race Tech. Maybe someone here at POG has ordered a set of those.
I'll confess my first set of shocks on my Six Day were the Red Wings, not sure if they are still available. They were rebuildable too. Finally, some folks use Progressives, but my understanding is that they are not rebuildable.
HAH - just saw your "wanted" shocks post over in the For Sale board. You're way ahead of me. ; - )
John - I had someone else "build" my '72 CMF bike with the later 35s and triples, and I didn't think there were any issues, but maybe Gary Ellis can offer his two cents on this one. I'll text him if he doesn't reply.
Bob,
I got with Larry Perkins. He had a later 35mm front end that he is selling me. He thinks that it should be a bolt on process. I would love to hear what Gary has to say. He's been a great wealth of knowledge. I really appreciate having people help me to not make dumb mistakes or try to reinvent the wheel. I'm good at both of those.
Buying the front end from Larry allows me to not cannibalize the Hare Scrambler. I just got off the phone with a friend that has wanted to build a Penton HS for years. He wants to do the HS project for me. I'm betting he'll end up in the group in no time.
John
Quotequote:Originally posted by tooclose racing
John - I had someone else "build" my '72 CMF bike with the later 35s and triples, and I didn't think there were any issues, but maybe Gary Ellis can offer his two cents on this one. I'll text him if he doesn't reply.
I pinged Gary, haven't heard back, but Larry has been hanging around Pentons for a long time - great to hear he still had his 35's. If they need to be rebuilt, Al has the seals.
Yes the 35mm will bolt right up...
Build Update - 1/6/20
Engine - I dropped my 6A engine off to get it completely rebuilt. All bearings and seals in the engine and transmission. New piston, rings, and rod kit. HPI ignition. Case protector. It should be finished this week.
Frame - I completely stripped the frame and used Rust-Oleum rusty metal primer and Metallic Matte Nickel 7277830. The paint is very easy to use. It dries very quickly. I like the color. I decided to go with paint over powder coating because I know that I'll be doing some touch-up work after getting some trail love.
Swingarm bushings - Unfortunately, the rubber was cracked and brittle. I tried everything to get them out. We heated the swingarm with a torch a few times. They were completely rusted in place. In the end, I used the trick listed here years ago. I used a torch to burn out the rubber bushings and remove the inner metal sleeve. Then I used a hacksaw to cut a line through the outer sleeve. It is very easy to go through the steel sleeve and into the CMF! You have to be careful. After the sleeves were cut, I used a chisel to lift them away from the swingarm. I used a 3/4 inch socket and extension to push the sleeves out once they were loosened up. The new bushings went in easily with a little grease and pressure from a vise.
Tires - I ordered tires and heavy duty tubes last night. I'm going to run the Pirelli MT16 80/100-21 front and Duro HF335 4.10-18 rear. I can't tell you how many hours I spent reading the tire threads (friendly discussions). In the end, I figure that I can try this set-up and change if I need to later.
Wheels - My rims are so badly beaten up. They have severe flat spots. Imagine more square than round. I am going get rims and spokes from Buchanans. I have a friend that is a really good wheelsmith. I just hope that I can get them done before the first event. Luckily, I have another "almost round" rusty set of wheels just in case.
Suspension - I have my Worx (new Works Performance) shocks in. They look really good. I'm waiting on the later 35mm front end that I bought from Larry. I can't wait to get the frame back together.
So, after driving to North Carolina to get the bike, ordering a small fortune of parts from Al, Gary, and Larry, and discovering time after time what I don't know about Pentons, I'm getting really close to having a running, race ready bike.
Thanks for all of the advice and help. It takes a village to save a Penton!
Penton race bikes = $$ [8D]
I'll mention controls, which I've maintained the same across 4 racing Pentons. I've always used Renthal Mini-High bars, modern (but cheap!) clutch/brake/throttle perches, and the Ascerbis Rally (full plastic) guards. I've had my Ascerbis for almost a decade, may finally need to replace one pair due to cracking/tree love sessions.
Just a quick update. I actually have some time now that the coronavirus has shut down the whole world.
I finished my 1972 Penton Six Day 125 in time for the first AHRMA cross country race of the year. Thanks to all of the help from this group. There is no way that it would have happened without several of you.
There were about 10 Pentons present at the White Lightning XC Race in Buffalo, SC! I know at least six of them raced. Clint (holeshothawk3) and James (skiracer) were there and represented Penton very well.
I held my own with the rookies. On Saturday, I came in first of 11 novices. On Sunday, I came in first of 10 novices. After riding a Honda XR200R last year in my first couple of rookie outings, I have a special appreciation for how well the Penton performed. I take a certain amount of pride in beating the newer and larger bikes (Hondas, Huskies, Yamahas, and Suzukis) with the nearly 50 year old little Penton.
Everything worked pretty well. The pegs from Gary Ellis were awesome! I had some problems starting the second day. I think that my clutch plates were hanging on the basket. The kickstart wouldn't catch. If I worked the clutch a little and rocked the bike back and forth a little, it would work fine. The rear suspension from Worx was excellent. The 35mm ribbed Cerianis need a little help up front. I ordered gold valves and springs from Racetech. I'm having a friend rebuild the (not-so-round-anymore original) wheels. I'm trying to take advantage of the postponed races to get the bike in shape for the next race.
I want to thank a few people in particular for their help: Al Buehner (parts/advice), Gary Ellis (parts/advice), Larry Perkins (parts/advice), Mike Winter (transportation/advice), Eddie Wilbanks (welding), and Fletcher Lambert (engine build). Of course, there are a lot more great people that helped. Especially, the POG forum. There is no way that I could have gotten this bike going without all the wisdom written down on these pages. It saved me a lot of time and avoided reinventing the wheel.
I hope to see all of you at a race some day. I'll be happy if I can learn to ride the bike to half of its potential. While at the race, one of the riders made a comment that really resonated with me. He said that this race was now in the history books. I have to admit that I'm proud to have my name listed in history as having raced a Penton (even in such a small way at a small race).
Best wishes to everyone!
John
It was nice meeting you there John! I have a few things to sort on mine as well and hopefully I can put the little Six Day in the top 5 overall when we finally get back to racing. I was glad to see a few more Pentons out and about.