Vintage Dirt Racing on a 350 Honda Twin

Did you do all the work on this? Looks like ceriani forks, girling shocks, handmade side cover, and lots of other interesting bits and pieces, not to mention the psychedelic "Honda" emblem, pretty cool!

Would like to hear from anyone who has knowledge regarding possible transmission gear ratios that would fit into the stock 71-72 Honda SL350 cases, am thinking along the lines of either a lower first gear ratio or higher top end ratio, depending on what is available.

The reason I'm interested is that a friend (OC aka Paul) that has raced Baja and will be again on his 350, had occasion to need a fairly low gear in the silt beds of Baja, but if he gears the bike suitably low would lose a lot of top end speed that is needed, especially on long transfer sections. I am thinking that a granny type low gear for just those boggy occasions and allowing a reasonably tight 2nd thru 5th ratio and top speed or vice versa 1st thru 4th ratios tight and lower with an overdrive 5th gear. These ideas would depend completely on what is available out there and what might interchange or work together in the stock cases. Any ideas anybody??

The bike stays stock!

You crack me up Rick

So in the last installment, I alluded to changing the carbs and using the quick throttle from the donor bike. This particular throttle, with its short throw, magnifies the spring tension and would be a killer on the right forearm. After a lot of thought I decided I did want the shorter throw but would need softer springs. One rider suggested I find some SL175 carb springs, but the local Honda delaer said these were discontinued and I did not find any on ebay.

Hmmmmm.....so then I decided to try cutting the stock springs to reduce the spring tension. I measured the springs and stock they are 4" long with 10 coils, so after cutting off 2.5 coils they would be approximately 3" long. I knew they would be softer, but would they still have adequate tension to shut the slides properly? Well here goes.....

Stock Springs (dimes are there to illustrate scale, these are small carbs)


Spring comparison after cutting the RH carb spring


After cutting both springs, I reassembled and tested with the quick throttle. Feels better and slides still slam shut when throttle closed, should work fine. Will be test riding Sunday and will have a better idea then. :huh

Still waiting for those rear shock springs, supposed to be here any day now.......

Hmmmmm.....so then I decided to try cutting the stock springs to reduce the spring tension.
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Sorry, the shorter the spring the shorter the lever thus creating a stiffer spring.

Dave

Dave,

Thanks for your response. I understand that from an engineering or mathematical point of view, that what you are saying might well be true. I would not argue your point as I have nothing to go by except the feel and I can report that it now takes less effort to turn the throttle. Will be taking the bike out for a test ride tomorrow and will report back then on how these many changes have worked out (or not!).

Sorry, the shorter the spring the shorter the lever thus creating a stiffer spring.

Dave[/QUOTE]

Took the SL350 out for a test ride yesterday and for the most part the changes have been positive. It feels just a little bit lighter, the throttle response is cripser, the rear brake is more functional and the rear shocks felt better.



On the down side of the changes, it did feel like I need more preload in the rear springs and will be talking to Alex at Konflict today for advice on that, and then the really big concern was that when I practiced some starts, the bike would bog badly about three feet after launching. Hoping it is just the float level, will tear down the carbs to readjust and try again. If all else fails I can put the CV's back on, but if there is any way to get the bike to launch properly with the slide carbs I'd prefer to keep them.

One thing I did discover was that until after the races next Sunday, I'll need to stay off of my modern ride, a TTR 250. When I got off of the TTR yesterday and got on the 350, it felt tiny and strange!

The to-do list is getting smaller, still need; new on-off toggle switch (the one that came with the harness is glitchy), float adjustment, rear spring pre-load, repair mounting screw for RH valve adjust cover, measure alternator output and possibly pair up the output wires (tip as found on Hondatwins.net), possibly change air filters (the new ones were for the CV's and don't fit, will have to see if the correct sized small ones can be found quickly or just use what I have) and last but not least the possible installation of a chain tensioner. I have one that will work but will need to fabricate a mount and weld to swing arm, just depends on how time goes the rest of the week. :eek1

Have been working on the bike every night, trying to figure out why it was so boggy when doing my second gear starts and last night finally figured it out. Since the last post, I had torn the slide carbs back apart, re-cleaned and readjusted and when test rode was no better. Then I gave up on the slide carbs and put the CV carbs back on and still no change. Talked to my buddy Brian about what was changed or different since the last race and decided I needed to put the original coils back on that we had ran at PIR. While I had it apart, I went ahead and installed the new toggle switch and made the kill switch fully functional. Got it back together about 8 PM last night, rode it and still no change. Grrrr.

So even though I had just put in new points before the PIR race and felt comfortable about their adjustment and timing, decided to pull the points cover and have a look. As it turns out, the points gap HAD closed up and correspondingly the timing was off as well. I believe the points had closed up because I had failed to use the points lobe grease causing excess wear. My bad!

Went thu the process of resetting the gaps and timing using my continuity tester as a"buzz box" to check when the points open and was getting errratic results, so decided to go really old school and set the points with a piece of paper, just like we did it back in the 70's. You insert a piece of thin paper into the points and slowly roll the engine thru it's firing marks (as indicated on the stator) and while maintaining a gentle tug on the paper, it will slowly release when they first start to open or "fire". When I was satisfied the gap and timing were on target, I put the covers back on and fired it up and it sounded very responsive, more like what I was expecting. By then it was pitch black out, so will have to ride tonite to verify success but am fairly confident it's fixed.



At this point if the test ride goes ok, I'm going to leave the CV carbs on and can experiment with the slide carbs over the winter. Still left to go; petcock seals and gaskets (should be in today at Forest Grove Honda), rear spring pre-load (have some nice 1/4" aluminum spacers made by my friend Schooner at Laser Cutting Services) and chain tensioner.

Last night's test ride showed a big improvement in acceleration, still not perfect but on a 1 to 10 scale, would rate the before as a 4 and as of now about an 8.5.

With the help of my brother-in-law Fred, got the preload spacers on and felt a noticeable difference. Alex at Konflict had recommended 4 to 4.5 mm of preload, and although this converts to approximately 3/16", the closest material we could come up with on short notice and make into spacers was 1/4".

Shocks without preload spacer


Shocks with preload spacer (at very top of spring)


Bike loaded up for trip to Chehalis



Although not everything on the wish list was completed, I'm excited to get out and ride it. Leaving work at noon today and going home to load up every tool and spare part that will fit in the truck and head out. Should be a lot of fun, my wife and youngest daughter are going and we will meet up with Paul (OC) and Lonnie in Chehalis tonite. We plan on watching Paul ride the trials tomorrow and hopefully we will be joined by Luke, Sherry (Ladybug) and Al. My old mechanic Randy is also supposed to be there on Sunday, I will have to see if I can sneak a picture of him this time (he avoided the camera entirely at the last race). Next report we will hopefully be bringing good news of a successful weekend, stay tuned!

Beautiful night here I chehalis. Ricks bike looks great and ready to race. Besides for the douchebag next door playing loud crappy music, perfect night visiting and seeing old bikes!

Chehalis Vintage MX & Trials Nationals 8-14-11 “The Farm”
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Friday afternoon I spent several hours just sorting thru all the parts and pieces we might need and worked at getting loaded up. At one point, being weary of the whole process and running short on time, I literally took several containers of metric fasteners and just dumped them into the bottom of one of the parts buckets. Too many things to sort and load and not enough time! Past experience has proven that if you don&#8217;t bring it you will need it and if you do bring it you most likely won&#8217;t, so we brought everything but the kitchen sink. On the trip up, the old Ford F250 4X4 was straining with its load of bikes, tools, spare parts and travel trailer, but after a nervous couple of hours, we made it. On the trip home we had to stop and add three quarts of oil, so you know the old beast was working pretty hard. Whew!
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We arrived at the track about 6:30 PM and wondered (a.) where was our friend Don Matthews and (b.) where was Paul? We didn&#8217;t have Don&#8217;s number with us and after a quick look around decided to just go ahead and park. We gave Paul a call and made sure he was on course and told him we were saving him a spot next to us. We also realized later we had parked directly across from Don & his crew after all! When we had our camp and pits all set up, we went to the barn and played bingo. Had a good time, met many new people and Jan even won a nice folding camp chair.
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Later, when back in camp, everyone was just sitting around enjoying a perfect moonlit night when Paul decided to get out his camera. He began to experiment with shutter speeds, and took all kinds of interesting pictures, even getting the kids into the act using glow sticks for special effects. This kept everyone pretty well amused until bed time. Besides being a very skilled rider, Paul is also endlessly entertaining!
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Saturday morning we all got up bright and early and set out to follow Paul thru his Observed Trials adventure. Luke and Al arrived (Lady Bug couldn't make it) on their adventure bikes and joined right in. A group of us (Lonnie, Al, Luke & Patrick) rode bicycles and followed Paul from section to section, while a few others walked back and forth between sections 1, 2 and 3 to watch. My daughter Christine and her friend Brad ended up walking to all 10 sections which was a pretty good feat in itself, considering how spread out they were and the terrain. There were a total of 10 sections and the riders had to complete each of the ten sections 3 times. There was also a time limit that became critical for Paul as the day progressed.
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Paul&#8217;s performance in the trials was pretty impressive, not only is the bike heavy and awkward, but it was also having carburetor or tuning issues and if we adjusted the carbs to keep it from stalling, it would intermittently start free revving. Luke and I concluded that it must have a valve on the left cylinder getting tight and possibly giving the carb an intermittently weak vacuum signal. There wasn&#8217;t time for a proper fix, so Paul just had to tough it out. Regardless of bike issues, Paul did an amazing job, the most memorable for me being section 5. This section featured a steep side hill with a sharp right hand approach up an embankment and then immediately followed by a tight left hand turn, causing several riders to literally loop out their bikes, even crashing back to the road below. And what did Paul do? He just went thru it with a perfect score! We were all hooting and hollering for joy, we were amazed. At the end of the process Paul had finished with a score that was about mid pack, no small thing for his first trials on a bike that was running poorly and ill suited for the event.
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On a side note, probably the most impressive trials rider was <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:Street w:st="on"><st1:address w:st="on">Tom Street</st1:address></st1:Street> riding a 1949 rigid frame Indian whose score for 30 sections was only a 3! I&#8217;ve never been to a trials event before but now have to admit, I&#8217;m hooked!
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After the trials concluded, the rest of the day was spent fiddling with bikes and gear, visiting and looking around at other bikes, the most amazing for me being the VME group from Seattle, with a whole bevy of Rickman framed Matchless, Norton, AJS and other huge vintage four strokes that were museum quality but used regularly for Trials and MX. Pretty amazing.
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Christine had made some team &#8220;Barn Fresh&#8221; shirts and due to demand, ended up going into town with Jan, buying more shirts and art supplies and making more. Al took a few pictures of the group wearing these shirts and will be posting them soon.
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Sunday morning dawned bright and early, first the riders meeting, then practice. The bike suddenly sprouted oil and fuel leaks we had not seen before, and the group consensus was my recent switch to synthetic oil was the culprit. I would go out for half a lap, see a new leak, come in the pits, get repaired, go out ride another half lap, find a new leak, make another repair and so on. I ended up getting only one full lap of practice at speed and then brought the bike to the pits to wait for Moto 1. The good news was we were the last race in both motos (races 16 & 32), so we had plenty of time to make repairs. Crew Chief Randy Hess soldiered on all day and with Paul and Lonnie's help plugged the tach drive that was suddenly squirting oil, rebuilt the fuel petcock (we already had new gaskets and seals), replaced all the fuel lines and rebuilt the gas cap and even made a new gasket for that. <o></o>
By the time Moto 1 rolled around at 12:00, I was feeling petty confident that the Barn Fresh crew had plugged all the leaks and I could just focus on riding. Decided to start from the far inside pole and have a shorter run to turn 1. I had a reasonably good start, ended up around 5<SUP>th</SUP> going into turn one and thru the course of the race gave up a few positions, the most most notable pass was when the top expert rider came up from behind and went around to lap (Wes Poole 19X, BSA 500 single), he was riding at a whole other level and was fun to watch, I tried to pick it up a little and attempted to ride his lines but could only keep him in sight for 3 or 4 turns until he was long gone. Impressive.
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Moto 2 got off to late start due to a serious crash and injury to one of the riders, I do not know his name but he crashed hard in turn one and had a double fracture of his arm, and other injuries unknown. The ambulance crew did a great job taking all due precautions, and once the track was cleared we began again. It was probably a little after 4:00 and my race was the absolute last race of the day, and the pits were beginning to empty out. I decided to try the far outside pole and although I had clearer run to the first turn, it was little longer and I think cost a few positions. I did feel very calm and ready and even though I had a worse finish, actually felt like I was riding better. Toward the end of the race I was shifting less due to fatigue, over revving the bike a little in some places, and on the last lap I could hear the engine starting to miss. I have no idea how I finished the day, but am guessing maybe 10<SUP>th</SUP> or 11<SUP>th</SUP> overall in class?
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After the race was over, I loaded the bike into the truck and was just sitting there trying to take in oxygen when Jan ran up and said, &#8220;Dick Mann is out on the track, you better get over there and get his autograph!&#8221; We had stopped by his motor home several times during the weekend to get an autograph but had just missed him each time. I ran out to the track (huffing and puffing) and was able to enjoy a brief moment with this legendary rider. Dick is my all time hero of motorcycle racing and getting his autograph and talking with him for a brief moment will always be a cherished memory.
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Overall Chehalis was great fun, I feel good about how both Paul and I performed, especially considering both of our bike&#8217;s limitations. We met quite a few people who have a great deal of experience or knowledge with the Honda twins which should prove helpful during the winter rebuilding process.
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Thanks again to all of my friends and family for their support and to my new Adventure Rider friends that continue to show enthusiasm and support. Thanks to my crew chief Randy Hess, to Paul, Lonnie, Patrick and Al, to my Daughter Christine and friend Brad, to pit chicks Cindy and Karen and most of all thanks to my amazingly supportive wife and best friend Jan. Also thanks to Alex Martens of Konflict Motorsports, Brian Timmons of Wide Open Motorsports and to Ken Quay of Forest Grove Honda. I&#8217;m a lucky guy and have a lot to be thankful for. Here are a few photos from the weekend;

Photograph of photographer being photographed


With Paul's bike after the trials



Rider with crew chief



Waiting for last moto



Sportsman 500 "double gate"; experts in front, intermediates behind



"Barn Fresh" pit chicks



Still working.......



Note lower left; still working!



Pit dog Danny



Rider with next generation rider

Rick did awesome...I have some pics and videos, I hope to get them up by tomorrow, gotta go through and get them uploaded.

I forgot to also thank Bobby Gravely (4 stroke expert 95B), who stopped by to visit on Saturday afternoon and ended up helping me sort out the shock preload and axle spacers. Thanks Bobby!

Here is Rick tearing up the course




You can see the rest here LINK

Sponsor shot




Heading out for the first moto




Crew chief Randy working his magic



First Moto

Here are a couple of video links from Chehalis, the first one was done by my crew chief Randy and the second one is from my daughter's boyfriend Brad,

Randy's video (a bit corny at times!!)

http://www.facebook.com/l.php?u=htt...QDvD7gWAQBbh9TsWa0PyxNCYA5Co0MtsjDEmCIk67iiEA

Brad's video (cool music)

http://www.facebook.com/l.php?u=htt...QBMjuO5AQD-0ZbR8pp8Q5XO7VIu70FhDxHEhOb1wRcIJA

These both give a sense of the track's size, it was pretty long, what you would call a "horsepower" track, When we first walked the track I was a little worried at how high the speeds might be, but AHRMA veteran Don Matthews assured me that as the track got rougher the speeds would come down, he was right!