Honda Tl-250 Weight Reduction

[mr clean]

I picked up a 1975 TL-250 in outstanding condition. Still had original Bridgestone tyres and chain and sprockets, and not much wear at all.

I always wanted to own a 4 stroke Trials bike and this fits the bill perfectly. I weight more than the bike and am physically strong so the reputed weight of the machine should be manageable. I'll find out later today when I do the intial test ride. The suspension works great and it has heavy duty shocks specific to my weight, and a little higher than stock for extra clearance and better turning.

Sammy Miller got his big Ariel down from 325 lbs to 245 lbs. Now I have read stories that Ariel Ht-5 owners are managing to get the weight of this bike down to 225lbs. Must be due to new parts and materials being available.

Works Beamish Suzuki 325's weighed in at 165lbs in the late 70's. A lot of Titanium, plastic and aluminum alloy screws, and shorter shocks. The wheel spokes were titanium.

I did some online searches and recalled from my memory things that can be done to get some ponds off this bike.

I saw online that the Bridgestone tyres can be replaced with modern units and the rear alone will be 2.5lb lighter. So I estiomate the weight savings and traction gained will be around 4lb. with the tyres, plus better traction when needed.

I read somewhere that something can be done to the seat by either removing or replacing a 4 lb metal plate for another 4 lbs off.

From memory I recall an all Aluminum exhaust system was once available, which is designed to replace the entire exhaust system saves a whopping 13lbs, and the engine runs slightly cooler from improved heat dissipation of the aluminum material.

I see online that there are or were frames available with improved geometry and unspecified weight savings. Different frames had different handling characteristics. I remember titanium frame kits for Ossa and Bultaco that dropped the weight of those bikes by around 12 pounds. This probably was not an inexpensive proposition. There have been many aftermarket frames made for many different trials bikes.

I remember that there used to be kit that could be purchased which could replace most of the bits and bolts with titanium and drop the bike weight 8 to 12 pounds. This included steering heads, wheel and swingarm axles.

I recall someone that stripped the motor and had parts inside the engine and transmission drilled , machined and replaced with lighter materials, dropping the motor weght by over 10 pounds. It was very expensive, and I probably wouldn't do that, but would like to be informed of the process involved.

So there must be bits and brackets in this bike that can be replaced with lighter materials. Is the airbox heavy? Can it be replaced with a weight saving item, like the 4 pound seat weight saving modification? handlebars?

All guideance and links to this sort of information would be greatly be appreciated.

Also sources for parts if I need them. The chain on this is a 428? Is there a 528 kit available for this bike? Is it needed? What to do if I wear out the rear sprocket?

I would also like to upgrade the footpegs on this bike and give it a folding shift lever, side pull throttle, and consider any recommendations you guys have.

I'm not a mechanical wizard, I prefer will probably not disassemble the wheels and motor and put in titanium bits in the very near future. However the seat mod, tires, and exhaust I would like to do sometime soon. 20 lbs off a Trials bike is very helpful.

Cheers

Edited July 30, 2006 by Mr Clean

[mr clean]

I have seen your bike online before Big John, looks quite impressive.

How does it ride?

I took the TL-250 out on its maiden voyage today. It was very hot and dry, 38 C, so I looked for shade and there was not much wind. It wa not a long ride due to the heat.

IMPRESSIONS:

Love the motor, the frame geometry, gearing, suspension, brakes, and riding positions were good.

It is definetly heavy, top heavy. When it starts to lean over or you bump into something and your path gets deflected, it takes a considerable effort to hold and change to the desired direction when compared to a lighter bike.

The smooth 4 stroke power makes this manageable if you use the power and engine braking to influence the direction of the machine. If two stroke were top heavy like this it would be very unpleasant to ride in trials.

It gets excellent traction and handling is predictable because of the smooth 4 stroke power delivery.

The bike is a fun ride and I really like it. If I can get the weight down and especially lower the centre of gravity it will be an excellent twinshock trials bike. If I can't get the weight down, I'll still probably keep it and ride it, because its so much fun Thumping around.

I sure hope that there are some inexpensive and effective ways to get the pounds off. Like the seat 4 pound saver (whatever that may be), and hopefully weight reduction in the exhaust system really is 13 pounds of tonnage.

[gbmoto]

I've been using a TL 250 for a while now. It is lighter than it was but still pretty heavy and tiring in tight stuff, excellent on big hills and mud tho'

As you can see in the pic the lower frame rails are removed together with the rear loop, lower rear guard is thin alloy, seat base is plastic, lots of alloy bolts, but have kept the original pipe as according to Sammy Miller it works really well, but an alloy one would save huge amounts of weight.

Engine wise it is bored to 280 with XL250 head ( bigger valves) and XL250 flywheel ( heavier strangely )

Recently tried a Fantic for a while, much easier and lighter but not so much fun! I ride for fun so have sold the Fantic. Apologies to those who have seen the pic before but I love this bike!

[mr clean]

Hi GBmoto:

Your TL-250 looks really nice. Do you know how much weight you have managed to save with what you have done so far?

Also, how do you do the seat mod? Do you buy a kit or can it easily be made by yourself?

Is the bashplate removal and replacement a kit that you buy, or did you have to fabricate from scratch. If purchaseable, where can I buy it?

I think that by replacing the entire exhaust system with alloy, the weight saving is around 13 pounds. That's nothing to sneeze at, and the bike would be much better to ride with that weight off of it!.

So funny, just like you I had a Fantic 240 twinshock that I sold, powervalve installed, very powerful, Outlaw Dave bought it, and is restoring it. Unfortunately I had no workshop to do this in. If the Fantic was in like new shape I would have kept it. Then I found a deal on a Beta TR-34C. After one ride I put it up for sale! Blech. Yuck. Phoey

This TL-250 came along in excellent shape, not a project bike at all. I have to say, that for years I wanted one of these, not a TL-125. It is not necessarily as competetive as something lighter and newer, it will be when the weight is reduced.

Also, for the fun factor, this bike has everything else I have owned beat hands down. NO CONTEST. I love my old Honda Trials thumper. I wish I found one in this good a shape a long time ago.

See my thread in Mechanical talk about pound age reduction.

[gbmoto]

Hi Mr Clean

Thank You, havn't really checked the weight, would probably gain more losing a few pounds myself.

For the seat I cut a sheet of plastic to shape, heated it in the oven, then moulded it over the bike, then fitted the standard mounts and cover.

The frame mods were done when I got the bike, one of a number imported long ago, I remember the story in TMX but cannot remember who done them, they also had betor shocks and decent tyres fitted.

Basically the rear lower cross frame tube is cut in half lengthways and a plate is welded along this to which the bash plate bolts, the down tube is cut diagonally just below the front motor mount, there is no lower mount, just rests on the bash plate.

By the way we have an Great Uncle in Steveson, Vancouver, small world etc.

Just seen a couple more questions!

I have used

Amal twist grip

IMS CR80 gear lever

Miller modded footrests, but Yam TTR250 aftermarket pegs fit with no mods.

Stick with the 428 chain, go bigger and you have clearance issues on the gearbox and all the bits weight more anyway, Miller used 428.

[trial pat]

Hello TL 250 lovers. I added part 5 of my Honda TL 250 project: http://www.twnclub.ch/classic_trial_files/honda.htm

I had to rebuild the engine, but it was worth it. Engine is 40kg.

I put the bike on a simple household balance: 45kg front plus 55kg back so about 100kg

I also put my Bultaco M49 from 1968 : 45kg front plus 53 back so about 98 kg.

Now, the Bultaco has more a cross engine, once you lost speed on a steep hill, you have troubles to go till the end. The TL 250 pulls like a truck, almost like my 4RT, really a great thumper ! As I am 86kg, I don't have troubles with the weight, I prefer a heavier but more powerful, torquey bike (that's why I was riding a Cota 349 instead of a Fantic back in 1983).

Keep the TL 250 running !

Patrick from Switzerland

[mr clean]

Thanks GB moto and Trial Pat!

Question for Big John:

What can you tell me about the frame and tank setup you have, and any other info? Is this a frame kit you can buy?

Please post at least one more pic of the other side of your wonderful bike!

[trial pat]

Hello Big John

Shield is original I think, was sand blasted and "bromatised" (kind of a chrom bath) by the former owner

I always like your postings. Now a (too?) personal question: I'm wondering about your surname. My sizes are 189cm, 86kg and foot 47 (12.5 UK). Do I come near you by any size? 20 years ago, they called me "el giraffo", because I could make a dab and save the 5 (like Felix Krahnst

Edited August 5, 2006 by Trial Pat

[mr clean]

Thanks Big John,

I was hoping that it was going to be a kit that could be purchased somewhere.

Oh well.

If he only made 4 frames, no doubt they were probably not inexpensive! I thought somewhere someone might have a warehouse with 40 such frames they would like to get rid of.

It is a very nice looking rig, what is it like to ride?

Edited August 6, 2006 by Mr Clean

[boogerblaster]

On 7/22/2006 at 12:08 PM, mr clean said:

I picked up a 1975 TL-250 in outstanding condition. Still had original Bridgestone tyres and chain and sprockets, and not much wear at all.

I always wanted to own a 4 stroke Trials bike and this fits the bill perfectly. I weight more than the bike and am physically strong so the reputed weight of the machine should be manageable. I'll find out later today when I do the intial test ride. The suspension works great and it has heavy duty shocks specific to my weight, and a little higher than stock for extra clearance and better turning.

Sammy Miller got his big Ariel down from 325 lbs to 245 lbs. Now I have read stories that Ariel Ht-5 owners are managing to get the weight of this bike down to 225lbs. Must be due to new parts and materials being available.

Works Beamish Suzuki 325's weighed in at 165lbs in the late 70's. A lot of Titanium, plastic and aluminum alloy screws, and shorter shocks. The wheel spokes were titanium.

I did some online searches and recalled from my memory things that can be done to get some ponds off this bike.

I saw online that the Bridgestone tyres can be replaced with modern units and the rear alone will be 2.5lb lighter. So I estiomate the weight savings and traction gained will be around 4lb. with the tyres, plus better traction when needed.

I read somewhere that something can be done to the seat by either removing or replacing a 4 lb metal plate for another 4 lbs off.

From memory I recall an all Aluminum exhaust system was once available, which is designed to replace the entire exhaust system saves a whopping 13lbs, and the engine runs slightly cooler from improved heat dissipation of the aluminum material.

I see online that there are or were frames available with improved geometry and unspecified weight savings. Different frames had different handling characteristics. I remember titanium frame kits for Ossa and Bultaco that dropped the weight of those bikes by around 12 pounds. This probably was not an inexpensive proposition. There have been many aftermarket frames made for many different trials bikes.

I remember that there used to be kit that could be purchased which could replace most of the bits and bolts with titanium and drop the bike weight 8 to 12 pounds. This included steering heads, wheel and swingarm axles.

I recall someone that stripped the motor and had parts inside the engine and transmission drilled , machined and replaced with lighter materials, dropping the motor weght by over 10 pounds. It was very expensive, and I probably wouldn't do that, but would like to be informed of the process involved.

So there must be bits and brackets in this bike that can be replaced with lighter materials. Is the airbox heavy? Can it be replaced with a weight saving item, like the 4 pound seat weight saving modification? handlebars?

All guideance and links to this sort of information would be greatly be appreciated.

Also sources for parts if I need them. The chain on this is a 428? Is there a 528 kit available for this bike? Is it needed? What to do if I wear out the rear sprocket?

I would also like to upgrade the footpegs on this bike and give it a folding shift lever, side pull throttle, and consider any recommendations you guys have.

I'm not a mechanical wizard, I prefer will probably not disassemble the wheels and motor and put in titanium bits in the very near future. However the seat mod, tires, and exhaust I would like to do sometime soon. 20 lbs off a Trials bike is very helpful.

Cheers

I'm restoring a TL 250 also and I'm making a seat base, and exhaust from 6061 - T6 aluminum. Also the fork plugs will be 6061 with an air valve for tuning. I'm also going to make axles and swingarm shaft from titanium. And I'm going to get a spline cutter to press through a block of aluminum for the beginning of a aluminum kick starter ( again 6061 ) . I've bought and returned several k. starters because of wrong spline size. Don't even try the inet nothing there will work. Also I'm going to make aluminum damping rods that give 25 mm more travel and no harsh bottoming. I may start selling some of these pieces after I finalize the designs. You TL250 riders give me a holler at grizzlegumpferdash@gmail.com if you would be interested in this. 

[boogerblaster]

On 7/22/2006 at 12:08 PM, mr clean said:

I picked up a 1975 TL-250 in outstanding condition. Still had original Bridgestone tyres and chain and sprockets, and not much wear at all.

I always wanted to own a 4 stroke Trials bike and this fits the bill perfectly. I weight more than the bike and am physically strong so the reputed weight of the machine should be manageable. I'll find out later today when I do the intial test ride. The suspension works great and it has heavy duty shocks specific to my weight, and a little higher than stock for extra clearance and better turning.

Sammy Miller got his big Ariel down from 325 lbs to 245 lbs. Now I have read stories that Ariel Ht-5 owners are managing to get the weight of this bike down to 225lbs. Must be due to new parts and materials being available.

Works Beamish Suzuki 325's weighed in at 165lbs in the late 70's. A lot of Titanium, plastic and aluminum alloy screws, and shorter shocks. The wheel spokes were titanium.

I did some online searches and recalled from my memory things that can be done to get some ponds off this bike.

I saw online that the Bridgestone tyres can be replaced with modern units and the rear alone will be 2.5lb lighter. So I estiomate the weight savings and traction gained will be around 4lb. with the tyres, plus better traction when needed.

I read somewhere that something can be done to the seat by either removing or replacing a 4 lb metal plate for another 4 lbs off.

From memory I recall an all Aluminum exhaust system was once available, which is designed to replace the entire exhaust system saves a whopping 13lbs, and the engine runs slightly cooler from improved heat dissipation of the aluminum material.

I see online that there are or were frames available with improved geometry and unspecified weight savings. Different frames had different handling characteristics. I remember titanium frame kits for Ossa and Bultaco that dropped the weight of those bikes by around 12 pounds. This probably was not an inexpensive proposition. There have been many aftermarket frames made for many different trials bikes.

I remember that there used to be kit that could be purchased which could replace most of the bits and bolts with titanium and drop the bike weight 8 to 12 pounds. This included steering heads, wheel and swingarm axles.

I recall someone that stripped the motor and had parts inside the engine and transmission drilled , machined and replaced with lighter materials, dropping the motor weght by over 10 pounds. It was very expensive, and I probably wouldn't do that, but would like to be informed of the process involved.

So there must be bits and brackets in this bike that can be replaced with lighter materials. Is the airbox heavy? Can it be replaced with a weight saving item, like the 4 pound seat weight saving modification? handlebars?

All guideance and links to this sort of information would be greatly be appreciated.

Also sources for parts if I need them. The chain on this is a 428? Is there a 528 kit available for this bike? Is it needed? What to do if I wear out the rear sprocket?

I would also like to upgrade the footpegs on this bike and give it a folding shift lever, side pull throttle, and consider any recommendations you guys have.

I'm not a mechanical wizard, I prefer will probably not disassemble the wheels and motor and put in titanium bits in the very near future. However the seat mod, tires, and exhaust I would like to do sometime soon. 20 lbs off a Trials bike is very helpful.

Cheers

I forgot to say that a larger size chain is not necessary as the TL only has 15.5 to 16 hp. A 528 is for high hp bikes. My 430 Husqvarna at 71 hp uses a 528 . A 528 on a TL would just offset the weight reduction you've gained. There are titanium pegs available. You can't beat a Gunner Gasser Throttle. 

[boogerblaster]

On 8/3/2006 at 6:08 PM, trial pat said:

Hello TL 250 lovers. I added part 5 of my Honda TL 250 project: http://www.twnclub.ch/classic_trial_files/honda.htm

I had to rebuild the engine, but it was worth it. Engine is 40kg.

I put the bike on a simple household balance: 45kg front plus 55kg back so about 100kg

I also put my Bultaco M49 from 1968 : 45kg front plus 53 back so about 98 kg.

Now, the Bultaco has more a cross engine, once you lost speed on a steep hill, you have troubles to go till the end. The TL 250 pulls like a truck, almost like my 4RT, really a great thumper ! As I am 86kg, I don't have troubles with the weight, I prefer a heavier but more powerful, torquey bike (that's why I was riding a Cota 349 instead of a Fantic back in 1983).

Keep the TL 250 running !

Patrick from Switzerland

You can get a long duration cam from Megacycle Cams.com if you want even more torque from your TL. Happy riding everyone.