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Old 06-23-2011, 10:10 AM   #1
rizzer OP
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Question Trials Bike Build/conversion?

alright, I've been losing sleep over this...I was wondering if anyone have done or seen a trial bike built from non-trial bikes? say a dirtbike converted to trials or the likes.

been browsing around for this but couldn't find any on this forum, and it seems like Google can't help me either.

see Trials are expensive bikes in my home country (Indonesia) and I don't think I could ever afford one back home. So I'm thinking of building one from a dirt/street bike, but need a lot of reference to compile. Has anyone here gone through the trouble of building one? or seen a thread of a build?

any info would be much appreciated! :)
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Old 06-24-2011, 04:15 AM   #2
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no takers???? alrite, I'll go back to my corner
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Old 06-24-2011, 04:52 AM   #3
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I think to make a modern trials bike from a dirt bike would be very expensive and extremely difficult to get anything remotely competitive. Maybe look into shipping a used trials bike home from the UK - they are surprisingly affordable in the UK. Have a close look at pictures of a modern trials bike - everything is extremely compact and it'd be rather difficult to get anywhere near that compact using dirt bike parts. Just getting the exhaust right would require some serious fabrication skill, then there's the frame, major engine work (you'd probably need to essentially make your own cylinder to get mild enough ports and a small enough intake port to work with an itty bitty trials bike carb), suspension (you won't get enough steering lock with modern dirt bike forks - too fat), wheels (rear needs to be tubliss - not too hard to do, but not free)...

Back in the old days folks did convert bikes to dirt and trials, but that was before bikes got very specialized and they really weren't very good

You could probably make something that wouldn't be too far off from say a Beta Alp or Gasgas Pampara by really stripping down a bike like the KDX 200 and fitting trials tires.
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Old 06-24-2011, 07:03 AM   #4
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A Trials motorcycle is just that, a motorcycle, ride what you've got.
Here in the U.S. at least, Novice sections can easily be mastered on a decent trail bike. Things to consider modifying on a bike include, grind or cut the steering stops for maximum turning (air cooled bikes frequently have more room than liquid cooled bikes), make sure very low gearing is available for the model you select as well as clearance for a proper Trials tire. Remounting footpegs can be very helpfull as well.
I don't know what bikes you have available so I can't make any specific reccomendations.
Riding Trials is about mastering what you have, not having the same bike as the world champ.
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Old 06-24-2011, 07:47 AM   #5
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I definitely couldn't ride a novice section in D6 on a non-trials bike. Sure I could do the big obstacles then blow the section boundries, but the sections are way, way too tight for a big bike. I'm newish to trials so maybe not the best proof its impossible (and its probably not), but it'd take someone very good at hopping to pull it off at the least. I cleaned the day in my class on a trials bike and have run top 5 overall in Vegas to Reno so I'm not a noob to bikes generally. You certainly don't need a trials bike for obstacles - in fact I'm not even sure a trials bike is all that great for most big obstacles, but a trials section is super tight, and to maneuver in such tight confines a proper trials bike is pretty necessary.

I could probably ride the 4 line in a vintage event on a non-trials bike (or my pickup truck ) though.

I completely agree with ride what ya got, but he asked about a trials bike.
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Old 06-24-2011, 08:16 AM   #6
rizzer OP
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yeay!!! repliesss!!!!

Bikepilot, do you have a list of specifications like frame dimensions, rake, wheel sizes etc to refer to?
I do agree that it's gonna be A LOT of work, but still a better chance over importing as we have a no used CBU import policy. and for those new CBU imports, they're subject to 180% tax of the invoice price

btw,that gas gas pampera looks pretty cool actually :)

Lamotovita, I like the spirit! another problem would be the base bikes/engine for the project actually. the biggest 2 stroke available on the market is a 150cc kwak ninja. we also have a range of 200-250cc 4 strokes but I don't think the weight of them would be ideal for trials. then again, I see back in the day they also used to have heavy brit bikes for trials.

I'm guessing trials have their power bands in the lower rpms, so longer strokes over bore? or would it be enough just to lower the gearing of a mid range powered bike?

I've also noticed on 2 stroke trial bikes, the expansion chamber starts a bit further back than it would on other purpose built 2 strokers. does this affect the engine character as well?

sorry for all the questions guys
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Old 06-24-2011, 10:02 AM   #7
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Quote:
Originally Posted by BikePilot View Post
I definitely couldn't ride a novice section in D6 on a non-trials bike.I completely agree with ride what ya got, but he asked about a trials bike.
I don't know where D6 is but I'm guessing you mean that you couldn't clean novice sections on a non Trials bike. If you're cleaning every thing you ride it's time to move up a class.


I guess what I'm trying to say is that a Trials bike is the bike you have to ride Trials on.

lamotovita screwed with this post 06-24-2011 at 10:13 AM
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Old 04-12-2012, 11:10 AM   #8
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My base is a Honda 125 XLS 1980, much easier to find that a old 4stroke trial... Sorry if I'm not so clear; I 'm french and normally more often on honda-125xl dot com forum...

- seat has been replaced by an aluminium plate
- feet resters are put 12 cm rear and 4cm higher ( so I had to modify the kick and break pedal)
- steering stop are removed, so I had to modify the tank... ( home made, hammer made...)
- swing arm is from a 348 Montesa, modified to keep same shock absorbers geometry
- T fork are replaced by honda Twin T fork, to get more maneuvrability
- Transmission is changed: 60/13 against 47/14
- bore is changed to 66 ( 165cc)
- etc...

Before:


This one just to show the actual tank:



and this one with the tank I have to finish:

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Old 04-16-2012, 01:54 AM   #9
rizzer OP
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Originally Posted by LucasLeader View Post
This type of bike you're trying to build is getting pretty popular. I'm really interested in building something similar just for a fun little bike to mess around on and practice some technical trials type skills. It's too bad trials isn't more popular so there would be more used bikes around at a more affordable price. Check out this thread as well for some similar ideas. http://www.advrider.com/forums/showthread.php?t=770250
Thanks for the link mate!

Quote:
Originally Posted by trialxls View Post
My base is a Honda 125 XLS 1980, much easier to find that a old 4stroke trial... Sorry if I'm not so clear; I 'm french and normally more often on honda-125xl dot com forum...

- seat has been replaced by an aluminium plate
- feet resters are put 12 cm rear and 4cm higher ( so I had to modify the kick and break pedal)
- steering stop are removed, so I had to modify the tank... ( home made, hammer made...)
- swing arm is from a 348 Montesa, modified to keep same shock absorbers geometry
- T fork are replaced by honda Twin T fork, to get more maneuvrability
- Transmission is changed: 60/13 against 47/14
- bore is changed to 66 ( 165cc)
- etc...

Before:


This one just to show the actual tank:



and this one with the tank I have to finish:

Nice! how does it perform?
I've got a home built scrambler at the moment, but I don't think I'll be converting it into a trials. I'm afraid I'll miss the trail rides too much if I turned it into a trials bike. Plus, mine is too tall for trials
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Old 04-16-2012, 04:12 PM   #10
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Quote:
Originally Posted by rizzer View Post
alright, I've been losing sleep over this...I was wondering if anyone have done or seen a trial bike built from non-trial bikes? say a dirtbike converted to trials or the likes.

been browsing around for this but couldn't find any on this forum, and it seems like Google can't help me either.

see Trials are expensive bikes in my home country (Indonesia) and I don't think I could ever afford one back home. So I'm thinking of building one from a dirt/street bike, but need a lot of reference to compile. Has anyone here gone through the trouble of building one? or seen a thread of a build?

any info would be much appreciated! :)
I used to be very active in vintage trials back in my AHRMA days. And one of the most unique bikes I ever saw over the years was a converted Honda Trail 90. The owner fabricated it himself over the course of a few seasons and every time I'd see him at an event the bike had been re-engineered in one way or another.



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Old 04-16-2012, 04:33 PM   #11
nsu max
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Quote:
Originally Posted by Bultaco206 View Post
I used to be very active in vintage trials back in my AHRMA days. And one of the most unique bikes I ever saw over the years was a converted Honda Trail 90. The owner fabricated it himself over the course of a few seasons and every time I'd see him at an event the bike had been re-engineered in one way or another.



DAMN IT, you guys!!!!!!!!!!!!!!!!! More insperation. I'll never thin out the herd with stuff like this to keep giving me ideas. Thanks.
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Old 06-27-2011, 10:30 AM   #12
rizzer OP
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Motojunky, many thanks for the link! they look awesome...+ a pic gallery of the builds

Nsu Max, wish I had a brother like yours...nice build man! good to hear the bike gets around in events as well...did you refer to textbook trials geometry or just went for gut feeling on the build? I mean like applying unparallel triples? etc.

Geode, nice find mate! I guess I couldn't find it in searches cause I was looking up the word "build" instead of conversion. been reading through that thread and it's mostly on twinshocks. I'd love to gather as much info on both twins and monos before deciding though. I do see there is a link for a CRF/XR trials conversion towards the end of the thread...cool build.

the main difference about my build and theirs is that they've actually started I can only start in 4-5 months at the soonest :(
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