The 2004 ATC450R (TRX Conversion)

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I'll keep the intro short. The motivation and reasoning behind this project can be seen at any given OTC race. It seems the 450 powered 4 stroke conversions eat up the 250cc 2-stroke trikes of the mid 1980s. Albeit - I love those machines - I feel that if I want to be competitve in the OTC race series - I must be on a 450.

STAGE 1

The Cut. (November 29, 2008)

Here is the candidate. A 2004 Honda TRX450R.

And now - the cut - the Snake.....................................

The Graft (December 4, 2008)

Trying yet a 3rd approach to this conversion, I will be grafting on the bottom 1/2 of the engine cradle, steering neck and down tube from an ATC250R - to the existing quad frame. The other 2 successful conversions were A) use a bike frame, and B) custom build the 250R parts I will be using. Derrick Adams approach also worked by using a larger craddled Tri-Z frame. By using the ATC250R front section of frame - I will be able to use the ATC250R triples, forks, and whole front end as at this point I am only starting to utilize it's full potential on a race track. I will have to custom build the top frame spurs from the steering neck to the existing quad dual split backbone. The spurs will need to be fit once all other 250R frame is tacked into place as to accept a CRF450R gas tank. This will also allow me to use the CRF shrouds and CRF450 radiators.

Today - 12/4/08 - My CRF tank arrived in the mail. Snake and I completed the graft this evening. First we bent the bottom ATC frame cradle about 1.5" out on each side to meet up with the TRX frame as the ATC frame rails were 5 inches center to center - and the TRX is 8 inches center to center. Then we took some final measurements. We then inserted 3/4" round stock steel slugs into the joints for strength and fit.

Next was the twin spur top sections. We used 1" X 2" 3/16 rectangle tubing for this piece. We also slugged these joints. Some leveling and measuring and we were right where we needed to be.

I have been working all week on getting the rake where I think it should be as well as ride height (ground clearance) - seat height - and wheel base. As you will see in the pictures below - this TRX/ATC is dang near exactly the same everything dimensionally as a 1986 ATC250R. Same seat height - wheel base (close) same rake (a degree or two less than the 86R actually). They really are close. What really came out great was rider position. As I already mentioned - the pegs need lowered - but other than that - this thing fits me like a glove. From the seat - the bars are a perfect distance for me - about 2 or 3 inches longer reach than the R. On my R I feel so cramped - sitting on this - it feels like it actually fits me.

For pictures below - I have it on my old 84R front end - obviously this is for fitment only and will not be used on the finished product.

Snake Cleans up his torch work - BTW - there was big rust holes found in the down tube back behind the big factory gussets - Down tube will need to be plated for structural integridty when finish welding.

Some initial frame work - lots of gussets and welding to come as this project progresses

Here she is as it sits today - a roller that will support my weight

The 250R comparison

A Good Quad - is a Quad like this one shown here

What Lou and Kintore will be seeing all year on the track is shown here


I am going to go ahead and play with the subframe as suggested by Jason Hall. I will either lengthen the bottom section and or mounts or shorten the upper section and or mounts. This will give the seat and fenders a more correct position. As of right now - it seems the seat and fenders are angled down too much in the back - giving it a lower look in the rear. This will also allow for a better gas tank position.

December 9, 2008

got the subframe set correctly and the correct shrouds came in today.

Final Mock Up!!!!!

12/11/08

Got the frame stripped down to nothingness. The swing arm bolt was siezed and needed to be cut out. That is never very much fun. The hardened collars sieze to the bolt - and will not let go. This happens to it seems every single Honda ATC / ATV with similar set ups. From my 84 R to my 86 R to 300/400EXs to this only 4 year old bolt. Please - if you own a trike or quad - pull the swinger bolt at least once a year and grease it up real good.

Snake took the frame home and within about 2 hours had it all finish welded and gusseted. Here is how she looks. Next step is to clean all grease / strip paint - prime it and give it a quick coat of paint. Then re-assebly. We will be tearing down one more time for final finish as we don't want to paint it up real nice then have to weld a bracket on somewhere and ruin the finish.

Plans are tenatively set to run this trike at Summit Indoor in less than one month! It will be a close one. Some other issues that I had not planned on buying now need bought - rear axle bearings - swingarm bearing kit - singer bolt and nut - but hey - these quad parts are a 1/4 of the cost of ATC parts it seems.

here is the frame all welded up and sexy looking!

STAGE 3

Fit and Finish (12/15/08)

I guess I am already in the fit and finish stages (V1.0). Reassembly will start NOW. Shelly painted the frame tonight. I started on cleaning parts for reassembly and have run into more CRAP - busted up bearing carrier - bad lower rear linkage bearings - swinger was not cooperating - SO I will install an 06 swinger I had on the shelf. This will gain me 1 inch plus it is a brand new take off.

12-17-08

A little more assembly tonight. Today I order the remaining parts I need to complete this project. Things are looking really good at this point as it is just some assembly work from here on out. I see my seat will need a little work o make it really fit perfect - but it does fit OK now. The plastics seam to really flow well I think. Here is how it looks as of right now - I always put the tank and shrouds and fenders on everynight I am done working on it - not sure why - just gives me a sense of accomplishment I guess...... Here are some pictures:

12-18-08

Yet a little more assembly. Front end is on and well. Oil cooler is hooked up. Radiators are 1/2 mounted. Need to fab up one more bracket for the inside top of the rads - then I think I will build a guard for the rads to protect them a bit more. Frame Shroud mounts got made and welded onto the frame as well. I sure hope all my parts come in today. I would like to finish assembly tomorrow!!!!

Yet a few more pictures:

I have everything ready to go except - Rear brake caliper - in route - being shipped from Iowa, Swing arm bolt - should be here tommorow, hot start cable - should be here tomorrow. I also need to get a 250R front fender to replace the 350X fender that is on there. Next year - maybe I will get some inverts on this bad boy. Here are some final pictures before the ride test.

Pictured below you can see that things just seem to fit "right" onto the ATC. The Oil Cooler for example: all we did was straighten the "L" brackets on the cooler - and it bolted right onto the stock holes in the triples.

Currently as it has been in service for 1 full race season and has made a trip to Southern California Dunes (Glamis) - this bike has held up very well with no major defects.