chuck4788

My 04 315R has blue chrome stanchions.

My 04 has dimpled plates. My 315R Parts List says 97+ use 22351-MG3-000 plates, but the first part of the number is wrong for Honda clutch plates, it should be 22321-MG3-000 which is also used on 83-07 XR500/600/650, & 89-90 GB500. Others have used CR250R plates, which are also dimpled, and discs for smooth clutch action. Four of the frictions in my 04 have Honda Product Code "FA4" marked on them which is 83-90 CR250/500. Since I bought the bike used I don't know if the discs/plates are OEM but my clutch is very smooth and no drag. The engine in the 315R seem to be a typical Honda design based on corporate design criteria and reusing previously designed parts. IMO the clutch is a mid size off road Honda clutch that is also used in other Montesa and Honda models. Apico sells clutch disc and plate kits for the 315R/4RT (same size plates & discs).

Besides the dimple disc, that Montesa finally switched to, oil has a big effect on clutch operation. Montesa specs a very thin Elf HTX740 synthetic gear oil, but it is expensive, and for me difficult to locate. My research. Thick oil slow hookup and increases drag Thin oil faster hookup and less drag. Regular ATF or Ford type vs Dextron type; Dextron has smoother lock up, regular ATF quicker lock up. Thick and thin above refers to the oil's viscosity at 40C. Gear Oils................................ @40oC........... @100oC GRO Gear Extreme 75W*......... 20.............. 5.2 Elf HTX740.syn........................ 21.4............. 7 Valvoline Dextron VI ATF syn.. 29.5........... 6.0 Motul ATF VI*..........................30,5...........6.10 Mobile 1 Dextron VI…………. 29.5…..…. 5.3 Royal Purple Max ATF........... 35.0............. 7.5 Valvoline +4........................... 34.13.......... 7.55 Allison Transynd syn ATF ..... 53.9............ 9.75 Elf HTX735.............................114............17.8 Amsoil 75W-90 syn**……….. 130……. 15.6 Amsoil 80W-140 syn**…….... 256……. 26.4 Silkolene Medium 85W-90... 150-340..... 15 Silkolene Light 75W-80......... 100-180..... 15 Silkolene Comp 80W-90........ 100-145.... 15 Silkolene Pro SRG 75............ 100-180..... 11 * info from Trials Central posts. ** Hypoid gear oil - do not use in a wet clutch I have CR250 plates and discs (dimpled) in my 315R and switched to Valvoline Dextron VI ATF syn and have the best clutch action of any bike I have owned, and much smoother clutch action than with the Elf oil.

West Systems is the epoxy to use. Modern fuels contain ethanol which soften polyester resins (the common resin for fiberglass).

I run Valvoline synthetic Dextron IV ATF, IMO it works better than the Montesa recommended ELF HTX740 syn gear oil. The other improvement for the clutch is to use Honda CR250R clutch plates, the dimpled steel plates and the cork frictions. I have an '04 but I think the carbs are the same 01-04. Stock Delorto: Pilot: #35, could go to #38 for a more sensitive mixture screw. Mixture screw: now 2 1/2 turns, well beyond its sensitive range. Needle jet: D34 or D37 Neddle: K270 Needle clip: stock 3rd groove Throttle valve: #4.5 or #5.0 Main: #110 Starter: #60 Spark plug: NGK BR6ES 14mm, ¾” reach I haven't had a tank leak yet but the best fix is a sealant on the inside of the tank.

What oil are you running in the tranny?

A friend's 05 4RT weighs 172lbs w/ half a tank, my 315R is 164lbs w/ half a tank. Half a tank equals about 1 qt of fuel or 1.5lbs

The USFS only allows street legal vehicles on their roads. So you need a plate from your state of residence to ride USFS roads. Depending on where you live this could be easy or very difficult. Usually requires hi/lo headlight, brake light, mirrors, horn, maybe turnsignals, etc.

Here is the answer on Keihin vs Dellorto. http://www.trialscentral.com/forums/topic/34754-phbl-versus-vhst-carb/page__st__15#entry261918 IMO Keihin and Mikuni make the best small engine carbs in the world. The Dellorto problem is poor mixture control at part throttle and the Keihin is much better. Some have had good luck fine tuning the Dellorto and others prefer the Keihin. I have a PWK ready to go on my 315R but I'm still fussin with the air boot, I would like a larger air boot than the Montesa unit. So a question; What air boot solution and/or carb adapter are you using on the 315R with a Keihin PWK carb?

So we have a cheap (?) 4rt and a good 4RT?

That'll work or you can buy Honda CR250R plates.

My fan makes enough noise that I hear it over the engine when stopped. So I would expect your fan to also be noisy if it is running at full speed. Overheating could also be a bad impeller in the pump. When starting a cold bike I use the fan turn on as an indicator that the engine is warm, usually happens in just a few minutes.

CR6EH-9 plug ot the 4RT is also common on a lot of other engines. Irridium equivalent would be: CR6EIX-9 or CR6EIA-9 ($8.89 + free shipping at Amazon.com http://www.amazon.com/NGK-CR6EIA-9-Iridium-Spark-Plug/dp/B001RLOE8U) Some of the quad guys go one heat range hotter: CR7EIX-9, they claim better idle, starting, and running. Snow machines are also using this plug.

I think I would parallel wire it in so I could also us the normal kill switch.

Also did you check the reeds? If they have any raised edges or are curled they will be slow to seal which causes loss of throttle response. If they are curled a bit but not flayed on the edges flip them over for a better seal and see if that improves things. On the PHBL it is a mixture screw not a air screw. Boyesen Reeds are an improvement and they now have some new reeds for Trials bikes.

Better to use a piece of 35mm film. They are Showa forks but I recommend using Honda (or Montesa) seals for better life and less stiction.

Is it a 97-99? or a 00-04? The latter is a model PHBL The latter have a single low speed jet and a #60 starter jet. My jetting is: Pilot: #35, should go to #38 Mixture screw: now 2 1/2 turns Needle jet: D34 & D37, has D37 Neddle: K270 Needle clip: stock 3rd groove: Throttle valve: #4.5 & #5.0, has 5.0 Main: #110 Starter: #60 Here is a video link on servicing the PHBL by GasGas: http://www.youtube.com/watch?v=1EbXacjIV78&feature=player_embedded And a Trilas Central thread: http://www.trialscentral.com/forums/topic/34754-phbl-versus-vhst-carb/page__st__15__p__261918#entry261918

Lots of compression from fresh rings will cause more ping. These engines require high octane fuel, and the spec in the Owner's manual is for RON 92-100, which is not available in the US. The US pump premium is usually about 91 AKI (Anti-Knock Index) which will be about 95-96 RON, and should be OK to use. Because ethanol can cause oil separation and is damaging to fiberglass fuel tanks I use non ethanol pump premium, and I don't store fuel more than a few weeks and I drain the system for storage. http://pure-gas.org/index.jsp?stateprov=WA Too much oil in the fuel will lean jetting and can cause ping, the OEM jetting is for 80:1 but you need a high quality synthetic to run that lean. Montesa recommends Elf HTX976.

Yes the carb parts are marked, sometimes you'll need a magnifying glass to read them. Genuine Keihin parts also have a copyrighted Keihin logo. Some recommended jets for 250cc Trials use. 122 main 42-45 pilot 3.5 slide JJH needle - middle clip position 1.5 turns out on mixture screw (initial) Do a search in the GasGas, Sherco, and Montesa forums for Keihin PWK carbs.

I have an 04 and the stock jetting is: Pilot: #35, could go to #38 Mixture screw: now 2 1/2 turns out Needle: D34 & D37, has D37 Needle clip: stock 3rd. Throttle valve: #4.5 or #5.0, has 5.0 Main: #110 Starter: #60 Video on the Delorto PHBL http://www.youtube.com/watch?v=1EbXacjIV78&feature=player_embedded

Record the jetting when you clean the carb, that way you'll have info to help you decide future tuning. Some new GasGas, and others, use the Keihin PWK flat slide so jetting info is available. I have Keihin PWK ready to go onto my '04 315R, just need to find the time. LOL

I have a 315R which has a similar muffler, I have repacked two of these and the it involves drilling out the rivets and then installing new rivets after replacing the packing. Aftermarket packing is available but 2Ts and 4Ts use different packing.

MR Cycles lists the Honda plates at $10.08 each. How much cheaper is Apico?

Or you can visit your local Honda dealer and buy 83-90 CR250R discs (same clutch family).

I agree that ATF seems to work very good in our wet clutches, but it was designed for wet clutches. Dextron 2 & 3 specs are no longer supported by Allison, and I also believe GM, so finding them can be difficult. Most of the auto trannies have switched to synthetic ATF because it provides longer tranny life and a longer change interval. My BMW ZF tranny uses synthetic ATF and is sealed for life, although some recommend changes. The Allison tranny in my motorhome uses synthetic ATF for a 250,000 mile change interval. As a side note not all BMWs use Dextron ATF; ZF trannies, depending on model, will use either Dextron or "F" type ATF. BMW also uses GM automatics in some models and those use Dextron.