These are our American-made billet gear reduction offerings for the 85'-88' ATC250ES Big Red, ATC250SX and TRX250. Our gears are machined from raw billet material into our custom designed proprietary sizes of 20% 40% 60% and 75% reduction. Requires gear indicator cup delete and neutral wire mod. 20% is ideal for 27"-28" tires, 40% for 29-30's, 60% for 31-32's and 75% for 33"+. We offer stiffer clutch springs for these reductions in the "TRX/ATC250" and "Parts" sections of the site listed as "TRX Springs". The stiffer springs can be ran with any size reduction but are necessary for the 60% and 75% to prevent clutch slippage. Product pic is an example and may not show correct size.
**Most if not all 85' models use a smaller diameter crankshaft, verify engine year by visually checking or measuring crank diameter and make a note when ordering. The small (85) crank is 24mm diameter and 86up is 27mm.
**75% is special order and price includes a $50 core charge on the stock parts. Please send in all of the original parts that the kit replaces and include a copy of the original purchase receipt for the $50 core refund. You can also send in your stock parts upfront to have the core charge waived when ordering, message us for more info.
We have an install video on YouTube for the TRX300 which is very similar to the 250's. The main difference is the 250 does not require grinding in the kick stopper area. The 75% also requires some grinding on the side of the oil pump.
Youtube link: https://youtu.be/5EDutObiCs8?si=FTYpLq1q9Byz3cSp
All of our primary reductions carry a limited lifetime warranty to the original purchaser. (See disclaimer on home page) We've been making gear reductions for Honda's for 10 years now with 20+ years of machining and metal-working experience. We've been repairing and modifying ATV's in general since the late 90's.
All reduction orders come with a free t-shirt! Please include your shirt size in the notes of your order (M, L, XL or 2XL). To purchase additional shirts use the link below.
https://reductionboss.com/collections/rb-gear/products/rb-promo-t-shirt